#include "json_project_storage.h"

#include <QFile>
#include <QJsonArray>
#include <QJsonDocument>
#include <QJsonObject>
#include <QJsonParseError>
#include <QSaveFile>

#include <cmath>
#include <limits>
#include <string>
#include <utility>

namespace {

// 当前读写实现支持的工程文件格式版本
constexpr const char *kCurrentFormatVersion = "1.0";

// 保存解析过程中遇到的第一个错误，避免后续失败覆盖根因
struct ParseState
{
    ProjectStorageError error = ProjectStorageError::None;
    std::string message;

    // 记录首次解析错误并返回 false，便于解析函数直接向上传播失败
    bool fail(ProjectStorageError new_error, const std::string &new_message)
    {
        if (error == ProjectStorageError::None)
        {
            error = new_error;
            message = new_message;
        }
        return false;
    }
};

// 将领域层使用的 UTF-8 字符串转换为 Qt 字符串
QString fromUtf8(const std::string &value)
{
    return QString::fromUtf8(value.data(), static_cast<int>(value.size()));
}

// 将 Qt 字符串转换为领域层使用的 UTF-8 字符串
std::string toUtf8(const QString &value)
{
    const QByteArray bytes = value.toUtf8();
    return std::string(bytes.constData(), static_cast<std::size_t>(bytes.size()));
}

// 拼接带上下文的字段路径，用于生成可定位的错误信息
std::string fieldPath(const std::string &context, const char *field)
{
    return context + '.' + field;
}

// 读取必填 JSON 字段，字段不存在时记录 MissingField 错误
bool readValue(
    const QJsonObject &object,
    const char *field,
    const std::string &context,
    QJsonValue *value,
    ParseState *state)
{
    const QString key = QString::fromLatin1(field);
    if (!object.contains(key))
    {
        return state->fail(
            ProjectStorageError::MissingField,
            "missing required field " + fieldPath(context, field));
    }
    *value = object.value(key);
    return true;
}

// 读取必填字符串字段并转换为 UTF-8 标准字符串
bool readString(
    const QJsonObject &object,
    const char *field,
    const std::string &context,
    std::string *value,
    ParseState *state)
{
    QJsonValue json_value;
    if (!readValue(object, field, context, &json_value, state))
    {
        return false;
    }
    if (!json_value.isString())
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            fieldPath(context, field) + " must be a string");
    }
    *value = toUtf8(json_value.toString());
    return true;
}

// 读取必填布尔字段并校验 JSON 类型
bool readBool(
    const QJsonObject &object,
    const char *field,
    const std::string &context,
    bool *value,
    ParseState *state)
{
    QJsonValue json_value;
    if (!readValue(object, field, context, &json_value, state))
    {
        return false;
    }
    if (!json_value.isBool())
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            fieldPath(context, field) + " must be a boolean");
    }
    *value = json_value.toBool();
    return true;
}

// 读取指定闭区间内的整数，拒绝小数、非有限值和越界值
bool readInt(
    const QJsonObject &object,
    const char *field,
    const std::string &context,
    int minimum,
    int maximum,
    int *value,
    ParseState *state)
{
    QJsonValue json_value;
    if (!readValue(object, field, context, &json_value, state))
    {
        return false;
    }
    if (!json_value.isDouble())
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            fieldPath(context, field) + " must be an integer");
    }

    // Qt JSON 统一用 double 表示数值，需要额外确认它能无损转换为 int
    const double number = json_value.toDouble();
    if (!std::isfinite(number) || std::floor(number) != number
        || number < minimum || number > maximum)
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            fieldPath(context, field) + " is outside the supported integer range");
    }
    *value = static_cast<int>(number);
    return true;
}

// 读取必填对象字段并校验 JSON 类型
bool readObject(
    const QJsonObject &object,
    const char *field,
    const std::string &context,
    QJsonObject *value,
    ParseState *state)
{
    QJsonValue json_value;
    if (!readValue(object, field, context, &json_value, state))
    {
        return false;
    }
    if (!json_value.isObject())
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            fieldPath(context, field) + " must be an object");
    }
    *value = json_value.toObject();
    return true;
}

