#include "videoviewerwidget.h"
#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QFormLayout>
#include <QGroupBox>
#include <QDebug>
#include <QPixmap>
#include <gst/video/video.h>

VideoViewerWidget::VideoViewerWidget(QWidget *parent)
    : QWidget(parent), m_pipeline(nullptr), m_appSink(nullptr),
      m_busWatchId(0)
{
    // Register QImage as meta type for signal/slot across threads
    qRegisterMetaType<QImage>("QImage");

    initGStreamer();
    setupUI();

    // Connect signal for frame display
    connect(this, &VideoViewerWidget::newFrameAvailable,
            this, &VideoViewerWidget::displayFrame, Qt::QueuedConnection);
}

VideoViewerWidget::~VideoViewerWidget()
{
    cleanupGStreamer();
}

void VideoViewerWidget::initGStreamer()
{
    gst_init(nullptr, nullptr);
}

void VideoViewerWidget::setupUI()
{
    QVBoxLayout* mainLayout = new QVBoxLayout(this);

    // Video display container
    QGroupBox* videoGroup = new QGroupBox("Video Display", this);
    QVBoxLayout* videoLayout = new QVBoxLayout();

    m_videoDisplay = new QLabel(this);
    m_videoDisplay->setMinimumSize(640, 480);
    m_videoDisplay->setStyleSheet("background-color: black;");
    m_videoDisplay->setAlignment(Qt::AlignCenter);
    m_videoDisplay->setScaledContents(true); // Enable scaling for zoom later

    videoLayout->addWidget(m_videoDisplay);
    videoGroup->setLayout(videoLayout);

    // Controls
    QGroupBox* controlGroup = new QGroupBox("Viewer Controls", this);
    QVBoxLayout* controlLayout = new QVBoxLayout();

    // Source type selection
    QHBoxLayout* sourceLayout = new QHBoxLayout();
    sourceLayout->addWidget(new QLabel("Source Type:", this));
    m_sourceType = new QComboBox(this);
    m_sourceType->addItem("UDP MJPEG Stream (No plugins needed)", "udp-mjpeg");
    m_sourceType->addItem("UDP H.264 Stream (Requires gst-libav)", "udp-h264");
    m_sourceType->addItem("TCP H.264 Stream", "tcp");
    m_sourceType->addItem("MJPEG HTTP Stream", "http");
    m_sourceType->addItem("Test Pattern", "test");
    connect(m_sourceType, QOverload<int>::of(&QComboBox::currentIndexChanged),
            this, &VideoViewerWidget::onSourceTypeChanged);
    sourceLayout->addWidget(m_sourceType);

    // Host and port
    QFormLayout* formLayout = new QFormLayout();
    m_hostEdit = new QLineEdit("127.0.0.1", this);
    m_portEdit = new QLineEdit("5000", this);
    formLayout->addRow("Host:", m_hostEdit);
    formLayout->addRow("Port:", m_portEdit);

    // Control buttons
    QHBoxLayout* buttonLayout = new QHBoxLayout();
    m_startBtn = new QPushButton("Start Viewer", this);
    m_stopBtn = new QPushButton("Stop Viewer", this);
    m_stopBtn->setEnabled(false);

    connect(m_startBtn, &QPushButton::clicked, this, &VideoViewerWidget::onStartViewer);
    connect(m_stopBtn, &QPushButton::clicked, this, &VideoViewerWidget::onStopViewer);

    buttonLayout->addWidget(m_startBtn);
    buttonLayout->addWidget(m_stopBtn);

    // Status label
    m_statusLabel = new QLabel("Status: Stopped", this);
    m_statusLabel->setStyleSheet("QLabel { background-color: #f0f0f0; padding: 5px; border-radius: 3px; }");

    controlLayout->addLayout(sourceLayout);
    controlLayout->addLayout(formLayout);
    controlLayout->addLayout(buttonLayout);
    controlLayout->addWidget(m_statusLabel);
    controlGroup->setLayout(controlLayout);

    mainLayout->addWidget(videoGroup, 1);
    mainLayout->addWidget(controlGroup);

    setLayout(mainLayout);
}

QString VideoViewerWidget::buildPipelineString()
{
    QString sourceType = m_sourceType->currentData().toString();
    QString host = m_hostEdit->text();
    QString port = m_portEdit->text();
    QString pipeline;

