/*
 * test_external_pcm — external PCM feed/tap API.
 *
 * Three headless behavior tests (no audio hardware, no simulator):
 *
 *  test_feed_pcm_round_trip  — A feeds mono 440 Hz sine via vc_stream_feed_pcm; B's pcm_sink
 *      fires with non-zero energy, proving the full pipeline (feed→encode→relay→decode→sink).
 *
 *  test_feed_pcm_stereo      — A and B join Music Room (stereo/128kbps). A feeds interleaved
 *      stereo PCM (loud-L / silent-R) via vc_stream_feed_pcm(channels=2). B's pcm_sink
 *      asserts L-channel energy > R-channel energy (real stereo bitstream, not a mono upmix).
 *
 *  test_pcm_sink             — Verifies sink metadata: correct user_id / stream_id per frame,
 *      sample_rate = 48000, and that cb=NULL disables delivery.
 */
#include <cstdio>

#ifdef VOICECAT_HAS_NET

#include <atomic>
#include <chrono>
#include <condition_variable>
#include <cmath>
#include <filesystem>
#include <mutex>
#include <string>
#include <thread>
#include <vector>

#include "voicecat.h"
#include "server.h"
#include "db.h"

// ── Helpers ───────────────────────────────────────────────────────────────────

static int g_failures = 0;
#define CHECK(cond) \
    do { if (!(cond)) { \
        std::printf("FAIL [%s:%d]: %s\n", __FILE__, __LINE__, #cond); \
        ++g_failures; \
    }} while (0)

struct EventStore {
    std::mutex              mu;
    std::condition_variable cv;
    bool      auth_ok{false};
    uint32_t  self_user_id{0};
    bool      channel_list_received{false};
    bool      join_ok{false};
    bool      voice_subscribed{false};
    std::vector<std::pair<uint32_t, uint32_t>> streams_started;  // (user_id, stream_id)
    vc_client* client{nullptr};
    const char* label{nullptr};
};

static void on_event(void* user, const vc_event* ev) {
    auto* s = static_cast<EventStore*>(user);
    std::lock_guard lk(s->mu);
    switch (ev->type) {
        case VC_EVENT_SERVER_IDENTITY:
            vc_confirm_server_identity(s->client, 1);
            break;
        case VC_EVENT_AUTH_RESULT:
            s->auth_ok      = (ev->result == VC_OK);
            s->self_user_id = ev->user_id;
            break;
        case VC_EVENT_CHANNEL_LIST:
            s->channel_list_received = true;
            break;
        case VC_EVENT_VOICE_STATE:
            s->voice_subscribed = (ev->u32a == 1);
            break;
        case VC_EVENT_JOIN_RESULT:
            s->join_ok = (ev->result == VC_OK);
            break;
        case VC_EVENT_STREAM_STARTED:
            s->streams_started.emplace_back(ev->user_id, ev->stream_id);
            break;
        default: break;
    }
    s->cv.notify_all();
}

template <typename Pred>
static bool wait_for(EventStore& s, Pred pred, int timeout_ms) {
    auto deadline = std::chrono::steady_clock::now() + std::chrono::milliseconds(timeout_ms);
    std::unique_lock lk(s.mu);
    return s.cv.wait_until(lk, deadline, [&] { return pred(s); });
}

static bool connect_guest(vc_client*& client, const char* name, const char* label,
                          uint16_t port, EventStore& ev) {
    vc_callbacks cb{on_event, nullptr, &ev};
    vc_config cfg{label, "0.1", VC_LOG_OFF};
    client = vc_client_create(&cfg, cb);
    if (!client) return false;
    ev.client = client;
    ev.label  = label;
    if (vc_connect(client, "127.0.0.1", port) != VC_OK) return false;
    if (vc_authenticate_guest(client, name) != VC_OK) return false;
    if (!wait_for(ev, [](EventStore& s) { return s.auth_ok; }, 8000)) return false;
    if (!wait_for(ev, [](EventStore& s) { return s.channel_list_received; }, 3000)) return false;
    if (vc_join_voice(client) != VC_OK) return false;
    if (!wait_for(ev, [](EventStore& s) { return s.voice_subscribed; }, 5000)) return false;
    return true;
}