// 读取必填数组字段并校验 JSON 类型
bool readArray(
    const QJsonObject &object,
    const char *field,
    const std::string &context,
    QJsonArray *value,
    ParseState *state)
{
    QJsonValue json_value;
    if (!readValue(object, field, context, &json_value, state))
    {
        return false;
    }
    if (!json_value.isArray())
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            fieldPath(context, field) + " must be an array");
    }
    *value = json_value.toArray();
    return true;
}

// 将寄存器地址序列化为包含区域和原始索引的 JSON 对象
QJsonObject serializeAddress(const RegisterAddress &address)
{
    QJsonObject object;
    object.insert(QStringLiteral("area"),
                  address.area() == RegisterArea::M ? QStringLiteral("M")
                                                           : QStringLiteral("D"));
    object.insert(QStringLiteral("index"), address.index());
    return object;
}

// 解析寄存器地址并校验区域名称及项目允许的索引范围
bool parseAddress(
    const QJsonObject &object,
    const std::string &context,
    RegisterAddress *address,
    ParseState *state)
{
    std::string area_text;
    int index = 0;
    if (!readString(object, "area", context, &area_text, state)
        || !readInt(
            object,
            "index",
            context,
            RegisterAddress::kMinimumIndex,
            RegisterAddress::kMaximumIndex,
            &index,
            state))
    {
        return false;
    }

    RegisterArea area = RegisterArea::M;
    if (area_text == "M")
    {
        area = RegisterArea::M;
    }
    else if (area_text == "D")
    {
        area = RegisterArea::D;
    }
    else
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            context + ".area must be M or D");
    }

    *address = RegisterAddress{area, index};
    return true;
}

// 将 HMI 控件类型枚举转换为工程文件中的稳定字符串
QString hmiControlTypeName(HmiControlType type)
{
    switch (type)
    {
    case HmiControlType::Button:
    {
        return QStringLiteral("button");
    }
    case HmiControlType::Indicator:
    {
        return QStringLiteral("indicator");
    }
    case HmiControlType::NumericDisplay:
    {
        return QStringLiteral("numericDisplay");
    }
    case HmiControlType::NumericInput:
    {
        return QStringLiteral("numericInput");
    }
    case HmiControlType::Label:
    {
        return QStringLiteral("label");
    }
    default:
    {
        return {};
    }
    }
}

// 将工程文件中的控件类型字符串转换为 HMI 控件类型枚举
bool parseHmiControlType(
    const std::string &value, HmiControlType *type, ParseState *state)
{
    if (value == "button")
    {
        *type = HmiControlType::Button;
    }
    else if (value == "indicator")
    {
        *type = HmiControlType::Indicator;
    }
    else if (value == "numericDisplay")
    {
        *type = HmiControlType::NumericDisplay;
    }
    else if (value == "numericInput")
    {
        *type = HmiControlType::NumericInput;
    }
    else if (value == "label")
    {
        *type = HmiControlType::Label;
    }
    else
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            "unsupported HMI control type " + value);
    }
    return true;
}

// 将 HMI 控件矩形区域序列化为 JSON 对象
QJsonObject serializeBounds(const HmiRect &bounds)
{
    QJsonObject object;
    object.insert(QStringLiteral("x"), bounds.x);
    object.insert(QStringLiteral("y"), bounds.y);
    object.insert(QStringLiteral("width"), bounds.width);
    object.insert(QStringLiteral("height"), bounds.height);
    return object;
}

// 解析控件矩形区域，允许任意坐标但要求宽高为正数
bool parseBounds(
    const QJsonObject &object,
    const std::string &context,
    HmiRect *bounds,
    ParseState *state)
{
    return readInt(
               object,
               "x",
               context,
               std::numeric_limits<int>::min(),
               std::numeric_limits<int>::max(),
               &bounds->x,
               state)
        && readInt(
               object,
               "y",
               context,
               std::numeric_limits<int>::min(),
               std::numeric_limits<int>::max(),
               &bounds->y,
               state)
        && readInt(
               object,
               "width",
               context,
               1,
               std::numeric_limits<int>::max(),
               &bounds->width,
               state)
        && readInt(
               object,
               "height",
               context,
               1,
               std::numeric_limits<int>::max(),
               &bounds->height,
               state);
}

