#include "logic_editor_service.h"

#include "project_service.h"

#include <algorithm>
#include <cctype>
#include <cstddef>
#include <iterator>
#include <unordered_set>
#include <type_traits>
#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; });
}

std::string makeUniqueLogicId(const Project &project)
{
    int suffix = 1;
    while (true)
    {
        const std::string candidate = "logic-" + std::to_string(suffix);
        const bool found = std::any_of(
            project.controlLogics.cbegin(), project.controlLogics.cend(),
            [&candidate](const ControlLogic &logic) { return logic.id == candidate; });
        if (!found)
        {
            return candidate;
        }
        ++suffix;
    }
}

LogicNode makeNode(const std::string &id, const LogicNodeConfig &config)
{
    return {id, config, false};
}

ConditionExpression makeContainer(
    const std::string &id,
    ConditionExpressionKind kind,
    ConditionExpression first,
    ConditionExpression second)
{
    ConditionExpression expression;
    expression.id = id;
    expression.kind = kind;
    expression.children.push_back(std::move(first));
    expression.children.push_back(std::move(second));
    return expression;
}

ConditionExpression *findParentExpression(
    ConditionExpression &expression, const std::string &child_id)
{
    for (ConditionExpression &child : expression.children)
    {
        if (child.id == child_id)
        {
            return &expression;
        }
        if (ConditionExpression *parent = findParentExpression(child, child_id))
        {
            return parent;
        }
    }
    return nullptr;
}

using NodeIdSet = std::unordered_set<std::string>;

NodeIdSet conditionLeafIds(const ConditionExpression &expression)
{
    NodeIdSet ids;
    if (expression.kind == ConditionExpressionKind::Node
        || expression.kind == ConditionExpressionKind::Wire)
    {
        ids.insert(expression.id);
        return ids;
    }
    for (const ConditionExpression &child : expression.children)
    {
        NodeIdSet child_ids = conditionLeafIds(child);
        ids.insert(child_ids.cbegin(), child_ids.cend());
    }
    return ids;
}

int expressionColumns(const ConditionExpression &expression)
{
    if (expression.kind == ConditionExpressionKind::Node)
    {
        return 1;
    }
    if (expression.kind == ConditionExpressionKind::Wire)
    {
        return expression.wire->columnSpan;
    }
    int columns = expression.kind == ConditionExpressionKind::Series ? 0 : 1;
    for (const ConditionExpression &child : expression.children)
    {
        const int child_columns = expressionColumns(child);
        columns = expression.kind == ConditionExpressionKind::Series
            ? columns + child_columns : std::max(columns, child_columns);
    }
    return columns;
}

bool isSubset(const NodeIdSet &subset, const NodeIdSet &values)
{
    return std::all_of(
        subset.cbegin(), subset.cend(),
        [&values](const std::string &value) { return values.count(value) != 0U; });
}

bool sameValues(const NodeIdSet &left, const NodeIdSet &right)
{
    return left.size() == right.size() && isSubset(left, right);
}

void addParallelSibling(
    ConditionExpression *target,
    ConditionExpression branch,
    const std::string &container_id)
{
    if (target->kind == ConditionExpressionKind::Parallel)
    {
        target->children.push_back(std::move(branch));
        return;
    }
    ConditionExpression original = std::move(*target);
    *target = makeContainer(
        container_id,
        ConditionExpressionKind::Parallel,
        std::move(original),
        std::move(branch));
}

bool addParallelForSelection(
    ConditionExpression *expression,
    const NodeIdSet &selected_ids,
    ConditionExpression *branch,
    const std::string &parallel_id,
    const std::string &series_id)
{
    const NodeIdSet expression_ids = conditionLeafIds(*expression);
    if (sameValues(expression_ids, selected_ids))
    {
        addParallelSibling(expression, std::move(*branch), parallel_id);
        return true;
    }

    std::vector<NodeIdSet> child_ids;
    child_ids.reserve(expression->children.size());
    std::vector<std::size_t> matching_children;
    for (std::size_t index = 0; index < expression->children.size(); ++index)
    {
        child_ids.push_back(conditionLeafIds(expression->children[index]));
        const bool intersects = std::any_of(
            child_ids.back().cbegin(), child_ids.back().cend(),
            [&selected_ids](const std::string &id)
            {
                return selected_ids.count(id) != 0U;
            });
        if (intersects)
        {
            matching_children.push_back(index);
        }
    }
    if (matching_children.empty())
    {
        return false;
    }
    if (matching_children.size() == 1U)
    {
        const std::size_t child_index = matching_children.front();
        if (expression->kind == ConditionExpressionKind::Parallel
            && sameValues(child_ids[child_index], selected_ids))
        {
            expression->children.push_back(std::move(*branch));
            return true;
        }
        return addParallelForSelection(
            &expression->children[child_index],
            selected_ids,
            branch,
            parallel_id,
            series_id);
    }
    if (expression->kind != ConditionExpressionKind::Series)
    {
        return false;
    }

