#include "hmi_editor_widget.h"

#include "services/hmi_editor_service.h"
#include "services/hmi_runtime_service.h"

#include <QGraphicsItem>
#include <QGraphicsRectItem>
#include <QGraphicsScene>
#include <QGraphicsSceneMouseEvent>
#include <QInputDialog>
#include <QPainter>
#include <QResizeEvent>
#include <QStyleOptionGraphicsItem>

#include <algorithm>
#include <cmath>
#include <cstdint>
#include <functional>
#include <limits>

namespace {

// 将领域层 HMI 控件投影为可绘制、可选择和可交互的场景图元
class HmiGraphicsItem final : public QGraphicsItem
{
public:
    // 保存控件快照、页面边界和回调，使图元不直接依赖服务层
    HmiGraphicsItem(
        const HmiControl &control,
        int page_width,
        int page_height,
        std::function<void(const std::string &, const QPointF &)> moved,
        std::function<void(const std::string &)> activated)
        : control_(control),
          page_width_(page_width),
          page_height_(page_height),
          moved_(std::move(moved)),
          activated_(std::move(activated))
    {
        // 领域坐标直接作为图元在场景中的初始位置
        setPos(control_.bounds.x, control_.bounds.y);
        // 所有控件均可选中，便于主窗口显示对应属性
        setFlag(ItemIsSelectable, true);
        // 开启可选中
        setFlag(ItemSendsGeometryChanges, true);
        // 画布只处理左键交互，保留其他按键给视图默认行为
        setAcceptedMouseButtons(Qt::LeftButton);
    }

    // 返回图元自身坐标系中的矩形范围，用于绘制和命中测试
    QRectF boundingRect() const override
    {
        return {0,
                0,
                static_cast<qreal>(control_.bounds.width),
                static_cast<qreal>(control_.bounds.height)};
    }

    void paint(
        QPainter *painter,
        const QStyleOptionGraphicsItem *option,
        QWidget *) override
    {
        // 留出一个像素边距，避免描边被图元边界裁剪
        const QRectF rect = boundingRect().adjusted(1, 1, -1, -1);
        painter->setRenderHint(QPainter::Antialiasing, true);
        painter->setPen(QPen(QColor(QStringLiteral("#47545f")), 1));

        switch (control_.type)
        {
        case HmiControlType::Button:
        {
            // 按钮显示文字，运行态点击行为由鼠标事件处理
            painter->setBrush(QColor(QStringLiteral("#dcece3")));
            painter->drawRoundedRect(rect, 4, 4);
            painter->setPen(QColor(QStringLiteral("#205c3b")));
            painter->drawText(rect, Qt::AlignCenter, textWithValue());
            break;
        }
        case HmiControlType::Indicator:
        {
            // 指示灯颜色由最近一次读取到的 M 位值决定
            const qreal diameter = std::min(rect.width(), rect.height() - 18.0);
            const QRectF lamp(
                rect.center().x() - diameter / 2.0,
                rect.top() + 2,
                diameter,
                diameter);
            painter->setBrush(bit_value_ ? QColor(QStringLiteral("#24a148"))
                                         : QColor(QStringLiteral("#b8c1c8")));
            painter->drawEllipse(lamp);
            painter->setPen(QColor(QStringLiteral("#24313b")));
            painter->drawText(
                QRectF(rect.left(), lamp.bottom() + 1, rect.width(), 16),
                Qt::AlignCenter,
                QString::fromUtf8(control_.text.data(),
                                  static_cast<int>(control_.text.size())));
            break;
        }
        case HmiControlType::NumericDisplay:
        {
            // 数值显示为只读样式，文本由运行值刷新
            painter->setBrush(QColor(QStringLiteral("#edf2f6")));
            painter->drawRect(rect);
            painter->setPen(QColor(QStringLiteral("#24313b")));
            painter->drawText(rect.adjusted(7, 0, -7, 0),
                              Qt::AlignVCenter | Qt::AlignLeft,
                              textWithValue());
            break;
        }
        case HmiControlType::NumericInput:
        {
            // 数值输入以白色编辑框样式呈现，双击后才请求写入
            painter->setBrush(QColor(QStringLiteral("#ffffff")));
            painter->drawRoundedRect(rect, 3, 3);
            painter->setPen(QColor(QStringLiteral("#24313b")));
            painter->drawText(rect.adjusted(7, 0, -7, 0),
                              Qt::AlignVCenter | Qt::AlignLeft,
                              textWithValue());
            break;
        }
        case HmiControlType::Label:
        default:
        {
            // 标签只显示固定文本，不绑定寄存器运行值
            painter->setPen(QColor(QStringLiteral("#24313b")));
            painter->drawText(rect, Qt::AlignCenter,
                              QString::fromUtf8(control_.text.data(),
                                                static_cast<int>(control_.text.size())));
            break;
        }
        }