// 将 HMI 控件的字符串扩展属性序列化为 JSON 对象
QJsonObject serializeProperties(const std::map<std::string, std::string> &properties)
{
    QJsonObject object;
    for (const auto &property : properties)
    {
        object.insert(fromUtf8(property.first), fromUtf8(property.second));
    }
    return object;
}

// 解析 HMI 控件扩展属性，并确保所有属性值都是字符串
bool parseProperties(
    const QJsonObject &object,
    std::map<std::string, std::string> *properties,
    ParseState *state)
{
    for (auto current = object.constBegin(); current != object.constEnd(); ++current)
    {
        if (!current.value().isString())
        {
            return state->fail(
                ProjectStorageError::InvalidField,
                "HMI control property values must be strings");
        }
        properties->emplace(toUtf8(current.key()), toUtf8(current.value().toString()));
    }
    return true;
}

// 将单个 HMI 控件及其可选寄存器绑定序列化为 JSON 对象
QJsonObject serializeHmiControl(const HmiControl &control)
{
    QJsonObject object;
    object.insert(QStringLiteral("id"), fromUtf8(control.id));
    object.insert(QStringLiteral("type"), hmiControlTypeName(control.type));
    object.insert(QStringLiteral("bounds"), serializeBounds(control.bounds));
    object.insert(QStringLiteral("text"), fromUtf8(control.text));
    // 使用 JSON null 明确表示控件没有寄存器绑定
    if (control.binding.has_value())
    {
        object.insert(QStringLiteral("binding"), serializeAddress(*control.binding));
    }
    else
    {
        object.insert(QStringLiteral("binding"), QJsonValue::Null);
    }
    object.insert(QStringLiteral("properties"), serializeProperties(control.properties));
    return object;
}

// 解析单个 HMI 控件，并逐层校验类型、区域、绑定和扩展属性
bool parseHmiControl(
    const QJsonObject &object,
    const std::string &context,
    HmiControl *control,
    ParseState *state)
{
    std::string type_text;
    QJsonObject bounds;
    QJsonObject properties;
    QJsonValue binding;
    if (!readString(object, "id", context, &control->id, state)
        || !readString(object, "type", context, &type_text, state)
        || !readObject(object, "bounds", context, &bounds, state)
        || !readString(object, "text", context, &control->text, state)
        || !readValue(object, "binding", context, &binding, state)
        || !readObject(object, "properties", context, &properties, state))
    {
        return false;
    }
    if (!parseHmiControlType(type_text, &control->type, state)
        || !parseBounds(bounds, context + ".bounds", &control->bounds, state)
        || !parseProperties(properties, &control->properties, state))
    {
        return false;
    }

    // binding 允许为 null，其余非空值必须是合法的寄存器地址对象
    if (binding.isNull())
    {
        control->binding.reset();
        return true;
    }
    if (!binding.isObject())
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            context + ".binding must be an object or null");
    }

    RegisterAddress address{RegisterArea::M, 0};
    if (!parseAddress(binding.toObject(), context + ".binding", &address, state))
    {
        return false;
    }
    control->binding = address;
    return true;
}

// 将 HMI 页面及其全部控件序列化为 JSON 对象
QJsonObject serializeHmiPage(const HmiPage &page)
{
    QJsonArray controls;
    for (const HmiControl &control : page.controls)
    {
        controls.append(serializeHmiControl(control));
    }

    QJsonObject object;
    object.insert(QStringLiteral("id"), fromUtf8(page.id));
    object.insert(QStringLiteral("name"), fromUtf8(page.name));
    object.insert(QStringLiteral("width"), page.width);
    object.insert(QStringLiteral("height"), page.height);
    object.insert(QStringLiteral("controls"), controls);
    return object;
}

// 解析 HMI 页面基础信息，并按数组顺序构造页面控件
bool parseHmiPage(
    const QJsonObject &object,
    const std::string &context,
    HmiPage *page,
    ParseState *state)
{
    QJsonArray controls;
    if (!readString(object, "id", context, &page->id, state)
        || !readString(object, "name", context, &page->name, state)
        || !readInt(object, "width", context, 1, std::numeric_limits<int>::max(),
                    &page->width, state)
        || !readInt(object, "height", context, 1, std::numeric_limits<int>::max(),
                    &page->height, state)
        || !readArray(object, "controls", context, &controls, state))
    {
        return false;
    }

