#include "call_video_engine.h"
#include "call_video_encoder.h"
#include "call_video_decoder.h"
#include "../../../src/call/call_video_port.h"
#include "../../../src/call/call_audio.h"
#include "debug_config.h"
#include "mem.h"
#include <thread>
#include <mutex>
#include <atomic>
#include <deque>
#include <chrono>
#ifdef HAVE_STREAM_CAPTURE
#include <QCamera>
#include <QCameraDevice>
#include <QMediaDevices>
#include <QMediaCaptureSession>
#include <QVideoSink>
#include <QVideoFrame>
#endif

namespace {
int64_t nowUs() { return std::chrono::duration_cast<std::chrono::microseconds>(std::chrono::steady_clock::now().time_since_epoch()).count(); }
void idle() { std::this_thread::sleep_for(std::chrono::milliseconds(5)); }
}
struct CallVideoEngine::Impl {
    std::mutex lock;
    std::thread tx, rx;
    std::atomic<bool> running{false};
    uint64_t id = 0, revision = 1;
    bool enabled = false;
    int width = 640, height = 480, codec = 0;
    int64_t pts = -1, backend = -1, anchor = -1;
    QImage shown;
    uint64_t shownSerial = 0, deliveredSerial = 0;
    int64_t previewPts = -1, previewAt = 0;
    bool previewVisible = false;
    QString status;
    bool statusDirty = false;
    void report(const QString& text) {
        std::lock_guard<std::mutex> guard(lock); status = text; statusDirty = true;
        DEBUG_INFO(DEBUG_CATEGORY_CALL, "desktop video: %s", qPrintable(text));
    }
#ifdef HAVE_STREAM_CAPTURE
    std::unique_ptr<QCamera> camera;
    std::unique_ptr<QMediaCaptureSession> capture;
    std::unique_ptr<QVideoSink> sink;
    QVideoFrame raw;
#endif
};
CallVideoEngine::CallVideoEngine(QObject* parent) : QObject(parent), m(std::make_unique<Impl>()) {
    m_timer.setInterval(20);
    connect(&m_timer, &QTimer::timeout, this, [this] {
        QImage image; QString status; bool changed = false, report = false;
        { std::lock_guard<std::mutex> guard(m->lock);
          if (m->shownSerial != m->deliveredSerial) { image = m->shown; m->deliveredSerial = m->shownSerial; changed = true; }
          if (m->statusDirty) { status = m->status; m->statusDirty = false; report = true; } }
        if (changed) emit imageChanged(image);
        if (report) emit statusChanged(status);
#ifdef HAVE_STREAM_CAPTURE
        QVideoFrame preview; bool clear = false;
        int64_t now = nowUs();
        { std::lock_guard<std::mutex> guard(m->lock);
          if (!m->enabled && m->previewVisible) { m->previewVisible = false; clear = true; }
          if (m->enabled && m->raw.isValid() && m->pts != m->previewPts && now - m->previewAt >= 100000) {
              preview = m->raw; m->previewPts = m->pts; m->previewAt = now;
          } }
        if (clear) emit localImageChanged({});
        if (preview.isValid()) {
            QImage local = preview.toImage();
            if (!local.isNull()) {
                m->previewVisible = true;
                emit localImageChanged(local.scaled(320, 240, Qt::KeepAspectRatio, Qt::SmoothTransformation));
            } else DEBUG_WARN(DEBUG_CATEGORY_CALL, "call camera preview conversion failed");
        }
#endif
    });
}
CallVideoEngine::~CallVideoEngine() { stop(); }
QList<QPair<QString, QByteArray>> CallVideoEngine::cameras() {
    QList<QPair<QString, QByteArray>> result;
#ifdef HAVE_STREAM_CAPTURE
    for (const auto& camera : QMediaDevices::videoInputs()) result.append({camera.description(), camera.id()});
#endif
    return result;
}
void CallVideoEngine::start(quint64 id) {
    if (m->running && m->id == id) return;
    stop(); m->id = id; m->running = true; m_timer.start();
