#include "CurvePlotWidget.h"
#include <QPainter>
#include <QtMath>
#include <limits>
#include <QDebug>
#include <QTime>
CurvePlotWidget::CurvePlotWidget(QWidget *parent) : QWidget(parent)
{
    setMinimumSize(300, 200);
}

void CurvePlotWidget::setTimeRange(double secs)
{
    m_tRange = qMax(secs, 1.0);
    m_xMax   = qMax(200, int(width() / 2));
    for (auto &c : m_curves) {
        c.tBuf.resize(m_xMax);
        c.yBuf.resize(m_xMax);
        c.head = 0;
    }
    update();
}

void CurvePlotWidget::initCurve(int id, const CurveCfg &cfg)
{
    Curve c;
    c.cfg  = cfg;
    // 确保阈值有效
   Q_ASSERT(cfg.thWarning < cfg.thFault);
   Q_ASSERT(cfg.thFault <= cfg.yMax);
    c.tBuf.resize(m_xMax);
    c.yBuf.resize(m_xMax);
    c.tBuf.fill(std::numeric_limits<double>::quiet_NaN());
    c.yBuf.fill(std::numeric_limits<double>::quiet_NaN());
    c.head = 0;
    m_curves.insert(id, c);
}

void CurvePlotWidget::clearAllCurves()
{
    m_curves.clear();
    m_t0set = false;
    update();
}

void CurvePlotWidget::appendPoint(int curveId, double timeStamp, double yValue)
{
    if (!m_curves.contains(curveId)) return;
    Curve &c = m_curves[curveId];
    if (!m_t0set) {
        m_t0 = timeStamp;
        m_t0set = true;
    }
    double t = timeStamp - m_t0;
    c.tBuf[c.head] = t;
    c.yBuf[c.head] = yValue;
    c.head = (c.head + 1) % m_xMax;
    update();
}

void CurvePlotWidget::paintEvent(QPaintEvent *)
{
    QPainter p(this);
    p.setRenderHint(QPainter::Antialiasing);

    QRectF plotRect(m_leftMargin, m_topMargin,
                    width() - m_leftMargin - m_rightMargin,
                    height() - m_topMargin - m_bottomMargin);

    /* ---------- 1. 顶部图例 ---------- */
    int legendX = m_leftMargin + 5;
    int legendY = m_topMargin - 15;
    for (const auto &c : m_curves) {
        p.setPen(QPen(c.cfg.normal, 2));
        p.drawLine(legendX, legendY, legendX + 15, legendY);
        p.setPen(QPen(Qt::white));
        p.drawText(legendX + 20, legendY + 4, c.cfg.name);
        legendX += 20 + p.fontMetrics().horizontalAdvance(c.cfg.name) + 15;
    }

    /* ---------- 2. 坐标轴 ---------- */
    p.setPen(Qt::white);
    /* Y 轴刻度 */
    if (!m_curves.isEmpty()) {
        const Curve &c = *m_curves.begin();
        double yMax = c.cfg.yMax;
        for (int i = 0; i <= 4; ++i) {
            double y = yMax * i / 4.0;
            QString txt = QString::number(y, 'f', 1);
            int ty = int(plotRect.bottom() - i * plotRect.height() / 4.0);
            p.drawText(5, ty + 4, txt);
        }
    }
    /* ---------- X 轴刻度（真实时钟） ---------- */
    // 当前这一帧可见窗口的绝对时间范围
    double tLeftEpoch  = QDateTime::currentDateTime().toSecsSinceEpoch() - m_tRange;
    double tRightEpoch = QDateTime::currentDateTime().toSecsSinceEpoch();

    for (int i = 0; i <= 4; ++i) {
        double tEpoch = tLeftEpoch + m_tRange * i / 4.0;               // 绝对秒
        QDateTime tm  = QDateTime::fromSecsSinceEpoch(qint64(tEpoch)); // 真实时钟
        QString txt   = tm.toString("hh:mm:ss");

        int tx = int(plotRect.left() + i * plotRect.width() / 4.0);
        p.drawText(tx - 25, height() - 5, txt);
    }

    /* ---------- 4. 曲线 ---------- */
    for (const auto &c : m_curves) {
        if (m_xMax <= 1) continue;

        // 改成同时缓存 QPointF 和 对应的 y 值
        struct Pt {
            QPointF pos;
            double  y;
        };
        QVector<Pt> pts;
        pts.reserve(m_xMax);

        for (int i = 0; i < m_xMax; ++i) {
            int idx = (c.head + i) % m_xMax;
            double t = c.tBuf[idx];
            double y = c.yBuf[idx];
            if (std::isnan(t) || std::isnan(y))
                continue;
            pts.append({mapToWidget(t, y, c), y});
        }
        if (pts.size() < 2) continue;

        // 逐段画线，颜色直接用 pts[k].y
        for (int k = 0; k < pts.size() - 1; ++k) {
            double y = pts[k].y;
            int level = 0;
            if (y >= c.cfg.thFault)        level = 2;
            else if (y >= c.cfg.thWarning) level = 1;

            QColor col = level == 0 ? c.cfg.normal
                       : level == 1 ? c.cfg.warning
                                    : c.cfg.fault;

            p.setPen(QPen(col, 2));
            p.drawLine(pts[k].pos, pts[k + 1].pos);
        }
    }
}

QPointF CurvePlotWidget::mapToWidget(double t, double y, const Curve &c) const
{
    QRectF plotRect(m_leftMargin, m_topMargin,
                    width() - m_leftMargin - m_rightMargin,
                    height() - m_topMargin - m_bottomMargin);

    double x = plotRect.left() + (t / m_tRange) * plotRect.width();
    double norm = qBound(0.0, y / c.cfg.yMax, 1.0);
    double wy   = plotRect.bottom() - norm * plotRect.height();
    return QPointF(x, wy);
}

void CurvePlotWidget::resizeEvent(QResizeEvent *)
{
    setTimeRange(m_tRange);   // 按新宽度重新计算点数
}