    const std::size_t first = matching_children.front();
    const std::size_t last = matching_children.back();
    if (last - first + 1U != matching_children.size())
    {
        return false;
    }
    NodeIdSet range_ids;
    for (std::size_t index = first; index <= last; ++index)
    {
        range_ids.insert(child_ids[index].cbegin(), child_ids[index].cend());
    }
    if (!sameValues(range_ids, selected_ids))
    {
        return false;
    }

    ConditionExpression range;
    range.id = series_id;
    range.kind = ConditionExpressionKind::Series;
    auto range_begin = expression->children.begin() + static_cast<std::ptrdiff_t>(first);
    auto range_end = expression->children.begin() + static_cast<std::ptrdiff_t>(last + 1U);
    range.children.insert(
        range.children.end(),
        std::make_move_iterator(range_begin),
        std::make_move_iterator(range_end));
    range_begin = expression->children.erase(range_begin, range_end);

    ConditionExpression parallel = makeContainer(
        parallel_id,
        ConditionExpressionKind::Parallel,
        std::move(range),
        std::move(*branch));
    expression->children.insert(range_begin, std::move(parallel));
    return true;
}

bool removeExpressionRecursive(
    ConditionExpression *expression, const std::string &expression_id)
{
    if (expression == nullptr
        || expression->kind == ConditionExpressionKind::Node
        || expression->kind == ConditionExpressionKind::Wire)
    {
        return false;
    }
    const auto removable = std::find_if(
        expression->children.begin(),
        expression->children.end(),
        [&expression_id](const ConditionExpression &child)
        {
            return child.id == expression_id;
        });
    if (removable != expression->children.end())
    {
        expression->children.erase(removable);
        return true;
    }
    for (ConditionExpression &child : expression->children)
    {
        if (removeExpressionRecursive(&child, expression_id))
        {
            return true;
        }
    }
    return false;
}

std::optional<int> selectedExpressionColumns(
    const ConditionExpression &expression,
    const NodeIdSet &selected_ids)
{
    const NodeIdSet expression_ids = conditionLeafIds(expression);
    if (sameValues(expression_ids, selected_ids))
    {
        return expressionColumns(expression);
    }
    if (expression.kind == ConditionExpressionKind::Node
        || expression.kind == ConditionExpressionKind::Wire)
    {
        return std::nullopt;
    }

    std::vector<NodeIdSet> child_ids;
    std::vector<std::size_t> matching_children;
    child_ids.reserve(expression.children.size());
    for (std::size_t index = 0; index < expression.children.size(); ++index)
    {
        child_ids.push_back(conditionLeafIds(expression.children[index]));
        const bool intersects = std::any_of(
            child_ids.back().cbegin(), child_ids.back().cend(),
            [&selected_ids](const std::string &id)
            {
                return selected_ids.count(id) != 0U;
            });
        if (intersects)
        {
            matching_children.push_back(index);
        }
    }
    if (matching_children.size() == 1U)
    {
        return selectedExpressionColumns(
            expression.children[matching_children.front()], selected_ids);
    }
    if (matching_children.empty()
        || expression.kind != ConditionExpressionKind::Series)
    {
        return std::nullopt;
    }
    const std::size_t first = matching_children.front();
    const std::size_t last = matching_children.back();
    if (last - first + 1U != matching_children.size())
    {
        return std::nullopt;
    }
    NodeIdSet range_ids;
    int columns = 0;
    for (std::size_t index = first; index <= last; ++index)
    {
        range_ids.insert(child_ids[index].cbegin(), child_ids[index].cend());
        columns += expressionColumns(expression.children[index]);
    }
    return sameValues(range_ids, selected_ids)
        ? std::optional<int>{columns} : std::nullopt;
}

