#include "call_video_engine.h"
#include "call_video_encoder.h"
#include "call_video_decoder.h"
#include "call_video_cadence.h"
#include "call_camera_capture.h"
#include "../../../src/call/call_video_port.h"
#include "../../../src/call/call_video_playout.h"
#include "../../../src/call/call_audio.h"
#include "debug_config.h"
#include "mem.h"
#include <thread>
#include <mutex>
#include <condition_variable>
#include <atomic>
#include <deque>
#include <chrono>

namespace {
int64_t nowUs() { return call_video_playout_now_us(); }
}
struct CallVideoEngine::Impl {
    std::mutex lock;
    std::condition_variable wake;
    uint64_t wakeSerial = 0;
    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;
    int64_t clockCorrection = 0;
    QImage capturedImage;
    QByteArray cameraId;
    bool captureActive = false;
    uint64_t captured = 0;
    QImage shown;
    int64_t shownPts = -1;
    uint64_t publicationEpoch = 0;
    bool publicationPending = false;
    int64_t shownAt = 0;
    int64_t previewReportAt = 0, previewMaxUs = 0;
    unsigned previewFrames = 0;
    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<CallCameraCapture> capture;
#endif
};
CallVideoEngine::CallVideoEngine(QObject* parent) : QObject(parent), m(std::make_unique<Impl>()) {
    m_timer.setInterval(20);
    m_timer.setTimerType(Qt::PreciseTimer);
    connect(&m_timer, &QTimer::timeout, this, [this] {
        QString status; bool report = false;
        { std::lock_guard<std::mutex> guard(m->lock);
          if (m->statusDirty) { status = m->status; m->statusDirty = false; report = true; } }
        if (report) emit statusChanged(status);
    });
#ifdef HAVE_STREAM_CAPTURE
    m->capture = std::make_unique<CallCameraCapture>();
    connect(m->capture.get(), &CallCameraCapture::devicesChanged, this, &CallVideoEngine::camerasChanged);
    connect(m->capture.get(), &CallCameraCapture::failed, this, [this](const QString& error) {
        { std::lock_guard<std::mutex> guard(m->lock);
          m->enabled = false; ++m->revision; ++m->wakeSerial; m->capturedImage = {}; m->pts = -1; }
        m->captureActive = false; m->wake.notify_one(); emit localImageChanged({});
        m->report(error); emit statusChanged(error);
    });
    connect(m->capture.get(), &CallCameraCapture::frameReady, this, [this](const QImage& image, qint64 pts, qint64 correction) {
        const int64_t now = nowUs();
        { std::lock_guard<std::mutex> guard(m->lock);
          if (!m->running || !m->enabled || pts <= m->pts) return;
          m->capturedImage = image; m->pts = pts; m->clockCorrection = correction; ++m->captured; ++m->wakeSerial; }
        m->wake.notify_one();
        emit localImageChanged(image.scaled(320, 240, Qt::KeepAspectRatio, Qt::FastTransformation));
        ++m->previewFrames; m->previewMaxUs = std::max(m->previewMaxUs, nowUs() - now);
        if (now - m->previewReportAt >= 1000000) {
            DEBUG_DEBUG(DEBUG_CATEGORY_CALL, "video local preview call=%llu frames=%u update_max_us=%lld capture_age_us=%lld",
                (unsigned long long)m->id, m->previewFrames, (long long)m->previewMaxUs, (long long)(now - pts));
            m->previewReportAt = now; m->previewFrames = 0; m->previewMaxUs = 0;
        }
    });
#endif
}
CallVideoEngine::~CallVideoEngine() { stop(); }
// В GUI одновременно не больше одного уведомления; при паузе UI остаётся последний выбранный кадр.