    try { m->tx = std::thread(&CallVideoEngine::transmit, this); m->rx = std::thread(&CallVideoEngine::receive, this); }
    catch (const std::exception& error) { DEBUG_ERROR(DEBUG_CATEGORY_CALL, "video worker start: %s", error.what()); stop(); emit statusChanged(error.what()); }
}
void CallVideoEngine::closeCamera() {
#ifdef HAVE_STREAM_CAPTURE
    if (m->sink) disconnect(m->sink.get(), nullptr, this, nullptr);
    if (m->camera) { disconnect(m->camera.get(), nullptr, this, nullptr); m->camera->stop(); }
    m->capture.reset(); m->camera.reset(); m->sink.reset();
    { std::lock_guard<std::mutex> guard(m->lock); m->raw = {}; m->pts = m->backend = m->anchor = -1; }
#endif
    m->previewPts = -1; m->previewVisible = false; emit localImageChanged({});
}
void CallVideoEngine::stop() {
    m->running = false; m_timer.stop(); closeCamera();
    if (m->tx.joinable()) m->tx.join();
    if (m->rx.joinable()) m->rx.join();
    if (m->id) call_video_port_close(m->id);
    m->id = 0; m->enabled = false; m->shown = {}; emit imageChanged({});
}
void CallVideoEngine::setVideo(bool enabled, const QByteArray& cameraId, int width, int height, int codec) {
    closeCamera();
    uint64_t revision;
    { std::lock_guard<std::mutex> guard(m->lock);
      m->enabled = enabled; m->width = width; m->height = height; m->codec = codec; revision = ++m->revision; }
    if (!enabled || !m->running) return;
#ifdef HAVE_STREAM_CAPTURE
    QCameraDevice selected;
    for (const auto& camera : QMediaDevices::videoInputs()) if (camera.id() == cameraId) selected = camera;
    if (selected.isNull()) { m->report(tr("Camera is unavailable")); return; }
    m->capture = std::make_unique<QMediaCaptureSession>(); m->sink = std::make_unique<QVideoSink>();
    m->camera = std::make_unique<QCamera>(selected); m->capture->setCamera(m->camera.get()); m->capture->setVideoSink(m->sink.get());
    QCameraFormat best; int distance = INT_MAX;
    for (const auto& f : selected.videoFormats()) {
        if (f.maxFrameRate() < 29.9) continue;
        int score = std::abs(f.resolution().width() - width) + std::abs(f.resolution().height() - height);
        if (score < distance) { best = f; distance = score; }
    }
    if (!best.isNull()) m->camera->setCameraFormat(best);
    connect(m->sink.get(), &QVideoSink::videoFrameChanged, this, [this, revision](const QVideoFrame& frame) {
        if (!frame.isValid() || !m->running) return;
        std::lock_guard<std::mutex> guard(m->lock);
        if (revision != m->revision) return;
        int64_t pts = nowUs();
        if (frame.startTime() >= 0) {
            if (m->backend < 0) {
                m->backend = frame.startTime(); m->anchor = pts;
                DEBUG_INFO(DEBUG_CATEGORY_CALL, "camera clock source=%lld monotonic=%lld calibration=arrival-estimate",
                    (long long)m->backend, (long long)m->anchor);
            }
            pts = m->anchor + frame.startTime() - m->backend;
        }
        if (pts > m->pts) { m->raw = frame; m->pts = pts; }
    }, Qt::DirectConnection);
    connect(m->camera.get(), &QCamera::errorOccurred, this, [this](QCamera::Error, const QString& error) {
        DEBUG_ERROR(DEBUG_CATEGORY_CALL, "call camera failed: %s", qPrintable(error)); m->report(error);
    });
    m->camera->start();
#else
    Q_UNUSED(cameraId); Q_UNUSED(revision); m->report(tr("Video capture is unavailable in this build"));
#endif
}

void CallVideoEngine::transmit() {
    call_video_caps caps = CallVideoDecoder::capabilities();
    // Не связываем приём с наличием собственного encoder.
