#include "logic_editor_service.h"

#include "project_service.h"

#include <algorithm>
#include <cctype>
#include <iterator>
#include <map>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>

namespace {

bool isBlank(const std::string &value)
{
    return value.empty()
        || std::all_of(
            value.cbegin(), value.cend(),
            [](unsigned char character)
            {
                return std::isspace(character) != 0;
            });
}

bool containsLineBreak(const std::string &value)
{
    return value.find('\r') != std::string::npos
        || value.find('\n') != std::string::npos;
}

std::string makeUniqueLogicId(const Project &project)
{
    for (std::size_t suffix = 1U;; ++suffix)
    {
        const std::string candidate = "logic-" + std::to_string(suffix);
        if (std::none_of(
                project.controlLogics.cbegin(), project.controlLogics.cend(),
                [&candidate](const ControlLogic &logic)
                {
                    return logic.id == candidate;
                }))
        {
            return candidate;
        }
    }
}

std::size_t totalRungCount(const Project &project)
{
    std::size_t count = 0U;
    for (const ControlLogic &logic : project.controlLogics)
    {
        count += logic.rungs.size();
    }
    return count;
}

ControlLogic *editableLogic(Project *project, const std::string &logic_id)
{
    if (project == nullptr)
    {
        return nullptr;
    }
    const auto found = std::find_if(
        project->controlLogics.begin(), project->controlLogics.end(),
        [&logic_id](const ControlLogic &logic) { return logic.id == logic_id; });
    return found == project->controlLogics.end() ? nullptr : &*found;
}

LadderRung *editableRung(ControlLogic *logic, const std::string &rung_id)
{
    if (logic == nullptr)
    {
        return nullptr;
    }
    const auto found = std::find_if(
        logic->rungs.begin(), logic->rungs.end(),
        [&rung_id](const LadderRung &rung) { return rung.id == rung_id; });
    return found == logic->rungs.end() ? nullptr : &*found;
}

std::size_t rungIndex(const ControlLogic &logic, const std::string &rung_id)
{
    const auto found = std::find_if(
        logic.rungs.cbegin(), logic.rungs.cend(),
        [&rung_id](const LadderRung &rung) { return rung.id == rung_id; });
    return found == logic.rungs.cend()
        ? logic.rungs.size()
        : static_cast<std::size_t>(std::distance(logic.rungs.cbegin(), found));
}

bool connectionMatches(
    const VerticalConnection &connection,
    const std::string &upper_rung_id,
    const std::string &lower_rung_id,
    int column_boundary)
{
    return connection.upperRungId == upper_rung_id
        && connection.lowerRungId == lower_rung_id
        && connection.columnBoundary == column_boundary;
}

struct SyntaxConnectivity
{
    std::size_t rowCount = 0U;
    std::vector<unsigned char> forwardBase;
    std::vector<unsigned char> forward;
    std::vector<unsigned char> backwardBase;
    std::vector<unsigned char> backward;
    std::vector<const VerticalConnection *> verticalByBoundaryAndUpperRow;

    std::size_t stateIndex(std::size_t row, int boundary) const
    {
        return row * static_cast<std::size_t>(
                         ProjectLimits::kMaximumConditionColumns + 1)
            + static_cast<std::size_t>(boundary);
    }

    bool stateAt(
        const std::vector<unsigned char> &states,
        std::size_t row,
        int boundary) const
    {
        return states[stateIndex(row, boundary)] != 0U;
    }

    const VerticalConnection *verticalAt(
        int boundary, std::size_t upper_row) const
    {
        if (rowCount < 2U || upper_row + 1U >= rowCount)
        {
            return nullptr;
        }
        return verticalByBoundaryAndUpperRow[
            static_cast<std::size_t>(boundary) * (rowCount - 1U) + upper_row];
    }
};

SyntaxConnectivity analyzeConnectivity(const ControlLogic &logic)
{
    SyntaxConnectivity analysis;
    analysis.rowCount = logic.rungs.size();
    const std::size_t state_count = analysis.rowCount
        * static_cast<std::size_t>(
            ProjectLimits::kMaximumConditionColumns + 1);
    analysis.forwardBase.assign(state_count, 0U);
    analysis.forward.assign(state_count, 0U);
    analysis.backwardBase.assign(state_count, 0U);
    analysis.backward.assign(state_count, 0U);
    if (analysis.rowCount == 0U)
    {
        return analysis;
    }

    analysis.verticalByBoundaryAndUpperRow.assign(
        static_cast<std::size_t>(
            ProjectLimits::kMaximumConditionColumns + 1)
            * (analysis.rowCount - 1U),
        nullptr);
    std::unordered_map<std::string, std::size_t> row_indices;
    row_indices.reserve(analysis.rowCount);
    for (std::size_t row = 0U; row < analysis.rowCount; ++row)
    {
        row_indices.emplace(logic.rungs[row].id, row);
    }
    for (const VerticalConnection &connection : logic.verticalConnections)
    {
        const std::size_t upper = row_indices.at(connection.upperRungId);
        analysis.verticalByBoundaryAndUpperRow[
            static_cast<std::size_t>(connection.columnBoundary)
                    * (analysis.rowCount - 1U)
                + upper] = &connection;
    }

    const auto mergeBoundaryComponents = [&analysis](
                                             int boundary,
                                             const std::vector<unsigned char> &base,
                                             std::vector<unsigned char> *merged)
    {
        std::size_t first = 0U;
        while (first < analysis.rowCount)
        {
            std::size_t last = first;
            while (last + 1U < analysis.rowCount
                   && analysis.verticalAt(boundary, last) != nullptr)
            {
                ++last;
            }
            bool active = false;
            for (std::size_t row = first; row <= last; ++row)
            {
                active = active || analysis.stateAt(base, row, boundary);
            }
            for (std::size_t row = first; row <= last; ++row)
            {
                (*merged)[analysis.stateIndex(row, boundary)] = active ? 1U : 0U;
            }
            first = last + 1U;
        }
    };

    for (int boundary = 0;
         boundary <= ProjectLimits::kMaximumConditionColumns;
         ++boundary)
    {
        for (std::size_t row = 0U; row < analysis.rowCount; ++row)
        {
            const bool active = boundary == 0
                || (analysis.stateAt(analysis.forward, row, boundary - 1)
                    && logic.rungs[row]
                           .cells[static_cast<std::size_t>(boundary - 1)]
                           .kind != LadderCellKind::Gap);
            analysis.forwardBase[analysis.stateIndex(row, boundary)] =
                active ? 1U : 0U;
        }
        mergeBoundaryComponents(
            boundary, analysis.forwardBase, &analysis.forward);
    }

    for (int boundary = ProjectLimits::kMaximumConditionColumns;
         boundary >= 0;
         --boundary)
    {
        for (std::size_t row = 0U; row < analysis.rowCount; ++row)
        {
            const bool active = boundary
                    == ProjectLimits::kMaximumConditionColumns
                ? logic.rungs[row].output.has_value()
                : logic.rungs[row]
                          .cells[static_cast<std::size_t>(boundary)]
                          .kind != LadderCellKind::Gap
                    && analysis.stateAt(
                        analysis.backward, row, boundary + 1);
            analysis.backwardBase[analysis.stateIndex(row, boundary)] =
                active ? 1U : 0U;
        }
        mergeBoundaryComponents(
            boundary, analysis.backwardBase, &analysis.backward);
    }
    return analysis;
}

std::vector<int> networkNumbersByRow(const ControlLogic &logic)
{
    std::vector<int> networks(logic.rungs.size(), 0);
    int network = 0;
    for (std::size_t row = 0U; row < logic.rungs.size(); ++row)
    {
        if (row > 0U)
        {
            const std::string &upper = logic.rungs[row - 1U].id;
            const std::string &lower = logic.rungs[row].id;
            const bool connected = std::any_of(
                logic.verticalConnections.cbegin(),
                logic.verticalConnections.cend(),
                [&upper, &lower](const VerticalConnection &connection)
                {
                    return connection.upperRungId == upper
                        && connection.lowerRungId == lower;
                });
            if (!connected)
            {
                ++network;
            }
        }
        networks[row] = network;
    }
    return networks;
}

std::unordered_set<std::string> activeVerticalConnections(
    const SyntaxConnectivity &analysis)
{
    std::unordered_set<std::string> active_connections;
    for (int boundary = 0;
         boundary <= ProjectLimits::kMaximumConditionColumns;
         ++boundary)
    {
        std::size_t first = 0U;
        while (first < analysis.rowCount)
        {
            std::size_t last = first;
            while (last + 1U < analysis.rowCount
                   && analysis.verticalAt(boundary, last) != nullptr)
            {
                ++last;
            }
            int total_forward = 0;
            int total_backward = 0;
            for (std::size_t row = first; row <= last; ++row)
            {
                total_forward += analysis.stateAt(
                    analysis.forwardBase, row, boundary) ? 1 : 0;
                total_backward += analysis.stateAt(
                    analysis.backwardBase, row, boundary) ? 1 : 0;
            }
            int upper_forward = 0;
            int upper_backward = 0;
            for (std::size_t upper = first; upper < last; ++upper)
            {
                upper_forward += analysis.stateAt(
                    analysis.forwardBase, upper, boundary) ? 1 : 0;
                upper_backward += analysis.stateAt(
                    analysis.backwardBase, upper, boundary) ? 1 : 0;
                const int lower_forward = total_forward - upper_forward;
                const int lower_backward = total_backward - upper_backward;
                if ((upper_forward > 0 && lower_backward > 0)
                    || (upper_backward > 0 && lower_forward > 0))
                {
                    active_connections.insert(
                        analysis.verticalAt(boundary, upper)->id);
                }
            }
            first = last + 1U;
        }
    }
    return active_connections;
}

struct LogicCleanupStats
{
    std::size_t wireCells = 0U;
    std::size_t verticalConnections = 0U;
};

LogicCleanupStats normalizeLogicWires(ControlLogic *logic)
{
    LogicCleanupStats stats;
    if (logic == nullptr || logic->rungs.empty())
    {
        return stats;
    }
    const SyntaxConnectivity analysis = analyzeConnectivity(*logic);
    const std::vector<int> networks = networkNumbersByRow(*logic);
    const int network_count = networks.empty() ? 0 : networks.back() + 1;
    std::vector<unsigned char> invalid_networks(
        static_cast<std::size_t>(network_count), 0U);
    for (std::size_t row = 0U; row < logic->rungs.size(); ++row)
    {
        if (logic->rungs[row].output.has_value()
            && !analysis.stateAt(
                analysis.forward,
                row,
                ProjectLimits::kMaximumConditionColumns))
        {
            invalid_networks[static_cast<std::size_t>(networks[row])] = 1U;
        }
    }

    const std::unordered_set<std::string> active_verticals =
        activeVerticalConnections(analysis);
    std::unordered_map<std::string, std::size_t> row_indices;
    row_indices.reserve(logic->rungs.size());
    for (std::size_t row = 0U; row < logic->rungs.size(); ++row)
    {
        row_indices.emplace(logic->rungs[row].id, row);
    }
    for (std::size_t row = 0U; row < logic->rungs.size(); ++row)
    {
        if (invalid_networks[static_cast<std::size_t>(networks[row])] != 0U)
        {
            continue;
        }
        for (int column = 0;
             column < ProjectLimits::kMaximumConditionColumns;
             ++column)
        {
            LadderCell &cell = logic->rungs[row]
                                   .cells[static_cast<std::size_t>(column)];
            if (cell.kind == LadderCellKind::Wire
                && !(analysis.stateAt(analysis.forward, row, column)
                     && analysis.stateAt(
                         analysis.backward, row, column + 1)))
            {
                cell.kind = LadderCellKind::Gap;
                ++stats.wireCells;
            }
        }
    }

    const auto new_end = std::remove_if(
        logic->verticalConnections.begin(),
        logic->verticalConnections.end(),
        [&row_indices, &networks, &invalid_networks, &active_verticals, &stats](
            const VerticalConnection &connection)
        {
            const std::size_t upper_row = row_indices.at(connection.upperRungId);
            if (invalid_networks[
                    static_cast<std::size_t>(networks[upper_row])] != 0U
                || active_verticals.find(connection.id)
                    != active_verticals.end())
            {
                return false;
            }
            ++stats.verticalConnections;
            return true;
        });
    logic->verticalConnections.erase(new_end, logic->verticalConnections.end());
    return stats;
}

std::optional<std::pair<LogicSyntaxLocation, std::string>> firstSyntaxIssue(
    const ControlLogic &logic)
{
    const std::vector<int> networks = networkNumbersByRow(logic);
    for (std::size_t row = 0U; row < logic.rungs.size(); ++row)
    {
        const LadderRung &rung = logic.rungs[row];
        for (std::size_t column = 0U; column < rung.cells.size(); ++column)
        {
            if (rung.cells[column].node.has_value()
                && !rung.cells[column].node->isConfigured())
            {
                LogicSyntaxLocation location{
                    logic.id,
                    rung.id,
                    networks[row] + 1,
                    static_cast<int>(row + 1U),
                    static_cast<int>(column + 1U)};
                return std::make_pair(
                    location,
                    "控制逻辑 " + logic.name + " 的网络 "
                        + std::to_string(location.network) + "，第 "
                        + std::to_string(location.row) + " 行第 "
                        + std::to_string(location.column)
                        + " 列：程序语法分析发生错误，条件指令尚未配置");
            }
        }
        if (rung.output.has_value() && !rung.output->isConfigured())
        {
            LogicSyntaxLocation location{
                logic.id,
                rung.id,
                networks[row] + 1,
                static_cast<int>(row + 1U),
                ProjectLimits::kMaximumLadderColumns};
            return std::make_pair(
                location,
                "控制逻辑 " + logic.name + " 的网络 "
                    + std::to_string(location.network) + "，第 "
                    + std::to_string(location.row) + " 行第 "
                    + std::to_string(location.column)
                    + " 列：程序语法分析发生错误，输出指令尚未配置");
        }
    }

    const SyntaxConnectivity analysis = analyzeConnectivity(logic);
    for (std::size_t row = 0U; row < logic.rungs.size(); ++row)
    {
        const LadderRung &rung = logic.rungs[row];
        if (!rung.output.has_value()
            || analysis.stateAt(
                analysis.forward,
                row,
                ProjectLimits::kMaximumConditionColumns))
        {
            continue;
        }
        int last_reachable_boundary = 0;
        for (int boundary = 0;
             boundary <= ProjectLimits::kMaximumConditionColumns;
             ++boundary)
        {
            if (analysis.stateAt(analysis.forward, row, boundary))
            {
                last_reachable_boundary = boundary;
            }
        }
        const int disconnected_column = std::min(
            last_reachable_boundary + 1,
            ProjectLimits::kMaximumConditionColumns);
        LogicSyntaxLocation location{
            logic.id,
            rung.id,
            networks[row] + 1,
            static_cast<int>(row + 1U),
            ProjectLimits::kMaximumLadderColumns};
        return std::make_pair(
            location,
            "控制逻辑 " + logic.name + " 的网络 "
                + std::to_string(location.network) + "，第 "
                + std::to_string(location.row) + " 行第 "
                + std::to_string(location.column)
                + " 列：程序语法分析发生错误，输出路径从第 "
                + std::to_string(disconnected_column)
                + " 列起断开，未连接到左母线");
    }
    return std::nullopt;
}