    // 预留准确容量，避免逐项加入控件时重复扩容
    page->controls.reserve(static_cast<std::size_t>(controls.size()));
    for (int index = 0; index < controls.size(); ++index)
    {
        if (!controls.at(index).isObject())
        {
            return state->fail(
                ProjectStorageError::InvalidField,
                context + ".controls items must be objects");
        }
        HmiControl control;
        if (!parseHmiControl(
            controls.at(index).toObject(),
            context + ".controls[" + std::to_string(index) + ']',
            &control,
            state))
        {
            return false;
        }
        page->controls.push_back(std::move(control));
    }
    return true;
}

// 将触点模式枚举转换为工程文件中的稳定字符串
QString contactModeName(ContactMode mode)
{
    return mode == ContactMode::NormallyOpen
        ? QStringLiteral("normallyOpen")
        : QStringLiteral("normallyClosed");
}

// 将工程文件中的触点模式字符串转换为枚举
bool parseContactMode(
    const std::string &value, ContactMode *mode, ParseState *state)
{
    if (value == "normallyOpen")
    {
        *mode = ContactMode::NormallyOpen;
    }
    else if (value == "normallyClosed")
    {
        *mode = ContactMode::NormallyClosed;
    }
    else
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            "unsupported contact mode " + value);
    }
    return true;
}

// 将线圈模式枚举转换为工程文件中的稳定字符串
QString coilModeName(CoilMode mode)
{
    switch (mode)
    {
    case CoilMode::Normal:
    {
        return QStringLiteral("normal");
    }
    case CoilMode::Set:
    {
        return QStringLiteral("set");
    }
    case CoilMode::Reset:
    {
        return QStringLiteral("reset");
    }
    default:
    {
        return {};
    }
    }
}

// 将工程文件中的线圈模式字符串转换为枚举
bool parseCoilMode(const std::string &value, CoilMode *mode, ParseState *state)
{
    if (value == "normal")
    {
        *mode = CoilMode::Normal;
    }
    else if (value == "set")
    {
        *mode = CoilMode::Set;
    }
    else if (value == "reset")
    {
        *mode = CoilMode::Reset;
    }
    else
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            "unsupported coil mode " + value);
    }
    return true;
}

// 将比较运算符枚举转换为工程文件中的稳定字符串
QString comparisonName(ComparisonOperator comparison)
{
    switch (comparison)
    {
    case ComparisonOperator::Equal:
    {
        return QStringLiteral("equal");
    }
    case ComparisonOperator::NotEqual:
    {
        return QStringLiteral("notEqual");
    }
    case ComparisonOperator::LessThan:
    {
        return QStringLiteral("lessThan");
    }
    case ComparisonOperator::LessThanOrEqual:
    {
        return QStringLiteral("lessThanOrEqual");
    }
    case ComparisonOperator::GreaterThan:
    {
        return QStringLiteral("greaterThan");
    }
    case ComparisonOperator::GreaterThanOrEqual:
    {
        return QStringLiteral("greaterThanOrEqual");
    }
    default:
    {
        return {};
    }
    }
}

// 将工程文件中的比较运算符字符串转换为枚举
bool parseComparison(
    const std::string &value,
    ComparisonOperator *comparison,
    ParseState *state)
{
    if (value == "equal")
    {
        *comparison = ComparisonOperator::Equal;
    }
    else if (value == "notEqual")
    {
        *comparison = ComparisonOperator::NotEqual;
    }
    else if (value == "lessThan")
    {
        *comparison = ComparisonOperator::LessThan;
    }
    else if (value == "lessThanOrEqual")
    {
        *comparison = ComparisonOperator::LessThanOrEqual;
    }
    else if (value == "greaterThan")
    {
        *comparison = ComparisonOperator::GreaterThan;
    }
    else if (value == "greaterThanOrEqual")
    {
        *comparison = ComparisonOperator::GreaterThanOrEqual;
    }
    else
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            "unsupported comparison operator " + value);
    }
    return true;
}