    for (unsigned codec = 1; codec <= 2 && m->running; ++codec) {
        call_video_format probe{1, 1280, 720, 30, 0, (uint8_t)codec, (uint8_t)(codec == 1 ? 31 : 93), 4000000,
            (uint8_t)(codec == 1 ? CALL_VIDEO_CONSTRAINED_BASELINE : CALL_VIDEO_MAIN)};
        CallVideoEncoder encoder;
        if (encoder.open(probe, 1000000)) {
            call_video_limit limit{1280, 720, 30, 1280 * 720 * 30, 4000000, probe.profile, probe.level};
            caps.encode[codec - 1] = limit;
        } else DEBUG_WARN(DEBUG_CATEGORY_CALL, "call codec probe unavailable codec=%u: %s", codec, qPrintable(encoder.error()));
    }
    if (!m->running) return;
    if (call_video_port_open(m->id, &caps) < 0) { m->report(tr("Video transport is unavailable")); return; }
    CallVideoEncoder encoder;
    call_video_format format{};
    uint64_t appliedRevision = 0, keySerial = 0, request = 0, frameId = 0;
    uint64_t userRevision = 0, rejectedGeneration = 0;
    unsigned excluded = 0;
    int64_t lastPts = -1, lastKey = -1;
    bool forceKey = true;
    while (m->running) {
        struct call_video_port_status state{};
        if (call_video_port_status(m->id, &state) < 0) break;
        if (state.error) { m->report(tr("Core rejected video format")); break; }
        uint64_t revision; bool enabled; int width, height, codec; int64_t pts;
#ifdef HAVE_STREAM_CAPTURE
        QVideoFrame raw;
#endif
        { std::lock_guard<std::mutex> guard(m->lock);
          revision = m->revision; enabled = m->enabled; width = m->width; height = m->height; codec = m->codec; pts = m->pts;
#ifdef HAVE_STREAM_CAPTURE
          raw = m->raw;
#endif
        }
        if (revision != userRevision) { userRevision = revision; excluded = 0; }
        if (format.generation && state.decoded_generation == format.generation && !state.decoded_accepted
            && rejectedGeneration != format.generation) {
            rejectedGeneration = format.generation; excluded |= 1u << format.codec;
            if (!codec) { appliedRevision = 0; lastKey = -1; m->report(tr("Receiver rejected video; selecting fallback")); }
            else {
                m->report(tr("Receiver cannot decode selected codec"));
                std::lock_guard<std::mutex> guard(m->lock); m->enabled = false; continue;
            }
        }
        if (format.generation && state.have_peer && !call_video_format_supported(&caps, &state.peer, &format)) appliedRevision = 0;
        if (!enabled || !state.have_peer || pts <= lastPts || (lastPts >= 0 && pts - lastPts < 33333)) { idle(); continue; }
        if (revision != appliedRevision) {
            if (lastKey >= 0 && pts - lastKey < 1000000) { idle(); continue; }
            call_video_format next{format.generation + 1, (uint16_t)width, (uint16_t)height, 30, 0, (uint8_t)codec, 0, 4000000, 0};
            bool opened = false;
            uint32_t minimum = state.minimum_bps ? state.minimum_bps : 300000;
            uint32_t maximum = state.maximum_bps ? state.maximum_bps : 4000000;
            uint32_t initialRate = std::max(minimum, std::min(maximum, encoder.bitrate() ? encoder.bitrate() : 1000000));
            for (int candidate = 2; candidate >= 1; --candidate) {
                if ((codec && codec != candidate) || (excluded & (1u << candidate))) continue;
                next.codec = candidate; next.level = next.profile = 0;
                if (call_video_choose(&caps, &state.peer, &next) > 0 && encoder.open(next, initialRate)) { opened = true; break; }
            }
            if (!opened) {
                m->report(tr("Selected video mode is unavailable to the peer"));
                std::lock_guard<std::mutex> guard(m->lock); if (m->revision == revision) m->enabled = false;
                continue;
            }
            format = next; appliedRevision = revision; forceKey = true; request = 0;
            if (call_video_port_format(m->id, &format, encoder.bitrate()) < 0) break;
            m->report(QString("%1 · %2×%3 · %4 kbit/s").arg(format.codec == 2 ? "H.265" : "H.264").arg(width).arg(height).arg(encoder.bitrate() / 1000));
        }
        if (state.configured_generation != format.generation) { idle(); continue; }
        if (state.key_serial != keySerial) { keySerial = state.key_serial; forceKey = true; }
        if (state.rate_generation == format.generation && state.rate_request > request) {