} // namespace

LogicEditorService::LogicEditorService(ProjectService &project_service)
    : project_service_(project_service)
{
}

LogicEditorService::HistoryState LogicEditorService::captureState() const
{
    return {project_service_.project().controlLogics};
}

void LogicEditorService::recordHistory(HistoryState before)
{
    history_.record(
        std::move(before), captureState(), &LogicEditorService::statesEqual);
}

void LogicEditorService::rollbackEdit(
    HistoryState before, bool modified_before)
{
    project_service_.editProject().controlLogics = std::move(before.logics);
    project_service_.restoreModifiedState(modified_before);
}

bool LogicEditorService::statesEqual(
    const HistoryState &left, const HistoryState &right)
{
    if (left.logics.size() != right.logics.size())
    {
        return false;
    }
    for (std::size_t index = 0U; index < left.logics.size(); ++index)
    {
        if (!logicsEqual(left.logics[index], right.logics[index]))
        {
            return false;
        }
    }
    return true;
}

bool LogicEditorService::logicsEqual(
    const ControlLogic &left, const ControlLogic &right)
{
    if (left.id != right.id || left.name != right.name
        || left.enabled != right.enabled
        || left.rungs.size() != right.rungs.size()
        || left.verticalConnections.size() != right.verticalConnections.size())
    {
        return false;
    }
    for (std::size_t index = 0U; index < left.rungs.size(); ++index)
    {
        if (!rungsEqual(left.rungs[index], right.rungs[index]))
        {
            return false;
        }
    }
    for (std::size_t index = 0U;
         index < left.verticalConnections.size();
         ++index)
    {
        const VerticalConnection &left_connection =
            left.verticalConnections[index];
        const VerticalConnection &right_connection =
            right.verticalConnections[index];
        if (left_connection.id != right_connection.id
            || left_connection.upperRungId != right_connection.upperRungId
            || left_connection.lowerRungId != right_connection.lowerRungId
            || left_connection.columnBoundary
                != right_connection.columnBoundary)
        {
            return false;
        }
    }
    return true;
}

bool LogicEditorService::rungsEqual(
    const LadderRung &left, const LadderRung &right)
{
    if (left.id != right.id || left.name != right.name
        || left.comment != right.comment
        || left.cells.size() != right.cells.size()
        || left.output.has_value() != right.output.has_value())
    {
        return false;
    }
    for (std::size_t index = 0U; index < left.cells.size(); ++index)
    {
        if (!cellsEqual(left.cells[index], right.cells[index]))
        {
            return false;
        }
    }
    return !left.output.has_value()
        || nodesEqual(*left.output, *right.output);
}

bool LogicEditorService::cellsEqual(
    const LadderCell &left, const LadderCell &right)
{
    return left.id == right.id && left.kind == right.kind
        && left.node.has_value() == right.node.has_value()
        && (!left.node.has_value() || nodesEqual(*left.node, *right.node));
}

bool LogicEditorService::nodesEqual(
    const LogicNode &left, const LogicNode &right)
{
    return left.id == right.id && left.configured == right.configured
        && configsEqual(left.config, right.config);
}

bool LogicEditorService::configsEqual(
    const LogicNodeConfig &left, const LogicNodeConfig &right)
{
    return std::visit(
        [](const auto &left_config, const auto &right_config)
        {
            using Left = std::decay_t<decltype(left_config)>;
            using Right = std::decay_t<decltype(right_config)>;
            if constexpr (!std::is_same_v<Left, Right>)
            {
                return false;
            }
            else if constexpr (std::is_same_v<Left, ContactNodeConfig>)
            {
                return left_config.address == right_config.address
                    && left_config.mode == right_config.mode;
            }
            else if constexpr (std::is_same_v<Left, EdgeContactNodeConfig>)
            {
                return left_config.address == right_config.address
                    && left_config.mode == right_config.mode;
            }
            else if constexpr (std::is_same_v<Left, CoilNodeConfig>)
            {
                return left_config.address == right_config.address
                    && left_config.mode == right_config.mode;
            }
            else if constexpr (std::is_same_v<Left, CompareNodeConfig>)
            {
                return left_config.address == right_config.address
                    && left_config.comparison == right_config.comparison
                    && left_config.value == right_config.value;
            }
            else if constexpr (std::is_same_v<Left, MoveNodeConfig>)
            {
                return left_config.source.kind == right_config.source.kind
                    && left_config.source.address == right_config.source.address
                    && left_config.source.constant == right_config.source.constant
                    && left_config.destination == right_config.destination;
            }
            else
            {
                return left_config.operation == right_config.operation
                    && left_config.left.kind == right_config.left.kind
                    && left_config.left.address == right_config.left.address
                    && left_config.left.constant == right_config.left.constant
                    && left_config.right.kind == right_config.right.kind
                    && left_config.right.address == right_config.right.address
                    && left_config.right.constant == right_config.right.constant
                    && left_config.destination == right_config.destination;
            }
        },
        left,
        right);
}

LogicEditorResult LogicEditorService::historyFailure(
    const std::string &message)
{
    return {false, LogicEditorError::InvalidOperation, message, {}};
}

const ControlLogic *LogicEditorService::findLogic(
    const std::string &logic_id) const
{
    const auto &logics = project_service_.project().controlLogics;
    const auto found = std::find_if(
        logics.cbegin(), logics.cend(),
        [&logic_id](const ControlLogic &logic) { return logic.id == logic_id; });
    return found == logics.cend() ? nullptr : &*found;
}

const LadderRung *LogicEditorService::findRung(
    const std::string &logic_id, const std::string &rung_id) const
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return nullptr;
    }
    const auto found = std::find_if(
        logic->rungs.cbegin(), logic->rungs.cend(),
        [&rung_id](const LadderRung &rung) { return rung.id == rung_id; });
    return found == logic->rungs.cend() ? nullptr : &*found;
}

const LadderCell *LogicEditorService::findCell(
    const std::string &logic_id,
    const std::string &rung_id,
    int column) const
{
    const LadderRung *rung = findRung(logic_id, rung_id);
    return rung == nullptr || column < 0
            || column >= static_cast<int>(rung->cells.size())
        ? nullptr
        : &rung->cells[static_cast<std::size_t>(column)];
}

const LadderCell *LogicEditorService::findCell(
    const std::string &logic_id,
    const std::string &rung_id,
    const std::string &cell_id) const
{
    const LadderRung *rung = findRung(logic_id, rung_id);
    return rung == nullptr ? nullptr : findLadderCell(*rung, cell_id);
}

const VerticalConnection *LogicEditorService::findConnection(
    const std::string &logic_id,
    const std::string &connection_id) const
{
    const ControlLogic *logic = findLogic(logic_id);
    return logic == nullptr
        ? nullptr : findVerticalConnection(*logic, connection_id);
}

const LogicNode *LogicEditorService::findNode(
    const std::string &logic_id, const std::string &node_id) const
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return nullptr;
    }
    for (const LadderRung &rung : logic->rungs)
    {
        for (const LadderCell &cell : rung.cells)
        {
            if (cell.node.has_value() && cell.node->id == node_id)
            {
                return &*cell.node;
            }
        }
        if (rung.output.has_value() && rung.output->id == node_id)
        {
            return &*rung.output;
        }
    }
    return nullptr;
}

std::string LogicEditorService::firstLogicId() const
{
    const auto &logics = project_service_.project().controlLogics;
    return logics.empty() ? std::string{} : logics.front().id;
}

std::string LogicEditorService::firstRungId(
    const std::string &logic_id) const
{
    const ControlLogic *logic = findLogic(logic_id);
    return logic == nullptr || logic->rungs.empty()
        ? std::string{} : logic->rungs.front().id;
}

std::string LogicEditorService::rungIdForNode(
    const std::string &logic_id, const std::string &node_id) const
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return {};
    }
    for (const LadderRung &rung : logic->rungs)
    {
        if (rung.output.has_value() && rung.output->id == node_id)
        {
            return rung.id;
        }
        for (const LadderCell &cell : rung.cells)
        {
            if (cell.node.has_value() && cell.node->id == node_id)
            {
                return rung.id;
            }
        }
    }
    return {};
}

std::string LogicEditorService::registerCommentFor(
    const RegisterAddress &address) const
{
    const RegisterComment *comment =
        project_service_.project().findRegisterComment(address);
    return comment == nullptr ? std::string{} : comment->text;
}

LogicEditorResult LogicEditorService::ensureDefaultLogic()
{
    if (!project_service_.project().controlLogics.empty())
    {
        return {true, LogicEditorError::None, {}, firstLogicId()};
    }
    ControlLogic logic;
    logic.id = "logic-1";
    logic.name = "控制逻辑 1";
    Project &project = project_service_.editProject();
    project.controlLogics.push_back(std::move(logic));
    return {true, LogicEditorError::None, {}, project.controlLogics.back().id};
}

LogicEditorResult LogicEditorService::addLogic(const std::string &name)
{
    if (isBlank(name) || name.size() > ProjectLimits::kMaximumTextBytes)
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "控制逻辑名称不能为空且不能超过 256 个 UTF-8 字节");
    }
    const Project &current = project_service_.project();
    if (current.controlLogics.size()
        >= project_service_.projectLimits().maximumControlLogics)
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "控制逻辑数量已经达到当前配置上限");
    }
    if (std::any_of(
            current.controlLogics.cbegin(), current.controlLogics.cend(),
            [&name](const ControlLogic &logic) { return logic.name == name; }))
    {
        return failure(LogicEditorError::DuplicateName, "控制逻辑名称必须唯一");
    }
    ControlLogic logic;
    logic.id = makeUniqueLogicId(current);
    logic.name = name;
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    project.controlLogics.push_back(std::move(logic));
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, project.controlLogics.back().id};
}

LogicEditorResult LogicEditorService::renameLogic(
    const std::string &logic_id, const std::string &name)
{
    if (isBlank(name) || name.size() > ProjectLimits::kMaximumTextBytes)
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "控制逻辑名称不能为空且不能超过 256 个 UTF-8 字节");
    }
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    const Project &current = project_service_.project();
    if (std::any_of(
            current.controlLogics.cbegin(), current.controlLogics.cend(),
            [&logic_id, &name](const ControlLogic &candidate)
            {
                return candidate.id != logic_id && candidate.name == name;
            }))
    {
        return failure(LogicEditorError::DuplicateName, "控制逻辑名称必须唯一");
    }
    if (logic->name == name)
    {
        return {true, LogicEditorError::None, {}, logic_id};
    }
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    editableLogic(&project, logic_id)->name = name;
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, logic_id};
}

LogicEditorResult LogicEditorService::removeLogic(
    const std::string &logic_id)
{
    const Project &current = project_service_.project();
    if (findLogic(logic_id) == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (current.controlLogics.size() <= 1U)
    {
        return failure(
            LogicEditorError::LastLogicRequired,
            "工程至少需要保留一个控制逻辑");
    }
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    project.controlLogics.erase(
        std::remove_if(
            project.controlLogics.begin(), project.controlLogics.end(),
            [&logic_id](const ControlLogic &logic)
            {
                return logic.id == logic_id;
            }),
        project.controlLogics.end());
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, logic_id};
}

