#include "audiopreviewwidget.h"
#include <QHeaderView>
#include <QtEndian>
#include <QPainter>
#include <QPen>
#include <QDir>
#include <QShowEvent>
#include <QResizeEvent>
#include <QTimer>

AudioPreviewWidget::AudioPreviewWidget(QWidget *parent)
    : QWidget(parent)
    , mPlayer(new QMediaPlayer(this))
    , mAudioOutput(new QAudioOutput(this))
    , mAudioBuffer(nullptr)
    , mPositionTimer(new QTimer(this))
    , mDuration(0)
    , mCalculatedDuration(0)
    , mSampleRate(0)
    , mChannels(0)
    , mBitsPerSample(0)
    , mDataSize(0)
    , mAudioFormat(0)
    , mBigEndian(false)
{
    mPlayer->setAudioOutput(mAudioOutput);
    mAudioOutput->setVolume(0.5);

    // Timer for updating position slider during playback
    mPositionTimer->setInterval(50);  // 50ms = 20 updates per second
    connect(mPositionTimer, &QTimer::timeout, this, &AudioPreviewWidget::onUpdatePosition);

    // Create UI
    auto *mainLayout = new QVBoxLayout(this);
    mainLayout->setContentsMargins(0, 0, 0, 0);

    // Splitter for preview and metadata
    auto *splitter = new QSplitter(Qt::Horizontal, this);

    // Left side - audio controls
    auto *controlsWidget = new QWidget(splitter);
    controlsWidget->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Preferred);
    auto *controlsLayout = new QVBoxLayout(controlsWidget);
    controlsLayout->setContentsMargins(4, 4, 4, 4);

    mFilenameLabel = new QLabel(this);
    mFilenameLabel->setAlignment(Qt::AlignLeft | Qt::AlignVCenter);
    mFilenameLabel->setStyleSheet("QLabel { background-color: #252526; color: #888; padding: 4px 8px; font-size: 11px; }");
    controlsLayout->addWidget(mFilenameLabel);

    // Waveform display - expands vertically
    mWaveformLabel = new QLabel(this);
    mWaveformLabel->setMinimumHeight(80);
    mWaveformLabel->setMinimumWidth(400);
    mWaveformLabel->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
    mWaveformLabel->setAlignment(Qt::AlignLeft | Qt::AlignVCenter);
    mWaveformLabel->setStyleSheet("QLabel { background-color: #1e1e1e; border: 1px solid #333; }");
    controlsLayout->addWidget(mWaveformLabel, 1);

    // Time and position
    auto *positionLayout = new QHBoxLayout();
    mTimeLabel = new QLabel("00:00 / 00:00", this);
    mPositionSlider = new QSlider(Qt::Horizontal, this);
    mPositionSlider->setRange(0, 0);
    mPositionSlider->setSingleStep(100);    // 100ms per arrow key
    mPositionSlider->setPageStep(1000);     // 1 second per page up/down
    mPositionSlider->setTracking(true);     // Update while dragging
    positionLayout->addWidget(mPositionSlider, 1);
    positionLayout->addWidget(mTimeLabel);
    controlsLayout->addLayout(positionLayout);

    // Playback controls
    auto *buttonLayout = new QHBoxLayout();
    mPlayButton = new QPushButton("Play", this);
    mStopButton = new QPushButton("Stop", this);
    mVolumeSlider = new QSlider(Qt::Horizontal, this);
    mVolumeSlider->setRange(0, 100);
    mVolumeSlider->setValue(50);
    mVolumeSlider->setMaximumWidth(100);

    auto *volumeLabel = new QLabel("Vol:", this);
    buttonLayout->addWidget(mPlayButton);
    buttonLayout->addWidget(mStopButton);
    buttonLayout->addStretch();
    buttonLayout->addWidget(volumeLabel);
    buttonLayout->addWidget(mVolumeSlider);
    controlsLayout->addLayout(buttonLayout);

    splitter->addWidget(controlsWidget);

    // Right side - metadata tree
    mMetadataTree = new QTreeWidget(splitter);
    mMetadataTree->setHeaderLabels({"Property", "Value"});
    mMetadataTree->header()->setSectionResizeMode(0, QHeaderView::ResizeToContents);
    mMetadataTree->header()->setSectionResizeMode(1, QHeaderView::Stretch);
    mMetadataTree->setAlternatingRowColors(true);
    splitter->addWidget(mMetadataTree);

    splitter->setSizes({400, 200});
    mainLayout->addWidget(splitter);