        if ((option->state & QStyle::State_Selected) != 0)
        {
            // 选中框独立于控件类型，提示当前可编辑对象
            painter->setBrush(Qt::NoBrush);
            painter->setPen(QPen(QColor(QStringLiteral("#1677a8")), 2));
            painter->drawRect(boundingRect().adjusted(0, 0, -1, -1));
        }
    }

    // 向场景和外部控件返回该图元对应的领域控件标识
    const std::string &controlId() const
    {
        return control_.id;
    }

    // 编辑态允许拖动，运行态保留点击或双击交互
    void setInteractionEnabled(bool editable)
    {
        setFlag(ItemIsMovable, editable);
    }

    // 缓存运行服务读出的值并触发 Qt 重绘
    void setRuntimeValue(bool bit_value, std::int16_t word_value, bool available)
    {
        bit_value_ = bit_value;
        word_value_ = word_value;
        has_runtime_value_ = available;
        update();
    }

protected:
    // 拖拽过程中将新位置限制在页面可见边界内
    QVariant itemChange(GraphicsItemChange change, const QVariant &value) override
    {
        // 只有开启 ItemIsMovable 拖拽时，才做坐标钳位
        if (change == ItemPositionChange && flags().testFlag(ItemIsMovable))
        {
            // 在图元层预先截断拖拽坐标，避免控件视觉上越出页面
            QPointF position = value.toPointF();
            const qreal maximum_x = std::max(
                0.0, static_cast<double>(page_width_ - control_.bounds.width));
            const qreal maximum_y = std::max(
                0.0, static_cast<double>(page_height_ - control_.bounds.height));
            position.setX(std::clamp(position.x(), 0.0, maximum_x));
            position.setY(std::clamp(position.y(), 0.0, maximum_y));
            return position;
        }
        return QGraphicsItem::itemChange(change, value);
    }

    // 运行态点击按钮时通知外层执行 M 位切换
    void mousePressEvent(QGraphicsSceneMouseEvent *event) override
    {
        // 条件：!ItemIsMovable 【也就是运行模式】 + 是按钮 + 有回调
        if (!flags().testFlag(ItemIsMovable)
            && control_.type == HmiControlType::Button && activated_)
        {
            // 运行态单击按钮才触发 M 位切换，编辑态只用于选择和拖动
            setSelected(true);
            activated_(control_.id);
            event->accept();
            return;
        }
        // 编辑模式：不进if分支，执行基类事件——只做选中、拖拽
        QGraphicsItem::mousePressEvent(event);
    }

    // 运行态双击数值输入时通知外层弹出数值编辑对话框
    void mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event) override
    {
        if (!flags().testFlag(ItemIsMovable)
            && control_.type == HmiControlType::NumericInput && activated_)
        {
            // 数值输入使用双击，避免普通选择操作意外写入 D 字
            setSelected(true);
            activated_(control_.id);
            event->accept();
            return;
        }
        QGraphicsItem::mouseDoubleClickEvent(event);
    }

    // 拖拽结束后才提交最终坐标，避免移动过程频繁修改领域模型
    void mouseReleaseEvent(QGraphicsSceneMouseEvent *event) override
    {
        QGraphicsItem::mouseReleaseEvent(event);
        // 只有ItemIsMovable打开（编辑态），松开鼠标才提交位置给业务层
        if (flags().testFlag(ItemIsMovable) && moved_)
        {
            moved_(control_.id, pos());
        }
    }

private:
    // 根据控件类型和运行数据组合当前应绘制的文字
    QString textWithValue() const
    {
        const QString text = QString::fromUtf8(
            control_.text.data(), static_cast<int>(control_.text.size()));
        if (!has_runtime_value_ || control_.type == HmiControlType::Button)
        {
            return text;
        }
        if (control_.type == HmiControlType::NumericDisplay
            || control_.type == HmiControlType::NumericInput)
        {
            return text + QStringLiteral(": ") + QString::number(word_value_);
        }
        return text;
    }