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

} // 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)
{
    const HistoryState after = captureState();
    history_.record(std::move(before), after, &LogicEditorService::statesEqual);
}

bool LogicEditorService::statesEqual(
    const HistoryState &left, const HistoryState &right)
{
    if (left.logics.size() != right.logics.size())
    {
        return false;
    }
    for (std::size_t index = 0; 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())
    {
        return false;
    }
    for (std::size_t index = 0; index < left.rungs.size(); ++index)
    {
        if (!rungsEqual(left.rungs[index], right.rungs[index]))
        {
            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.condition.has_value() != right.condition.has_value()
        || left.output.has_value() != right.output.has_value())
    {
        return false;
    }
    return (!left.condition.has_value()
            || expressionsEqual(*left.condition, *right.condition))
        && (!left.output.has_value() || nodesEqual(*left.output, *right.output));
}

bool LogicEditorService::expressionsEqual(
    const ConditionExpression &left, const ConditionExpression &right)
{
    if (left.id != right.id || left.kind != right.kind
        || left.node.has_value() != right.node.has_value()
        || left.wire.has_value() != right.wire.has_value()
        || left.children.size() != right.children.size())
    {
        return false;
    }
    if (left.node.has_value() && !nodesEqual(*left.node, *right.node))
    {
        return false;
    }
    if (left.wire.has_value()
        && left.wire->columnSpan != right.wire->columnSpan)
    {
        return false;
    }
    for (std::size_t index = 0; index < left.children.size(); ++index)
    {
        if (!expressionsEqual(left.children[index], right.children[index]))
        {
            return false;
        }
    }
    return true;
}

bool LogicEditorService::nodesEqual(
    const LogicNode &left, const LogicNode &right)
{
    return left.id == right.id && left.config.index() == right.config.index()
        && 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, TimerContactNodeConfig>)
            {
                return left_config.address == right_config.address
                    && left_config.mode == right_config.mode;
            }
            else if constexpr (std::is_same_v<Left, CounterContactNodeConfig>)
            {
                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, TonNodeConfig>)
            {
                return left_config.address == right_config.address
                    && left_config.presetMs == right_config.presetMs;
            }
            else if constexpr (std::is_same_v<Left, CounterNodeConfig>)
            {
                return left_config.address == right_config.address
                    && left_config.mode == right_config.mode
                    && left_config.currentValueAddress == right_config.currentValueAddress
                    && left_config.preset.kind == right_config.preset.kind
                    && left_config.preset.address == right_config.preset.address
                    && left_config.preset.constant == right_config.preset.constant
                    && left_config.resetAddress == right_config.resetAddress;
            }
            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 logic = std::find_if(
        logics.cbegin(), logics.cend(),
        [&logic_id](const ControlLogic &candidate) { return candidate.id == logic_id; });
    return logic == logics.cend() ? nullptr : &*logic;
}

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 rung = std::find_if(
        logic->rungs.cbegin(), logic->rungs.cend(),
        [&rung_id](const LadderRung &candidate) { return candidate.id == rung_id; });
    return rung == logic->rungs.cend() ? nullptr : &*rung;
}

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)
    {
        if (rung.output.has_value() && rung.output->id == node_id)
        {
            return &*rung.output;
        }
        if (rung.condition.has_value())
        {
            if (const LogicNode *node = findConditionNode(*rung.condition, node_id))
            {
                return node;
            }
        }
    }
    return nullptr;
}

const ConditionExpression *LogicEditorService::findExpression(
    const std::string &logic_id,
    const std::string &rung_id,
    const std::string &expression_id) const
{
    const LadderRung *rung = findRung(logic_id, rung_id);
    return rung == nullptr || !rung->condition.has_value()
        ? nullptr : findConditionExpression(*rung->condition, expression_id);
}

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)
            || (rung.condition.has_value()
                && findConditionNode(*rung.condition, node_id) != nullptr))
        {
            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";
    logic.rungs.push_back({"rung-1", "网络 1", {}, std::nullopt, std::nullopt});
    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))
    {
        return failure(LogicEditorError::InvalidOperation, "控制逻辑名称不能为空");
    }
    const Project &current = project_service_.project();
    const bool duplicate = std::any_of(
        current.controlLogics.cbegin(), current.controlLogics.cend(),
        [&name](const ControlLogic &logic) { return logic.name == name; });
    if (duplicate)
    {
        return failure(LogicEditorError::DuplicateName, "控制逻辑名称必须唯一");
    }