    // Connect signals
    connect(mPlayButton, &QPushButton::clicked, this, &AudioPreviewWidget::onPlayPause);
    connect(mStopButton, &QPushButton::clicked, this, &AudioPreviewWidget::onStop);
    connect(mPositionSlider, &QSlider::sliderMoved, this, &AudioPreviewWidget::onSliderMoved);
    connect(mVolumeSlider, &QSlider::valueChanged, this, [this](int value) {
        mAudioOutput->setVolume(value / 100.0);
    });

    connect(mPlayer, &QMediaPlayer::positionChanged, this, &AudioPreviewWidget::onPositionChanged);
    connect(mPlayer, &QMediaPlayer::durationChanged, this, &AudioPreviewWidget::onDurationChanged);
    connect(mPlayer, &QMediaPlayer::mediaStatusChanged, this, &AudioPreviewWidget::onMediaStatusChanged);

    // Connect to theme changes
    connect(&Settings::instance(), &Settings::themeChanged, this, &AudioPreviewWidget::applyTheme);

    // Apply current theme
    applyTheme(Settings::instance().theme());
}

AudioPreviewWidget::~AudioPreviewWidget()
{
    mPlayer->stop();
    if (mAudioBuffer) {
        mAudioBuffer->close();
        delete mAudioBuffer;
    }
}

void AudioPreviewWidget::parseWavHeader(const QByteArray &data)
{
    if (data.size() < 44) return;

    const uchar *d = reinterpret_cast<const uchar*>(data.constData());

    // Check RIFF header - RIFF = little-endian, RIFX = big-endian
    mBigEndian = false;
    if (data.left(4) == "RIFX") {
        mBigEndian = true;
    } else if (data.left(4) != "RIFF") {
        return;
    }
    if (data.mid(8, 4) != "WAVE") return;

    // Helper lambdas for endian-aware reading
    auto readU16 = [d, this](int offset) -> quint16 {
        return mBigEndian ? qFromBigEndian<quint16>(d + offset) : qFromLittleEndian<quint16>(d + offset);
    };
    auto readU32 = [d, this](int offset) -> quint32 {
        return mBigEndian ? qFromBigEndian<quint32>(d + offset) : qFromLittleEndian<quint32>(d + offset);
    };

    // Find fmt chunk
    int pos = 12;
    while (pos < data.size() - 8) {
        QString chunkId = QString::fromLatin1(data.mid(pos, 4));
        quint32 chunkSize = readU32(pos + 4);

        if (chunkId == "fmt ") {
            if (static_cast<qint64>(pos) + 8 + chunkSize <= data.size()) {
                mAudioFormat = readU16(pos + 8);
                mChannels = readU16(pos + 10);
                mSampleRate = readU32(pos + 12);
                mBitsPerSample = readU16(pos + 22);
            }
        } else if (chunkId == "data") {
            mDataSize = chunkSize;
            break;
        }

        pos += 8 + chunkSize;
        if (chunkSize % 2) pos++; // Padding
    }
}

bool AudioPreviewWidget::loadFromData(const QByteArray &data, const QString &filename)
{
    mFilename = filename;
    mFilenameLabel->setText(filename);
    mAudioData = data;

    // Parse WAV header for info
    parseWavHeader(data);

    // Add WAV info to metadata tree
    mMetadataTree->clear();

    auto *formatItem = new QTreeWidgetItem(mMetadataTree);
    formatItem->setText(0, "Format");
    QString formatStr = mBigEndian ? "WAV (RIFX/BE)" : "WAV (RIFF/LE)";
    formatItem->setText(1, formatStr);

    if (mAudioFormat > 0) {
        auto *codecItem = new QTreeWidgetItem(mMetadataTree);
        codecItem->setText(0, "Audio Codec");
        QString codecStr;
        switch (mAudioFormat) {
            case 1: codecStr = "PCM"; break;
            case 2: codecStr = "MS ADPCM"; break;
            case 6: codecStr = "A-law"; break;
            case 7: codecStr = "u-law"; break;
            case 17: codecStr = "IMA ADPCM"; break;
            case 85: codecStr = "MP3"; break;
            case 0x165: codecStr = "XMA"; break;
            case 0x166: codecStr = "XMA2"; break;
            default: codecStr = QString("0x%1").arg(mAudioFormat, 0, 16); break;
        }
        codecItem->setText(1, codecStr);
    }

    if (mSampleRate > 0) {
        auto *srItem = new QTreeWidgetItem(mMetadataTree);
        srItem->setText(0, "Sample Rate");
        srItem->setText(1, QString("%1 Hz").arg(mSampleRate));
    }