// 将触点节点配置序列化，并写入用于反序列化分派的类型标记
QJsonObject serializeNodeConfig(const ContactNodeConfig &config)
{
    QJsonObject object;
    object.insert(QStringLiteral("type"), QStringLiteral("contact"));
    object.insert(QStringLiteral("address"), serializeAddress(config.address));
    object.insert(QStringLiteral("mode"), contactModeName(config.mode));
    return object;
}

// 将线圈节点配置序列化，并写入用于反序列化分派的类型标记
QJsonObject serializeNodeConfig(const CoilNodeConfig &config)
{
    QJsonObject object;
    object.insert(QStringLiteral("type"), QStringLiteral("coil"));
    object.insert(QStringLiteral("address"), serializeAddress(config.address));
    object.insert(QStringLiteral("mode"), coilModeName(config.mode));
    return object;
}

// 将数值比较节点配置序列化，并保留有符号 16 位比较常量
QJsonObject serializeNodeConfig(const CompareNodeConfig &config)
{
    QJsonObject object;
    object.insert(QStringLiteral("type"), QStringLiteral("compare"));
    object.insert(QStringLiteral("address"), serializeAddress(config.address));
    object.insert(QStringLiteral("comparison"), comparisonName(config.comparison));
    object.insert(QStringLiteral("value"), config.value);
    return object;
}

// 将逻辑节点序列化，并根据 variant 中的实际配置类型选择对应重载
QJsonObject serializeLogicNode(const LogicNode &node)
{
    QJsonObject object;
    object.insert(QStringLiteral("id"), fromUtf8(node.id));
    object.insert(QStringLiteral("configured"), node.configured);
    // std::visit 将不同节点配置统一转换为 config JSON 对象
    object.insert(
        QStringLiteral("config"),
        std::visit(
            [](const auto &config)
            {
                return serializeNodeConfig(config);
            },
            node.config));
    return object;
}

// 根据 type 字段解析具体节点配置，并写入 LogicNodeConfig 变体
bool parseNodeConfig(
    const QJsonObject &object,
    const std::string &context,
    LogicNodeConfig *config,
    ParseState *state)
{
    std::string type;
    QJsonObject address_object;
    if (!readString(object, "type", context, &type, state)
        || !readObject(object, "address", context, &address_object, state))
    {
        return false;
    }

    RegisterAddress address{RegisterArea::M, 0};
    if (!parseAddress(address_object, context + ".address", &address, state))
    {
        return false;
    }

    // 每种节点只读取自身需要的字段，避免无关配置进入领域模型
    if (type == "contact")
    {
        std::string mode_text;
        ContactMode mode = ContactMode::NormallyOpen;
        if (!readString(object, "mode", context, &mode_text, state)
            || !parseContactMode(mode_text, &mode, state))
        {
            return false;
        }
        *config = ContactNodeConfig{address, mode};
        return true;
    }
    if (type == "coil")
    {
        std::string mode_text;
        CoilMode mode = CoilMode::Normal;
        if (!readString(object, "mode", context, &mode_text, state)
            || !parseCoilMode(mode_text, &mode, state))
        {
            return false;
        }
        *config = CoilNodeConfig{address, mode};
        return true;
    }
    if (type == "compare")
    {
        std::string comparison_text;
        int value = 0;
        ComparisonOperator comparison = ComparisonOperator::Equal;
        if (!readString(object, "comparison", context, &comparison_text, state)
            || !readInt(
                object,
                "value",
                context,
                std::numeric_limits<std::int16_t>::min(),
                std::numeric_limits<std::int16_t>::max(),
                &value,
                state)
            || !parseComparison(comparison_text, &comparison, state))
        {
            return false;
        }
        // 先按 int 校验范围，再安全收窄为领域模型要求的 int16_t
        *config = CompareNodeConfig{
            address, comparison, static_cast<std::int16_t>(value)};
        return true;
    }

    return state->fail(
        ProjectStorageError::InvalidField,
        "unsupported logic node type " + type);
}

// 解析逻辑节点标识及其多态配置
bool parseLogicNode(
    const QJsonObject &object,
    const std::string &context,
    LogicNode *node,
    ParseState *state)
{
    QJsonObject config;
    if (!readString(object, "id", context, &node->id, state)
        || !readBool(object, "configured", context, &node->configured, state)
        || !readObject(object, "config", context, &config, state)
        || !parseNodeConfig(config, context + ".config", &node->config, state))
    {
        return false;
    }
    return true;
}