            request = state.rate_request;
            if (!encoder.requestBitrate(format.generation, request, state.rate_bps))
                call_video_port_applied(m->id, format.generation, request, 0);
        }
#ifdef HAVE_STREAM_CAPTURE
        QImage image = raw.toImage();
        if (image.isNull()) { DEBUG_WARN(DEBUG_CATEGORY_CALL, "camera frame conversion failed"); lastPts = pts; continue; }
        LiveEncodedFrame output; CallVideoRateCompletion completion;
        bool encoded = encoder.encode(image, pts, forceKey, output, completion); lastPts = pts;
        if (completion.request) {
            call_video_port_applied(m->id, completion.generation, completion.request, completion.bitrate);
            m->report(QString("%1 · %2×%3 · %4 kbit/s").arg(format.codec == 2 ? "H.265" : "H.264")
                .arg(format.width).arg(format.height).arg(encoder.bitrate() / 1000));
        }
        if (!encoded) { forceKey = true; m->report(encoder.error()); continue; }
        if (output.key) lastKey = pts;
        call_video_frame packet{};
        packet.call_id = m->id; packet.frame_id = ++frameId; packet.pts_us = pts; packet.format = format;
        packet.size = packet.length = output.data.size(); packet.data = reinterpret_cast<const uint8_t*>(output.data.constData());
        packet.flags = output.key ? CALL_VIDEO_KEY : 0;
        forceKey = call_video_port_send(&packet) != 1;
#else
        idle();
#endif
    }
}

void CallVideoEngine::receive() {
    struct Picture { int64_t pts; QImage image; };
    std::deque<Picture> pictures;
    CallVideoDecoder decoder;
    uint64_t sourceEpoch = 0; int64_t lastShown = -1, report = 0, lastPictureAt = 0; unsigned shown = 0;
    uint64_t reportedGeneration = 0, rejectedGeneration = 0;
    while (m->running) {
        int64_t now = nowUs(); call_clock_snapshot clock{};
        call_audio_get_clock(m->id, now, &clock);
        if (clock.valid) {
            if (sourceEpoch && sourceEpoch != clock.source_epoch) {
                pictures.clear(); decoder.close(); call_video_port_request_key(m->id); lastShown = -1;
                DEBUG_INFO(DEBUG_CATEGORY_CALL, "video playback audio source epoch changed");
            }
            sourceEpoch = clock.source_epoch;
            QImage selected;
            while (!pictures.empty() && pictures.front().pts <= clock.pts_us) {
                if (pictures.front().pts > lastShown && pictures.front().pts >= clock.pts_us - 500000) {
                    selected = pictures.front().image; lastShown = pictures.front().pts;
                }
                pictures.pop_front();
            }
            if (!selected.isNull()) {
                std::lock_guard<std::mutex> guard(m->lock); m->shown = selected; ++m->shownSerial; ++shown; lastPictureAt = now;
            }
        }
        // VIDEO_OFF пока отсутствует в протоколе: убираем застывшую картинку после прекращения показа.
        if (lastPictureAt && now - lastPictureAt >= 5000000) {
            std::lock_guard<std::mutex> guard(m->lock); m->shown = {}; ++m->shownSerial; lastPictureAt = 0;
            DEBUG_INFO(DEBUG_CATEGORY_CALL, "video playback hidden: no playable frame for 5s");
        }
        if (pictures.size() < 16) {
            call_video_frame packet{};
            if (call_video_port_pull(m->id, &packet) == 1) {
                if (packet.format.generation == rejectedGeneration) { u_free((void*)packet.data); continue; }
                QImage image;
                if (decoder.decode(packet, image)) {
                    pictures.push_back({packet.pts_us, image});
                    if (reportedGeneration != packet.format.generation) {
                        reportedGeneration = packet.format.generation; call_video_port_decoded(m->id, reportedGeneration, 1);
                    }
                } else {
                    rejectedGeneration = packet.format.generation; call_video_port_decoded(m->id, rejectedGeneration, 0);
                }
                u_free((void*)packet.data); continue;
            }
        }
        if (now - report >= 1000000) {
            DEBUG_DEBUG(DEBUG_CATEGORY_CALL, "video playback shown=%u queue=%zu audio_valid=%d audio_pts=%lld video_pts=%lld",
                shown, pictures.size(), clock.valid, (long long)clock.pts_us, (long long)lastShown); report = now;
        }
        idle();
    }
}