    if (mChannels > 0) {
        auto *chItem = new QTreeWidgetItem(mMetadataTree);
        chItem->setText(0, "Channels");
        chItem->setText(1, mChannels == 1 ? "Mono" : (mChannels == 2 ? "Stereo" : QString::number(mChannels)));
    }

    if (mBitsPerSample > 0) {
        auto *bpsItem = new QTreeWidgetItem(mMetadataTree);
        bpsItem->setText(0, "Bit Depth");
        bpsItem->setText(1, QString("%1-bit").arg(mBitsPerSample));
    }

    if (mDataSize > 0) {
        auto *sizeItem = new QTreeWidgetItem(mMetadataTree);
        sizeItem->setText(0, "Data Size");
        sizeItem->setText(1, QString("%1 bytes").arg(mDataSize));
    }

    // Calculate duration from WAV header data
    mCalculatedDuration = 0;
    // Always try to play - QMediaPlayer/Windows Media Foundation may support more formats
    bool canPlay = true;

    if (mSampleRate > 0 && mChannels > 0 && mDataSize > 0 && mBitsPerSample > 0) {
        // Calculate duration assuming PCM - many "XMA2" labeled files contain PCM data
        int bytesPerSample = mBitsPerSample / 8;
        mCalculatedDuration = static_cast<double>(mDataSize) / (mSampleRate * mChannels * bytesPerSample);

        auto *durItem = new QTreeWidgetItem(mMetadataTree);
        durItem->setText(0, "Duration");
        int mins = static_cast<int>(mCalculatedDuration) / 60;
        int secs = static_cast<int>(mCalculatedDuration) % 60;
        int ms = static_cast<int>((mCalculatedDuration - static_cast<int>(mCalculatedDuration)) * 1000);
        durItem->setText(1, QString("%1:%2.%3")
            .arg(mins, 2, 10, QChar('0'))
            .arg(secs, 2, 10, QChar('0'))
            .arg(ms, 3, 10, QChar('0')));
    }

    // Disable playback for unsupported formats
    if (!canPlay) {
        mPlayButton->setEnabled(false);
        mPlayButton->setText("N/A");
        mPlayButton->setToolTip("XMA/XMA2 playback not supported");
        mStopButton->setEnabled(false);
        mPositionSlider->setEnabled(false);
    } else {
        mPlayButton->setEnabled(true);
        mPlayButton->setText("Play");
        mPlayButton->setToolTip("");
        mStopButton->setEnabled(true);
        mPositionSlider->setEnabled(true);
    }

    auto *fileSizeItem = new QTreeWidgetItem(mMetadataTree);
    fileSizeItem->setText(0, "File Size");
    fileSizeItem->setText(1, QString("%1 bytes").arg(data.size()));

    // Debug: show first 32 bytes as hex (includes fmt chunk start)
    auto *headerItem = new QTreeWidgetItem(mMetadataTree);
    headerItem->setText(0, "Header (hex)");
    QString headerHex;
    for (int i = 0; i < qMin(32, data.size()); i++) {
        headerHex += QString("%1 ").arg(static_cast<uchar>(data[i]), 2, 16, QChar('0'));
    }
    headerItem->setText(1, headerHex.trimmed());

    // Debug: show raw format value
    auto *rawFmtItem = new QTreeWidgetItem(mMetadataTree);
    rawFmtItem->setText(0, "Raw Format");
    rawFmtItem->setText(1, QString("0x%1 (%2)").arg(mAudioFormat, 4, 16, QChar('0')).arg(mAudioFormat));

    // Setup audio buffer for playback
    if (mAudioBuffer) {
        mAudioBuffer->close();
        delete mAudioBuffer;
    }

    mAudioBuffer = new QBuffer(this);
    mAudioBuffer->setData(mAudioData);
    mAudioBuffer->open(QIODevice::ReadOnly);

    mPlayer->setSourceDevice(mAudioBuffer);

    // Initialize slider and time display with calculated duration (authoritative)
    if (mCalculatedDuration > 0) {
        mDuration = static_cast<qint64>(mCalculatedDuration * 1000);
        mPositionSlider->setRange(0, static_cast<int>(mDuration));
        mPositionSlider->setValue(0);
    }
    updateTimeLabel();

    // Draw waveform visualization
    drawWaveform();

    return true;
}

void AudioPreviewWidget::drawWaveform()
{
    if (mAudioData.isEmpty()) return;