QString expressionKindText(ConditionExpressionKind kind)
{
    switch (kind)
    {
    case ConditionExpressionKind::Node:
        return QStringLiteral("node");
    case ConditionExpressionKind::Series:
        return QStringLiteral("series");
    case ConditionExpressionKind::Parallel:
        return QStringLiteral("parallel");
    }
    return {};
}

QJsonObject serializeConditionExpression(const ConditionExpression &expression)
{
    QJsonObject object;
    object.insert(QStringLiteral("id"), fromUtf8(expression.id));
    object.insert(QStringLiteral("kind"), expressionKindText(expression.kind));
    if (expression.kind == ConditionExpressionKind::Node)
    {
        object.insert(QStringLiteral("node"), serializeLogicNode(*expression.node));
    }
    else
    {
        QJsonArray children;
        for (const ConditionExpression &child : expression.children)
        {
            children.append(serializeConditionExpression(child));
        }
        object.insert(QStringLiteral("children"), children);
    }
    return object;
}

bool parseConditionExpression(
    const QJsonObject &object,
    const std::string &context,
    ConditionExpression *expression,
    ParseState *state)
{
    std::string kind;
    if (!readString(object, "id", context, &expression->id, state)
        || !readString(object, "kind", context, &kind, state))
    {
        return false;
    }
    if (kind == "node")
    {
        QJsonObject node;
        if (!readObject(object, "node", context, &node, state))
        {
            return false;
        }
        LogicNode parsed_node;
        if (!parseLogicNode(node, context + ".node", &parsed_node, state))
        {
            return false;
        }
        expression->kind = ConditionExpressionKind::Node;
        expression->node = std::move(parsed_node);
        return true;
    }
    if (kind != "series" && kind != "parallel")
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            context + ".kind must be node, series or parallel");
    }
    QJsonArray children;
    if (!readArray(object, "children", context, &children, state))
    {
        return false;
    }
    expression->kind = kind == "series"
        ? ConditionExpressionKind::Series : ConditionExpressionKind::Parallel;
    expression->children.reserve(static_cast<std::size_t>(children.size()));
    for (int index = 0; index < children.size(); ++index)
    {
        if (!children.at(index).isObject())
        {
            return state->fail(
                ProjectStorageError::InvalidField,
                context + ".children items must be objects");
        }
        ConditionExpression child;
        if (!parseConditionExpression(
                children.at(index).toObject(),
                context + ".children[" + std::to_string(index) + ']',
                &child,
                state))
        {
            return false;
        }
        expression->children.push_back(std::move(child));
    }
    return true;
}

QJsonObject serializeLadderRung(const LadderRung &rung)
{
    QJsonObject object;
    object.insert(QStringLiteral("id"), fromUtf8(rung.id));
    object.insert(QStringLiteral("name"), fromUtf8(rung.name));
    object.insert(
        QStringLiteral("condition"),
        rung.condition.has_value()
            ? QJsonValue(serializeConditionExpression(*rung.condition))
            : QJsonValue(QJsonValue::Null));
    object.insert(
        QStringLiteral("output"),
        rung.output.has_value() ? QJsonValue(serializeLogicNode(*rung.output))
                                : QJsonValue(QJsonValue::Null));
    return object;
}

bool parseLadderRung(
    const QJsonObject &object,
    const std::string &context,
    LadderRung *rung,
    ParseState *state)
{
    QJsonValue condition;
    QJsonValue output;
    if (!readString(object, "id", context, &rung->id, state)
        || !readString(object, "name", context, &rung->name, state)
        || !readValue(object, "output", context, &output, state))
    {
        return false;
    }
    if (!readValue(object, "condition", context, &condition, state))
    {
        return false;
    }
    if (condition.isNull())
    {
        rung->condition.reset();
    }
    else if (!condition.isObject())
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            context + ".condition must be an object or null");
    }
    else
    {
        ConditionExpression parsed_condition;
        if (!parseConditionExpression(
                condition.toObject(), context + ".condition", &parsed_condition, state))
        {
            return false;
        }
        rung->condition = std::move(parsed_condition);
    }
    if (output.isNull())
    {
        rung->output.reset();
        return true;
    }
    if (!output.isObject())
    {
        return state->fail(
            ProjectStorageError::InvalidField,
            context + ".output must be an object or null");
    }
    LogicNode node;
    if (!parseLogicNode(output.toObject(), context + ".output", &node, state))
    {
        return false;
    }
    rung->output = std::move(node);
    return true;
}