void CallVideoEngine::publishImage(const QImage& image, int64_t pts) {
    uint64_t epoch;
    { std::lock_guard<std::mutex> guard(m->lock);
      m->shown = image; m->shownPts = pts; m->shownAt = nowUs();
      if (m->publicationPending) return;
      m->publicationPending = true; epoch = m->publicationEpoch; }
    QMetaObject::invokeMethod(this, [this, epoch] {
        QImage image; int64_t pts, selected;
        { std::lock_guard<std::mutex> guard(m->lock);
          if (epoch != m->publicationEpoch) return;
          image = m->shown; pts = m->shownPts; selected = m->shownAt; m->publicationPending = false; }
        emit imageChanged(image);
        if (!image.isNull() && pts >= 0 && pts % 1000000 < 34000)
            DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG, "video timing stage=publish call=%llu pts=%lld mono_us=%lld ui_wait_us=%lld",
                (unsigned long long)m->id, (long long)pts, (long long)nowUs(), (long long)(nowUs() - selected));
    }, Qt::QueuedConnection);
}
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->captureActive) m->capture->configure(false, m->cameraId, m->width, m->height);
#endif
    m->captureActive = false;
    { std::lock_guard<std::mutex> guard(m->lock); m->capturedImage = {}; m->pts = -1; ++m->wakeSerial; }
    m->wake.notify_one(); 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);
    { std::lock_guard<std::mutex> guard(m->lock);
      ++m->publicationEpoch; m->publicationPending = false; m->shown = {}; m->shownPts = -1; }
    m->id = 0; m->enabled = false; emit imageChanged({});
}
void CallVideoEngine::setVideo(bool enabled, const QByteArray& cameraId, int width, int height, int codec) {
    const bool active = enabled && m->running;
    const bool captureChanged = active != m->captureActive || cameraId != m->cameraId || width != m->width || height != m->height;
    { std::lock_guard<std::mutex> guard(m->lock);
      if (m->enabled == enabled && cameraId == m->cameraId && width == m->width && height == m->height && codec == m->codec
          && !captureChanged) return;
      m->enabled = enabled; m->width = width; m->height = height; m->codec = codec; ++m->revision; ++m->wakeSerial;
      if (captureChanged) { m->capturedImage = {}; m->pts = -1; } }
    m->cameraId = cameraId; m->captureActive = active; m->wake.notify_one();
    if (!captureChanged) return;
    emit localImageChanged({});
#ifdef HAVE_STREAM_CAPTURE
    m->capture->configure(active, cameraId, width, height);
#else
    if (active) 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;
    bool forceKey = true;
    int64_t reportAt = nowUs(), encodeMax = 0;
    uint64_t captureBase = 0;
    unsigned encodedCount = 0, keyCount = 0, sendBusy = 0, paced = 0;
    CallVideoCadence cadence;
    uint64_t wakeSerial = 0;
    auto idle = [this, &wakeSerial] {
        std::unique_lock<std::mutex> guard(m->lock);
        m->wake.wait_for(guard, std::chrono::milliseconds(5), [&] { return !m->running || m->wakeSerial != wakeSerial; });
    };
    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, captured; bool enabled; int width, height, codec; int64_t pts, clockCorrection;
        QImage image;
        { 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;
          captured = m->captured;
          clockCorrection = m->clockCorrection; image = m->capturedImage; wakeSerial = m->wakeSerial;
        }
        int64_t now = nowUs();
        if (now - reportAt >= 1000000) {
            DEBUG_DEBUG(DEBUG_CATEGORY_CALL,
                "video capture flow call=%llu interval_us=%lld captured=%llu encoded=%u keys=%u send_busy=%u paced=%u "
                "encode_max_us=%lld capture_age_us=%lld pts=%lld clock_correction_us=%lld",
                (unsigned long long)m->id, (long long)(now - reportAt), (unsigned long long)(captured - captureBase),
                encodedCount, keyCount, sendBusy, paced, (long long)encodeMax,
                (long long)(pts >= 0 ? now - pts : 0), (long long)pts, (long long)clockCorrection);
            reportAt = now; captureBase = captured; encodedCount = keyCount = sendBusy = paced = 0; encodeMax = 0;
        }
        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; 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) { idle(); continue; }
        if (revision != appliedRevision) {
            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
        if (!cadence.accept(pts)) { lastPts = pts; ++paced; idle(); continue; }
        if (image.isNull() || nowUs() - pts > CallCameraMaxFrameAgeUs) {
            DEBUG_WARN(DEBUG_CATEGORY_CALL, "video TX skips old capture age_us=%lld", (long long)(nowUs() - pts));
            lastPts = pts; continue;
        }
        LiveEncodedFrame output; CallVideoRateCompletion completion;
        int64_t encodeStarted = nowUs();
        bool encoded = encoder.encode(image, pts, forceKey, output, completion); lastPts = pts;
        encodeMax = std::max(encodeMax, nowUs() - encodeStarted);
        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; }
        ++encodedCount; if (output.key) ++keyCount;
        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;
        { std::lock_guard<std::mutex> guard(m->lock);
          if (!m->running || !m->enabled || m->revision != revision || nowUs() - pts > CallCameraMaxFrameAgeUs) {
              DEBUG_WARN(DEBUG_CATEGORY_CALL, "video TX discards obsolete encoded frame revision=%llu/%llu enabled=%d age_us=%lld",
                  (unsigned long long)revision, (unsigned long long)m->revision, m->enabled, (long long)(nowUs() - pts));
              forceKey = true; continue;
          }
          forceKey = call_video_port_send(&packet) != 1; }
        // Одинаковое окно исходного PTS на всех этапах: примерно один кадр в секунду, без трассы каждого кадра.