    ControlLogic logic;
    logic.id = makeUniqueLogicId(current);
    logic.name = name;
    logic.rungs.push_back({"rung-1", "网络 1", {}, std::nullopt, std::nullopt});
    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))
    {
        return failure(LogicEditorError::InvalidOperation, "控制逻辑名称不能为空");
    }
    const Project &current = project_service_.project();
    const auto logic = std::find_if(
        current.controlLogics.cbegin(), current.controlLogics.cend(),
        [&logic_id](const ControlLogic &candidate) { return candidate.id == logic_id; });
    if (logic == current.controlLogics.cend())
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    const bool duplicate = std::any_of(
        current.controlLogics.cbegin(), current.controlLogics.cend(),
        [&logic_id, &name](const ControlLogic &candidate)
        {
            return candidate.id != logic_id && candidate.name == name;
        });
    if (duplicate)
    {
        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();
    auto editable = std::find_if(
        project.controlLogics.begin(), project.controlLogics.end(),
        [&logic_id](const ControlLogic &candidate) { return candidate.id == logic_id; });
    editable->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();
    const auto logic = std::find_if(
        current.controlLogics.cbegin(), current.controlLogics.cend(),
        [&logic_id](const ControlLogic &candidate) { return candidate.id == logic_id; });
    if (logic == current.controlLogics.cend())
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (current.controlLogics.size() <= 1)
    {
        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 &candidate) { return candidate.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 logic = std::find_if(
        current.controlLogics.cbegin(), current.controlLogics.cend(),
        [&logic_id](const ControlLogic &candidate) { return candidate.id == logic_id; });
    if (logic == current.controlLogics.cend())
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    const auto index = std::distance(current.controlLogics.cbegin(), logic);
    const std::ptrdiff_t target_index = index + offset;
    if (target_index < 0
        || target_index
            >= 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_index);
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, logic_id};
}

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

LogicEditorResult LogicEditorService::addRung(const std::string &logic_id)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    LadderRung rung;
    rung.id = makeUniqueRungId(*logic);
    rung.name = "网络 " + std::to_string(logic->rungs.size() + 1U);
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    auto target = std::find_if(
        project.controlLogics.begin(), project.controlLogics.end(),
        [&logic_id](const ControlLogic &candidate) { return candidate.id == logic_id; });
    target->rungs.push_back(std::move(rung));
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, target->rungs.back().id};
}

LogicEditorResult LogicEditorService::removeRung(
    const std::string &logic_id, const std::string &rung_id)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr)
    {
        return failure(LogicEditorError::LogicNotFound, "未找到控制逻辑");
    }
    if (findRung(logic_id, rung_id) == nullptr)
    {
        return failure(LogicEditorError::RungNotFound, "未找到梯形图网络");
    }
    if (logic->rungs.size() == 1U)
    {
        return failure(LogicEditorError::InvalidOperation, "控制逻辑至少需要保留一个网络");
    }
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    auto target = std::find_if(
        project.controlLogics.begin(), project.controlLogics.end(),
        [&logic_id](const ControlLogic &candidate) { return candidate.id == logic_id; });
    target->rungs.erase(
        std::remove_if(
            target->rungs.begin(), target->rungs.end(),
            [&rung_id](const LadderRung &rung) { return rung.id == rung_id; }),
        target->rungs.end());
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, rung_id};
}

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, "未找到梯形图网络");
    }
    if (rung->comment == comment)
    {
        return {true, LogicEditorError::None, {}, rung_id};
    }
    HistoryState before = captureState();
    LadderRung &editable = *findEditableRung(
        project_service_.editProject(), logic_id, rung_id);
    editable.comment = comment;
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, rung_id};
}

LogicEditorResult LogicEditorService::appendCondition(
    const std::string &logic_id,
    const std::string &rung_id,
    const LogicNodeConfig &config)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr || findRung(logic_id, rung_id) == nullptr)
    {
        return failure(
            logic == nullptr ? LogicEditorError::LogicNotFound : LogicEditorError::RungNotFound,
            logic == nullptr ? "未找到控制逻辑" : "未找到梯形图网络");
    }
    if (!isConditionConfig(config))
    {
        return failure(LogicEditorError::InvalidNode, "梯形图条件不能使用线圈节点");
    }
    const std::string node_id = makeUniqueNodeId(*logic, nodePrefix(config));
    ConditionExpression leaf = ConditionExpression::fromNode(makeNode(node_id, config));
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    LadderRung *rung = findEditableRung(project, logic_id, rung_id);
    if (!rung->condition.has_value())
    {
        rung->condition = std::move(leaf);
    }
    else if (rung->condition->kind == ConditionExpressionKind::Series)
    {
        rung->condition->children.push_back(std::move(leaf));
    }
    else
    {
        rung->condition = makeContainer(
            makeUniqueExpressionId(*logic),
            ConditionExpressionKind::Series,
            std::move(*rung->condition),
            std::move(leaf));
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, node_id};
}