    // Use actual label size for dynamic sizing
    int width = qMax(400, mWaveformLabel->width());
    int height = qMax(80, mWaveformLabel->height());

    mWaveformPixmap = QPixmap(width, height);
    mWaveformPixmap.fill(mBgColor);

    QPainter painter(&mWaveformPixmap);
    painter.setRenderHint(QPainter::Antialiasing);

    int centerY = height / 2;
    int amplitudeHeight = height / 4;  // Half of available space (25% above + 25% below center)

    // Draw center line
    painter.setPen(mBorderColor);
    painter.drawLine(0, centerY, width, centerY);

    // Find data section
    int dataStart = 44; // Standard WAV header
    if (mAudioData.size() > dataStart)
    {
        const qint16 *samples = reinterpret_cast<const qint16*>(mAudioData.constData() + dataStart);
        int numSamples = (mAudioData.size() - dataStart) / 2;
        int samplesPerPixel = qMax(1, numSamples / width);

        painter.setPen(mAccentColor);  // Theme accent color

        for (int x = 0; x < width && x * samplesPerPixel < numSamples; x++)
        {
            qint16 minVal = 0, maxVal = 0;
            for (int i = 0; i < samplesPerPixel && (x * samplesPerPixel + i) < numSamples; i++)
            {
                qint16 sample = samples[x * samplesPerPixel + i];
                minVal = qMin(minVal, sample);
                maxVal = qMax(maxVal, sample);
            }

            // Scale to full amplitude height
            int yMin = centerY - (maxVal * amplitudeHeight / 32768);
            int yMax = centerY - (minVal * amplitudeHeight / 32768);
            painter.drawLine(x, yMin, x, yMax);
        }
    }

    painter.end();
    updateWaveformPosition();
}

void AudioPreviewWidget::applyTheme(const Theme &theme)
{
    mAccentColor = QColor(theme.accentColor);
    mBgColor = QColor(theme.backgroundColor);
    mPanelColor = QColor(theme.panelColor);
    mTextColor = QColor(theme.textColor);
    mTextColorMuted = QColor(theme.textColorMuted);
    mBorderColor = QColor(theme.borderColor);

    // Update UI element styles
    mFilenameLabel->setStyleSheet(QString(
        "QLabel { background-color: %1; color: %2; padding: 4px 8px; font-size: 11px; }"
    ).arg(theme.panelColor, theme.textColorMuted));

    mWaveformLabel->setStyleSheet(QString(
        "QLabel { background-color: %1; border: 1px solid %2; }"
    ).arg(theme.backgroundColor, theme.borderColor));

    mMetadataTree->setStyleSheet(QString(
        "QTreeWidget { background-color: %1; color: %2; border: none; }"
        "QTreeWidget::item:selected { background-color: %3; color: white; }"
        "QTreeWidget::item:alternate { background-color: %4; }"
        "QHeaderView::section { background-color: %4; color: %5; padding: 4px; border: none; }"
    ).arg(theme.backgroundColor, theme.textColor, theme.accentColor, theme.panelColor, theme.textColorMuted));

    // Redraw waveform with new colors
    if (!mAudioData.isEmpty()) {
        drawWaveform();
    }
}

void AudioPreviewWidget::updateWaveformPosition()
{
    if (mWaveformPixmap.isNull()) return;

    QPixmap displayPixmap = mWaveformPixmap.copy();
    QPainter painter(&displayPixmap);

    // Use calculated duration as authoritative source (in ms)
    qint64 durationMs = static_cast<qint64>(mCalculatedDuration * 1000);
    if (durationMs <= 0) durationMs = mDuration;

    // Draw playback position line
    if (durationMs > 0)
    {
        qint64 pos = mPlayer->position();
        double progress = static_cast<double>(pos) / static_cast<double>(durationMs);
        int xPos = static_cast<int>(progress * displayPixmap.width());

        // Use lighter version of accent color for position line
        painter.setPen(QPen(mAccentColor.lighter(140), 3));
        painter.drawLine(xPos, 0, xPos, displayPixmap.height());
    }

    painter.end();

    // Scale to fill the label
    int targetWidth = mWaveformLabel->width();
    int targetHeight = mWaveformLabel->height();
    if (targetWidth < 100) targetWidth = 400;
    if (targetHeight < 50) targetHeight = 120;
    mWaveformLabel->setPixmap(displayPixmap.scaled(targetWidth, targetHeight, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
}

void AudioPreviewWidget::setMetadata(const QVariantMap &metadata)
{
    // Add custom metadata from parsed fields
    for (auto it = metadata.begin(); it != metadata.end(); ++it) {
        if (it.key().startsWith("_")) continue; // Skip internal fields

        auto *item = new QTreeWidgetItem(mMetadataTree);
        item->setText(0, it.key());