        if (pts % 1000000 < 34000)
            DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG,
                "video timing stage=encode call=%llu frame=%llu pts=%lld mono_us=%lld encode_us=%lld accepted=%d",
                (unsigned long long)m->id, (unsigned long long)frameId, (long long)pts, (long long)nowUs(),
                (long long)(nowUs() - encodeStarted), !forceKey);
        if (forceKey) ++sendBusy;
#else
        idle();
#endif
    }
}

void CallVideoEngine::receive() {
    struct Picture { call_video_playout_frame timing; QImage image; };
    std::deque<Picture> pictures;
    CallVideoDecoder decoder;
    call_video_playout playout; call_video_playout_init(&playout, m->id);
    int64_t lastPictureAt = 0;
    uint64_t reportedGeneration = 0, rejectedGeneration = 0;
    while (m->running) {
        // Один кадр ждёт своего срока, второй позволяет пропустить устаревший показ после паузы CPU.
        while (pictures.size() < 2 && m->running) {
            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;
                const int64_t decodeStarted = nowUs();
                if (decoder.decode(packet, image)) {
                    pictures.push_back({{packet.pts_us, packet.received_us}, image});
                    if (packet.pts_us % 1000000 < 34000)
                        DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG,
                            "video timing stage=decode call=%llu frame=%llu pts=%lld mono_us=%lld decode_us=%lld queue=%zu",
                            (unsigned long long)m->id, (unsigned long long)packet.frame_id, (long long)packet.pts_us,
                            (long long)nowUs(), (long long)(nowUs() - decodeStarted), pictures.size());
                    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);
            } else break;
        }
        int64_t now = nowUs(); call_clock_snapshot clock{};
        call_audio_get_clock(m->id, now, &clock);
        auto action = call_video_playout_poll(&playout, pictures.empty() ? nullptr : &pictures.front().timing,
            pictures.size() > 1 ? &pictures[1].timing : nullptr, now, clock.valid, clock.pts_us);
        if (action != CALL_VIDEO_PLAYOUT_WAIT) {
            if (action == CALL_VIDEO_PLAYOUT_SHOW) {
                const auto& f = pictures.front(); publishImage(f.image, f.timing.pts_us); lastPictureAt = now;
                if (f.timing.pts_us % 1000000 < 34000)
                    DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG, "video timing stage=select call=%llu pts=%lld mono_us=%lld audio_pts=%lld",
                        (unsigned long long)m->id, (long long)f.timing.pts_us, (long long)now, (long long)clock.pts_us);
            }
            pictures.pop_front();
            continue;
        }
        // VIDEO_OFF пока отсутствует в протоколе: убираем застывшую картинку после прекращения показа.
        if (lastPictureAt && now - lastPictureAt >= 5000000) {
            publishImage({}, -1); lastPictureAt = 0;
            DEBUG_INFO(DEBUG_CATEGORY_CALL, "video playback hidden: no playable frame for 5s");
        }
        std::this_thread::sleep_for(std::chrono::microseconds(std::max<int64_t>(100, std::min<int64_t>(5000, playout.deadline_us - nowUs()))));
    }
}