// SPDX-FileCopyrightText: 2025 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only

#include "JFJochSimpleChartView.h"

#include <QMenu>
#include <QClipboard>
#include <QApplication>
#include <QCategoryAxis>

JFJochSimpleChartView::JFJochSimpleChartView(QWidget *parent)
        : QChartView(new QChart(), parent) {
    chart()->legend()->hide();
    setFixedHeight(300);
    setRenderHint(QPainter::Antialiasing);
    setMouseTracking(true);
    //setRubberBand(QChartView::RubberBand::HorizontalRubberBand);
}

void JFJochSimpleChartView::UpdateData(const std::vector<float> &in_x, const std::vector<float> &in_y,
        QString legend_x, QString legend_y) {
    x = in_x;
    y = in_y;

    // Remove hover line if any
    if (m_hoverLine) {
        chart()->scene()->removeItem(m_hoverLine);
        delete m_hoverLine;
        m_hoverLine = nullptr;
    }
    m_series = nullptr;

    chart()->removeAllSeries();
    // Remove all axes to avoid duplicates
    for (auto ax: chart()->axes()) chart()->removeAxis(ax);

    if (x.empty() || x.size() != y.size()) return;

    auto *series = new QLineSeries(this);
    for (size_t i = 0; i < x.size(); ++i) series->append(x[i], y[i]);
    chart()->addSeries(series);
    m_series = series;

    auto *axY = new QValueAxis();
    axY->setTitleText(legend_y);
    chart()->addAxis(axY, Qt::AlignLeft);
    series->attachAxis(axY);

    // Build X range
    auto [minXIt, maxXIt] = std::minmax_element(x.begin(), x.end());
    const double xmin = *minXIt, xmax = *maxXIt;

    // Normal value axis at bottom
    auto *axX = new QValueAxis();
    axX->setRange(xmin, xmax);
    axX->setTitleText(legend_x);
    chart()->addAxis(axX, Qt::AlignBottom);
    series->attachAxis(axX);
}

void JFJochSimpleChartView::ClearData() {
    x.clear();
    y.clear();
    m_series = nullptr;
    if (m_hoverLine) {
        chart()->scene()->removeItem(m_hoverLine);
        delete m_hoverLine;
        m_hoverLine = nullptr;
    }
    chart()->removeAllSeries();
}

void JFJochSimpleChartView::contextMenuEvent(QContextMenuEvent *event) {
    QMenu menu(this);
    QAction *copyXY = menu.addAction("Copy (x y) points");
    copyXY->setEnabled(!x.empty() && x.size() == y.size());

    QAction *chosen = menu.exec(event->globalPos());
    if (chosen == copyXY) {
        QString out;
        out.reserve(static_cast<int>(x.size() * 16)); // rough prealloc
        for (size_t i = 0; i < x.size() && i < y.size(); ++i) {
            out.append(QString::number(x[i], 'g', 10));
            out.append(' ');
            out.append(QString::number(y[i], 'g', 10));
            if (i + 1 < x.size()) out.append('\n');
        }
        QClipboard *cb = QApplication::clipboard();
        cb->setText(out);
    }
}

void JFJochSimpleChartView::mouseMoveEvent(QMouseEvent *event) {
    QChartView::mouseMoveEvent(event);
    if (!m_series || x.empty() || x.size() != y.size())
        return;

    // Map mouse position to chart coordinates
    const QPointF chartPos = chart()->mapToValue(event->pos(), m_series);
    const double  xVal     = chartPos.x();

    // Find closest index in x[]
    auto it = std::lower_bound(x.begin(), x.end(), static_cast<float>(xVal));
    if (it == x.end() && !x.empty())
        it = std::prev(x.end());
    if (it == x.end())
        return;

    size_t idx = static_cast<size_t>(std::distance(x.begin(), it));
    if (idx > 0) {
        const float xPrev = x[idx - 1];
        if (std::abs(xPrev - xVal) < std::abs(x[idx] - xVal))
            --idx;
    }

    const float xNearest = x[idx];
    const float yNearest = y[idx];

    // Map that data point to scene coords to get the x position
    const QPointF ptOnSeries = chart()->mapToPosition(QPointF(xNearest, yNearest), m_series);
    const QRectF  plotArea   = chart()->plotArea();

    if (!m_hoverLine) {
        m_hoverLine = new QGraphicsLineItem;
        m_hoverLine->setPen(QPen(QColor(200, 0, 0, 150), 1.0));
        chart()->scene()->addItem(m_hoverLine);
    }

    m_hoverLine->setLine(QLineF(ptOnSeries.x(), plotArea.top(),
                                ptOnSeries.x(), plotArea.bottom()));

    // Send to status bar
    emit writeStatusBar(getText(idx),6000);
}

QString JFJochSimpleChartView::getText(size_t idx) {
    if (idx < x.size())
        return QString("x = %1, y = %2")
                .arg(x[idx], 0, 'g', 6)
                .arg(y[idx], 0, 'g', 6);
    return QString();
}

void JFJochSimpleChartView::leaveEvent(QEvent *event) {
    QChartView::leaveEvent(event);
    if (m_hoverLine) {
        chart()->scene()->removeItem(m_hoverLine);
        delete m_hoverLine;
        m_hoverLine = nullptr;
    }
    emit writeStatusBar(QString(), 0); // clear status bar when leaving
}