// src/MainWindow.cpp

#include "MainWindow.h"
#include <QApplication>
#include <QHeaderView>
#include <QScrollBar>
#include <QFileInfo>
#include <QCloseEvent>
#include <QFileDialog>
#include <QScroller>
#include <QThread>
#include <QJsonDocument>
#include <QJsonObject>
#include <QDir>
#include <QStandardPaths>
#include <QUrl>
#include <QProgressDialog>
#include <algorithm>

#if defined(Q_OS_ANDROID) || defined(Q_OS_IOS)
#ifndef IS_MOBILE
#define IS_MOBILE
#endif
#endif

MainWindow::MainWindow(QWidget* parent) : QMainWindow(parent) {
    setWindowTitle("Yr Crystals");
    resize(1280, 800);

    m_stack = new QStackedWidget(this);
    setCentralWidget(m_stack);

    m_welcome = new WelcomeWidget(this);
    connect(m_welcome, &WelcomeWidget::openFileClicked, this, &MainWindow::onOpenFile);
    connect(m_welcome, &WelcomeWidget::openFolderClicked, this, &MainWindow::onOpenFolder);
    m_stack->addWidget(m_welcome);

    initUi();

    m_engine = new AudioEngine();
    QThread* audioThread = new QThread(this);
    m_engine->moveToThread(audioThread);

    connect(audioThread, &QThread::finished, m_engine, &QObject::deleteLater);
    connect(m_engine, &AudioEngine::playbackFinished, this, &MainWindow::onTrackFinished);
    connect(m_engine, &AudioEngine::trackLoaded, this, &MainWindow::onTrackLoaded);
    connect(m_engine, &AudioEngine::positionChanged, m_playerPage->playback(), &PlaybackWidget::updateSeek);
    connect(m_engine, &AudioEngine::spectrumReady, m_playerPage->visualizer(), &VisualizerWidget::updateData);

    // Buffering Logic
    connect(m_engine, &AudioEngine::bufferingStart, this, [this](){
        if (!m_waitDialog) {
            m_waitDialog = new QProgressDialog("Buffering...", QString(), 0, 0, this);
            m_waitDialog->setWindowModality(Qt::ApplicationModal);
            m_waitDialog->setCancelButton(nullptr);
            m_waitDialog->setMinimumDuration(0);
        }
        m_waitDialog->show();
    });
    
    connect(m_engine, &AudioEngine::bufferingEnd, this, [this](){
        if (m_waitDialog) m_waitDialog->hide();
    });

    audioThread->start();
}

MainWindow::~MainWindow() {
    if (m_engine) {
        QMetaObject::invokeMethod(m_engine, "stop", Qt::BlockingQueuedConnection);
        m_engine->thread()->quit();
        m_engine->thread()->wait();
    }
}

void MainWindow::initUi() {
    m_playerPage = new PlayerPage(this);

    m_playlist = new QListWidget();
    m_playlist->setStyleSheet("QListWidget { background-color: #111; border: none; } QListWidget::item { border-bottom: 1px solid #222; padding: 5px; } QListWidget::item:selected { background-color: #333; }");
    m_playlist->setSelectionMode(QAbstractItemView::SingleSelection);
    QScroller::grabGesture(m_playlist, QScroller::LeftMouseButtonGesture);
    connect(m_playlist, &QListWidget::itemDoubleClicked, this, &MainWindow::onTrackDoubleClicked);

