#include "logic_command_service.h"

#include "logic_editor_service.h"

#include <algorithm>
#include <cctype>
#include <limits>
#include <sstream>
#include <unordered_map>

namespace {

std::vector<std::string> splitTokens(const std::string &text)
{
    std::istringstream stream(text);
    std::vector<std::string> tokens;
    std::string token;
    while (stream >> token)
    {
        tokens.push_back(std::move(token));
    }
    return tokens;
}

std::string upperAscii(std::string value)
{
    std::transform(
        value.begin(), value.end(), value.begin(),
        [](unsigned char character)
        {
            return static_cast<char>(std::toupper(character));
        });
    return value;
}

LogicCommandParseResult parseFailure(const std::string &message)
{
    return {false, message, {}};
}

bool requiresOperands(
    const std::vector<std::string> &tokens,
    std::size_t count,
    const std::string &example,
    LogicCommandParseResult *failure)
{
    if (tokens.size() == count + 1U)
    {
        return true;
    }
    *failure = parseFailure(
        tokens.front() + " 需要 " + std::to_string(count)
        + " 个操作数，例如 " + example);
    return false;
}

bool parseAddress(
    const std::string &text,
    RegisterArea expected_area,
    const std::string &instruction,
    RegisterAddress *address,
    LogicCommandParseResult *failure)
{
    const RegisterAddressParseResult parsed = parseRegisterAddress(text);
    const char expected_prefix = expected_area == RegisterArea::M ? 'M' : 'D';
    if (!parsed.succeeded)
    {
        const std::string range = std::string(1, expected_prefix) + "0~"
            + expected_prefix + std::to_string(RegisterAddress::kMaximumIndex);
        *failure = parseFailure(
            parsed.error == RegisterAddressParseError::OutOfRange
                ? std::string(1, expected_prefix) + " 地址超出范围，应为 " + range
                : "地址格式错误，应为 " + range);
        return false;
    }
    if (parsed.address.area() != expected_area)
    {
        *failure = parseFailure(
            instruction + " 只支持 " + std::string(1, expected_prefix) + " 地址");
        return false;
    }
    *address = parsed.address;
    return true;
}

bool parseInt16(
    const std::string &text,
    const std::string &instruction,
    std::int16_t *value,
    LogicCommandParseResult *failure);

bool parseWordOperand(
    const std::string &text,
    const std::string &instruction,
    WordOperand *operand,
    LogicCommandParseResult *failure)
{
    const RegisterAddressParseResult parsed = parseRegisterAddress(text);
    if (parsed.succeeded)
    {
        if (parsed.address.area() != RegisterArea::D)
        {
            *failure = parseFailure(instruction + " 的寄存器操作数必须使用 D 地址");
            return false;
        }
        *operand = WordOperand{
            WordOperandKind::Register, parsed.address, 0};
        return true;
    }
    if (!text.empty()
        && (text.front() == 'D' || text.front() == 'd'
            || text.front() == 'M' || text.front() == 'm'))
    {
        RegisterAddress address{RegisterArea::D, 0};
        return parseAddress(
            text, RegisterArea::D, instruction, &address, failure)
            && ((*operand = WordOperand{
                     WordOperandKind::Register, address, 0}), true);
    }
    std::int16_t constant = 0;
    if (!parseInt16(text, instruction, &constant, failure))
    {
        return false;
    }
    *operand = WordOperand{
        WordOperandKind::Constant,
        RegisterAddress{RegisterArea::D, 0},
        constant};
    return true;
}

bool isLoad(LogicCommandOpcode opcode)
{
    return opcode == LogicCommandOpcode::Load
        || opcode == LogicCommandOpcode::LoadInverse
        || opcode == LogicCommandOpcode::LoadRising
        || opcode == LogicCommandOpcode::LoadFalling
        || opcode == LogicCommandOpcode::CompareEqual
        || opcode == LogicCommandOpcode::CompareNotEqual
        || opcode == LogicCommandOpcode::CompareLessThan
        || opcode == LogicCommandOpcode::CompareLessThanOrEqual
        || opcode == LogicCommandOpcode::CompareGreaterThan
        || opcode == LogicCommandOpcode::CompareGreaterThanOrEqual;
}