LogicEditorResult LogicEditorService::moveLogic(
    const std::string &logic_id, int offset)
{
    if (offset != -1 && offset != 1)
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "控制逻辑每次只能上移或下移一位");
    }
    const Project &current = project_service_.project();
    const auto found = std::find_if(
        current.controlLogics.cbegin(), current.controlLogics.cend(),
        [&logic_id](const ControlLogic &logic) { return logic.id == logic_id; });
    if (found == current.controlLogics.cend())
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    const std::ptrdiff_t index =
        std::distance(current.controlLogics.cbegin(), found);
    const std::ptrdiff_t target = index + offset;
    if (target < 0
        || target >= static_cast<std::ptrdiff_t>(current.controlLogics.size()))
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "控制逻辑已经位于目标边界");
    }
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    std::iter_swap(
        project.controlLogics.begin() + index,
        project.controlLogics.begin() + target);
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, logic_id};
}

LogicEditorResult LogicEditorService::setLogicEnabled(
    const std::string &logic_id, bool enabled)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (logic->enabled == enabled)
    {
        return {true, LogicEditorError::None, {}, logic_id};
    }
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    editableLogic(&project, logic_id)->enabled = enabled;
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, logic_id};
}

LogicSyntaxCheckResult LogicEditorService::checkSyntax(
    const std::string &logic_id)
{
    if (findLogic(logic_id) == nullptr)
    {
        LogicSyntaxCheckResult result;
        result.message = "未找到要检查的控制逻辑";
        return result;
    }
    return checkSyntaxForLogics({logic_id});
}

LogicSyntaxCheckResult LogicEditorService::checkDoubleCoils(
    const std::string &logic_id) const
{
    LogicSyntaxCheckResult result;
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        result.message = "未找到要检查的控制逻辑";
        return result;
    }
    result.completed = true;
    result.valid = true;
    result.checkedLogicCount = 1U;
    const std::vector<int> networks = networkNumbersByRow(*logic);
    std::map<int, std::size_t> first_rows_by_address;
    for (std::size_t row = 0U; row < logic->rungs.size(); ++row)
    {
        const LadderRung &rung = logic->rungs[row];
        if (!rung.output.has_value())
        {
            continue;
        }
        const auto *coil = std::get_if<CoilNodeConfig>(&rung.output->config);
        if (coil == nullptr)
        {
            continue;
        }
        const auto inserted = first_rows_by_address.emplace(
            coil->address.index(), row);
        if (inserted.second)
        {
            continue;
        }
        const std::size_t first_row = inserted.first->second;
        LogicSyntaxLocation location{
            logic->id,
            rung.id,
            networks[row] + 1,
            static_cast<int>(row + 1U),
            ProjectLimits::kMaximumLadderColumns};
        result.valid = false;
        result.location = location;
        result.message = "控制逻辑 " + logic->name + " 的网络 "
            + std::to_string(location.network) + "，第 "
            + std::to_string(location.row) + " 行第 "
            + std::to_string(location.column) + " 列：发现双线圈输出 "
            + coil->address.toString() + "，首次输出位于第 "
            + std::to_string(first_row + 1U) + " 行";
        return result;
    }
    result.message = "双线圈检查通过";
    return result;
}

LogicSyntaxCheckResult LogicEditorService::checkEnabledSyntax()
{
    std::vector<std::string> logic_ids;
    for (const ControlLogic &logic : project_service_.project().controlLogics)
    {
        if (logic.enabled)
        {
            logic_ids.push_back(logic.id);
        }
    }
    return checkSyntaxForLogics(logic_ids);
}

LogicSyntaxCheckResult LogicEditorService::checkSyntaxForLogics(
    const std::vector<std::string> &logic_ids)
{
    LogicSyntaxCheckResult result;
    result.checkedLogicCount = logic_ids.size();
    HistoryState before = captureState();
    HistoryState candidate = before;

    for (const std::string &logic_id : logic_ids)
    {
        ControlLogic *logic = nullptr;
        const auto found = std::find_if(
            candidate.logics.begin(),
            candidate.logics.end(),
            [&logic_id](const ControlLogic &item) { return item.id == logic_id; });
        if (found != candidate.logics.end())
        {
            logic = &*found;
        }
        if (logic == nullptr)
        {
            result.message = "语法检查期间未找到控制逻辑";
            return result;
        }
        std::string structure_error;
        if (!logic->validateStructure(
                project_service_.projectLimits(), &structure_error))
        {
            result.completed = true;
            result.message = "程序语法分析发生错误：" + structure_error;
            return result;
        }
    }

    for (const std::string &logic_id : logic_ids)
    {
        const auto found = std::find_if(
            candidate.logics.begin(),
            candidate.logics.end(),
            [&logic_id](const ControlLogic &item) { return item.id == logic_id; });
        const LogicCleanupStats stats = normalizeLogicWires(&*found);
        result.removedWireCells += stats.wireCells;
        result.removedVerticalConnections += stats.verticalConnections;
    }

    for (const std::string &logic_id : logic_ids)
    {
        const auto found = std::find_if(
            candidate.logics.cbegin(),
            candidate.logics.cend(),
            [&logic_id](const ControlLogic &item) { return item.id == logic_id; });
        const auto issue = firstSyntaxIssue(*found);
        if (issue.has_value())
        {
            result.location = issue->first;
            result.message = issue->second;
            break;
        }
    }

    result.completed = true;
    result.valid = !result.location.has_value();
    result.changed = !statesEqual(before, candidate);
    if (result.changed)
    {
        project_service_.editProject().controlLogics = std::move(candidate.logics);
        recordHistory(std::move(before));
    }
    if (result.valid)
    {
        result.message = "语法检查通过";
    }
    return result;
}

LogicEditorResult LogicEditorService::addRung(const std::string &logic_id)
{
    return insertRung(logic_id, {}, true);
}

LogicEditorResult LogicEditorService::insertRung(
    const std::string &logic_id,
    const std::string &reference_rung_id,
    bool after)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (logic->rungs.size()
            >= project_service_.projectLimits().maximumRungsPerLogic
        || totalRungCount(project_service_.project())
            >= ProjectLimits::kMaximumRungsPerProject)
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "梯形图行数已经达到当前上限");
    }
    std::size_t position = logic->rungs.size();
    if (!reference_rung_id.empty())
    {
        const std::size_t reference = rungIndex(*logic, reference_rung_id);
        if (reference == logic->rungs.size())
        {
            return failure(LogicEditorError::RungNotFound, "未找到梯形图行");
        }
        position = reference + (after ? 1U : 0U);
    }

    HistoryState before = captureState();
    const bool modified_before = project_service_.isModified();
    Project &project = project_service_.editProject();
    ControlLogic *editable = editableLogic(&project, logic_id);
    const std::string new_id = insertEmptyRungAt(editable, position);
    std::string error;
    if (!editable->validateStructure(project_service_.projectLimits(), &error))
    {
        rollbackEdit(std::move(before), modified_before);
        return failure(LogicEditorError::InvalidOperation, error);
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, new_id};
}

LogicEditorResult LogicEditorService::removeRung(
    const std::string &logic_id, const std::string &rung_id)
{
    return removeRungs(logic_id, {rung_id});
}

LogicEditorResult LogicEditorService::removeRungs(
    const std::string &logic_id,
    const std::vector<std::string> &rung_ids)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (rung_ids.empty())
    {
        return failure(LogicEditorError::InvalidOperation, "请先选择要删除的行");
    }
    std::unordered_set<std::string> unique_ids;
    std::vector<std::size_t> indices;
    for (const std::string &rung_id : rung_ids)
    {
        const std::size_t index = rungIndex(*logic, rung_id);
        if (!unique_ids.insert(rung_id).second)
        {
            return failure(
                LogicEditorError::InvalidOperation,
                "删除列表中存在重复行");
        }
        if (index == logic->rungs.size())
        {
            return failure(LogicEditorError::RungNotFound, "未找到梯形图行");
        }
        indices.push_back(index);
    }
    std::sort(indices.begin(), indices.end(), std::greater<std::size_t>());

    HistoryState before = captureState();
    const bool modified_before = project_service_.isModified();
    Project &project = project_service_.editProject();
    ControlLogic *editable = editableLogic(&project, logic_id);
    for (std::size_t index : indices)
    {
        removeRungAt(editable, index);
    }
    std::string error;
    if (!editable->validateStructure(project_service_.projectLimits(), &error))
    {
        rollbackEdit(std::move(before), modified_before);
        return failure(LogicEditorError::InvalidOperation, error);
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, rung_ids.front()};
}

LogicEditorResult LogicEditorService::updateRungComment(
    const std::string &logic_id,
    const std::string &rung_id,
    const std::string &comment)
{
    const LadderRung *rung = findRung(logic_id, rung_id);
    if (rung == nullptr)
    {
        return failure(LogicEditorError::RungNotFound, "未找到梯形图行");
    }
    if (containsLineBreak(comment)
        || comment.size() > ProjectLimits::kMaximumRungCommentBytes)
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "行注释必须是最多 128 个 UTF-8 字节的单行文本");
    }
    if (rung->comment == comment)
    {
        return {true, LogicEditorError::None, {}, rung_id};
    }
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    editableRung(editableLogic(&project, logic_id), rung_id)->comment = comment;
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, rung_id};
}

LogicEditorResult LogicEditorService::setConditionAtColumn(
    const std::string &logic_id,
    const std::string &rung_id,
    int column,
    const LogicNodeConfig &config,
    bool configured)
{
    const LadderCell *cell = findCell(logic_id, rung_id, column);
    if (cell == nullptr)
    {
        return failure(LogicEditorError::CellNotFound, "未找到目标条件网格");
    }
    if (!isConditionConfig(config))
    {
        return failure(LogicEditorError::InvalidNode, "条件区只能放置条件指令");
    }
    LogicNode candidate{"candidate", config, configured};
    std::string error;
    if (!candidate.validate(&error))
    {
        return failure(LogicEditorError::InvalidNode, error);
    }
    HistoryState before = captureState();
    const bool modified_before = project_service_.isModified();
    Project &project = project_service_.editProject();
    ControlLogic *logic = editableLogic(&project, logic_id);
    LadderRung *rung = editableRung(logic, rung_id);
    LadderCell &editable_cell = rung->cells[static_cast<std::size_t>(column)];
    const std::string node_id = makeUniqueId(*logic, nodePrefix(config));
    editable_cell.kind = LadderCellKind::Node;
    editable_cell.node = LogicNode{node_id, config, configured};
    if (!logic->validateStructure(project_service_.projectLimits(), &error))
    {
        rollbackEdit(std::move(before), modified_before);
        return failure(LogicEditorError::InvalidOperation, error);
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, node_id};
}

LogicEditResult LogicEditorService::applyConditionAndAdvance(
    const std::string &logic_id,
    const LogicEditCursor &cursor,
    const LogicNodeConfig &config,
    bool configured)
{
    return applyCellAndAdvance(
        logic_id, cursor, &config, configured);
}

LogicEditorResult LogicEditorService::insertConditionAtColumn(
    const std::string &logic_id,
    const std::string &rung_id,
    int column,
    const LogicNodeConfig &config,
    bool configured)
{
    const LadderRung *existing = findRung(logic_id, rung_id);
    if (existing == nullptr || column < 0
        || column >= ProjectLimits::kMaximumConditionColumns)
    {
        return failure(LogicEditorError::CellNotFound, "未找到目标条件网格");
    }
    if (!isConditionConfig(config))
    {
        return failure(LogicEditorError::InvalidNode, "条件区只能放置条件指令");
    }
    if (existing->cells.back().kind != LadderCellKind::Gap)
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "第 10 列已有内容，无法继续向右插入");
    }

    HistoryState before = captureState();
    const bool modified_before = project_service_.isModified();
    Project &project = project_service_.editProject();
    ControlLogic *logic = editableLogic(&project, logic_id);
    LadderRung *rung = editableRung(logic, rung_id);
    for (int index = ProjectLimits::kMaximumConditionColumns - 1;
         index > column;
         --index)
    {
        rung->cells[static_cast<std::size_t>(index)] =
            std::move(rung->cells[static_cast<std::size_t>(index - 1)]);
    }
    // 插入列会让右侧网格右移，边界 10 是固定输出侧边界，不能继续右移
    for (VerticalConnection &connection : logic->verticalConnections)
    {
        if ((connection.upperRungId == rung_id
             || connection.lowerRungId == rung_id)
            && connection.columnBoundary >= column
            && connection.columnBoundary < ProjectLimits::kMaximumConditionColumns)
        {
            ++connection.columnBoundary;
        }
    }
    LadderCell inserted;
    inserted.id = makeUniqueId(*logic, "cell");
    inserted.kind = LadderCellKind::Node;
    const std::string node_id = makeUniqueId(*logic, nodePrefix(config));
    inserted.node = LogicNode{node_id, config, configured};
    rung->cells[static_cast<std::size_t>(column)] = std::move(inserted);
    std::string error;
    if (!logic->validateStructure(project_service_.projectLimits(), &error))
    {
        rollbackEdit(std::move(before), modified_before);
        return failure(LogicEditorError::InvalidOperation, error);
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, node_id};
}