    PlaybackWidget* pb = m_playerPage->playback();
    SettingsWidget* set = m_playerPage->settings();
    VisualizerWidget* viz = m_playerPage->visualizer();

    connect(pb, &PlaybackWidget::playClicked, this, &MainWindow::play);
    connect(pb, &PlaybackWidget::pauseClicked, this, &MainWindow::pause);
    connect(pb, &PlaybackWidget::nextClicked, this, &MainWindow::nextTrack);
    connect(pb, &PlaybackWidget::prevClicked, this, &MainWindow::prevTrack);
    connect(pb, &PlaybackWidget::seekChanged, this, &MainWindow::seek);

    connect(set, &SettingsWidget::paramsChanged, viz, &VisualizerWidget::setParams);
    connect(set, &SettingsWidget::dspParamsChanged, this, &MainWindow::onDspChanged);
    connect(set, &SettingsWidget::binsChanged, this, &MainWindow::onBinsChanged);

    connect(set, &SettingsWidget::paramsChanged, this, &MainWindow::saveSettings);
    connect(set, &SettingsWidget::binsChanged, this, &MainWindow::saveSettings);

    connect(m_playerPage, &PlayerPage::toggleFullScreen, this, &MainWindow::onToggleFullScreen);
    
    // Pause on Settings Open, Resume (Safe) on Close
    connect(m_playerPage, &PlayerPage::settingsOpened, this, &MainWindow::pause);
    connect(m_playerPage, &PlayerPage::settingsClosed, this, [this](){
        QMetaObject::invokeMethod(m_engine, "playSafe", Qt::QueuedConnection);
        m_playerPage->playback()->setPlaying(true);
    });

#ifdef IS_MOBILE
    m_mobileTabs = new QTabWidget();
    m_mobileTabs->setStyleSheet("QTabWidget::pane { border: 0; } QTabBar::tab { background: #222; color: white; padding: 15px; min-width: 100px; } QTabBar::tab:selected { background: #444; }");

    m_mobileTabs->addTab(m_playerPage, "Visualizer");
    m_mobileTabs->addTab(m_playlist, "Playlist");

    m_stack->addWidget(m_mobileTabs);
#else
    m_dock = new QDockWidget("Playlist", this);
    m_dock->setWidget(m_playlist);
    addDockWidget(Qt::LeftDockWidgetArea, m_dock);
    m_stack->addWidget(m_playerPage);
#endif
}

void MainWindow::onToggleFullScreen() {
    static bool isFs = false;
    isFs = !isFs;

    m_playerPage->setFullScreen(isFs);

#ifdef IS_MOBILE
    if (m_mobileTabs) {
        QTabBar* bar = m_mobileTabs->findChild<QTabBar*>();
        if (bar) bar->setVisible(!isFs);
    }
#else
    if (m_dock) m_dock->setVisible(!isFs);
#endif
}

void MainWindow::onOpenFile() {
    m_pendingAction = PendingAction::File;
    QMetaObject::invokeMethod(this, "onPermissionsResult", Qt::QueuedConnection, Q_ARG(bool, true));
}

void MainWindow::onOpenFolder() {
    m_pendingAction = PendingAction::Folder;
    QMetaObject::invokeMethod(this, "onPermissionsResult", Qt::QueuedConnection, Q_ARG(bool, true));
}

void MainWindow::onPermissionsResult(bool granted) {
    if (!granted) return;

#ifdef Q_OS_IOS
    auto callback = [this, recursive = (m_pendingAction == PendingAction::Folder)](QString path) {
        if (!path.isEmpty()) loadPath(path, recursive);
    };
    Utils::openIosPicker(m_pendingAction == PendingAction::Folder, callback);
#else
    QString initialPath;
    QString filter = "Audio (*.mp3 *.m4a *.wav *.flac *.ogg)";

#ifdef Q_OS_ANDROID
    initialPath = QStandardPaths::writableLocation(QStandardPaths::MusicLocation);
    if (initialPath.isEmpty()) initialPath = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation);
#else
    initialPath = QStandardPaths::writableLocation(QStandardPaths::MusicLocation);
#endif