        QVariant val = it.value();
        if (val.typeId() == QMetaType::QByteArray) {
            QByteArray ba = val.toByteArray();
            item->setText(1, QString("<%1 bytes>").arg(ba.size()));
        } else {
            item->setText(1, val.toString());
        }
    }
}

void AudioPreviewWidget::onPlayPause()
{
    if (mPlayer->playbackState() == QMediaPlayer::PlayingState) {
        mPlayer->pause();
        mPlayButton->setText("Play");
        mPositionTimer->stop();
    } else {
        mPlayer->play();
        mPlayButton->setText("Pause");
        mPositionTimer->start();
    }
}

void AudioPreviewWidget::onStop()
{
    mPlayer->stop();
    mPositionTimer->stop();
    mPlayButton->setText("Play");
    updateWaveformPosition();
}

void AudioPreviewWidget::onPositionChanged(qint64 position)
{
    if (!mPositionSlider->isSliderDown()) {
        mPositionSlider->setValue(static_cast<int>(position));
    }
    updateTimeLabel();
    updateWaveformPosition();
}

void AudioPreviewWidget::onDurationChanged(qint64 duration)
{
    // Prefer calculated duration from WAV header as it's more reliable
    if (mCalculatedDuration > 0) {
        mDuration = static_cast<qint64>(mCalculatedDuration * 1000);
    } else if (duration > 0) {
        mDuration = duration;
    }
    mPositionSlider->setRange(0, static_cast<int>(mDuration));
    updateTimeLabel();
}

void AudioPreviewWidget::onSliderMoved(int position)
{
    mPlayer->setPosition(position);
    updateWaveformPosition();
}

void AudioPreviewWidget::onMediaStatusChanged(QMediaPlayer::MediaStatus status)
{
    if (status == QMediaPlayer::EndOfMedia) {
        mPositionTimer->stop();
        mPlayButton->setText("Play");
        mPlayer->setPosition(0);
        updateWaveformPosition();
    } else if (status == QMediaPlayer::LoadedMedia) {
        // Set duration from calculated value (authoritative)
        if (mCalculatedDuration > 0) {
            mDuration = static_cast<qint64>(mCalculatedDuration * 1000);
            mPositionSlider->setRange(0, static_cast<int>(mDuration));
            updateTimeLabel();
        }
    }
}

void AudioPreviewWidget::onUpdatePosition()
{
    // Always update when timer fires - let the timer start/stop control this
    qint64 position = mPlayer->position();

    // Update slider if not being dragged
    if (!mPositionSlider->isSliderDown()) {
        mPositionSlider->blockSignals(true);
        mPositionSlider->setValue(static_cast<int>(position));
        mPositionSlider->blockSignals(false);
    }

    updateTimeLabel();
    updateWaveformPosition();
}

void AudioPreviewWidget::updateTimeLabel()
{
    qint64 pos = mPlayer->position();
    // Always use calculated duration as authoritative source
    qint64 dur = static_cast<qint64>(mCalculatedDuration * 1000);
    if (dur <= 0) dur = mDuration;

    // Format: MM:SS.mmm
    QString posStr = QString("%1:%2.%3")
        .arg(pos / 60000, 2, 10, QChar('0'))
        .arg((pos / 1000) % 60, 2, 10, QChar('0'))
        .arg(pos % 1000, 3, 10, QChar('0'));

    QString durStr = QString("%1:%2.%3")
        .arg(dur / 60000, 2, 10, QChar('0'))
        .arg((dur / 1000) % 60, 2, 10, QChar('0'))
        .arg(dur % 1000, 3, 10, QChar('0'));

    mTimeLabel->setText(posStr + " / " + durStr);
}

void AudioPreviewWidget::showEvent(QShowEvent *event)
{
    QWidget::showEvent(event);
    // Redraw waveform now that widget is properly sized
    if (!mAudioData.isEmpty()) {
        QTimer::singleShot(0, this, &AudioPreviewWidget::drawWaveform);
    }
}

void AudioPreviewWidget::resizeEvent(QResizeEvent *event)
{
    QWidget::resizeEvent(event);
    // Redraw waveform at new size
    if (!mAudioData.isEmpty()) {
        drawWaveform();
    }
}