LogicEditorResult LogicEditorService::appendCondition(
    const std::string &logic_id,
    const std::string &rung_id,
    const LogicNodeConfig &config,
    bool configured)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (!isConditionConfig(config))
    {
        return failure(LogicEditorError::InvalidNode, "条件区只能放置条件指令");
    }
    std::string target_rung_id = rung_id;
    if (target_rung_id.empty())
    {
        if (logic->rungs.size()
                >= project_service_.projectLimits().maximumRungsPerLogic
            || totalRungCount(project_service_.project())
                >= ProjectLimits::kMaximumRungsPerProject)
        {
            return failure(
                LogicEditorError::InvalidOperation,
                "梯形图行数已经达到当前上限");
        }
        // 新建首行和放置首个节点必须共用一条历史记录
        HistoryState before = captureState();
        const bool modified_before = project_service_.isModified();
        Project &project = project_service_.editProject();
        ControlLogic *editable = editableLogic(&project, logic_id);
        target_rung_id = insertEmptyRungAt(editable, editable->rungs.size());
        LadderRung *created = editableRung(editable, target_rung_id);
        const auto empty = std::find_if(
            created->cells.begin(), created->cells.end(),
            [](const LadderCell &cell)
            {
                return cell.kind == LadderCellKind::Gap;
            });
        if (empty == created->cells.end())
        {
            rollbackEdit(std::move(before), modified_before);
            return failure(
                LogicEditorError::InvalidOperation,
                "条件区 10 列已经占满");
        }
        const std::string node_id = makeUniqueId(*editable, nodePrefix(config));
        LadderCell &cell = created->cells[
            static_cast<std::size_t>(std::distance(created->cells.begin(), empty))];
        cell.kind = LadderCellKind::Node;
        cell.node = LogicNode{node_id, config, configured};
        std::string error;
        if (!editable->validateStructure(project_service_.projectLimits(), &error))
        {
            rollbackEdit(std::move(before), modified_before);
            return failure(LogicEditorError::InvalidOperation, error);
        }
        recordHistory(std::move(before));
        return {true, LogicEditorError::None, {}, node_id};
    }
    const LadderRung *rung = findRung(logic_id, target_rung_id);
    if (rung == nullptr)
    {
        return failure(LogicEditorError::RungNotFound, "未找到梯形图行");
    }
    const auto empty = std::find_if(
        rung->cells.cbegin(), rung->cells.cend(),
        [](const LadderCell &cell) { return cell.kind == LadderCellKind::Gap; });
    if (empty == rung->cells.cend())
    {
        return failure(LogicEditorError::InvalidOperation, "条件区 10 列已经占满");
    }
    return setConditionAtColumn(
        logic_id,
        target_rung_id,
        static_cast<int>(std::distance(rung->cells.cbegin(), empty)),
        config,
        configured);
}

LogicEditorResult LogicEditorService::appendWire(
    const std::string &logic_id,
    const std::string &rung_id,
    int column_span)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (column_span <= 0
        || column_span > ProjectLimits::kMaximumConditionColumns)
    {
        return failure(LogicEditorError::InvalidOperation, "横线参数无效");
    }
    if (rung_id.empty())
    {
        if (logic->rungs.size()
                >= project_service_.projectLimits().maximumRungsPerLogic
            || totalRungCount(project_service_.project())
                >= ProjectLimits::kMaximumRungsPerProject)
        {
            return failure(
                LogicEditorError::InvalidOperation,
                "梯形图行数已经达到当前上限");
        }
        HistoryState before = captureState();
        const bool modified_before = project_service_.isModified();
        Project &project = project_service_.editProject();
        ControlLogic *editable = editableLogic(&project, logic_id);
        const std::string new_rung_id = insertEmptyRungAt(
            editable, editable->rungs.size());
        LadderRung *rung = editableRung(editable, new_rung_id);
        const int first = ProjectLimits::kMaximumConditionColumns - column_span;
        for (int column = first;
             column < ProjectLimits::kMaximumConditionColumns;
             ++column)
        {
            rung->cells[static_cast<std::size_t>(column)].kind =
                LadderCellKind::Wire;
        }
        std::string error;
        if (!editable->validateStructure(project_service_.projectLimits(), &error))
        {
            rollbackEdit(std::move(before), modified_before);
            return failure(LogicEditorError::InvalidOperation, error);
        }
        recordHistory(std::move(before));
        return {true, LogicEditorError::None, {}, new_rung_id};
    }
    const LadderRung *rung = findRung(logic_id, rung_id);
    if (rung == nullptr)
    {
        return failure(LogicEditorError::RungNotFound, "未找到梯形图行");
    }
    const int first = ProjectLimits::kMaximumConditionColumns - column_span;
    return setHorizontalWireRange(logic_id, rung_id, first,
                                  ProjectLimits::kMaximumConditionColumns - 1,
                                  true);
}

LogicEditResult LogicEditorService::applyWireAndAdvance(
    const std::string &logic_id,
    const LogicEditCursor &cursor)
{
    return applyCellAndAdvance(logic_id, cursor, nullptr, false);
}

LogicEditorResult LogicEditorService::setHorizontalWireRange(
    const std::string &logic_id,
    const std::string &rung_id,
    int first_column,
    int last_column,
    bool connected)
{
    if (first_column > last_column)
    {
        std::swap(first_column, last_column);
    }
    if (findRung(logic_id, rung_id) == nullptr || first_column < 0
        || last_column >= ProjectLimits::kMaximumConditionColumns)
    {
        return failure(LogicEditorError::CellNotFound, "横线范围超出条件网格");
    }
    std::vector<std::pair<std::string, int>> cells;
    for (int column = first_column; column <= last_column; ++column)
    {
        cells.emplace_back(rung_id, column);
    }
    return setWireCells(logic_id, cells, connected);
}

LogicEditorResult LogicEditorService::setWireCells(
    const std::string &logic_id,
    const std::vector<std::pair<std::string, int>> &cells,
    bool connected)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (cells.empty())
    {
        return failure(LogicEditorError::InvalidOperation, "没有需要修改的横线网格");
    }
    std::unordered_set<std::string> positions;
    for (const auto &position : cells)
    {
        const std::string key = position.first + "\n" + std::to_string(position.second);
        if (!positions.insert(key).second)
        {
            return failure(LogicEditorError::InvalidOperation, "横线范围包含重复网格");
        }
        if (findCell(logic_id, position.first, position.second) == nullptr)
        {
            return failure(LogicEditorError::CellNotFound, "横线范围包含无效网格");
        }
    }

    HistoryState before = captureState();
    const bool modified_before = project_service_.isModified();
    Project &project = project_service_.editProject();
    ControlLogic *editable = editableLogic(&project, logic_id);
    for (const auto &position : cells)
    {
        LadderCell &cell = editableRung(editable, position.first)
            ->cells[static_cast<std::size_t>(position.second)];
        if (cell.kind == LadderCellKind::Node)
        {
            continue;
        }
        cell.kind = connected ? LadderCellKind::Wire : LadderCellKind::Gap;
        cell.node.reset();
    }
    std::string error;
    if (!editable->validateStructure(project_service_.projectLimits(), &error))
    {
        rollbackEdit(std::move(before), modified_before);
        return failure(LogicEditorError::InvalidOperation, error);
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, cells.front().first};
}

LogicEditorResult LogicEditorService::clearCells(
    const std::string &logic_id,
    const std::vector<std::pair<std::string, int>> &cells)
{
    if (findLogic(logic_id) == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (cells.empty())
    {
        return failure(LogicEditorError::InvalidOperation, "没有需要清空的网格");
    }
    for (const auto &position : cells)
    {
        if (findCell(logic_id, position.first, position.second) == nullptr)
        {
            return failure(LogicEditorError::CellNotFound, "清空范围包含无效网格");
        }
    }
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    ControlLogic *logic = editableLogic(&project, logic_id);
    for (const auto &position : cells)
    {
        LadderCell &cell = editableRung(logic, position.first)
            ->cells[static_cast<std::size_t>(position.second)];
        cell.kind = LadderCellKind::Gap;
        cell.node.reset();
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, cells.front().first};
}

LogicEditorResult LogicEditorService::setVerticalConnection(
    const std::string &logic_id,
    const std::string &upper_rung_id,
    const std::string &lower_rung_id,
    int column_boundary,
    bool connected)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    const std::size_t upper = rungIndex(*logic, upper_rung_id);
    const std::size_t lower = rungIndex(*logic, lower_rung_id);
    if (upper == logic->rungs.size() || lower != upper + 1U)
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "竖线只能连接相邻的上下两行");
    }
    return setVerticalConnectionRange(
        logic_id,
        upper_rung_id,
        lower_rung_id,
        column_boundary,
        connected);
}

LogicVerticalEditResult LogicEditorService::applyVerticalConnectionAndAdvance(
    const std::string &logic_id,
    const std::string &upper_rung_id,
    int column_boundary)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return {
            failure(LogicEditorError::LogicNotFound, "未找到控制逻辑"),
            {},
            -1,
            false};
    }
    if (column_boundary < 0
        || column_boundary > ProjectLimits::kMaximumConditionColumns)
    {
        return {
            failure(
                LogicEditorError::InvalidOperation,
                "请先选择一个列边界或网格，再插入竖线"),
            {},
            -1,
            false};
    }
    const std::size_t upper = rungIndex(*logic, upper_rung_id);
    if (upper == logic->rungs.size())
    {
        return {
            failure(LogicEditorError::RungNotFound, "未找到梯形图行"),
            {},
            -1,
            false};
    }
    if (upper + 1U >= logic->rungs.size())
    {
        return {
            failure(
                LogicEditorError::InvalidOperation,
                "当前已经是末行，无法继续建立竖线"),
            {},
            -1,
            false};
    }

    const std::string lower_rung_id = logic->rungs[upper + 1U].id;
    const bool already_connected = std::any_of(
        logic->verticalConnections.cbegin(),
        logic->verticalConnections.cend(),
        [&upper_rung_id, &lower_rung_id, column_boundary](
            const VerticalConnection &connection)
        {
            return connectionMatches(
                connection,
                upper_rung_id,
                lower_rung_id,
                column_boundary);
        });
    LogicEditorResult edit = setVerticalConnection(
        logic_id,
        upper_rung_id,
        lower_rung_id,
        column_boundary,
        true);
    if (!edit.succeeded)
    {
        return {std::move(edit), {}, -1, false};
    }
    edit.message = already_connected
        ? "竖线已经存在，已移至下一行"
        : "竖线连接已建立，已移至下一行";
    return {
        std::move(edit),
        lower_rung_id,
        column_boundary,
        !already_connected};
}

LogicEditorResult LogicEditorService::setVerticalConnectionRange(
    const std::string &logic_id,
    const std::string &first_rung_id,
    const std::string &last_rung_id,
    int column_boundary,
    bool connected)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    std::size_t first = rungIndex(*logic, first_rung_id);
    std::size_t last = rungIndex(*logic, last_rung_id);
    if (first == logic->rungs.size() || last == logic->rungs.size()
        || first == last || column_boundary < 0
        || column_boundary > ProjectLimits::kMaximumConditionColumns)
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "竖线范围必须跨越至少两行且位于 0~10 列边界");
    }
    if (first > last)
    {
        std::swap(first, last);
    }

    bool changed = false;
    for (std::size_t row = first; row < last; ++row)
    {
        const std::string &upper_id = logic->rungs[row].id;
        const std::string &lower_id = logic->rungs[row + 1U].id;
        const bool exists = std::any_of(
            logic->verticalConnections.cbegin(),
            logic->verticalConnections.cend(),
            [&upper_id, &lower_id, column_boundary](
                const VerticalConnection &connection)
            {
                return connectionMatches(
                    connection, upper_id, lower_id, column_boundary);
            });
        if (exists != connected)
        {
            changed = true;
            break;
        }
    }
    if (!changed)
    {
        return {
            true,
            LogicEditorError::None,
            connected ? "竖线连接已经存在" : "目标位置没有竖线",
            first_rung_id};
    }

    HistoryState before = captureState();
    const bool modified_before = project_service_.isModified();
    Project &project = project_service_.editProject();
    ControlLogic *editable = editableLogic(&project, logic_id);
    for (std::size_t row = first; row < last; ++row)
    {
        const std::string upper_id = editable->rungs[row].id;
        const std::string lower_id = editable->rungs[row + 1U].id;
        const auto found = std::find_if(
            editable->verticalConnections.begin(),
            editable->verticalConnections.end(),
            [&upper_id, &lower_id, column_boundary](
                const VerticalConnection &connection)
            {
                return connectionMatches(
                    connection, upper_id, lower_id, column_boundary);
            });
        if (connected && found == editable->verticalConnections.end())
        {
            editable->verticalConnections.push_back({
                makeUniqueId(*editable, "vertical"),
                upper_id,
                lower_id,
                column_boundary});
        }
        else if (!connected && found != editable->verticalConnections.end())
        {
            editable->verticalConnections.erase(found);
        }
    }
    std::string error;
    if (!editable->validateStructure(project_service_.projectLimits(), &error))
    {
        rollbackEdit(std::move(before), modified_before);
        return failure(LogicEditorError::InvalidOperation, error);
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, first_rung_id};
}

LogicEditorResult LogicEditorService::removeVerticalConnections(
    const std::string &logic_id,
    const std::vector<std::string> &connection_ids)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (connection_ids.empty())
    {
        return failure(LogicEditorError::InvalidOperation, "请先选择要删除的竖线");
    }
    std::unordered_set<std::string> ids;
    for (const std::string &id : connection_ids)
    {
        if (!ids.insert(id).second
            || findVerticalConnection(*logic, id) == nullptr)
        {
            return failure(
                LogicEditorError::ConnectionNotFound,
                "竖线删除列表包含重复或不存在的对象");
        }
    }
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    ControlLogic *editable = editableLogic(&project, logic_id);
    editable->verticalConnections.erase(
        std::remove_if(
            editable->verticalConnections.begin(),
            editable->verticalConnections.end(),
            [&ids](const VerticalConnection &connection)
            {
                return ids.count(connection.id) != 0U;
            }),
        editable->verticalConnections.end());
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, connection_ids.front()};
}