    QString path;
    if (m_pendingAction == PendingAction::File) {
        path = QFileDialog::getOpenFileName(nullptr, "Open Audio", initialPath, filter);
        if (!path.isEmpty()) loadPath(path, false);
    } else if (m_pendingAction == PendingAction::Folder) {
        path = QFileDialog::getExistingDirectory(nullptr, "Open Folder", initialPath);
        if (!path.isEmpty()) loadPath(path, true);
    }
#endif
    m_pendingAction = PendingAction::None;
}

void MainWindow::loadPath(const QString& rawPath, bool recursive) {
    QString path = rawPath;
    QUrl url(rawPath);
    
    if (url.isValid() && url.isLocalFile()) {
        path = url.toLocalFile();
    } else if (rawPath.startsWith("file://")) {
        path = QUrl::fromPercentEncoding(rawPath.toUtf8()).mid(7);
    }

    m_tracks.clear();
    m_playlist->clear();

    QFileInfo info(path);
    bool isDir = info.isDir();
    bool isFile = info.isFile();

    if (!isDir && !isFile && QFile::exists(path)) {
        if (path.endsWith(".mp3") || path.endsWith(".m4a") || path.endsWith(".wav") || path.endsWith(".flac") || path.endsWith(".ogg")) {
            isFile = true;
        } else {
            isDir = true;
        }
    }

    if (isDir || path.startsWith("content://")) {
        m_settingsDir = path;
        QStringList files = Utils::scanDirectory(path, recursive);
        for (const auto& f : files) m_tracks.append({f, Utils::getMetadata(f)});

        std::sort(m_tracks.begin(), m_tracks.end(), [](const TrackInfo& a, const TrackInfo& b) {
            if (a.meta.album != b.meta.album) return a.meta.album < b.meta.album;
            if (a.meta.trackNumber != b.meta.trackNumber) return a.meta.trackNumber < b.meta.trackNumber;
            return a.meta.title < b.meta.title;
        });

        for (const auto& t : m_tracks) {
            QListWidgetItem* item = new QListWidgetItem(m_playlist);
            item->setSizeHint(QSize(0, 70));
            m_playlist->addItem(item);
            m_playlist->setItemWidget(item, new PlaylistItemWidget(t.meta));
        }
        if (!m_tracks.isEmpty()) loadIndex(0);

    } else if (isFile) {
        m_settingsDir = info.path();
        TrackInfo t = {path, Utils::getMetadata(path)};
        m_tracks.append(t);
        QListWidgetItem* item = new QListWidgetItem(m_playlist);
        item->setSizeHint(QSize(0, 70));
        m_playlist->addItem(item);
        m_playlist->setItemWidget(item, new PlaylistItemWidget(t.meta));
        loadIndex(0);
    }

    loadSettings();

#ifdef IS_MOBILE
    m_stack->setCurrentWidget(m_mobileTabs);
#else
    m_stack->setCurrentWidget(m_playerPage);
#endif
}

void MainWindow::loadSettings() {
    if (m_settingsDir.isEmpty()) return;
    if (m_settingsDir.startsWith("content://")) return;

    QFile f(QDir(m_settingsDir).filePath(".yrcrystals.json"));
    if (f.open(QIODevice::ReadOnly)) {
        QJsonDocument doc = QJsonDocument::fromJson(f.readAll());
        QJsonObject root = doc.object();

        bool glass = root["glass"].toBool(true);
        bool focus = root["focus"].toBool(false);
        bool trails = root["trails"].toBool(false);
        bool albumColors = root["albumColors"].toBool(false);
        bool shadow = root["shadow"].toBool(false);
        bool mirrored = root["mirrored"].toBool(false);
        int bins = root["bins"].toInt(26);
        float brightness = root["brightness"].toDouble(1.0);
        float entropy = root["entropy"].toDouble(1.0);

        m_playerPage->settings()->setParams(glass, focus, trails, albumColors, shadow, mirrored, bins, brightness, entropy);
    }
}

void MainWindow::saveSettings() {
    if (m_settingsDir.isEmpty()) return;
    if (m_settingsDir.startsWith("content://")) return;