bool isOr(LogicCommandOpcode opcode)
{
    return opcode == LogicCommandOpcode::Or
        || opcode == LogicCommandOpcode::OrInverse;
}

bool isCondition(LogicCommandOpcode opcode)
{
    return isLoad(opcode) || isOr(opcode)
        || opcode == LogicCommandOpcode::And
        || opcode == LogicCommandOpcode::AndInverse;
}

bool isConditionTarget(LogicCommandTargetKind kind)
{
    return kind != LogicCommandTargetKind::Output;
}

bool isOutput(LogicCommandOpcode opcode)
{
    return opcode == LogicCommandOpcode::Output
        || opcode == LogicCommandOpcode::Set
        || opcode == LogicCommandOpcode::Reset
        || opcode == LogicCommandOpcode::Move
        || opcode == LogicCommandOpcode::Add
        || opcode == LogicCommandOpcode::Subtract;
}

bool parseInt16(
    const std::string &text,
    const std::string &instruction,
    std::int16_t *value,
    LogicCommandParseResult *failure)
{
    try
    {
        std::size_t consumed = 0;
        const long parsed = std::stol(text, &consumed, 10);
        if (consumed != text.size()
            || parsed < std::numeric_limits<std::int16_t>::min()
            || parsed > std::numeric_limits<std::int16_t>::max())
        {
            throw std::out_of_range("int16");
        }
        *value = static_cast<std::int16_t>(parsed);
        return true;
    }
    catch (const std::exception &)
    {
        *failure = parseFailure(
            instruction + " 的第二个操作数应为 -32768~32767 的常量");
        return false;
    }
}

LogicCommandResult executionFailure(
    const std::string &message, LogicCommandOpcode opcode)
{
    return {false, message, {}, {}, opcode};
}

} // namespace

LogicCommandService::LogicCommandService(LogicEditorService &editor_service)
    : editor_service_(editor_service)
{
}

LogicCommandParseResult LogicCommandService::parse(const std::string &text)
{
    std::vector<std::string> tokens = splitTokens(text);
    if (tokens.empty())
    {
        return parseFailure("请输入 PLC 指令");
    }
    tokens.front() = upperAscii(tokens.front());
    const std::string &mnemonic = tokens.front();
    LogicCommandParseResult failure;