LogicEditorResult LogicEditorService::deleteSelection(
    const std::string &logic_id,
    const LogicSelectionDeleteRequest &selection)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (selection.cells.empty() && selection.outputRungIds.empty()
        && selection.verticalConnectionIds.empty())
    {
        return failure(LogicEditorError::InvalidOperation, "没有可删除的选中对象");
    }

    std::unordered_set<std::string> cell_positions;
    for (const auto &position : selection.cells)
    {
        const std::string key = position.first + "\n"
            + std::to_string(position.second);
        const LadderCell *cell = findCell(
            logic_id, position.first, position.second);
        if (!cell_positions.insert(key).second || cell == nullptr)
        {
            return failure(
                LogicEditorError::CellNotFound,
                "删除列表包含重复或不存在的网格");
        }
        if (cell->kind == LadderCellKind::Gap)
        {
            return failure(
                LogicEditorError::InvalidOperation,
                "删除列表包含空白网格");
        }
    }

    std::unordered_set<std::string> output_rung_ids;
    for (const std::string &rung_id : selection.outputRungIds)
    {
        const LadderRung *rung = findRung(logic_id, rung_id);
        if (!output_rung_ids.insert(rung_id).second || rung == nullptr
            || !rung->output.has_value())
        {
            return failure(
                LogicEditorError::NodeNotFound,
                "删除列表包含重复或不存在的输出指令");
        }
    }

    std::unordered_set<std::string> connection_ids;
    for (const std::string &connection_id
         : selection.verticalConnectionIds)
    {
        if (!connection_ids.insert(connection_id).second
            || findVerticalConnection(*logic, connection_id) == nullptr)
        {
            return failure(
                LogicEditorError::ConnectionNotFound,
                "删除列表包含重复或不存在的竖线");
        }
    }

    HistoryState before = captureState();
    const bool modified_before = project_service_.isModified();
    Project &project = project_service_.editProject();
    ControlLogic *editable = editableLogic(&project, logic_id);
    for (const auto &position : selection.cells)
    {
        LadderCell &cell = editableRung(editable, position.first)
            ->cells[static_cast<std::size_t>(position.second)];
        cell.kind = LadderCellKind::Gap;
        cell.node.reset();
    }
    for (const std::string &rung_id : selection.outputRungIds)
    {
        editableRung(editable, rung_id)->output.reset();
    }
    editable->verticalConnections.erase(
        std::remove_if(
            editable->verticalConnections.begin(),
            editable->verticalConnections.end(),
            [&connection_ids](const VerticalConnection &connection)
            {
                return connection_ids.count(connection.id) != 0U;
            }),
        editable->verticalConnections.end());

    std::string error;
    if (!editable->validateStructure(project_service_.projectLimits(), &error))
    {
        rollbackEdit(std::move(before), modified_before);
        return failure(LogicEditorError::InvalidOperation, error);
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, logic_id};
}

LogicEditorResult LogicEditorService::addParallelBranch(
    const std::string &logic_id,
    const std::string &rung_id,
    const std::vector<std::string> &selected_node_ids,
    const LogicNodeConfig &config,
    bool configured)
{
    const ControlLogic *logic = findLogic(logic_id);
    const LadderRung *rung = findRung(logic_id, rung_id);
    if (logic == nullptr || rung == nullptr)
    {
        return failure(LogicEditorError::RungNotFound, "未找到梯形图行");
    }
    if (!isConditionConfig(config)
        || !areConditionNodesContiguous(logic_id, rung_id, selected_node_ids))
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "请先选择同一行中连续的条件节点");
    }
    if (logic->rungs.size()
            >= project_service_.projectLimits().maximumRungsPerLogic
        || totalRungCount(project_service_.project())
            >= ProjectLimits::kMaximumRungsPerProject)
    {
        return failure(LogicEditorError::InvalidOperation, "梯形图行数已经达到上限");
    }
    int first_column = ProjectLimits::kMaximumConditionColumns;
    int last_column = -1;
    for (int column = 0; column < ProjectLimits::kMaximumConditionColumns; ++column)
    {
        const LadderCell &cell = rung->cells[static_cast<std::size_t>(column)];
        if (cell.node.has_value()
            && std::find(
                selected_node_ids.cbegin(), selected_node_ids.cend(),
                cell.node->id) != selected_node_ids.cend())
        {
            first_column = std::min(first_column, column);
            last_column = std::max(last_column, column);
        }
    }

    HistoryState before = captureState();
    const bool modified_before = project_service_.isModified();
    Project &project = project_service_.editProject();
    ControlLogic *editable = editableLogic(&project, logic_id);
    const std::size_t source_index = rungIndex(*editable, rung_id);
    const std::string new_rung_id = insertEmptyRungAt(editable, source_index + 1U);
    LadderRung *branch = editableRung(editable, new_rung_id);
    const std::string node_id = makeUniqueId(*editable, nodePrefix(config));
    branch->cells[static_cast<std::size_t>(first_column)].kind =
        LadderCellKind::Node;
    branch->cells[static_cast<std::size_t>(first_column)].node =
        LogicNode{node_id, config, configured};
    for (int column = first_column + 1; column <= last_column; ++column)
    {
        branch->cells[static_cast<std::size_t>(column)].kind =
            LadderCellKind::Wire;
    }
    const auto ensure_branch_edge = [editable, &rung_id, &new_rung_id](
        int boundary)
    {
        const bool exists = std::any_of(
            editable->verticalConnections.cbegin(),
            editable->verticalConnections.cend(),
            [&rung_id, &new_rung_id, boundary](
                const VerticalConnection &connection)
            {
                return connectionMatches(
                    connection, rung_id, new_rung_id, boundary);
            });
        if (!exists)
        {
            editable->verticalConnections.push_back({
                makeUniqueId(*editable, "vertical"),
                rung_id,
                new_rung_id,
                boundary});
        }
    };
    ensure_branch_edge(first_column);
    ensure_branch_edge(last_column + 1);
    std::string error;
    if (!editable->validateStructure(project_service_.projectLimits(), &error))
    {
        rollbackEdit(std::move(before), modified_before);
        return failure(LogicEditorError::InvalidOperation, error);
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, node_id};
}

LogicEditorResult LogicEditorService::addParallelToWholeCondition(
    const std::string &logic_id,
    const std::string &rung_id,
    const LogicNodeConfig &config,
    bool configured)
{
    const LadderRung *rung = findRung(logic_id, rung_id);
    if (rung == nullptr)
    {
        return failure(LogicEditorError::RungNotFound, "未找到梯形图行");
    }
    std::vector<std::string> node_ids;
    for (const LadderCell &cell : rung->cells)
    {
        if (cell.node.has_value())
        {
            node_ids.push_back(cell.node->id);
        }
    }
    if (node_ids.empty())
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "当前行还没有可并联的条件节点");
    }
    return addParallelBranch(
        logic_id, rung_id, node_ids, config, configured);
}

LogicEditorResult LogicEditorService::setOutput(
    const std::string &logic_id,
    const std::string &rung_id,
    const LogicNodeConfig &config,
    bool configured)
{
    const ControlLogic *existing_logic = findLogic(logic_id);
    if (existing_logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (!isOutputConfig(config))
    {
        return failure(LogicEditorError::InvalidNode, "输出槽只能放置输出指令");
    }
    if (rung_id.empty())
    {
        if (existing_logic->rungs.size()
                >= project_service_.projectLimits().maximumRungsPerLogic
            || totalRungCount(project_service_.project())
                >= ProjectLimits::kMaximumRungsPerProject)
        {
            return failure(
                LogicEditorError::InvalidOperation,
                "梯形图行数已经达到当前上限");
        }
        HistoryState before = captureState();
        const bool modified_before = project_service_.isModified();
        Project &project = project_service_.editProject();
        ControlLogic *logic = editableLogic(&project, logic_id);
        const std::string new_rung_id = insertEmptyRungAt(
            logic, logic->rungs.size());
        LadderRung *rung = editableRung(logic, new_rung_id);
        const std::string node_id = makeUniqueId(*logic, nodePrefix(config));
        rung->output = LogicNode{node_id, config, configured};
        std::string error;
        if (!logic->validateStructure(project_service_.projectLimits(), &error))
        {
            rollbackEdit(std::move(before), modified_before);
            return failure(LogicEditorError::InvalidNode, error);
        }
        recordHistory(std::move(before));
        return {true, LogicEditorError::None, {}, node_id};
    }
    if (findRung(logic_id, rung_id) == nullptr)
    {
        return failure(LogicEditorError::RungNotFound, "未找到梯形图行");
    }
    HistoryState before = captureState();
    const bool modified_before = project_service_.isModified();
    Project &project = project_service_.editProject();
    ControlLogic *logic = editableLogic(&project, logic_id);
    LadderRung *rung = editableRung(logic, rung_id);
    const std::string node_id = makeUniqueId(*logic, nodePrefix(config));
    rung->output = LogicNode{node_id, config, configured};
    std::string error;
    if (!logic->validateStructure(project_service_.projectLimits(), &error))
    {
        rollbackEdit(std::move(before), modified_before);
        return failure(LogicEditorError::InvalidNode, error);
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, node_id};
}

LogicEditResult LogicEditorService::applyOutputAndAdvance(
    const std::string &logic_id,
    const LogicEditCursor &cursor,
    const LogicNodeConfig &config,
    bool configured)
{
    const ControlLogic *existing_logic = findLogic(logic_id);
    if (existing_logic == nullptr)
    {
        return {failure(LogicEditorError::LogicNotFound, "未找到控制逻辑"), {}};
    }
    if (!isOutputConfig(config))
    {
        return {failure(LogicEditorError::InvalidNode,
                        "输出槽只能放置输出指令"), {}};
    }
    LogicNode candidate{"candidate", config, configured};
    std::string error;
    if (!candidate.validate(&error))
    {
        return {failure(LogicEditorError::InvalidNode, error), {}};
    }

    std::string target_rung_id = cursor.rungId;
    std::size_t target_index = existing_logic->rungs.size();
    bool create_output_rung = target_rung_id.empty();
    if (create_output_rung)
    {
        if (!existing_logic->rungs.empty())
        {
            return {failure(LogicEditorError::RungNotFound,
                            "请先选择输出所在行"), {}};
        }
    }
    else
    {
        target_index = rungIndex(*existing_logic, target_rung_id);
        if (target_index == existing_logic->rungs.size())
        {
            return {failure(LogicEditorError::RungNotFound,
                            "未找到梯形图行"), {}};
        }
    }

    std::size_t group_end = target_index;
    if (!create_output_rung)
    {
        while (group_end + 1U < existing_logic->rungs.size())
        {
            const std::string &upper_id = existing_logic->rungs[group_end].id;
            const std::string &lower_id = existing_logic->rungs[group_end + 1U].id;
            const bool connected = std::any_of(
                existing_logic->verticalConnections.cbegin(),
                existing_logic->verticalConnections.cend(),
                [&upper_id, &lower_id](const VerticalConnection &connection)
                {
                    return connection.upperRungId == upper_id
                        && connection.lowerRungId == lower_id;
                });
            if (!connected)
            {
                break;
            }
            ++group_end;
        }
    }
    const bool append_next_rung = create_output_rung
        || group_end + 1U == existing_logic->rungs.size();
    const std::size_t rows_to_add = append_next_rung
        ? (create_output_rung ? 2U : 1U) : 0U;
    if (existing_logic->rungs.size() + rows_to_add
            > project_service_.projectLimits().maximumRungsPerLogic
        || totalRungCount(project_service_.project()) + rows_to_add
            > ProjectLimits::kMaximumRungsPerProject)
    {
        return {failure(
                    LogicEditorError::InvalidOperation,
                    "输出后无法创建下一空行，梯形图行数已经达到当前上限"),
                {}};
    }

    HistoryState before = captureState();
    const bool modified_before = project_service_.isModified();
    Project &project = project_service_.editProject();
    ControlLogic *logic = editableLogic(&project, logic_id);
    if (create_output_rung)
    {
        target_rung_id = insertEmptyRungAt(logic, logic->rungs.size());
        target_index = logic->rungs.size() - 1U;
        group_end = target_index;
    }
    LadderRung *rung = editableRung(logic, target_rung_id);
    int rightmost_content = -1;
    for (int column = 0;
         column < ProjectLimits::kMaximumConditionColumns;
         ++column)
    {
        if (rung->cells[static_cast<std::size_t>(column)].kind
            != LadderCellKind::Gap)
        {
            rightmost_content = column;
        }
    }
    // 空网络直接输出时补满横线；已有内容时只补尾部，不跨越中间断点
    for (int column = rightmost_content + 1;
         column < ProjectLimits::kMaximumConditionColumns;
         ++column)
    {
        LadderCell &cell = rung->cells[static_cast<std::size_t>(column)];
        cell.kind = LadderCellKind::Wire;
        cell.node.reset();
    }
    const std::string node_id = makeUniqueId(*logic, nodePrefix(config));
    rung->output = LogicNode{node_id, config, configured};

    std::string next_rung_id;
    if (append_next_rung)
    {
        next_rung_id = insertEmptyRungAt(logic, logic->rungs.size());
    }
    else
    {
        next_rung_id = logic->rungs[group_end + 1U].id;
    }
    if (!logic->validateStructure(project_service_.projectLimits(), &error))
    {
        rollbackEdit(std::move(before), modified_before);
        return {failure(LogicEditorError::InvalidNode, error), {}};
    }
    recordHistory(std::move(before));
    return {
        {true, LogicEditorError::None, {}, node_id},
        {next_rung_id, 0, false}};
}

