#include "SpectrogramWidget.h"
#include "GradientDialog.h"
#include <QTimer>
#include <QSurfaceFormat>
#include <QFile>
#include <QMouseEvent>
#include <QColorDialog>
#include <QJsonDocument>
#include <QJsonArray>
#include <QJsonObject>
#include <QDir>
#include <QStandardPaths>
#include <cmath>
#include <cstring>

SpectrogramWidget::SpectrogramWidget(QWidget *parent)
    : QOpenGLWidget(parent)
{
    setAttribute(Qt::WA_OpaquePaintEvent);

    QSurfaceFormat fmt;
    fmt.setVersion(3, 3);
    fmt.setProfile(QSurfaceFormat::CoreProfile);
    fmt.setSwapInterval(1);
    fmt.setSwapBehavior(QSurfaceFormat::DoubleBuffer);
    setFormat(fmt);

    setMinimumSize(400, 200);
    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);

    m_barHeights.resize(BAR_COUNT);
    m_barPeaksVec.resize(BAR_COUNT);

    loadBarColors();

    auto *timer = new QTimer(this);
    connect(timer, &QTimer::timeout,
            this, QOverload<>::of(&SpectrogramWidget::update));
    timer->start(16); 
}

SpectrogramWidget::~SpectrogramWidget()
{
    makeCurrent();
    glDeleteTextures(1, &m_heatmapTex);
    glDeleteVertexArrays(1, &m_vaoBars);
    doneCurrent();
}

void SpectrogramWidget::receiveFft(const QVector<float> &mag)
{
    QMutexLocker lk(&m_queueMtx);
    while (m_fftQueue.size() >= 4)
        m_fftQueue.dequeue();
    m_fftQueue.enqueue(mag);
    update();
}

void SpectrogramWidget::reset()
{
    {
        QMutexLocker lk(&m_queueMtx);
        m_fftQueue.clear();
    }
    m_currentMag .fill(0.f);
    m_barSmoothed.fill(0.f);
    m_barPeak    .fill(0.f);
    m_peakTimer  .fill(0);
    update();
}

void SpectrogramWidget::initializeGL()
{
    initializeOpenGLFunctions();
    initShaders();
    buildHeatmapTexture();

    glGenVertexArrays(1, &m_vaoBars);
    glDisable(GL_BLEND);
}

void SpectrogramWidget::initShaders()
{
    auto load = [](const QString &path) -> QByteArray {
        QFile f(path);
        if (!f.open(QIODevice::ReadOnly | QIODevice::Text)) {
            qWarning() << "Cannot open shader:" << path;
            return {};
        }
        return f.readAll();
    };

    if (!m_barsProg.addShaderFromSourceCode(QOpenGLShader::Vertex,   load(":/shaders/bars.vert")))
        qWarning() << "Bars vert error:" << m_barsProg.log();
    if (!m_barsProg.addShaderFromSourceCode(QOpenGLShader::Fragment, load(":/shaders/bars.frag")))
        qWarning() << "Bars frag error:" << m_barsProg.log();
    if (!m_barsProg.link())
        qWarning() << "Bars link error:" << m_barsProg.log();

    m_uBarHeights = m_barsProg.uniformLocation("barHeights");
    m_uBarPeaks   = m_barsProg.uniformLocation("barPeaks");
    m_uBarCount   = m_barsProg.uniformLocation("barCount");
    m_uBarWidth   = m_barsProg.uniformLocation("barWidth");
    m_uGap        = m_barsProg.uniformLocation("gap");
    m_uBottomY    = m_barsProg.uniformLocation("bottomY");
    m_uTopClip    = m_barsProg.uniformLocation("topClip");
    m_uHeatmap    = m_barsProg.uniformLocation("heatmap");
}

void SpectrogramWidget::buildHeatmapTexture()
{
    updateHeatmapTexture();   // use current m_stops
}

void SpectrogramWidget::updateHeatmapTexture()
{
    if (m_heatmapTex) {
        glDeleteTextures(1, &m_heatmapTex);
        m_heatmapTex = 0;
    }

    if (m_stops.size() < 2)
        m_stops = { QColor(0,0,0), QColor(255,255,255) };

    const int nSegs = m_stops.size() - 1;

    auto lerp = [](int x, int y, float f) {
        return std::clamp(int(x + (y - x) * f), 0, 255);
    };

    for (int i = 0; i < 256; i++) {
        float t   = float(i) / 255.f * nSegs;
        int   seg = std::min(int(t), nSegs - 1);
        float f   = t - seg;
        QColor a = m_stops[seg], b = m_stops[seg+1];
        m_heatmap[i] = qRgb(lerp(a.red(), b.red(), f),
                            lerp(a.green(), b.green(), f),
                            lerp(a.blue(), b.blue(), f));
    }

    glGenTextures(1, &m_heatmapTex);
    glBindTexture(GL_TEXTURE_1D, m_heatmapTex);
    std::vector<GLubyte> td(256 * 3);
    for (int i = 0; i < 256; i++) {
        td[3*i+0] = quint8(qRed  (m_heatmap[i]));
        td[3*i+1] = quint8(qGreen(m_heatmap[i]));
        td[3*i+2] = quint8(qBlue (m_heatmap[i]));
    }
    glTexImage1D(GL_TEXTURE_1D, 0, GL_RGB, 256, 0,
                 GL_RGB, GL_UNSIGNED_BYTE, td.data());
    glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
}

void SpectrogramWidget::setStops(const QVector<QColor> &stops)
{
    if (stops.size() < 2) return;
    m_stops = stops;
    makeCurrent();
    updateHeatmapTexture();
    doneCurrent();
    update();
    saveBarColors();
}

void SpectrogramWidget::loadBarColors()
{
    QString configDir = QStandardPaths::writableLocation(QStandardPaths::HomeLocation) + "/.subwave";
    QDir().mkpath(configDir);
    QString path = configDir + "/barcolors.json";
    QFile f(path);
    if (!f.open(QIODevice::ReadOnly))
        return;