    // Using appsink to get frames for embedded display in Qt widget
    // All pipelines convert to RGB format for easy QImage conversion
    QString sinkPipeline = "videoconvert ! video/x-raw,format=RGB ! appsink name=videosink emit-signals=true";

    if (sourceType == "udp-mjpeg") {
        pipeline = QString("udpsrc port=%1 ! application/x-rtp,encoding-name=JPEG,payload=26 ! "
                          "rtpjpegdepay ! jpegdec ! %2")
                          .arg(port).arg(sinkPipeline);
    } else if (sourceType == "udp-h264") {
        pipeline = QString("udpsrc port=%1 ! application/x-rtp,encoding-name=H264 ! "
                          "rtph264depay ! h264parse ! avdec_h264 ! %2")
                          .arg(port).arg(sinkPipeline);
    } else if (sourceType == "tcp") {
        pipeline = QString("tcpclientsrc host=%1 port=%2 ! tsdemux ! h264parse ! avdec_h264 ! %3")
                          .arg(host).arg(port).arg(sinkPipeline);
    } else if (sourceType == "http") {
        pipeline = QString("souphttpsrc location=http://%1:%2 ! multipartdemux ! jpegdec ! %3")
                          .arg(host).arg(port).arg(sinkPipeline);
    } else if (sourceType == "test") {
        pipeline = QString("videotestsrc ! %1").arg(sinkPipeline);
    }

    return pipeline;
}

void VideoViewerWidget::startPipeline()
{
    if (m_pipeline) {
        stopPipeline();
    }

    QString pipelineStr = buildPipelineString();
    qDebug() << "[VideoViewer] Starting pipeline:" << pipelineStr;

    GError* error = nullptr;

    m_pipeline = gst_parse_launch(pipelineStr.toUtf8().constData(), &error);

    if (error) {
        m_statusLabel->setText(QString("Status: Pipeline Error - %1").arg(error->message));
        m_statusLabel->setStyleSheet("QLabel { background-color: #FFB6C1; padding: 5px; border-radius: 3px; }");
        g_error_free(error);
        return;
    }

    if (!m_pipeline) {
        m_statusLabel->setText("Status: Failed to create pipeline");
        m_statusLabel->setStyleSheet("QLabel { background-color: #FFB6C1; padding: 5px; border-radius: 3px; }");
        return;
    }

    // Set up bus callback
    GstBus* bus = gst_element_get_bus(m_pipeline);
    m_busWatchId = gst_bus_add_watch(bus, busCallback, this);
    gst_object_unref(bus);

    // Get appsink element and configure it
    m_appSink = gst_bin_get_by_name(GST_BIN(m_pipeline), "videosink");
    if (!m_appSink) {
        m_statusLabel->setText("Status: Failed to get appsink element");
        m_statusLabel->setStyleSheet("QLabel { background-color: #FFB6C1; padding: 5px; border-radius: 3px; }");
        cleanupGStreamer();
        return;
    }

    // Configure appsink
    g_object_set(m_appSink, "emit-signals", TRUE, "sync", FALSE, "max-buffers", 1, "drop", TRUE, nullptr);

    // Set callback for new samples - properly initialize all fields
    GstAppSinkCallbacks callbacks = { 0 };
    callbacks.new_sample = newSampleCallback;
    callbacks.eos = nullptr;
    callbacks.new_preroll = nullptr;
#if GST_CHECK_VERSION(1,20,0)
    callbacks.new_event = nullptr;
#endif
    gst_app_sink_set_callbacks(GST_APP_SINK(m_appSink), &callbacks, this, nullptr);