    // 图元创建时的领域控件快照，提供类型、尺寸、文本和标识
    HmiControl control_;
    // 当前页面宽度，用于限制图元横向拖拽范围
    int page_width_ = 0;
    // 当前页面高度，用于限制图元纵向拖拽范围
    int page_height_ = 0;
    // 拖拽完成后回调 HmiEditorWidget 提交控件新位置
    std::function<void(const std::string &, const QPointF &)> moved_;
    // 运行模式点击按钮 / 双击输入框回调，通知外层做寄存器读写
    std::function<void(const std::string &)> activated_;
    // 指示灯读取到的 M 位值
    bool bit_value_ = false;
    // 数值控件读取到的 D 字值
    std::int16_t word_value_ = 0;
    // 标记当前缓存值是否来自一次成功的运行时读取
    bool has_runtime_value_ = false;
};

// 将场景通用图元安全转换为本文件定义的 HMI 控件图元
HmiGraphicsItem *asHmiItem(QGraphicsItem *item)
{
    return dynamic_cast<HmiGraphicsItem *>(item);
}

} // namespace

HmiEditorWidget::HmiEditorWidget(
    HmiEditorService &editor_service,
    HmiRuntimeService &runtime_service,
    QWidget *parent)
    : QGraphicsView(parent),
      editor_service_(editor_service),
      runtime_service_(runtime_service),
      scene_(new QGraphicsScene(this))
{
    setObjectName(QStringLiteral("hmiEditorWidget"));
    setScene(scene_);
    setRenderHint(QPainter::Antialiasing, true);
    setDragMode(QGraphicsView::RubberBandDrag);
    setBackgroundBrush(QColor(QStringLiteral("#dfe5e9")));
    connect(scene_, &QGraphicsScene::selectionChanged,
            this, &HmiEditorWidget::handleSelectionChanged);
}

// 切换显示页面
void HmiEditorWidget::setPageId(const std::string &page_id)
{
    if (page_id_ == page_id)
    {
        return;
    }
    page_id_ = page_id;
    reloadPage();
}

void HmiEditorWidget::setEditingEnabled(bool enabled)
{
    editing_enabled_ = enabled;
    setDragMode(enabled ? QGraphicsView::RubberBandDrag : QGraphicsView::NoDrag);
    updateItemInteractions();
}

void HmiEditorWidget::setRuntimeActive(bool active)
{
    runtime_active_ = active;
    if (!runtime_active_)
    {
        for (QGraphicsItem *item : scene_->items())
        {
            HmiGraphicsItem *control_item = asHmiItem(item);
            if (control_item != nullptr)
            {
                control_item->setRuntimeValue(false, 0, false);
            }
        }
    }
}

// 全部重新加载当前页面，把内存模型 HmiPage 渲染成画面上图形
void HmiEditorWidget::reloadPage()
{
    // 画布始终从当前领域页面重建，避免保留已删除控件的图元
    scene_->clear();
    const HmiPage *page = editor_service_.findPage(page_id_);
    if (page == nullptr)
    {
        scene_->setSceneRect({});
        emit controlSelected({});
        return;
    }

    scene_->setSceneRect(0, 0, page->width, page->height);
    QGraphicsRectItem *page_border = scene_->addRect(
        scene_->sceneRect(), QPen(QColor(QStringLiteral("#8a98a3")), 1), Qt::white);
    page_border->setZValue(-1);
    page_border->setAcceptedMouseButtons(Qt::NoButton);

    for (const HmiControl &control : page->controls)
    {
        auto *item = new HmiGraphicsItem(
            control,
            page->width,
            page->height,
            [this](const std::string &control_id, const QPointF &position)
            {
                handleControlMoved(control_id, position);
            },
            [this](const std::string &control_id)
            {
                handleControlActivated(control_id);
            });
        scene_->addItem(item);
        item->setInteractionEnabled(editing_enabled_);
    }
    fitCurrentPage();
    refreshRuntimeValues();
}