    QJsonDocument doc = QJsonDocument::fromJson(f.readAll());
    f.close();
    if (!doc.isArray())
        return;

    QJsonArray arr = doc.array();
    QVector<QColor> loaded;
    for (const auto &v : arr) {
        QJsonObject obj = v.toObject();
        int r = obj["r"].toInt(0);
        int g = obj["g"].toInt(0);
        int b = obj["b"].toInt(0);
        loaded.append(QColor(r, g, b));
    }
    if (loaded.size() >= 2)
        m_stops = loaded;
}

void SpectrogramWidget::saveBarColors()
{
    QString configDir = QStandardPaths::writableLocation(QStandardPaths::HomeLocation) + "/.subwave";
    QDir().mkpath(configDir);
    QString path = configDir + "/barcolors.json";
    QFile f(path);
    if (!f.open(QIODevice::WriteOnly))
        return;

    QJsonArray arr;
    for (const QColor &c : m_stops) {
        QJsonObject obj;
        obj["r"] = c.red();
        obj["g"] = c.green();
        obj["b"] = c.blue();
        arr.append(obj);
    }
    QJsonDocument doc(arr);
    f.write(doc.toJson());
    f.close();
}

void SpectrogramWidget::mousePressEvent(QMouseEvent *e)
{
    if (e->button() == Qt::LeftButton) {
        GradientDialog dlg(m_stops, this);
        if (dlg.exec() == QDialog::Accepted) {
            setStops(dlg.stops());
        }
    }
    QOpenGLWidget::mousePressEvent(e);
}

void SpectrogramWidget::computeBars()
{
    const int fftLen = m_currentMag.size();
    const double logMin = std::log10(20.0), logMax = std::log10(22050.0);
    QVector<float> bars(BAR_COUNT, 0.f);

    for (int b = 0; b < BAR_COUNT; b++) {
        double f1   = std::pow(10.0, logMin + (logMax-logMin)* b   /BAR_COUNT);
        double f2   = std::pow(10.0, logMin + (logMax-logMin)*(b+1)/BAR_COUNT);
        int    bin1 = std::clamp(int(f1/22050.0*fftLen), 0, fftLen-1);
        int    bin2 = std::clamp(int(f2/22050.0*fftLen), bin1, fftLen-1);
        float  sum  = 0.f; int cnt = 0;
        for (int k = bin1; k <= bin2; k++) { sum += m_currentMag[k]; cnt++; }
        bars[b] = cnt > 0 ? sum/cnt : 0.f;
    }
    for (int b = 0; b < BAR_COUNT; b++) {
        float db = bars[b] > 0 ? 20.f*std::log10(bars[b]) : DB_MIN;
        bars[b]  = std::clamp((db - DB_MIN) / (DB_MAX - DB_MIN), 0.f, 1.f);
    }
    for (int b = 0; b < BAR_COUNT; b++) {
        m_barSmoothed[b] = m_barSmoothed[b]*0.65f + bars[b]*0.35f;
        if (m_barSmoothed[b] >= m_barPeak[b]) {
            m_barPeak[b]   = m_barSmoothed[b];
            m_peakTimer[b] = 25;
        } else if (m_peakTimer[b] > 0) {
            m_peakTimer[b]--;
        } else {
            m_barPeak[b] = std::max(0.f, m_barPeak[b] - 0.006f);
        }
        m_barHeights [b] = m_barSmoothed[b];
        m_barPeaksVec[b] = m_barPeak[b];
    }
}

void SpectrogramWidget::paintGL()
{
    {
        QMutexLocker lk(&m_queueMtx);
        while (!m_fftQueue.isEmpty())
            m_currentMag = m_fftQueue.dequeue();
    }

    computeBars();

    QColor bg = palette().color(QPalette::Window);
    glClearColor(bg.redF(), bg.greenF(), bg.blueF(), 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    if (m_barsProg.isLinked()) {
        const float barWidth  = 2.0f / BAR_COUNT;
        const float gap       = barWidth * 0.2f;
        const float drawWidth = barWidth - gap;

        m_barsProg.bind();
        glUniform1fv(m_uBarHeights, BAR_COUNT, m_barHeights .constData());
        glUniform1fv(m_uBarPeaks,   BAR_COUNT, m_barPeaksVec.constData());
        glUniform1i (m_uBarCount,   BAR_COUNT);
        glUniform1f (m_uBarWidth,   drawWidth);
        glUniform1f (m_uGap,        gap);
        glUniform1f (m_uBottomY,   -1.0f);
        glUniform1f (m_uTopClip,    1.0f);
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_1D, m_heatmapTex);
        glUniform1i(m_uHeatmap, 0);
        glBindVertexArray(m_vaoBars);
        glDrawArraysInstanced(GL_TRIANGLES, 0, 6, BAR_COUNT);
        glBindVertexArray(0);
        m_barsProg.release();
    }
}