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 || findRung(logic_id, rung_id) == nullptr)
    {
        return failure(
            logic == nullptr ? LogicEditorError::LogicNotFound
                             : LogicEditorError::RungNotFound,
            logic == nullptr ? "未找到控制逻辑" : "未找到梯形图网络");
    }
    WireSegment wire{column_span};
    std::string error;
    if (!wire.validate(&error))
    {
        return failure(LogicEditorError::InvalidOperation, error);
    }
    const std::string wire_id = makeUniqueWireId(*logic);
    ConditionExpression leaf = ConditionExpression::fromWire(wire_id, column_span);
    HistoryState before = captureState();
    LadderRung *rung = findEditableRung(
        project_service_.editProject(), logic_id, rung_id);
    if (!rung->condition.has_value())
    {
        rung->condition = std::move(leaf);
    }
    else if (rung->condition->kind == ConditionExpressionKind::Series)
    {
        rung->condition->children.push_back(std::move(leaf));
    }
    else
    {
        rung->condition = makeContainer(
            makeUniqueExpressionId(*logic),
            ConditionExpressionKind::Series,
            std::move(*rung->condition),
            std::move(leaf));
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, wire_id};
}

LogicEditorResult LogicEditorService::insertConditionAfter(
    const std::string &logic_id,
    const std::string &rung_id,
    const std::string &target_node_id,
    const LogicNodeConfig &config)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr || findRung(logic_id, rung_id) == nullptr)
    {
        return failure(LogicEditorError::RungNotFound, "未找到梯形图网络");
    }
    const LadderRung *existing_rung = findRung(logic_id, rung_id);
    if (!isConditionConfig(config)
        || existing_rung == nullptr
        || !existing_rung->condition.has_value()
        || findConditionNode(*existing_rung->condition, target_node_id) == nullptr)
    {
        return failure(LogicEditorError::NodeNotFound, "未找到串联插入目标");
    }
    const std::string node_id = makeUniqueNodeId(*logic, nodePrefix(config));
    ConditionExpression leaf = ConditionExpression::fromNode(makeNode(node_id, config));
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    LadderRung *rung = findEditableRung(project, logic_id, rung_id);
    ConditionExpression *target = findConditionExpression(*rung->condition, target_node_id);
    ConditionExpression *parent = findParentExpression(*rung->condition, target_node_id);
    if (parent != nullptr && parent->kind == ConditionExpressionKind::Series)
    {
        const auto target_iterator = std::find_if(
            parent->children.begin(), parent->children.end(),
            [&target_node_id](const ConditionExpression &child)
            {
                return child.id == target_node_id;
            });
        parent->children.insert(target_iterator + 1, std::move(leaf));
    }
    else
    {
        ConditionExpression original = std::move(*target);
        *target = makeContainer(
            makeUniqueExpressionId(*logic),
            ConditionExpressionKind::Series,
            std::move(original),
            std::move(leaf));
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, node_id};
}

LogicEditorResult LogicEditorService::insertWireAfter(
    const std::string &logic_id,
    const std::string &rung_id,
    const std::string &target_expression_id,
    int column_span)
{
    const ControlLogic *logic = findLogic(logic_id);
    const LadderRung *existing_rung = findRung(logic_id, rung_id);
    const ConditionExpression *target = findExpression(
        logic_id, rung_id, target_expression_id);
    WireSegment wire{column_span};
    std::string error;
    if (logic == nullptr || existing_rung == nullptr || target == nullptr)
    {
        return failure(LogicEditorError::ExpressionNotFound, "未找到横线插入位置");
    }
    if ((target->kind != ConditionExpressionKind::Node
         && target->kind != ConditionExpressionKind::Wire)
        || !wire.validate(&error))
    {
        return failure(
            LogicEditorError::InvalidOperation,
            error.empty() ? "只能在触点或横线后插入横线" : error);
    }
    const std::string wire_id = makeUniqueWireId(*logic);
    ConditionExpression leaf = ConditionExpression::fromWire(wire_id, column_span);
    HistoryState before = captureState();
    LadderRung *rung = findEditableRung(
        project_service_.editProject(), logic_id, rung_id);
    ConditionExpression *editable_target = findConditionExpression(
        *rung->condition, target_expression_id);
    ConditionExpression *parent = findParentExpression(
        *rung->condition, target_expression_id);
    if (parent != nullptr && parent->kind == ConditionExpressionKind::Series)
    {
        const auto target_iterator = std::find_if(
            parent->children.begin(), parent->children.end(),
            [&target_expression_id](const ConditionExpression &child)
            {
                return child.id == target_expression_id;
            });
        parent->children.insert(target_iterator + 1, std::move(leaf));
    }
    else
    {
        ConditionExpression original = std::move(*editable_target);
        *editable_target = makeContainer(
            makeUniqueExpressionId(*logic),
            ConditionExpressionKind::Series,
            std::move(original),
            std::move(leaf));
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, wire_id};
}