    // Start playing
    GstStateChangeReturn ret = gst_element_set_state(m_pipeline, GST_STATE_PLAYING);

    qDebug() << "[VideoViewer] Pipeline state change return:" << ret;

    if (ret == GST_STATE_CHANGE_FAILURE) {
        m_statusLabel->setText("Status: Failed to start pipeline");
        m_statusLabel->setStyleSheet("QLabel { background-color: #FFB6C1; padding: 5px; border-radius: 3px; }");
        cleanupGStreamer();
        return;
    }

    qDebug() << "[VideoViewer] Pipeline started successfully";
    m_statusLabel->setText("Status: Playing");
    m_statusLabel->setStyleSheet("QLabel { background-color: #90EE90; padding: 5px; border-radius: 3px; }");
    m_startBtn->setEnabled(false);
    m_stopBtn->setEnabled(true);
}

void VideoViewerWidget::stopPipeline()
{
    if (m_pipeline) {
        gst_element_set_state(m_pipeline, GST_STATE_NULL);
        gst_object_unref(m_pipeline);
        m_pipeline = nullptr;
    }

    if (m_appSink) {
        gst_object_unref(m_appSink);
        m_appSink = nullptr;
    }

    if (m_busWatchId > 0) {
        g_source_remove(m_busWatchId);
        m_busWatchId = 0;
    }

    // Clear video display
    m_videoDisplay->clear();
    m_videoDisplay->setText("");

    m_statusLabel->setText("Status: Stopped");
    m_statusLabel->setStyleSheet("QLabel { background-color: #f0f0f0; padding: 5px; border-radius: 3px; }");
    m_startBtn->setEnabled(true);
    m_stopBtn->setEnabled(false);
}

void VideoViewerWidget::cleanupGStreamer()
{
    stopPipeline();
}

gboolean VideoViewerWidget::busCallback(GstBus* bus, GstMessage* msg, gpointer data)
{
    VideoViewerWidget* viewer = static_cast<VideoViewerWidget*>(data);

    switch (GST_MESSAGE_TYPE(msg)) {
        case GST_MESSAGE_ERROR: {
            GError* err;
            gchar* debug_info;
            gst_message_parse_error(msg, &err, &debug_info);

            QString errorMsg = QString("GStreamer Error: %1\nDebug: %2")
                                .arg(err->message)
                                .arg(debug_info ? debug_info : "none");

            qDebug() << "[VideoViewer] ERROR:" << errorMsg;

            QMetaObject::invokeMethod(viewer, [viewer, errorMsg]() {
                viewer->m_statusLabel->setText("Status: Stream Error - " + errorMsg);
                viewer->m_statusLabel->setStyleSheet("QLabel { background-color: #FFB6C1; padding: 5px; border-radius: 3px; }");
                viewer->stopPipeline();
            }, Qt::QueuedConnection);

            g_error_free(err);
            g_free(debug_info);
            break;
        }
        case GST_MESSAGE_EOS:
            qDebug() << "[VideoViewer] End of stream";
            QMetaObject::invokeMethod(viewer, [viewer]() {
                viewer->m_statusLabel->setText("Status: End of Stream");
                viewer->stopPipeline();
            }, Qt::QueuedConnection);
            break;
        case GST_MESSAGE_STATE_CHANGED:
            if (GST_MESSAGE_SRC(msg) == GST_OBJECT(viewer->m_pipeline)) {
                GstState oldState, newState, pendingState;
                gst_message_parse_state_changed(msg, &oldState, &newState, &pendingState);
                qDebug() << "[VideoViewer] State changed:"
                         << gst_element_state_get_name(oldState) << "->"
                         << gst_element_state_get_name(newState);
            }
            break;
        case GST_MESSAGE_WARNING: {
            GError* err;
            gchar* debug_info;
            gst_message_parse_warning(msg, &err, &debug_info);
            qDebug() << "[VideoViewer] WARNING:" << err->message;
            g_error_free(err);
            g_free(debug_info);
            break;
        }
        case GST_MESSAGE_INFO: {
            GError* err;
            gchar* debug_info;
            gst_message_parse_info(msg, &err, &debug_info);
            qDebug() << "[VideoViewer] INFO:" << err->message;
            g_error_free(err);
            g_free(debug_info);
            break;
        }
        default:
            break;
    }

    return TRUE;
}

void VideoViewerWidget::onStartViewer()
{
    startPipeline();
}

void VideoViewerWidget::onStopViewer()
{
    stopPipeline();
}

void VideoViewerWidget::onSourceTypeChanged(int index)
{
    QString sourceType = m_sourceType->currentData().toString();

    bool needsNetwork = (sourceType != "test");
    bool isUdp = (sourceType == "udp-mjpeg" || sourceType == "udp-h264");
    m_hostEdit->setEnabled(needsNetwork && !isUdp);
    m_portEdit->setEnabled(needsNetwork);
}