    const std::unordered_map<std::string, LogicCommandOpcode> condition_opcodes{
        {"LD", LogicCommandOpcode::Load},
        {"LDI", LogicCommandOpcode::LoadInverse},
        {"LDP", LogicCommandOpcode::LoadRising},
        {"LDF", LogicCommandOpcode::LoadFalling},
        {"AND", LogicCommandOpcode::And},
        {"ANI", LogicCommandOpcode::AndInverse},
        {"OR", LogicCommandOpcode::Or},
        {"ORI", LogicCommandOpcode::OrInverse}};
    const std::unordered_map<std::string, LogicCommandOpcode> compare_opcodes{
        {"LD=", LogicCommandOpcode::CompareEqual},
        {"LD<>", LogicCommandOpcode::CompareNotEqual},
        {"LD<", LogicCommandOpcode::CompareLessThan},
        {"LD<=", LogicCommandOpcode::CompareLessThanOrEqual},
        {"LD>", LogicCommandOpcode::CompareGreaterThan},
        {"LD>=", LogicCommandOpcode::CompareGreaterThanOrEqual}};
    const auto compare = compare_opcodes.find(mnemonic);
    if (compare != compare_opcodes.end())
    {
        if (!requiresOperands(tokens, 2U, mnemonic + " D0 0", &failure))
        {
            return failure;
        }
        RegisterAddress address{RegisterArea::D, 0};
        if (!parseAddress(tokens[1], RegisterArea::D, mnemonic, &address, &failure))
        {
            return failure;
        }
        std::int16_t value = 0;
        if (!parseInt16(tokens[2], mnemonic, &value, &failure))
        {
            return failure;
        }
        ComparisonOperator operation = ComparisonOperator::Equal;
        switch (compare->second)
        {
        case LogicCommandOpcode::CompareEqual:
            operation = ComparisonOperator::Equal;
            break;
        case LogicCommandOpcode::CompareNotEqual:
            operation = ComparisonOperator::NotEqual;
            break;
        case LogicCommandOpcode::CompareLessThan:
            operation = ComparisonOperator::LessThan;
            break;
        case LogicCommandOpcode::CompareLessThanOrEqual:
            operation = ComparisonOperator::LessThanOrEqual;
            break;
        case LogicCommandOpcode::CompareGreaterThan:
            operation = ComparisonOperator::GreaterThan;
            break;
        case LogicCommandOpcode::CompareGreaterThanOrEqual:
            operation = ComparisonOperator::GreaterThanOrEqual;
            break;
        default:
            break;
        }
        return {true, {}, {compare->second,
                           CompareNodeConfig{address, operation, value}}};
    }
    const auto condition = condition_opcodes.find(mnemonic);
    if (condition != condition_opcodes.end())
    {
        if (!requiresOperands(tokens, 1U, mnemonic + " M0", &failure))
        {
            return failure;
        }
        RegisterAddress address{RegisterArea::M, 0};
        if (!parseAddress(tokens[1], RegisterArea::M, mnemonic, &address, &failure))
        {
            return failure;
        }
        LogicNodeConfig config;
        if (condition->second == LogicCommandOpcode::LoadRising
            || condition->second == LogicCommandOpcode::LoadFalling)
        {
            config = EdgeContactNodeConfig{
                address,
                condition->second == LogicCommandOpcode::LoadRising
                    ? EdgeMode::Rising : EdgeMode::Falling};
        }
        else
        {
            const bool inverse = condition->second == LogicCommandOpcode::LoadInverse
                || condition->second == LogicCommandOpcode::AndInverse
                || condition->second == LogicCommandOpcode::OrInverse;
            config = ContactNodeConfig{
                address,
                inverse ? ContactMode::NormallyClosed
                        : ContactMode::NormallyOpen};
        }
        return {true, {}, {condition->second, std::move(config)}};
    }

    const std::unordered_map<std::string, LogicCommandOpcode> coil_opcodes{
        {"OUT", LogicCommandOpcode::Output},
        {"SET", LogicCommandOpcode::Set},
        {"RST", LogicCommandOpcode::Reset}};
    const auto coil = coil_opcodes.find(mnemonic);
    if (coil != coil_opcodes.end())
    {
        if (!requiresOperands(tokens, 1U, mnemonic + " M0", &failure))
        {
            return failure;
        }
        RegisterAddress address{RegisterArea::M, 0};
        if (!parseAddress(tokens[1], RegisterArea::M, mnemonic, &address, &failure))
        {
            return failure;
        }
        const CoilMode mode = coil->second == LogicCommandOpcode::Set
            ? CoilMode::Set
            : coil->second == LogicCommandOpcode::Reset
                ? CoilMode::Reset : CoilMode::Normal;
        return {true, {}, {coil->second, CoilNodeConfig{address, mode}}};
    }

    if (mnemonic == "MOV")
    {
        if (!requiresOperands(tokens, 2U, "MOV D0 D1", &failure))
        {
            return failure;
        }
        RegisterAddress destination{RegisterArea::D, 0};
        WordOperand source;
        if (!parseWordOperand(tokens[1], mnemonic, &source, &failure)
            || !parseAddress(tokens[2], RegisterArea::D, mnemonic, &destination, &failure))
        {
            return failure;
        }
        return {
            true, {},
            {LogicCommandOpcode::Move,
             MoveNodeConfig{source, destination}}};
    }