static std::vector<int16_t> make_sine_mono(int n) {
    std::vector<int16_t> pcm(static_cast<size_t>(n));
    for (int i = 0; i < n; ++i) {
        float t = static_cast<float>(i) / 48000.0f;
        pcm[i]  = static_cast<int16_t>(std::sin(2.0f * 3.14159265f * 440.0f * t) * 16000.0f);
    }
    return pcm;
}

// Loud-left / silent-right interleaved stereo (n samples per channel).
static std::vector<int16_t> make_sine_stereo(int n) {
    std::vector<int16_t> pcm(static_cast<size_t>(n) * 2);
    for (int i = 0; i < n; ++i) {
        float t        = static_cast<float>(i) / 48000.0f;
        pcm[i * 2]     = static_cast<int16_t>(std::sin(2.0f * 3.14159265f * 440.0f * t) * 16000.0f);
        pcm[i * 2 + 1] = 0;
    }
    return pcm;
}

// ── PCM sink state ────────────────────────────────────────────────────────────

struct SinkData {
    std::mutex              mu;
    std::condition_variable cv;
    std::atomic<int>        call_count{0};
    uint32_t last_user_id    = 0;
    uint32_t last_stream_id  = 0;
    uint32_t last_channels   = 0;
    uint32_t last_sample_rate = 0;
    int64_t  total_energy    = 0;
    int64_t  left_energy     = 0;   // sum |pcm[i*2]| for stereo frames
    int64_t  right_energy    = 0;   // sum |pcm[i*2+1]| for stereo frames
};

static void pcm_sink(void* user, uint32_t uid, uint32_t sid,
                     const int16_t* pcm, size_t n, uint32_t channels, uint32_t sr) {
    auto* d = static_cast<SinkData*>(user);
    std::lock_guard lk(d->mu);
    d->last_user_id     = uid;
    d->last_stream_id   = sid;
    d->last_channels    = channels;
    d->last_sample_rate = sr;
    for (size_t i = 0; i < n; ++i) {
        if (channels == 2) {
            d->left_energy  += std::abs(static_cast<int>(pcm[i * 2]));
            d->right_energy += std::abs(static_cast<int>(pcm[i * 2 + 1]));
        }
        for (uint32_t c = 0; c < channels; ++c)
            d->total_energy += std::abs(static_cast<int>(pcm[i * channels + c]));
    }
    d->call_count.fetch_add(1, std::memory_order_relaxed);
    d->cv.notify_all();
}

static bool sink_wait(SinkData& d, int timeout_ms) {
    auto deadline = std::chrono::steady_clock::now() + std::chrono::milliseconds(timeout_ms);
    std::unique_lock lk(d.mu);
    return d.cv.wait_until(lk, deadline, [&] { return d.call_count.load() > 0; });
}

// ── test_feed_pcm_round_trip ──────────────────────────────────────────────────

static void test_feed_pcm_round_trip(uint16_t port) {
    std::printf("test_feed_pcm_round_trip: start\n");

    EventStore evA, evB;
    vc_client *clientA = nullptr, *clientB = nullptr;
    CHECK(connect_guest(clientA, "PcmA", "pcm-a", port, evA));
    CHECK(connect_guest(clientB, "PcmB", "pcm-b", port, evB));
    if (!clientA || !clientB) goto cleanup_rt;

    {
        uint32_t a_uid = 0;
        { std::lock_guard lk(evA.mu); a_uid = evA.self_user_id; }

        // B registers a sink before A starts speaking.
        SinkData sink;
        CHECK(vc_set_pcm_sink(clientB, pcm_sink, &sink) == VC_OK);

        std::this_thread::sleep_for(std::chrono::milliseconds(500));