GstFlowReturn VideoViewerWidget::newSampleCallback(GstAppSink* appsink, gpointer user_data)
{
    VideoViewerWidget* viewer = static_cast<VideoViewerWidget*>(user_data);
    if (!viewer) {
        qDebug() << "[VideoViewer] Callback: viewer is null";
        return GST_FLOW_ERROR;
    }

    // Pull the sample from appsink
    GstSample* sample = gst_app_sink_pull_sample(appsink);
    if (!sample) {
        qDebug() << "[VideoViewer] Callback: Failed to pull sample";
        return GST_FLOW_ERROR;
    }

    // Get the buffer from the sample
    GstBuffer* buffer = gst_sample_get_buffer(sample);
    if (!buffer) {
        qDebug() << "[VideoViewer] Callback: No buffer in sample";
        gst_sample_unref(sample);
        return GST_FLOW_ERROR;
    }

    // Get the caps to extract width and height
    GstCaps* caps = gst_sample_get_caps(sample);
    if (!caps) {
        qDebug() << "[VideoViewer] Callback: No caps in sample";
        gst_sample_unref(sample);
        return GST_FLOW_ERROR;
    }

    GstStructure* structure = gst_caps_get_structure(caps, 0);
    int width = 0, height = 0;
    if (!gst_structure_get_int(structure, "width", &width) ||
        !gst_structure_get_int(structure, "height", &height)) {
        qDebug() << "[VideoViewer] Callback: Failed to get dimensions";
        gst_sample_unref(sample);
        return GST_FLOW_ERROR;
    }

    // Map the buffer to access the raw data
    GstMapInfo map;
    if (!gst_buffer_map(buffer, &map, GST_MAP_READ)) {
        qDebug() << "[VideoViewer] Callback: Failed to map buffer";
        gst_sample_unref(sample);
        return GST_FLOW_ERROR;
    }

    // Calculate expected size for RGB888 format
    gsize expected_size = width * height * 3;
    if (map.size < expected_size) {
        qDebug() << "[VideoViewer] Callback: Buffer too small. Expected:" << expected_size << "Got:" << map.size;
        gst_buffer_unmap(buffer, &map);
        gst_sample_unref(sample);
        return GST_FLOW_ERROR;
    }

    // Create QImage from the RGB data with proper stride
    // QImage::Format_RGB888 expects RGB data
    QImage frame(map.data, width, height, width * 3, QImage::Format_RGB888);

    // Make a deep copy since the buffer will be unmapped
    QImage frameCopy = frame.copy();

    // Unmap and cleanup
    gst_buffer_unmap(buffer, &map);
    gst_sample_unref(sample);

    // Use QMetaObject::invokeMethod for thread-safe signal emission
    QMetaObject::invokeMethod(viewer, "newFrameAvailable", Qt::QueuedConnection,
                            Q_ARG(QImage, frameCopy));

    return GST_FLOW_OK;
}

void VideoViewerWidget::displayFrame(const QImage& frame)
{
    if (frame.isNull()) {
        qDebug() << "[VideoViewer] displayFrame: Frame is null";
        return;
    }

    static bool firstFrame = true;
    if (firstFrame) {
        qDebug() << "[VideoViewer] First frame received! Size:" << frame.width() << "x" << frame.height();
        firstFrame = false;
    }

    // Convert QImage to QPixmap and display in label
    QPixmap pixmap = QPixmap::fromImage(frame);
    m_videoDisplay->setPixmap(pixmap.scaled(m_videoDisplay->size(), Qt::KeepAspectRatio, Qt::SmoothTransformation));
}