// 遍历场景所有图元，找到对应 id 的图元，设置选中，视图滚动到把控件显示出来
void HmiEditorWidget::selectControl(const std::string &control_id)
{
    for (QGraphicsItem *item : scene_->items())
    {
        HmiGraphicsItem *control_item = asHmiItem(item);
        if (control_item != nullptr && control_item->controlId() == control_id)
        {
            control_item->setSelected(true);
            ensureVisible(control_item);
            return;
        }
    }
}

std::string HmiEditorWidget::selectedControlId() const
{
    const QList<QGraphicsItem *> selected = scene_->selectedItems();
    for (QGraphicsItem *item : selected)
    {
        const HmiGraphicsItem *control_item = asHmiItem(item);
        if (control_item != nullptr)
        {
            return control_item->controlId();
        }
    }
    return {};
}

void HmiEditorWidget::refreshRuntimeValues()
{
    if (!runtime_active_)
    {
        return;
    }
    for (QGraphicsItem *item : scene_->items())
    {
        HmiGraphicsItem *control_item = asHmiItem(item);
        if (control_item == nullptr)
        {
            continue;
        }
        const HmiControl *control = editor_service_.findControl(
            page_id_, control_item->controlId());
        if (control == nullptr)
        {
            continue;
        }
        // 运行值通过服务读取，图元不直接接触寄存器仓库
        const HmiRuntimeReadResult value = runtime_service_.readControl(*control);
        control_item->setRuntimeValue(value.bit_value, value.word_value, value.succeeded);
    }
}

void HmiEditorWidget::resizeEvent(QResizeEvent *event)
{
    QGraphicsView::resizeEvent(event);
    fitCurrentPage();
}

void HmiEditorWidget::fitCurrentPage()
{
    if (scene_->sceneRect().isEmpty())
    {
        return;
    }
    fitInView(
        scene_->sceneRect().adjusted(-16, -16, 16, 16),
        Qt::KeepAspectRatio);
}

void HmiEditorWidget::updateItemInteractions()
{
    // 遍历所有控件图元，统一设置flag
    for (QGraphicsItem *item : scene_->items())
    {
        HmiGraphicsItem *control_item = asHmiItem(item);
        if (control_item != nullptr)
        {
            control_item->setInteractionEnabled(editing_enabled_);
        }
    }
}

void HmiEditorWidget::handleSelectionChanged()
{
    emit controlSelected(QString::fromStdString(selectedControlId()));
}

void HmiEditorWidget::handleControlMoved(
    const std::string &control_id, const QPointF &position)
{
    const HmiControl *control = editor_service_.findControl(page_id_, control_id);
    if (control == nullptr)
    {
        return;
    }
    // 鼠标坐标取整后再交给服务校验并写回模型
    HmiRect bounds = control->bounds;
    bounds.x = static_cast<int>(std::lround(position.x()));
    bounds.y = static_cast<int>(std::lround(position.y()));
    const HmiEditorResult result = editor_service_.moveControl(
        page_id_, control_id, bounds);
    if (!result.succeeded)
    {
        emit editorError(QString::fromStdString(result.message));
        reloadPage();
        return;
    }
    emit controlChanged(QString::fromStdString(control_id));
}

void HmiEditorWidget::handleControlActivated(const std::string &control_id)
{
    if (!runtime_active_)
    {
        return;
    }
    const HmiControl *control = editor_service_.findControl(page_id_, control_id);
    if (control == nullptr)
    {
        return;
    }
    HmiRuntimeWriteResult result;
    // 只有可写控件允许激活，其余控件只展示最新运行值
    if (control->type == HmiControlType::Button)
    {
        result = runtime_service_.toggleButton(*control);
    }
    else if (control->type == HmiControlType::NumericInput)
    {
        bool accepted = false;
        const HmiRuntimeReadResult current = runtime_service_.readControl(*control);
        const int initial = current.succeeded ? current.word_value : 0;
        const int value = QInputDialog::getInt(
            this,
            tr("输入数值"),
            QString::fromUtf8(control->text.data(), static_cast<int>(control->text.size())),
            initial,
            std::numeric_limits<std::int16_t>::min(),
            std::numeric_limits<std::int16_t>::max(),
            1,
            &accepted);
        if (!accepted)
        {
            return;
        }
        result = runtime_service_.writeNumericInput(
            *control, static_cast<std::int16_t>(value));
    }
    else
    {
        return;
    }
    if (!result.succeeded)
    {
        emit editorError(tr("寄存器操作失败"));
        return;
    }
    refreshRuntimeValues();
}