LogicEditorResult LogicEditorService::replaceWireWithCondition(
    const std::string &logic_id,
    const std::string &rung_id,
    const std::string &wire_expression_id,
    const LogicNodeConfig &config)
{
    const ControlLogic *logic = findLogic(logic_id);
    const ConditionExpression *wire = findExpression(
        logic_id, rung_id, wire_expression_id);
    if (logic == nullptr || wire == nullptr
        || wire->kind != ConditionExpressionKind::Wire)
    {
        return failure(LogicEditorError::ExpressionNotFound, "未找到要替换的横线");
    }
    if (!isConditionConfig(config))
    {
        return failure(LogicEditorError::InvalidNode, "横线只能替换为条件节点");
    }
    const std::string node_id = makeUniqueNodeId(*logic, nodePrefix(config));
    HistoryState before = captureState();
    LadderRung *rung = findEditableRung(
        project_service_.editProject(), logic_id, rung_id);
    ConditionExpression *editable = findConditionExpression(
        *rung->condition, wire_expression_id);
    *editable = ConditionExpression::fromNode(makeNode(node_id, config));
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, node_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)
{
    const ControlLogic *logic = findLogic(logic_id);
    if (logic == nullptr || findRung(logic_id, rung_id) == nullptr)
    {
        return failure(LogicEditorError::RungNotFound, "未找到梯形图网络");
    }
    if (!isConditionConfig(config) || selected_node_ids.empty())
    {
        return failure(LogicEditorError::InvalidOperation, "建立并联支路前必须选择节点");
    }
    const LadderRung *existing_rung = findRung(logic_id, rung_id);
    if (!existing_rung->condition.has_value())
    {
        return failure(LogicEditorError::InvalidOperation, "梯形图网络尚无条件节点");
    }
    NodeIdSet selected_ids(selected_node_ids.cbegin(), selected_node_ids.cend());
    if (selected_ids.size() != selected_node_ids.size())
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "并联选择中存在重复节点");
    }
    const NodeIdSet available_ids = conditionLeafIds(*existing_rung->condition);
    if (!isSubset(selected_ids, available_ids))
    {
        return failure(
            LogicEditorError::NodeNotFound,
            "并联选择中包含未知节点");
    }
    const std::string node_id = makeUniqueNodeId(*logic, nodePrefix(config));
    ConditionExpression leaf = ConditionExpression::fromNode(makeNode(node_id, config));
    const std::string parallel_id = makeUniqueExpressionId(*logic);
    std::string series_id = parallel_id + "-range";
    while (findExpression(logic_id, rung_id, series_id) != nullptr)
    {
        series_id += "-range";
    }
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    LadderRung *rung = findEditableRung(project, logic_id, rung_id);
    if (!addParallelForSelection(
            &*rung->condition,
            selected_ids,
            &leaf,
            parallel_id,
            series_id))
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "并联选择必须是一个连续的逻辑范围");
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, node_id};
}

LogicEditorResult LogicEditorService::addParallelWireBranch(
    const std::string &logic_id,
    const std::string &rung_id,
    const std::vector<std::string> &selected_expression_ids)
{
    const ControlLogic *logic = findLogic(logic_id);
    const LadderRung *existing_rung = findRung(logic_id, rung_id);
    if (logic == nullptr || existing_rung == nullptr
        || !existing_rung->condition.has_value())
    {
        return failure(LogicEditorError::RungNotFound, "未找到梯形图条件网络");
    }
    if (selected_expression_ids.empty())
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "建立竖线连接前必须选择连续的触点或横线");
    }
    NodeIdSet selected_ids(
        selected_expression_ids.cbegin(), selected_expression_ids.cend());
    if (selected_ids.size() != selected_expression_ids.size())
    {
        return failure(LogicEditorError::InvalidOperation, "并联选择中存在重复对象");
    }
    const NodeIdSet available_ids = conditionLeafIds(*existing_rung->condition);
    if (!isSubset(selected_ids, available_ids))
    {
        return failure(LogicEditorError::ExpressionNotFound, "并联选择中包含未知对象");
    }
    const std::optional<int> column_span = selectedExpressionColumns(
        *existing_rung->condition, selected_ids);
    if (!column_span.has_value()
        || *column_span > WireSegment::kMaximumColumnSpan)
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "竖线连接只能围绕同一支路中的连续逻辑范围");
    }

    const std::string wire_id = makeUniqueWireId(*logic);
    ConditionExpression wire = ConditionExpression::fromWire(
        wire_id, *column_span);
    const std::string parallel_id = makeUniqueExpressionId(*logic);
    std::string series_id = parallel_id + "-range";
    while (findExpression(logic_id, rung_id, series_id) != nullptr)
    {
        series_id += "-range";
    }
    HistoryState before = captureState();
    LadderRung *rung = findEditableRung(
        project_service_.editProject(), logic_id, rung_id);
    if (!addParallelForSelection(
            &*rung->condition,
            selected_ids,
            &wire,
            parallel_id,
            series_id))
    {
        return failure(
            LogicEditorError::InvalidOperation,
            "竖线连接只能围绕同一支路中的连续逻辑范围");
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, wire_id};
}

