#ifndef PLCDOCUMENT_H
#define PLCDOCUMENT_H

#include "basedocument.h"
#include "plcitems.h"
#include <QGraphicsScene>
#include <QGraphicsView>
#include <QGraphicsLineItem>
#include <QGraphicsRectItem>
#include <QGraphicsEllipseItem>
#include <QMap>
#include <QSet>
#include <QVector>
#include <QDragEnterEvent>
#include <QDragMoveEvent>
#include <QDropEvent>
#include <QMimeData>
#include <QPair>

const int DEFAULT_ROWS = 11;
const int DEFAULT_COLUMNS = 24;
const int DEFAULT_CELL_SIZE = 70;

class PLCItem;
class ConnectionLine;

class PLCDocument : public BaseDocument
{
    Q_OBJECT
public:
    enum TerminalType
    {
        NoTerminal = 0,
        LeftTerminal,
        RightTerminal,
        RowTerminal
    };

    enum ConnectionSourceType
    {
        ConnectionNone,           // 无连接
        ConnectionFromItem,       // 起点是元件的端子
        ConnectionFromRowTerminal // 起点是行触点
    };

    explicit PLCDocument(QWidget *parent = nullptr);
    ~PLCDocument() override;

    QString title() const override;
    QGraphicsView *view() const { return m_view; }
    QGraphicsScene *scene() const { return m_scene; }

    bool saveToFile(const QString &filePath) override;
    bool loadFromFile(const QString &filePath) override;

    void createPLCItem(const QString &type, const QPointF &pos);
    void startConnection(PLCItem *startItem, TerminalType startTerminal);
    void startConnectionFromRowTerminal(int row);
    void clearCurrentConnection();
    bool tryEndConnection(PLCItem *endItem, TerminalType endTerminal);
    void setSimulationRunning(bool running);
    void resetSimulation();
    void setCurrentTool(const QString &tool) { m_currentTool = tool; }

    int rowCount() const { return m_rows; }
    int columnCount() const { return m_columns; }
    int cellSize() const { return m_cellSize; }

    QPointF snapToCellCenter(const QPointF &pos) const;
    QPointF constrainToTable(const QPointF &pos) const;

    void setTitle(const QString &title) { m_title = title; }

    void deleteSelectedItems();
    void copySelectedItem();
    void pasteItem();

protected:
    bool eventFilter(QObject *obj, QEvent *event) override;
    void keyPressEvent(QKeyEvent* event) override;

private slots:
    void handleSceneChanged();
    void onRowTerminalConnection();

private:
    QList<ConnectionLine*> findConnectionsUnderItem(PLCItem* item) const;
    bool lineIntersectsRect(const QLineF& line, const QRectF& rect) const;
    bool splitConnection(ConnectionLine* originalLine, PLCItem* insertItem);
    bool isPointOnLineSegment(const QPointF& point, const QLineF& line) const;
    void createRealTable();
    TerminalType whichTerminal(const QPointF& scenePos, PLCItem* item) const;
    bool isTerminalUsed(PLCItem* item, TerminalType terminal) const;
    void handleItemPositionChange(PLCItem *item);
    bool isCellOccupied(int col, int row, PLCItem* excludeItem) const;
    void updateConnections();
    void createContextMenu(QPoint globalPos);
    PLCItem* createItemByType(PLCItem::ItemType type);
    void removeInvalidConnectionsForItem(PLCItem* movedItem);
    QList<PLCItem*> allPLCItems() const;

    // 新增：获取元件在连线上的位置比例（0-1）
    qreal getPositionRatioOnLine(PLCItem* item, ConnectionLine* line) const;

    QGraphicsScene *m_scene;
    QGraphicsView *m_view;
    QString m_currentTool;
    ConnectionSourceType m_connectionSourceType = ConnectionNone;
    PLCItem *m_connectionStartItem = nullptr;
    TerminalType m_startTerminal = NoTerminal;
    int m_connectionStartRow = -1;
    QGraphicsLineItem *m_tempLine = nullptr;
    QList<ConnectionLine*> m_connections;
    QMap<PLCItem*, QMap<TerminalType, bool>> terminalConnections;
    bool m_simulationRunning = false;
    QSet<PLCItem*> m_activeItems;
    int m_rows = DEFAULT_ROWS;
    int m_columns = DEFAULT_COLUMNS;
    int m_cellSize = DEFAULT_CELL_SIZE;
    QGraphicsRectItem* m_tableFrame = nullptr;
    QVector<QGraphicsLineItem*> m_horizontalLines;
    QVector<QGraphicsLineItem*> m_verticalLines;
    QString m_title;
    QVector<QGraphicsEllipseItem*> m_rowTerminals;
    QMap<QGraphicsEllipseItem*, int> m_rowTerminalMap;
    QMap<PLCItem*, QPointF> m_lastValidPositions;
    QSet<PLCItem*> m_processingItems;
    bool m_loadingFile = false;

    PLCItem* m_copiedItem = nullptr;
};

class ConnectionLine : public QGraphicsLineItem
{
public:
    ConnectionLine(
        PLCItem *startItem, PLCDocument::TerminalType startTerminal,
        PLCItem *endItem, PLCDocument::TerminalType endTerminal,
        QGraphicsItem *parent = nullptr
    );

    void updatePosition();

    PLCItem* startItem() const { return m_startItem; }
    PLCItem* endItem() const { return m_endItem; }
    PLCDocument::TerminalType startTerminal() const { return m_startTerminal; }
    PLCDocument::TerminalType endTerminal() const { return m_endTerminal; }
    void setRowTerminalTargetRow(int row) { m_rowTerminalTargetRow = row; }
    int rowTerminalTargetRow() const { return m_rowTerminalTargetRow; }
    void setRowTerminalSourceRow(int row) { m_rowTerminalSourceRow = row; }
    int rowTerminalSourceRow() const { return m_rowTerminalSourceRow; }
    void setStartTerminalPoint(const QPointF& point) { m_startTerminalPoint = point; }
    void setEndTerminalPoint(const QPointF& point) { m_endTerminalPoint = point; }

    // 新增：设置这条连线是否正在被处理
    void setProcessing(bool processing) { m_processing = processing; }
    bool isProcessing() const { return m_processing; }

private:
    PLCItem *m_startItem;
    PLCDocument::TerminalType m_startTerminal;
    PLCItem *m_endItem;
    PLCDocument::TerminalType m_endTerminal;
    QPointF m_startTerminalPoint;
    QPointF m_endTerminalPoint;
    int m_rowTerminalTargetRow = -1;
    int m_rowTerminalSourceRow = -1;
    bool m_processing = false; // 用于防止递归处理
};

#endif // PLCDOCUMENT_H