    if (mnemonic == "ADD" || mnemonic == "SUB")
    {
        if (!requiresOperands(tokens, 3U, mnemonic + " D0 D1 D2", &failure))
        {
            return failure;
        }
        WordOperand left;
        WordOperand right;
        RegisterAddress destination{RegisterArea::D, 0};
        if (!parseWordOperand(tokens[1], mnemonic, &left, &failure)
            || !parseWordOperand(tokens[2], mnemonic, &right, &failure)
            || !parseAddress(tokens[3], RegisterArea::D, mnemonic, &destination, &failure))
        {
            return failure;
        }
        const LogicCommandOpcode opcode = mnemonic == "ADD"
            ? LogicCommandOpcode::Add : LogicCommandOpcode::Subtract;
        return {
            true, {},
            {opcode,
             ArithmeticNodeConfig{
                 opcode == LogicCommandOpcode::Add
                     ? ArithmeticOperation::Add : ArithmeticOperation::Subtract,
                 left,
                 right,
                 destination}}};
    }

    return parseFailure("当前指令暂不支持：" + mnemonic);
}

const std::vector<LogicCommandSuggestion> &LogicCommandService::suggestions()
{
    static const std::vector<LogicCommandSuggestion> values{
        {"LD", "常开触点", "M 地址"},
        {"LDI", "常闭触点", "M 地址"},
        {"LDP", "上升沿触点", "M 地址"},
        {"LDF", "下降沿触点", "M 地址"},
        {"LD=", "D 值等于常量", "D 地址 + 常量"},
        {"LD<>", "D 值不等于常量", "D 地址 + 常量"},
        {"LD<", "D 值小于常量", "D 地址 + 常量"},
        {"LD<=", "D 值小于等于常量", "D 地址 + 常量"},
        {"LD>", "D 值大于常量", "D 地址 + 常量"},
        {"LD>=", "D 值大于等于常量", "D 地址 + 常量"},
        {"AND", "串联常开触点", "M 地址"},
        {"ANI", "串联常闭触点", "M 地址"},
        {"OR", "并联常开触点", "M 地址"},
        {"ORI", "并联常闭触点", "M 地址"},
        {"OUT", "普通线圈", "M 地址"},
        {"SET", "置位线圈", "M 地址"},
        {"RST", "复位线圈", "M 地址"},
        {"MOV", "数据传送", "D 地址 -> D 地址"},
        {"ADD", "加法", "D 地址 + D 地址 -> D 地址"},
        {"SUB", "减法", "D 地址 - D 地址 -> D 地址"},
        {"TON", "暂不支持", "T 地址", false},
        {"CTU", "暂不支持", "C 地址", false}};
    return values;
}

LogicCommandResult LogicCommandService::execute(
    const LogicCommandRequest &request)
{
    const LogicCommandParseResult parsed = parse(request.text);
    if (!parsed.succeeded)
    {
        return executionFailure(parsed.message, parsed.command.opcode);
    }
    const LogicCommandOpcode opcode = parsed.command.opcode;
    LogicEditorResult edited;