LogicEditorResult LogicEditorService::setOutput(
    const std::string &logic_id,
    const std::string &rung_id,
    const LogicNodeConfig &config,
    bool configured)
{
    const ControlLogic *logic = findLogic(logic_id);
    const LadderRung *existing_rung = findRung(logic_id, rung_id);
    if (logic == nullptr || existing_rung == nullptr || !isOutputConfig(config))
    {
        return failure(
            LogicEditorError::InvalidNode,
            "梯形图输出必须使用有效的输出指令");
    }
    const std::string node_id = existing_rung->output.has_value()
        ? existing_rung->output->id : makeUniqueNodeId(*logic, nodePrefix(config));
    LogicNode node = makeNode(node_id, config);
    node.configured = configured;
    if (existing_rung->output.has_value()
        && nodesEqual(*existing_rung->output, node))
    {
        return {true, LogicEditorError::None, {}, node_id};
    }
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    findEditableRung(project, logic_id, rung_id)->output = std::move(node);
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, node_id};
}

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->config.index() != config.index())
    {
        return failure(
            LogicEditorError::UnsupportedNodeChange,
            "节点创建后不能修改节点类别");
    }
    LogicNode candidate{node_id, config, true};
    std::string error;
    if (!candidate.validate(&error))
    {
        return failure(LogicEditorError::InvalidNode, error);
    }
    if (nodesEqual(*node, candidate))
    {
        return {true, LogicEditorError::None, {}, node_id};
    }
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    for (ControlLogic &logic : project.controlLogics)
    {
        if (logic.id != logic_id)
        {
            continue;
        }
        for (LadderRung &rung : logic.rungs)
        {
            if (rung.output.has_value() && rung.output->id == node_id)
            {
                *rung.output = candidate;
                recordHistory(std::move(before));
                return {true, LogicEditorError::None, {}, node_id};
            }
            if (rung.condition.has_value())
            {
                if (LogicNode *editable = findConditionNode(*rung.condition, node_id))
                {
                    *editable = candidate;
                    recordHistory(std::move(before));
                    return {true, LogicEditorError::None, {}, node_id};
                }
            }
        }
    }
    return failure(LogicEditorError::NodeNotFound, "未找到逻辑节点");
}

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, "请先选择要删除的逻辑节点");
    }
    std::unordered_set<std::string> selected_ids;
    for (const std::string &node_id : node_ids)
    {
        if (!selected_ids.insert(node_id).second)
        {
            return failure(LogicEditorError::InvalidOperation, "删除列表中存在重复节点");
        }
        if (findNode(logic_id, node_id) == nullptr)
        {
            return failure(LogicEditorError::NodeNotFound, "未找到逻辑节点");
        }
    }

    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    ControlLogic *editable_logic = nullptr;
    for (ControlLogic &candidate : project.controlLogics)
    {
        if (candidate.id == logic_id)
        {
            editable_logic = &candidate;
            break;
        }
    }
    for (LadderRung &rung : editable_logic->rungs)
    {
        if (rung.output.has_value()
            && selected_ids.find(rung.output->id) != selected_ids.end())
        {
            rung.output.reset();
        }
        if (rung.condition.has_value())
        {
            for (const std::string &node_id : node_ids)
            {
                if (rung.condition->kind == ConditionExpressionKind::Node
                    && rung.condition->id == node_id)
                {
                    rung.condition.reset();
                    break;
                }
                removeExpressionRecursive(&*rung.condition, node_id);
            }
            if (rung.condition.has_value())
            {
                normalizeConditionExpression(&rung.condition);
            }
        }
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, node_ids.front()};
}

LogicEditorResult LogicEditorService::removeExpression(
    const std::string &logic_id,
    const std::string &rung_id,
    const std::string &expression_id)
{
    if (findExpression(logic_id, rung_id, expression_id) == nullptr)
    {
        return failure(LogicEditorError::ExpressionNotFound, "未找到条件支路");
    }
    HistoryState before = captureState();
    Project &project = project_service_.editProject();
    LadderRung *rung = findEditableRung(project, logic_id, rung_id);
    if (rung->condition->id == expression_id)
    {
        rung->condition.reset();
    }
    else
    {
        removeExpressionRecursive(&*rung->condition, expression_id);
        normalizeConditionExpression(&rung->condition);
    }
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, expression_id};
}