QJsonObject serializeControlLogic(const ControlLogic &logic)
{
    QJsonArray rungs;
    for (const LadderRung &rung : logic.rungs)
    {
        rungs.append(serializeLadderRung(rung));
    }
    QJsonObject object;
    object.insert(QStringLiteral("id"), fromUtf8(logic.id));
    object.insert(QStringLiteral("name"), fromUtf8(logic.name));
    object.insert(QStringLiteral("enabled"), logic.enabled);
    object.insert(QStringLiteral("rungs"), rungs);
    return object;
}

bool parseControlLogic(
    const QJsonObject &object,
    const std::string &context,
    ControlLogic *logic,
    ParseState *state)
{
    QJsonArray rungs;
    if (!readString(object, "id", context, &logic->id, state)
        || !readString(object, "name", context, &logic->name, state)
        || !readBool(object, "enabled", context, &logic->enabled, state)
        || !readArray(object, "rungs", context, &rungs, state))
    {
        return false;
    }
    logic->rungs.reserve(static_cast<std::size_t>(rungs.size()));
    for (int index = 0; index < rungs.size(); ++index)
    {
        if (!rungs.at(index).isObject())
        {
            return state->fail(
                ProjectStorageError::InvalidField,
                context + ".rungs items must be objects");
        }
        LadderRung rung;
        if (!parseLadderRung(
                rungs.at(index).toObject(),
                context + ".rungs[" + std::to_string(index) + ']',
                &rung,
                state))
        {
            return false;
        }
        logic->rungs.push_back(std::move(rung));
    }
    return true;
}

// 将完整领域工程聚合为工程文件的顶层 JSON 对象
QJsonObject serializeProject(const Project &project)
{
    QJsonArray pages;
    for (const HmiPage &page : project.hmiPages)
    {
        pages.append(serializeHmiPage(page));
    }

    QJsonArray logics;
    for (const ControlLogic &logic : project.controlLogics)
    {
        logics.append(serializeControlLogic(logic));
    }

    QJsonObject object;
    object.insert(QStringLiteral("formatVersion"), fromUtf8(project.metadata.formatVersion));
    object.insert(QStringLiteral("id"), fromUtf8(project.metadata.id));
    object.insert(QStringLiteral("name"), fromUtf8(project.metadata.name));
    object.insert(QStringLiteral("hmiPages"), pages);
    object.insert(QStringLiteral("controlLogics"), logics);
    return object;
}

// 从顶层 JSON 对象解析完整工程，并在解析子对象前检查格式版本
bool parseProject(
    const QJsonObject &object, Project *project, ParseState *state)
{
    QJsonArray pages;
    QJsonArray logics;
    if (!readString(
        object,
        "formatVersion",
        "project",
        &project->metadata.formatVersion,
        state))
    {
        return false;
    }
    // 不尝试猜测其他版本的结构，避免按当前格式错误解释数据
    if (project->metadata.formatVersion != kCurrentFormatVersion)
    {
        return state->fail(
            ProjectStorageError::UnsupportedVersion,
            "unsupported project format version " + project->metadata.formatVersion);
    }

    if (!readString(object, "id", "project", &project->metadata.id, state)
        || !readString(object, "name", "project", &project->metadata.name, state)
        || !readArray(object, "hmiPages", "project", &pages, state)
        || !readArray(object, "controlLogics", "project", &logics, state))
    {
        return false;
    }