    if (request.target.kind == LogicCommandTargetKind::ExistingNode)
    {
        const LogicNode *existing = editor_service_.findNode(
            request.logicId, request.target.expressionId);
        if (existing == nullptr)
        {
            return executionFailure("未找到要编辑的逻辑节点", opcode);
        }
        if (existing->isCondition())
        {
            if (!isLoad(opcode))
            {
                return executionFailure(
                    "已有条件节点只能替换为 LD/LDI/LDP/LDF 指令", opcode);
            }
        }
        else if (existing->isOutput())
        {
            if (!isOutput(opcode))
            {
                return executionFailure(
                    "已有输出节点只能替换为 OUT/SET/RST/MOV/ADD/SUB 指令",
                    opcode);
            }
        }
        else
        {
            return executionFailure("当前节点类型不支持命令替换", opcode);
        }
        edited = editor_service_.updateNodeConfig(
            request.logicId, request.target.expressionId,
            parsed.command.config);
    }
    else if (isCondition(opcode))
    {
        if (isLoad(opcode) && request.continuing)
        {
            edited = editor_service_.appendCondition(
                request.logicId, {}, parsed.command.config, true);
        }
        else if (isOr(opcode))
        {
            const std::string rung_id = request.continuing
                ? request.currentRungId : request.target.rungId;
            if (request.continuing)
            {
                edited = editor_service_.addParallelToWholeCondition(
                    request.logicId, rung_id, parsed.command.config, true);
            }
            else if (request.parallelNodeIds.empty())
            {
                return executionFailure(
                    "OR/ORI 需要先选中同一网络中的连续条件", opcode);
            }
            else
            {
                edited = editor_service_.addParallelBranch(
                    request.logicId,
                    rung_id,
                    request.parallelNodeIds,
                    parsed.command.config,
                    true);
            }
        }
        else if (request.continuing)
        {
            const LadderRung *rung = editor_service_.findRung(
                request.logicId, request.currentRungId);
            if (rung != nullptr && rung->output.has_value())
            {
                return executionFailure(
                    "当前网络已有输出，下一条只能输入 LD/LDI/LDP/LDF 新建网络",
                    opcode);
            }
            edited = editor_service_.appendCondition(
                request.logicId, request.currentRungId,
                parsed.command.config, true);
        }
        else
        {
            if (!isConditionTarget(request.target.kind))
            {
                return executionFailure(
                    "条件指令只能输入在第 1~10 列条件区", opcode);
            }
            if ((opcode == LogicCommandOpcode::And
                    || opcode == LogicCommandOpcode::AndInverse)
                && (!request.target.rungId.empty()
                    && (editor_service_.findRung(
                            request.logicId, request.target.rungId) == nullptr
                        || !editor_service_.findRung(
                            request.logicId, request.target.rungId)
                               ->condition.has_value())))
            {
                return executionFailure(
                    "AND/ANI 前必须先输入 LD/LDI/LDP/LDF", opcode);
            }
            switch (request.target.kind)
            {
            case LogicCommandTargetKind::EmptyColumn:
                edited = editor_service_.insertConditionAtColumn(
                    request.logicId, request.target.rungId,
                    request.target.column, parsed.command.config, true);
                break;
            case LogicCommandTargetKind::BranchEmptyColumn:
                edited = editor_service_.insertConditionInBranchAtColumn(
                    request.logicId, request.target.rungId,
                    request.target.expressionId, request.target.column,
                    parsed.command.config, true);
                break;
            case LogicCommandTargetKind::WireColumn:
                edited = editor_service_.replaceWireColumnWithCondition(
                    request.logicId, request.target.rungId,
                    request.target.expressionId, request.target.column,
                    parsed.command.config, true);
                break;
            case LogicCommandTargetKind::GapColumn:
                edited = editor_service_.replaceGapColumnWithCondition(
                    request.logicId, request.target.rungId,
                    request.target.expressionId, request.target.column,
                    parsed.command.config, true);
                break;
            case LogicCommandTargetKind::Output:
                break;
            case LogicCommandTargetKind::ExistingNode:
                break;
            }
        }
    }
    else
    {
        const std::string rung_id = request.continuing
            ? request.currentRungId : request.target.rungId;
        if (!request.continuing
            && request.target.kind != LogicCommandTargetKind::Output)
        {
            return executionFailure(
                "输出指令只能输入在第 11 列输出区", opcode);
        }
        const LadderRung *rung = editor_service_.findRung(
            request.logicId, rung_id);
        if (request.continuing && rung != nullptr && rung->output.has_value())
        {
            return executionFailure(
                "当前网络已经有输出，下一条请输入 LD/LDI/LDP/LDF 新建网络",
                opcode);
        }
        edited = editor_service_.setOutput(
            request.logicId, rung_id, parsed.command.config, true);
    }

    if (!edited.succeeded)
    {
        return executionFailure(edited.message, opcode);
    }
    return {
        true, {}, edited.id,
        editor_service_.rungIdForNode(request.logicId, edited.id),
        opcode};
}