LogicEditorResult LogicEditorService::removeExpressions(
    const std::string &logic_id,
    const std::string &rung_id,
    const std::vector<std::string> &expression_ids)
{
    const LadderRung *existing_rung = findRung(logic_id, rung_id);
    if (existing_rung == nullptr || !existing_rung->condition.has_value())
    {
        return failure(LogicEditorError::RungNotFound, "未找到梯形图条件网络");
    }
    if (expression_ids.empty())
    {
        return failure(LogicEditorError::InvalidOperation, "请先选择要删除的条件或横线");
    }
    NodeIdSet unique_ids;
    for (const std::string &expression_id : expression_ids)
    {
        const ConditionExpression *expression = findExpression(
            logic_id, rung_id, expression_id);
        if (!unique_ids.insert(expression_id).second)
        {
            return failure(LogicEditorError::InvalidOperation, "删除列表中存在重复对象");
        }
        if (expression == nullptr)
        {
            return failure(
                LogicEditorError::ExpressionNotFound,
                "删除列表中包含未知条件表达式");
        }
    }

    HistoryState before = captureState();
    LadderRung *rung = findEditableRung(
        project_service_.editProject(), logic_id, rung_id);
    for (const std::string &expression_id : expression_ids)
    {
        if (!rung->condition.has_value())
        {
            break;
        }
        if (rung->condition->id == expression_id)
        {
            rung->condition.reset();
            break;
        }
        removeExpressionRecursive(&*rung->condition, expression_id);
    }
    normalizeConditionExpression(&rung->condition);
    recordHistory(std::move(before));
    return {true, LogicEditorError::None, {}, expression_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();
}

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

bool LogicEditorService::isOutputConfig(const LogicNodeConfig &config)
{
    return std::holds_alternative<CoilNodeConfig>(config)
        || std::holds_alternative<TonNodeConfig>(config)
        || std::holds_alternative<CounterNodeConfig>(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, TimerContactNodeConfig>)
            {
                return "timer-contact";
            }
            else if constexpr (std::is_same_v<Config, CounterContactNodeConfig>)
            {
                return "counter-contact";
            }
            else if constexpr (std::is_same_v<Config, CoilNodeConfig>)
            {
                return "coil";
            }
            else if constexpr (std::is_same_v<Config, TonNodeConfig>)
            {
                return "ton";
            }
            else if constexpr (std::is_same_v<Config, CounterNodeConfig>)
            {
                return "counter";
            }
            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::makeUniqueNodeId(
    const ControlLogic &logic, const std::string &prefix)
{
    for (std::size_t index = 1;; ++index)
    {
        const std::string candidate = prefix + '-' + std::to_string(index);
        bool found = false;
        for (const LadderRung &rung : logic.rungs)
        {
            found = found || (rung.output.has_value() && rung.output->id == candidate)
                || (rung.condition.has_value()
                    && findConditionNode(*rung.condition, candidate) != nullptr);
        }
        if (!found)
        {
            return candidate;
        }
    }
}

std::string LogicEditorService::makeUniqueWireId(const ControlLogic &logic)
{
    for (std::size_t index = 1;; ++index)
    {
        const std::string candidate = "wire-" + std::to_string(index);
        const bool found = std::any_of(
            logic.rungs.cbegin(), logic.rungs.cend(),
            [&candidate](const LadderRung &rung)
            {
                return rung.condition.has_value()
                    && findConditionExpression(*rung.condition, candidate) != nullptr;
            });
        if (!found)
        {
            return candidate;
        }
    }
}

std::string LogicEditorService::makeUniqueExpressionId(const ControlLogic &logic)
{
    for (std::size_t index = 1;; ++index)
    {
        const std::string candidate = "expression-" + std::to_string(index);
        bool found = false;
        for (const LadderRung &rung : logic.rungs)
        {
            found = found || (rung.condition.has_value()
                && findConditionExpression(*rung.condition, candidate) != nullptr);
        }
        if (!found)
        {
            return candidate;
        }
    }
}

std::string LogicEditorService::makeUniqueRungId(const ControlLogic &logic)
{
    for (std::size_t index = 1;; ++index)
    {
        const std::string candidate = "rung-" + std::to_string(index);
        if (std::none_of(
                logic.rungs.cbegin(), logic.rungs.cend(),
                [&candidate](const LadderRung &rung) { return rung.id == candidate; }))
        {
            return candidate;
        }
    }
}

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