LogicEditorResult LogicEditorService::updateNodeConfig(
    const std::string &logic_id,
    const std::string &node_id,
    const LogicNodeConfig &config)
{
    const LogicNode *node = findNode(logic_id, node_id);
    if (node == nullptr)
    {
        return failure(LogicEditorError::NodeNotFound, "未找到逻辑节点");
    }
    if (node->isCondition() != isConditionConfig(config)
        || node->isOutput() != isOutputConfig(config))
    {
        return failure(
            LogicEditorError::UnsupportedNodeChange,
            "条件节点和输出节点不能互相改型");
    }
    LogicNode candidate{node_id, config, true};
    std::string error;
    if (!candidate.validate(&error))
    {
        return failure(LogicEditorError::InvalidNode, error);
    }
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    ControlLogic *logic = editableLogic(&project, logic_id);
    for (LadderRung &rung : logic->rungs)
    {
        for (LadderCell &cell : rung.cells)
        {
            if (cell.node.has_value() && cell.node->id == node_id)
            {
                cell.node->config = config;
                cell.node->configured = true;
                recordHistory(std::move(before));
                return {true, LogicEditorError::None, {}, node_id};
            }
        }
        if (rung.output.has_value() && rung.output->id == node_id)
        {
            rung.output->config = config;
            rung.output->configured = true;
            recordHistory(std::move(before));
            return {true, LogicEditorError::None, {}, node_id};
        }
    }
    return failure(LogicEditorError::NodeNotFound, "未找到逻辑节点");
}

LogicClipboardCopyResult LogicEditorService::copySelection(
    const std::string &logic_id,
    const LogicSelectionCopyRequest &selection) const
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return {failure(LogicEditorError::LogicNotFound, "未找到控制逻辑"), {}};
    }

    const bool has_grid_objects = !selection.cells.empty()
        || !selection.outputRungIds.empty()
        || !selection.verticalConnectionIds.empty();
    if (!selection.wholeRungIds.empty())
    {
        if (has_grid_objects)
        {
            return {failure(
                LogicEditorError::InvalidOperation,
                "整行选择不能和网格对象混合复制"), {}};
        }
        std::unordered_set<std::string> unique_ids;
        std::vector<std::size_t> indices;
        indices.reserve(selection.wholeRungIds.size());
        for (const std::string &rung_id : selection.wholeRungIds)
        {
            const std::size_t index = rungIndex(*logic, rung_id);
            if (!unique_ids.insert(rung_id).second
                || index == logic->rungs.size())
            {
                return {failure(
                    LogicEditorError::InvalidOperation,
                    "整行复制选择中存在重复或失效的行"), {}};
            }
            indices.push_back(index);
        }
        std::sort(indices.begin(), indices.end());
        for (std::size_t index = 1U; index < indices.size(); ++index)
        {
            if (indices[index] != indices[index - 1U] + 1U)
            {
                return {failure(
                    LogicEditorError::InvalidOperation,
                    "整行复制只支持连续的视觉行"), {}};
            }
        }

        LogicClipboardFragment fragment;
        fragment.mode = LogicClipboardMode::WholeRows;
        fragment.rowSpan = static_cast<int>(indices.size());
        fragment.columnSpan = ProjectLimits::kMaximumLadderColumns;
        fragment.rows.reserve(indices.size());
        for (std::size_t index : indices)
        {
            const LadderRung &rung = logic->rungs[index];
            fragment.rows.push_back({rung.comment, rung.cells, rung.output});
        }
        const std::size_t first = indices.front();
        const std::size_t last = indices.back();
        for (const VerticalConnection &connection : logic->verticalConnections)
        {
            const std::size_t upper = rungIndex(*logic, connection.upperRungId);
            const std::size_t lower = rungIndex(*logic, connection.lowerRungId);
            if (upper >= first && lower <= last && lower == upper + 1U)
            {
                fragment.verticalConnections.push_back({
                    static_cast<int>(upper - first),
                    connection.columnBoundary});
            }
        }
        return {{
            true,
            LogicEditorError::None,
            {},
            logic->rungs[first].id}, std::move(fragment)};
    }

    if (!has_grid_objects)
    {
        return {failure(
            LogicEditorError::InvalidOperation,
            "请先选择横线、指令、输出或竖线"), {}};
    }

    LogicClipboardFragment fragment;
    fragment.mode = LogicClipboardMode::GridObjects;
    std::size_t minimum_row = logic->rungs.size();
    std::size_t maximum_row = 0U;
    int minimum_column = ProjectLimits::kMaximumLadderColumns;
    int maximum_column = 0;
    const auto include_position = [
        &minimum_row,
        &maximum_row,
        &minimum_column,
        &maximum_column](std::size_t row, int column)
    {
        minimum_row = std::min(minimum_row, row);
        maximum_row = std::max(maximum_row, row);
        minimum_column = std::min(minimum_column, column);
        maximum_column = std::max(maximum_column, column);
    };

    std::unordered_set<std::string> unique_cells;
    for (const auto &position : selection.cells)
    {
        const std::size_t row = rungIndex(*logic, position.first);
        const LadderCell *cell = findCell(
            logic_id, position.first, position.second);
        const std::string key = position.first + ":"
            + std::to_string(position.second);
        if (row == logic->rungs.size() || cell == nullptr
            || !unique_cells.insert(key).second
            || cell->kind == LadderCellKind::Gap)
        {
            return {failure(
                LogicEditorError::InvalidOperation,
                "复制选择中存在重复、空白或失效的网格"), {}};
        }
        fragment.cells.push_back({
            static_cast<int>(row),
            position.second,
            cell->kind,
            cell->node});
        include_position(row, position.second);
    }

    std::unordered_set<std::string> unique_outputs;
    for (const std::string &rung_id : selection.outputRungIds)
    {
        const std::size_t row = rungIndex(*logic, rung_id);
        const LadderRung *rung = findRung(logic_id, rung_id);
        if (row == logic->rungs.size() || rung == nullptr
            || !rung->output.has_value()
            || !unique_outputs.insert(rung_id).second)
        {
            return {failure(
                LogicEditorError::InvalidOperation,
                "复制选择中存在重复、空白或失效的输出槽"), {}};
        }
        fragment.outputs.push_back({
            static_cast<int>(row),
            ProjectLimits::kMaximumConditionColumns,
            *rung->output});
        include_position(row, ProjectLimits::kMaximumConditionColumns);
    }

    std::unordered_set<std::string> unique_connections;
    for (const std::string &connection_id : selection.verticalConnectionIds)
    {
        const VerticalConnection *connection = findConnection(
            logic_id, connection_id);
        if (connection == nullptr
            || !unique_connections.insert(connection_id).second)
        {
            return {failure(
                LogicEditorError::InvalidOperation,
                "复制选择中存在重复或失效的竖线"), {}};
        }
        const std::size_t upper = rungIndex(*logic, connection->upperRungId);
        const std::size_t lower = rungIndex(*logic, connection->lowerRungId);
        if (upper == logic->rungs.size() || lower != upper + 1U)
        {
            return {failure(
                LogicEditorError::InvalidOperation,
                "复制选择中存在悬空竖线"), {}};
        }
        fragment.verticalConnections.push_back({
            static_cast<int>(upper), connection->columnBoundary});
        include_position(upper, connection->columnBoundary);
        include_position(lower, connection->columnBoundary);
    }

    for (LogicClipboardCell &cell : fragment.cells)
    {
        cell.relativeRow -= static_cast<int>(minimum_row);
        cell.relativeColumn -= minimum_column;
    }
    for (LogicClipboardOutput &output : fragment.outputs)
    {
        output.relativeRow -= static_cast<int>(minimum_row);
        output.relativeColumn -= minimum_column;
    }
    for (LogicClipboardVerticalConnection &connection
         : fragment.verticalConnections)
    {
        connection.upperRelativeRow -= static_cast<int>(minimum_row);
        connection.relativeColumnBoundary -= minimum_column;
    }
    fragment.rowSpan = static_cast<int>(maximum_row - minimum_row + 1U);
    fragment.columnSpan = maximum_column - minimum_column + 1;
    std::sort(
        fragment.cells.begin(), fragment.cells.end(),
        [](const LogicClipboardCell &left, const LogicClipboardCell &right)
        {
            return left.relativeRow != right.relativeRow
                ? left.relativeRow < right.relativeRow
                : left.relativeColumn < right.relativeColumn;
        });
    std::sort(
        fragment.outputs.begin(), fragment.outputs.end(),
        [](const LogicClipboardOutput &left, const LogicClipboardOutput &right)
        {
            return left.relativeRow < right.relativeRow;
        });
    std::sort(
        fragment.verticalConnections.begin(),
        fragment.verticalConnections.end(),
        [](const LogicClipboardVerticalConnection &left,
           const LogicClipboardVerticalConnection &right)
        {
            return left.upperRelativeRow != right.upperRelativeRow
                ? left.upperRelativeRow < right.upperRelativeRow
                : left.relativeColumnBoundary
                    < right.relativeColumnBoundary;
        });
    return {{true, LogicEditorError::None, {}, {}}, std::move(fragment)};
}

LogicClipboardPasteResult LogicEditorService::pasteClipboard(
    const std::string &logic_id,
    const LogicClipboardFragment &fragment,
    const LogicPasteTarget &target)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return {failure(LogicEditorError::LogicNotFound, "未找到控制逻辑"), {}, {}};
    }

    if (fragment.mode == LogicClipboardMode::WholeRows)
    {
        if (fragment.rows.empty() || !fragment.cells.empty()
            || !fragment.outputs.empty())
        {
            return {failure(
                LogicEditorError::InvalidOperation,
                "整行剪贴板内容无效"), {}, {}};
        }
        if (logic->rungs.size() + fragment.rows.size()
                > project_service_.projectLimits().maximumRungsPerLogic
            || totalRungCount(project_service_.project()) + fragment.rows.size()
                > ProjectLimits::kMaximumRungsPerProject)
        {
            return {failure(
                LogicEditorError::InvalidOperation,
                "粘贴整行后将超过梯形图行数上限"), {}, {}};
        }
        std::size_t position = 0U;
        if (!logic->rungs.empty())
        {
            const std::size_t reference = rungIndex(*logic, target.rungId);
            if (reference == logic->rungs.size())
            {
                return {failure(
                    LogicEditorError::RungNotFound,
                    "请先选择整行粘贴位置"), {}, {}};
            }
            position = reference + 1U;
        }
        for (const LogicClipboardRow &row : fragment.rows)
        {
            if (row.cells.size()
                    != static_cast<std::size_t>(
                        ProjectLimits::kMaximumConditionColumns)
                || containsLineBreak(row.comment)
                || row.comment.size() > ProjectLimits::kMaximumRungCommentBytes)
            {
                return {failure(
                    LogicEditorError::InvalidOperation,
                    "复制的整行结构或注释无效"), {}, {}};
            }
            for (const LadderCell &cell : row.cells)
            {
                if (!cell.validate()
                    || (cell.node.has_value() && !cell.node->isCondition()))
                {
                    return {failure(
                        LogicEditorError::InvalidNode,
                        "复制的整行包含无效条件"), {}, {}};
                }
            }
            if (row.output.has_value()
                && (!row.output->validate() || !row.output->isOutput()))
            {
                return {failure(
                    LogicEditorError::InvalidNode,
                    "复制的整行包含无效输出"), {}, {}};
            }
        }
        std::unordered_set<std::string> unique_connections;
        for (const LogicClipboardVerticalConnection &connection
             : fragment.verticalConnections)
        {
            const std::string key = std::to_string(connection.upperRelativeRow)
                + ":" + std::to_string(connection.relativeColumnBoundary);
            if (connection.upperRelativeRow < 0
                || connection.upperRelativeRow + 1
                    >= static_cast<int>(fragment.rows.size())
                || connection.relativeColumnBoundary < 0
                || connection.relativeColumnBoundary
                    > ProjectLimits::kMaximumConditionColumns
                || !unique_connections.insert(key).second)
            {
                return {failure(
                    LogicEditorError::InvalidOperation,
                    "复制的整行包含无效竖线"), {}, {}};
            }
        }