    SettingsWidget* s = m_playerPage->settings();
    QJsonObject root;
    root["glass"] = s->isGlass();
    root["focus"] = s->isFocus();
    root["trails"] = s->isTrails();
    root["albumColors"] = s->isAlbumColors();
    root["shadow"] = s->isShadow();
    root["mirrored"] = s->isMirrored();
    root["bins"] = s->getBins();
    root["brightness"] = s->getBrightness();
    root["entropy"] = s->getEntropy();

    QFile f(QDir(m_settingsDir).filePath(".yrcrystals.json"));
    if (f.open(QIODevice::WriteOnly)) {
        f.write(QJsonDocument(root).toJson());
    }
}

void MainWindow::loadIndex(int index) {
    if (index < 0 || index >= m_tracks.size()) return;
    m_currentIndex = index;
    const auto& t = m_tracks[index];
    m_playlist->setCurrentRow(index);

    int bins = m_playerPage->settings()->findChild<QSlider*>()->value();
    auto colors = Utils::extractAlbumColors(t.meta.art, bins);
    std::vector<QColor> stdColors;
    for(const auto& c : colors) stdColors.push_back(c);
    m_playerPage->visualizer()->setAlbumPalette(stdColors);

    QMetaObject::invokeMethod(m_engine, "loadTrack", Qt::QueuedConnection, Q_ARG(QString, t.path));
    
    int nextIndex = (m_currentIndex + 1) % m_tracks.size();
    if (nextIndex != m_currentIndex) {
        QMetaObject::invokeMethod(m_engine, "queueNextTrack", Qt::QueuedConnection, Q_ARG(QString, m_tracks[nextIndex].path));
    }
}

void MainWindow::onTrackLoaded(bool success) {
    if (success) {
        play();
        if (m_currentIndex >= 0) {
            const auto& t = m_tracks[m_currentIndex];
            QString title = t.meta.title;
            if (!t.meta.artist.isEmpty()) title += " - " + t.meta.artist;
            setWindowTitle(title);
        }
    } else {
        nextTrack();
    }
}

void MainWindow::onTrackDoubleClicked(QListWidgetItem* item) {
    loadIndex(m_playlist->row(item));
}

void MainWindow::play() {
    QMetaObject::invokeMethod(m_engine, "play", Qt::QueuedConnection);
    m_playerPage->playback()->setPlaying(true);
}
void MainWindow::pause() {
    QMetaObject::invokeMethod(m_engine, "pause", Qt::QueuedConnection);
    m_playerPage->playback()->setPlaying(false);
}
void MainWindow::nextTrack() { 
    int next = m_currentIndex + 1; 
    if (next >= static_cast<int>(m_tracks.size())) next = 0; 
    loadIndex(next); 
}
void MainWindow::prevTrack() { 
    int prev = m_currentIndex - 1; 
    if (prev < 0) prev = static_cast<int>(m_tracks.size()) - 1; 
    loadIndex(prev); 
}
void MainWindow::seek(float pos) {
    QMetaObject::invokeMethod(m_engine, "seek", Qt::QueuedConnection, Q_ARG(float, pos));
}
void MainWindow::onTrackFinished() { nextTrack(); }
void MainWindow::updateLoop() {
}
void MainWindow::onDspChanged(int fft, int hop) {
    QMetaObject::invokeMethod(m_engine, "setDspParams", Qt::QueuedConnection, Q_ARG(int, fft), Q_ARG(int, hop));
}
void MainWindow::closeEvent(QCloseEvent* event) {
    event->accept();
}

void MainWindow::onBinsChanged(int n) {
    QMetaObject::invokeMethod(m_engine, "setNumBins", Qt::QueuedConnection, Q_ARG(int, n));
    m_playerPage->visualizer()->setNumBins(n);

    if (m_currentIndex >= 0 && m_currentIndex < m_tracks.size()) {
        const auto& t = m_tracks[m_currentIndex];
        auto colors = Utils::extractAlbumColors(t.meta.art, n);
        std::vector<QColor> stdColors;
        for(const auto& c : colors) stdColors.push_back(c);
        m_playerPage->visualizer()->setAlbumPalette(stdColors);
    }
}