    // 逐层解析时持续传递字段路径，任何失败都保留最初的具体位置
    project->hmiPages.reserve(static_cast<std::size_t>(pages.size()));
    for (int index = 0; index < pages.size(); ++index)
    {
        if (!pages.at(index).isObject())
        {
            return state->fail(
                ProjectStorageError::InvalidField,
                "project.hmiPages items must be objects");
        }
        HmiPage page;
        if (!parseHmiPage(
            pages.at(index).toObject(),
            "project.hmiPages[" + std::to_string(index) + ']',
            &page,
            state))
        {
            return false;
        }
        project->hmiPages.push_back(std::move(page));
    }

    project->controlLogics.reserve(static_cast<std::size_t>(logics.size()));
    for (int index = 0; index < logics.size(); ++index)
    {
        if (!logics.at(index).isObject())
        {
            return state->fail(
                ProjectStorageError::InvalidField,
                "project.controlLogics items must be objects");
        }
        ControlLogic logic;
        if (!parseControlLogic(
            logics.at(index).toObject(),
            "project.controlLogics[" + std::to_string(index) + ']',
            &logic,
            state))
        {
            return false;
        }
        project->controlLogics.push_back(std::move(logic));
    }
    return true;
}

// 将 Qt 文件错误转换为领域层统一的工程保存失败结果
ProjectSaveResult saveFailure(
    ProjectStorageError error, const QString &message)
{
    return {false, error, toUtf8(message)};
}

} // namespace

// 校验工程后将其序列化，并通过 QSaveFile 原子写入目标文件
ProjectSaveResult JsonProjectStorage::save(
    const Project &project, const std::string &file_path)
{
    // 写文件前先执行领域校验，防止持久化内部关系不合法的工程
    std::string validation_error;
    if (!project.validate(&validation_error))
    {
        return {false, ProjectStorageError::InvalidProject, validation_error};
    }
    if (project.metadata.formatVersion != kCurrentFormatVersion)
    {
        return {false,
                ProjectStorageError::UnsupportedVersion,
                "unsupported project format version " + project.metadata.formatVersion};
    }

    // QSaveFile 先写临时文件，仅在 commit 成功后替换目标文件
    QSaveFile file(fromUtf8(file_path));
    if (!file.open(QIODevice::WriteOnly))
    {
        return saveFailure(ProjectStorageError::FileOpenFailed, file.errorString());
    }

    const QByteArray data = QJsonDocument(serializeProject(project)).toJson(
        QJsonDocument::Indented);
    // 短写入也视为失败，并取消临时文件提交
    if (file.write(data) != data.size())
    {
        file.cancelWriting();
        return saveFailure(ProjectStorageError::FileWriteFailed, file.errorString());
    }
    if (!file.commit())
    {
        return saveFailure(ProjectStorageError::FileWriteFailed, file.errorString());
    }
    return {true, ProjectStorageError::None, {}};
}

// 读取并解析工程文件，全部校验通过后才返回新的领域工程
ProjectLoadResult JsonProjectStorage::load(const std::string &file_path)
{
    QFile file(fromUtf8(file_path));
    if (!file.open(QIODevice::ReadOnly))
    {
        return {false,
                {},
                ProjectStorageError::FileOpenFailed,
                toUtf8(file.errorString())};
    }

    const QByteArray data = file.readAll();
    if (file.error() != QFileDevice::NoError)
    {
        return {false,
                {},
                ProjectStorageError::FileReadFailed,
                toUtf8(file.errorString())};
    }

    // 顶层必须是 JSON 对象，数组或标量不能表示完整工程
    QJsonParseError parse_error;
    const QJsonDocument document = QJsonDocument::fromJson(data, &parse_error);
    if (parse_error.error != QJsonParseError::NoError || !document.isObject())
    {
        const QString message = parse_error.error == QJsonParseError::NoError
            ? QStringLiteral("project JSON root must be an object")
            : parse_error.errorString();
        return {false,
                {},
                ProjectStorageError::InvalidJson,
                toUtf8(message)};
    }

    // 先在局部对象中完成结构解析，失败时不会暴露半成品工程
    Project project;
    ParseState state;
    if (!parseProject(document.object(), &project, &state))
    {
        return {false, {}, state.error, state.message};
    }

    // JSON 字段合法不代表业务关系合法，还需执行领域层整体校验
    std::string validation_error;
    if (!project.validate(&validation_error))
    {
        return {false,
                {},
                ProjectStorageError::InvalidProject,
                validation_error};
    }
    return {true, std::move(project), ProjectStorageError::None, {}};
}