        HistoryState before = captureState();
        const bool modified_before = project_service_.isModified();
        Project &project = project_service_.editProject();
        ControlLogic *editable = editableLogic(&project, logic_id);
        std::vector<std::string> inserted_ids;
        inserted_ids.reserve(fragment.rows.size());
        for (std::size_t offset = 0U; offset < fragment.rows.size(); ++offset)
        {
            const std::string inserted_id = insertEmptyRungAt(
                editable, position + offset);
            LadderRung *destination = editableRung(editable, inserted_id);
            const LogicClipboardRow &source = fragment.rows[offset];
            destination->comment = source.comment;
            for (std::size_t column = 0U; column < source.cells.size(); ++column)
            {
                destination->cells[column].kind = source.cells[column].kind;
                destination->cells[column].node.reset();
                if (source.cells[column].node.has_value())
                {
                    const LogicNode &source_node = *source.cells[column].node;
                    destination->cells[column].node = LogicNode{
                        makeUniqueId(*editable, nodePrefix(source_node.config)),
                        source_node.config,
                        source_node.configured};
                }
            }
            if (source.output.has_value())
            {
                destination->output = LogicNode{
                    makeUniqueId(*editable, nodePrefix(source.output->config)),
                    source.output->config,
                    source.output->configured};
            }
            inserted_ids.push_back(inserted_id);
        }
        for (const LogicClipboardVerticalConnection &source
             : fragment.verticalConnections)
        {
            const std::string &upper = inserted_ids[
                static_cast<std::size_t>(source.upperRelativeRow)];
            const std::string &lower = inserted_ids[
                static_cast<std::size_t>(source.upperRelativeRow + 1)];
            const auto existing = std::find_if(
                editable->verticalConnections.cbegin(),
                editable->verticalConnections.cend(),
                [&upper, &lower, &source](const VerticalConnection &connection)
                {
                    return connectionMatches(
                        connection,
                        upper,
                        lower,
                        source.relativeColumnBoundary);
                });
            if (existing == editable->verticalConnections.cend())
            {
                editable->verticalConnections.push_back({
                    makeUniqueId(*editable, "vertical"),
                    upper,
                    lower,
                    source.relativeColumnBoundary});
            }
        }
        std::string error;
        if (!editable->validateStructure(project_service_.projectLimits(), &error))
        {
            rollbackEdit(std::move(before), modified_before);
            return {failure(LogicEditorError::InvalidOperation, error), {}, {}};
        }
        refreshRungNames(editable);
        recordHistory(std::move(before));
        return {{
            true,
            LogicEditorError::None,
            {},
            inserted_ids.front()}, {}, std::move(inserted_ids)};
    }

    if (!fragment.rows.empty()
        || (fragment.cells.empty() && fragment.outputs.empty()
            && fragment.verticalConnections.empty())
        || fragment.rowSpan <= 0 || fragment.columnSpan <= 0)
    {
        return {failure(
            LogicEditorError::InvalidOperation,
            "网格剪贴板内容无效"), {}, {}};
    }
    const std::size_t target_row = rungIndex(*logic, target.rungId);
    if (target_row == logic->rungs.size())
    {
        return {failure(
            LogicEditorError::RungNotFound,
            "请先选择粘贴目标"), {}, {}};
    }
    const bool only_vertical = fragment.cells.empty()
        && fragment.outputs.empty();
    const bool only_output = fragment.cells.empty()
        && fragment.verticalConnections.empty();
    if ((only_vertical && (!target.boundary || target.output))
        || (only_output && (!target.output || target.boundary)))
    {
        return {failure(
            LogicEditorError::InvalidOperation,
            "剪贴板对象类型与当前粘贴位置不匹配"), {}, {}};
    }
    if (target.column < 0
        || target.column > ProjectLimits::kMaximumConditionColumns
        || target_row + static_cast<std::size_t>(fragment.rowSpan)
            > logic->rungs.size())
    {
        return {failure(
            LogicEditorError::InvalidOperation,
            "粘贴片段超出当前梯形图行列范围"), {}, {}};
    }

    std::unordered_set<std::string> destination_cells;
    for (const LogicClipboardCell &source : fragment.cells)
    {
        const int column = target.column + source.relativeColumn;
        const std::size_t row = target_row
            + static_cast<std::size_t>(source.relativeRow);
        const std::string key = std::to_string(row) + ":"
            + std::to_string(column);
        if (source.relativeRow < 0
            || source.relativeRow >= fragment.rowSpan
            || source.relativeColumn < 0
            || column < 0
            || column >= ProjectLimits::kMaximumConditionColumns
            || !destination_cells.insert(key).second
            || (source.kind != LadderCellKind::Wire
                && source.kind != LadderCellKind::Node)
            || (source.kind == LadderCellKind::Node
                && (!source.node.has_value()
                    || !source.node->validate()
                    || !source.node->isCondition()))
            || (source.kind == LadderCellKind::Wire
                && source.node.has_value()))
        {
            return {failure(
                LogicEditorError::InvalidOperation,
                "复制片段包含无效或越界的条件网格"), {}, {}};
        }
        const LadderCell &destination = logic->rungs[row].cells[
            static_cast<std::size_t>(column)];
        if (destination.kind == LadderCellKind::Node)
        {
            return {failure(
                LogicEditorError::InvalidOperation,
                "粘贴目标已有触点或比较指令，未执行任何修改"), {}, {}};
        }
    }

    const bool explicit_output_replace = only_output
        && fragment.outputs.size() == 1U && fragment.rowSpan == 1;
    std::unordered_set<std::size_t> destination_outputs;
    for (const LogicClipboardOutput &source : fragment.outputs)
    {
        const int column = target.column + source.relativeColumn;
        const std::size_t row = target_row
            + static_cast<std::size_t>(source.relativeRow);
        if (source.relativeRow < 0
            || source.relativeRow >= fragment.rowSpan
            || source.relativeColumn < 0
            || column != ProjectLimits::kMaximumConditionColumns
            || !destination_outputs.insert(row).second
            || !source.node.validate() || !source.node.isOutput())
        {
            return {failure(
                LogicEditorError::InvalidOperation,
                "复制片段包含无效或错位的输出"), {}, {}};
        }
        if (logic->rungs[row].output.has_value() && !explicit_output_replace)
        {
            return {failure(
                LogicEditorError::InvalidOperation,
                "混合片段的目标输出槽已有指令，未执行任何修改"), {}, {}};
        }
    }

    std::unordered_set<std::string> destination_connections;
    for (const LogicClipboardVerticalConnection &source
         : fragment.verticalConnections)
    {
        const int boundary = target.column + source.relativeColumnBoundary;
        const std::size_t upper = target_row
            + static_cast<std::size_t>(source.upperRelativeRow);
        const std::string key = std::to_string(upper) + ":"
            + std::to_string(boundary);
        if (source.upperRelativeRow < 0
            || source.upperRelativeRow + 1 >= fragment.rowSpan
            || source.relativeColumnBoundary < 0
            || upper + 1U >= logic->rungs.size()
            || boundary < 0
            || boundary > ProjectLimits::kMaximumConditionColumns
            || !destination_connections.insert(key).second)
        {
            return {failure(
                LogicEditorError::InvalidOperation,
                "复制片段包含无效、重复或悬空的竖线"), {}, {}};
        }
    }

    HistoryState before = captureState();
    const bool modified_before = project_service_.isModified();
    Project &project = project_service_.editProject();
    ControlLogic *editable = editableLogic(&project, logic_id);
    LogicClipboardPasteResult result;
    for (const LogicClipboardCell &source : fragment.cells)
    {
        const std::size_t row = target_row
            + static_cast<std::size_t>(source.relativeRow);
        const int column = target.column + source.relativeColumn;
        LadderCell &destination = editable->rungs[row].cells[
            static_cast<std::size_t>(column)];
        destination.kind = source.kind;
        destination.node.reset();
        if (source.node.has_value())
        {
            const std::string node_id = makeUniqueId(
                *editable, nodePrefix(source.node->config));
            destination.node = LogicNode{
                node_id, source.node->config, source.node->configured};
            if (result.edit.id.empty())
            {
                result.edit.id = node_id;
            }
        }
        result.selection.cells.emplace_back(editable->rungs[row].id, column);
        if (result.edit.id.empty())
        {
            result.edit.id = destination.id;
        }
    }
    for (const LogicClipboardOutput &source : fragment.outputs)
    {
        const std::size_t row = target_row
            + static_cast<std::size_t>(source.relativeRow);
        const std::string node_id = makeUniqueId(
            *editable, nodePrefix(source.node.config));
        editable->rungs[row].output = LogicNode{
            node_id, source.node.config, source.node.configured};
        result.selection.outputRungIds.push_back(editable->rungs[row].id);
        if (result.edit.id.empty())
        {
            result.edit.id = node_id;
        }
    }
    for (const LogicClipboardVerticalConnection &source
         : fragment.verticalConnections)
    {
        const std::size_t upper = target_row
            + static_cast<std::size_t>(source.upperRelativeRow);
        const int boundary = target.column + source.relativeColumnBoundary;
        const std::string &upper_id = editable->rungs[upper].id;
        const std::string &lower_id = editable->rungs[upper + 1U].id;
        auto existing = std::find_if(
            editable->verticalConnections.begin(),
            editable->verticalConnections.end(),
            [&upper_id, &lower_id, boundary](const VerticalConnection &connection)
            {
                return connectionMatches(
                    connection, upper_id, lower_id, boundary);
            });
        if (existing == editable->verticalConnections.end())
        {
            editable->verticalConnections.push_back({
                makeUniqueId(*editable, "vertical"),
                upper_id,
                lower_id,
                boundary});
            existing = std::prev(editable->verticalConnections.end());
        }
        result.selection.verticalConnectionIds.push_back(existing->id);
        if (result.edit.id.empty())
        {
            result.edit.id = existing->id;
        }
    }
    std::string error;
    if (!editable->validateStructure(project_service_.projectLimits(), &error))
    {
        rollbackEdit(std::move(before), modified_before);
        return {failure(LogicEditorError::InvalidOperation, error), {}, {}};
    }
    recordHistory(std::move(before));
    result.edit.succeeded = true;
    result.edit.error = LogicEditorError::None;
    return result;
}

LogicEditorResult LogicEditorService::pasteConditionNodes(
    const std::string &logic_id,
    const std::string &rung_id,
    const std::vector<LogicNode> &nodes,
    int start_column)
{
    const ControlLogic *logic = findLogic(logic_id);
    const LadderRung *rung = findRung(logic_id, rung_id);
    if (logic == nullptr || rung == nullptr)
    {
        return failure(LogicEditorError::RungNotFound, "未找到粘贴目标行");
    }
    if (nodes.empty()
        || nodes.size()
            > static_cast<std::size_t>(ProjectLimits::kMaximumConditionColumns))
    {
        return failure(LogicEditorError::InvalidOperation, "复制的条件数量无效");
    }
    for (const LogicNode &node : nodes)
    {
        if (!node.validate() || !node.isCondition())
        {
            return failure(LogicEditorError::InvalidNode, "只能粘贴有效的条件节点");
        }
    }
    if (start_column < 0)
    {
        for (int candidate = 0;
             candidate + static_cast<int>(nodes.size())
                <= ProjectLimits::kMaximumConditionColumns;
             ++candidate)
        {
            bool available = true;
            for (std::size_t offset = 0U; offset < nodes.size(); ++offset)
            {
                available = available
                    && rung->cells[static_cast<std::size_t>(candidate) + offset].kind
                        == LadderCellKind::Gap;
            }
            if (available)
            {
                start_column = candidate;
                break;
            }
        }
    }
    if (start_column < 0
        || start_column + static_cast<int>(nodes.size())
            > ProjectLimits::kMaximumConditionColumns)
    {
        return failure(LogicEditorError::InvalidOperation, "目标行没有足够连续空格");
    }

    HistoryState before = captureState();
    const bool modified_before = project_service_.isModified();
    Project &project = project_service_.editProject();
    ControlLogic *editable = editableLogic(&project, logic_id);
    LadderRung *target = editableRung(editable, rung_id);
    std::string first_id;
    for (std::size_t offset = 0U; offset < nodes.size(); ++offset)
    {
        LadderCell &cell = target->cells[
            static_cast<std::size_t>(start_column) + offset];
        const std::string id = makeUniqueId(
            *editable, nodePrefix(nodes[offset].config));
        cell.kind = LadderCellKind::Node;
        cell.node = LogicNode{id, nodes[offset].config, nodes[offset].configured};
        if (first_id.empty())
        {
            first_id = id;
        }
    }
    std::string error;
    if (!editable->validateStructure(project_service_.projectLimits(), &error))
    {
        rollbackEdit(std::move(before), modified_before);
        return failure(LogicEditorError::InvalidOperation, error);
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, first_id};
}

bool LogicEditorService::areConditionNodesContiguous(
    const std::string &logic_id,
    const std::string &rung_id,
    const std::vector<std::string> &node_ids) const
{
    const LadderRung *rung = findRung(logic_id, rung_id);
    if (rung == nullptr || node_ids.empty())
    {
        return false;
    }
    std::unordered_set<std::string> requested(
        node_ids.cbegin(), node_ids.cend());
    if (requested.size() != node_ids.size())
    {
        return false;
    }
    std::vector<int> columns;
    for (int column = 0; column < ProjectLimits::kMaximumConditionColumns; ++column)
    {
        const LadderCell &cell = rung->cells[static_cast<std::size_t>(column)];
        if (cell.node.has_value() && requested.count(cell.node->id) != 0U)
        {
            columns.push_back(column);
        }
    }
    return columns.size() == node_ids.size()
        && columns.back() - columns.front() + 1
            == static_cast<int>(columns.size());
}

LogicEditorResult LogicEditorService::pasteRung(
    const std::string &logic_id,
    const LadderRung &source)
{
    const ControlLogic *logic = findLogic(logic_id);
    std::string error;
    if (logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (!source.validateStructure(&error))
    {
        return failure(LogicEditorError::InvalidOperation, error);
    }
    if (logic->rungs.size()
            >= project_service_.projectLimits().maximumRungsPerLogic
        || totalRungCount(project_service_.project())
            >= ProjectLimits::kMaximumRungsPerProject)
    {
        return failure(LogicEditorError::InvalidOperation, "梯形图行数已经达到上限");
    }
    HistoryState before = captureState();
    const bool modified_before = project_service_.isModified();
    Project &project = project_service_.editProject();
    ControlLogic *editable = editableLogic(&project, logic_id);
    LadderRung pasted = makeEmptyRung(*editable, editable->rungs.size());
    pasted.comment = source.comment;
    for (std::size_t column = 0U; column < source.cells.size(); ++column)
    {
        pasted.cells[column].kind = source.cells[column].kind;
        if (source.cells[column].node.has_value())
        {
            const LogicNode &source_node = *source.cells[column].node;
            pasted.cells[column].node = LogicNode{
                makeUniqueId(*editable, nodePrefix(source_node.config)),
                source_node.config,
                source_node.configured};
        }
    }
    if (source.output.has_value())
    {
        pasted.output = LogicNode{
            makeUniqueId(*editable, nodePrefix(source.output->config)),
            source.output->config,
            source.output->configured};
    }
    const std::string pasted_id = pasted.id;
    editable->rungs.push_back(std::move(pasted));
    refreshRungNames(editable);
    if (!editable->validateStructure(project_service_.projectLimits(), &error))
    {
        rollbackEdit(std::move(before), modified_before);
        return failure(LogicEditorError::InvalidOperation, error);
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, pasted_id};
}

