#include "DraggableLine.h"
#include <QGraphicsSceneMouseEvent>
#include <QPainter>
#include <QDebug>
#include <QGraphicsScene>

void DraggableLine::mousePressEvent(QGraphicsSceneMouseEvent* event) {
    QPointF pos = event->pos(); // 获取相对于项的坐标
    QLineF currentLine = line();

    if (isNearPoint(pos, currentLine.p1())) {
        draggingStart = true;
        offset = currentLine.p1() - pos;
    }
    else if (isNearPoint(pos, currentLine.p2())) {
        draggingEnd = true;
        offset = currentLine.p2() - pos;
    }
    else {
        // 如果没有点击控制点，可以处理其他逻辑或忽略
        QGraphicsLineItem::mousePressEvent(event);
        return;
    }
    event->accept(); // 标记事件已处理
}


void DraggableLine::mouseMoveEvent(QGraphicsSceneMouseEvent* event) {
    if (draggingStart || draggingEnd) {
        QLineF currentLine = line();
        QPointF newPos = event->pos() + offset; // 计算新的端点位置

        if (draggingStart) {
            currentLine.setP1(newPos);
        }
        else {
            currentLine.setP2(newPos);
        }

        setLine(currentLine); // 更新线段
        scene()->update(); // 请求重绘
        event->accept();
    }
    else {
        QGraphicsLineItem::mouseMoveEvent(event);
    }
}


void DraggableLine::mouseReleaseEvent(QGraphicsSceneMouseEvent* event) {
    draggingStart = false;
    draggingEnd = false;

    QLineF currentLine = line();
    qDebug() << "线段长度:" << currentLine.length();

    QGraphicsLineItem::mouseReleaseEvent(event);
}


void DraggableLine::paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget) {
    // 先调用基类方法绘制线段
    QGraphicsLineItem::paint(painter, option, widget);

    // 绘制起点和终点的控制点
    painter->setBrush(Qt::red);
    painter->drawEllipse(line().p1(), 5, 5);

    painter->setBrush(Qt::blue);
    painter->drawEllipse(line().p2(), 5, 5);
}


bool DraggableLine::isNearPoint(const QPointF& pos, const QPointF& point) const
{
    QLineF line(pos, point);
    return (line.length() < 20); // 10像素范围内判定为点击控制点
}