LogicEditorResult LogicEditorService::removeNode(
    const std::string &logic_id, const std::string &node_id)
{
    return removeNodes(logic_id, {node_id});
}

LogicEditorResult LogicEditorService::removeNodes(
    const std::string &logic_id,
    const std::vector<std::string> &node_ids)
{
    if (findLogic(logic_id) == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (node_ids.empty())
    {
        return failure(LogicEditorError::InvalidOperation, "请先选择要删除的节点");
    }
    std::unordered_set<std::string> ids;
    for (const std::string &id : node_ids)
    {
        if (!ids.insert(id).second || findNode(logic_id, id) == nullptr)
        {
            return failure(
                LogicEditorError::NodeNotFound,
                "节点删除列表包含重复或不存在的对象");
        }
    }
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    ControlLogic *logic = editableLogic(&project, logic_id);
    for (LadderRung &rung : logic->rungs)
    {
        for (LadderCell &cell : rung.cells)
        {
            if (cell.node.has_value() && ids.count(cell.node->id) != 0U)
            {
                cell.kind = LadderCellKind::Gap;
                cell.node.reset();
            }
        }
        if (rung.output.has_value() && ids.count(rung.output->id) != 0U)
        {
            rung.output.reset();
        }
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, node_ids.front()};
}

bool LogicEditorService::canUndo() const
{
    return history_.canUndo();
}

bool LogicEditorService::canRedo() const
{
    return history_.canRedo();
}

LogicEditorResult LogicEditorService::undo()
{
    const std::optional<HistoryState> target = history_.undo(captureState());
    if (!target.has_value())
    {
        return historyFailure("没有可撤销的梯形图编辑操作");
    }
    project_service_.editProject().controlLogics = target->logics;
    return {true, LogicEditorError::None, {}, {}};
}

LogicEditorResult LogicEditorService::redo()
{
    const std::optional<HistoryState> target = history_.redo(captureState());
    if (!target.has_value())
    {
        return historyFailure("没有可重做的梯形图编辑操作");
    }
    project_service_.editProject().controlLogics = target->logics;
    return {true, LogicEditorError::None, {}, {}};
}

void LogicEditorService::clearHistory()
{
    history_.clear();
}

LogicEditResult LogicEditorService::applyCellAndAdvance(
    const std::string &logic_id,
    const LogicEditCursor &cursor,
    const LogicNodeConfig *config,
    bool configured)
{
    const ControlLogic *existing_logic = findLogic(logic_id);
    if (existing_logic == nullptr)
    {
        return {failure(LogicEditorError::LogicNotFound, "未找到控制逻辑"), {}};
    }
    if (cursor.output || cursor.column < 0
        || cursor.column >= ProjectLimits::kMaximumConditionColumns)
    {
        return {failure(LogicEditorError::CellNotFound,
                        "条件指令只能放在第 1~10 列"), {}};
    }
    if (config != nullptr)
    {
        if (!isConditionConfig(*config))
        {
            return {failure(LogicEditorError::InvalidNode,
                            "条件区只能放置条件指令"), {}};
        }
        LogicNode candidate{"candidate", *config, configured};
        std::string candidate_error;
        if (!candidate.validate(&candidate_error))
        {
            return {failure(LogicEditorError::InvalidNode, candidate_error), {}};
        }
    }

    std::string target_rung_id = cursor.rungId;
    int target_column = cursor.column;
    const bool create_first_rung = target_rung_id.empty();
    if (create_first_rung)
    {
        if (!existing_logic->rungs.empty())
        {
            return {failure(LogicEditorError::RungNotFound,
                            "请先选择要编辑的梯形图行"), {}};
        }
        if (existing_logic->rungs.size()
                >= project_service_.projectLimits().maximumRungsPerLogic
            || totalRungCount(project_service_.project())
                >= ProjectLimits::kMaximumRungsPerProject)
        {
            return {failure(LogicEditorError::InvalidOperation,
                            "梯形图行数已经达到当前上限"), {}};
        }
        target_column = 0;
    }
    else
    {
        const LadderCell *existing_cell = findCell(
            logic_id, target_rung_id, target_column);
        if (existing_cell == nullptr)
        {
            return {failure(LogicEditorError::CellNotFound,
                            "未找到目标条件网格"), {}};
        }
        if (config == nullptr && existing_cell->kind == LadderCellKind::Node)
        {
            return {failure(LogicEditorError::InvalidOperation,
                            "横线不能覆盖已有条件指令"), {}};
        }
    }

    HistoryState before = captureState();
    const bool modified_before = project_service_.isModified();
    Project &project = project_service_.editProject();
    ControlLogic *logic = editableLogic(&project, logic_id);
    if (create_first_rung)
    {
        target_rung_id = insertEmptyRungAt(logic, 0U);
    }
    LadderCell &cell = editableRung(logic, target_rung_id)
        ->cells[static_cast<std::size_t>(target_column)];
    std::string edited_id = cell.id;
    if (config == nullptr)
    {
        cell.kind = LadderCellKind::Wire;
        cell.node.reset();
    }
    else
    {
        edited_id = makeUniqueId(*logic, nodePrefix(*config));
        cell.kind = LadderCellKind::Node;
        cell.node = LogicNode{edited_id, *config, configured};
    }

    std::string error;
    if (!logic->validateStructure(project_service_.projectLimits(), &error))
    {
        rollbackEdit(std::move(before), modified_before);
        return {failure(LogicEditorError::InvalidOperation, error), {}};
    }
    recordHistory(std::move(before));
    LogicEditCursor next{target_rung_id, target_column + 1, false};
    if (next.column >= ProjectLimits::kMaximumConditionColumns)
    {
        next.column = ProjectLimits::kMaximumConditionColumns;
        next.output = true;
    }
    return {
        {true, LogicEditorError::None, {}, edited_id},
        std::move(next)};
}

bool LogicEditorService::isConditionConfig(const LogicNodeConfig &config)
{
    return std::holds_alternative<ContactNodeConfig>(config)
        || std::holds_alternative<EdgeContactNodeConfig>(config)
        || std::holds_alternative<CompareNodeConfig>(config);
}

bool LogicEditorService::isOutputConfig(const LogicNodeConfig &config)
{
    return std::holds_alternative<CoilNodeConfig>(config)
        || std::holds_alternative<MoveNodeConfig>(config)
        || std::holds_alternative<ArithmeticNodeConfig>(config);
}

std::string LogicEditorService::nodePrefix(const LogicNodeConfig &config)
{
    return std::visit(
        [](const auto &value) -> std::string
        {
            using Config = std::decay_t<decltype(value)>;
            if constexpr (std::is_same_v<Config, ContactNodeConfig>)
            {
                return "contact";
            }
            else if constexpr (std::is_same_v<Config, EdgeContactNodeConfig>)
            {
                return "edge";
            }
            else if constexpr (std::is_same_v<Config, CoilNodeConfig>)
            {
                return "coil";
            }
            else if constexpr (std::is_same_v<Config, MoveNodeConfig>)
            {
                return "move";
            }
            else if constexpr (std::is_same_v<Config, ArithmeticNodeConfig>)
            {
                return "arithmetic";
            }
            else
            {
                return "compare";
            }
        },
        config);
}

std::string LogicEditorService::makeUniqueId(
    const ControlLogic &logic, const std::string &prefix)
{
    const auto exists = [&logic](const std::string &candidate)
    {
        if (logic.id == candidate)
        {
            return true;
        }
        for (const LadderRung &rung : logic.rungs)
        {
            if (rung.id == candidate
                || (rung.output.has_value() && rung.output->id == candidate))
            {
                return true;
            }
            for (const LadderCell &cell : rung.cells)
            {
                if (cell.id == candidate
                    || (cell.node.has_value() && cell.node->id == candidate))
                {
                    return true;
                }
            }
        }
        return std::any_of(
            logic.verticalConnections.cbegin(),
            logic.verticalConnections.cend(),
            [&candidate](const VerticalConnection &connection)
            {
                return connection.id == candidate;
            });
    };
    for (std::size_t index = 1U;; ++index)
    {
        const std::string candidate = prefix + '-' + std::to_string(index);
        if (!exists(candidate))
        {
            return candidate;
        }
    }
}

LadderRung LogicEditorService::makeEmptyRung(
    const ControlLogic &logic, std::size_t visual_index)
{
    LadderRung rung;
    rung.id = makeUniqueId(logic, "rung");
    rung.name = "行 " + std::to_string(visual_index + 1U);
    rung.cells.reserve(
        static_cast<std::size_t>(ProjectLimits::kMaximumConditionColumns));
    for (int column = 0;
         column < ProjectLimits::kMaximumConditionColumns;
         ++column)
    {
        rung.cells.push_back({
            rung.id + "-cell-" + std::to_string(column + 1),
            LadderCellKind::Gap,
            std::nullopt});
    }
    return rung;
}

std::string LogicEditorService::insertEmptyRungAt(
    ControlLogic *logic, std::size_t position)
{
    if (logic == nullptr || position > logic->rungs.size())
    {
        return {};
    }
    const std::string upper_id = position > 0U
        ? logic->rungs[position - 1U].id : std::string{};
    const std::string lower_id = position < logic->rungs.size()
        ? logic->rungs[position].id : std::string{};
    std::vector<VerticalConnection> bridges;
    if (!upper_id.empty() && !lower_id.empty())
    {
        for (const VerticalConnection &connection : logic->verticalConnections)
        {
            if (connection.upperRungId == upper_id
                && connection.lowerRungId == lower_id)
            {
                bridges.push_back(connection);
            }
        }
        logic->verticalConnections.erase(
            std::remove_if(
                logic->verticalConnections.begin(),
                logic->verticalConnections.end(),
                [&upper_id, &lower_id](const VerticalConnection &connection)
                {
                    return connection.upperRungId == upper_id
                        && connection.lowerRungId == lower_id;
                }),
            logic->verticalConnections.end());
    }
    LadderRung rung = makeEmptyRung(*logic, position);
    const std::string new_id = rung.id;
    logic->rungs.insert(
        logic->rungs.begin() + static_cast<std::ptrdiff_t>(position),
        std::move(rung));
    for (VerticalConnection &bridge : bridges)
    {
        bridge.lowerRungId = new_id;
        logic->verticalConnections.push_back(bridge);
    }
    for (const VerticalConnection &bridge : bridges)
    {
        logic->verticalConnections.push_back({
            makeUniqueId(*logic, "vertical"),
            new_id,
            lower_id,
            bridge.columnBoundary});
    }
    refreshRungNames(logic);
    return new_id;
}

void LogicEditorService::removeRungAt(
    ControlLogic *logic, std::size_t position)
{
    if (logic == nullptr || position >= logic->rungs.size())
    {
        return;
    }
    const std::string removed_id = logic->rungs[position].id;
    const std::string upper_id = position > 0U
        ? logic->rungs[position - 1U].id : std::string{};
    const std::string lower_id = position + 1U < logic->rungs.size()
        ? logic->rungs[position + 1U].id : std::string{};
    std::map<int, std::string> upper_connections;
    std::map<int, std::string> lower_connections;
    for (const VerticalConnection &connection : logic->verticalConnections)
    {
        if (connection.upperRungId == upper_id
            && connection.lowerRungId == removed_id)
        {
            upper_connections[connection.columnBoundary] = connection.id;
        }
        if (connection.upperRungId == removed_id
            && connection.lowerRungId == lower_id)
        {
            lower_connections[connection.columnBoundary] = connection.id;
        }
    }
    logic->verticalConnections.erase(
        std::remove_if(
            logic->verticalConnections.begin(),
            logic->verticalConnections.end(),
            [&removed_id](const VerticalConnection &connection)
            {
                return connection.upperRungId == removed_id
                    || connection.lowerRungId == removed_id;
            }),
        logic->verticalConnections.end());
    logic->rungs.erase(
        logic->rungs.begin() + static_cast<std::ptrdiff_t>(position));
    if (!upper_id.empty() && !lower_id.empty())
    {
        for (const auto &upper : upper_connections)
        {
            if (lower_connections.count(upper.first) != 0U)
            {
                logic->verticalConnections.push_back({
                    upper.second,
                    upper_id,
                    lower_id,
                    upper.first});
            }
        }
    }
    refreshRungNames(logic);
}

void LogicEditorService::refreshRungNames(ControlLogic *logic)
{
    if (logic == nullptr)
    {
        return;
    }
    for (std::size_t index = 0U; index < logic->rungs.size(); ++index)
    {
        logic->rungs[index].name = "行 " + std::to_string(index + 1U);
    }
}

LogicEditorResult LogicEditorService::failure(
    LogicEditorError error, const std::string &message)
{
    return {false, error, message, {}};
}