        // A announces a MIC stream in Lobby.
        vc_stream_desc desc{};
        desc.kind = VC_STREAM_MIC;
        uint32_t a_sid = 0;
        CHECK(vc_stream_start(clientA, &desc, &a_sid) == VC_OK);

        bool b_saw_a = wait_for(evB, [&](EventStore& s) {
            for (auto& [uid, sid] : s.streams_started)
                if (uid == a_uid) return true;
            return false;
        }, 5000);
        CHECK(b_saw_a);

        std::this_thread::sleep_for(std::chrono::milliseconds(300));

        // A feeds 250 mono frames via the new public API.
        auto sine = make_sine_mono(960);
        for (int i = 0; i < 250; ++i)
            CHECK(vc_stream_feed_pcm(clientA, a_sid, sine.data(), 960, 1) == VC_OK);

        // Wait for the sink to fire at least once (decode arrived).
        bool fired = sink_wait(sink, 5000);
        CHECK(fired);

        std::this_thread::sleep_for(std::chrono::milliseconds(1500));

        int calls = sink.call_count.load();
        int64_t energy = sink.total_energy;
        std::printf("test_feed_pcm_round_trip: sink calls=%d energy=%lld\n",
                    calls, static_cast<long long>(energy));
        CHECK(calls > 0);
        CHECK(energy > 0);

        vc_stream_stop(clientA, a_sid);
    }

cleanup_rt:
    if (clientA) { vc_disconnect(clientA); vc_client_destroy(clientA); }
    if (clientB) { vc_disconnect(clientB); vc_client_destroy(clientB); }
    std::printf("test_feed_pcm_round_trip: done\n");
}

// ── test_feed_pcm_stereo ──────────────────────────────────────────────────────

static void test_feed_pcm_stereo(uint16_t port) {
    std::printf("test_feed_pcm_stereo: start\n");

    EventStore evA, evB;
    vc_client *clientA = nullptr, *clientB = nullptr;
    CHECK(connect_guest(clientA, "StA", "stereo-a", port, evA));
    CHECK(connect_guest(clientB, "StB", "stereo-b", port, evB));
    if (!clientA || !clientB) goto cleanup_st;

    {
        uint32_t a_uid = 0;
        { std::lock_guard lk(evA.mu); a_uid = evA.self_user_id; }

        // Both join Music Room (channel 2, stereo/128kbps) so the encoder is stereo.
        CHECK(vc_join_channel(clientA, 2, nullptr) == VC_OK);
        CHECK(vc_join_channel(clientB, 2, nullptr) == VC_OK);
        std::this_thread::sleep_for(std::chrono::milliseconds(600));

        SinkData sink;
        CHECK(vc_set_pcm_sink(clientB, pcm_sink, &sink) == VC_OK);

        std::this_thread::sleep_for(std::chrono::milliseconds(300));

        // A announces a MIC stream — effective_params will be stereo (Music Room config).
        vc_stream_desc desc{};
        desc.kind = VC_STREAM_MIC;
        uint32_t a_sid = 0;
        CHECK(vc_stream_start(clientA, &desc, &a_sid) == VC_OK);

        bool b_saw_a = wait_for(evB, [&](EventStore& s) {
            for (auto& [uid, sid] : s.streams_started)
                if (uid == a_uid) return true;
            return false;
        }, 5000);
        CHECK(b_saw_a);

        std::this_thread::sleep_for(std::chrono::milliseconds(300));

        // A feeds 250 stereo frames: loud-L / silent-R.
        auto stereo = make_sine_stereo(960);
        for (int i = 0; i < 250; ++i)
            CHECK(vc_stream_feed_pcm(clientA, a_sid, stereo.data(), 960, 2) == VC_OK);

        bool fired = sink_wait(sink, 5000);
        CHECK(fired);

        std::this_thread::sleep_for(std::chrono::milliseconds(1500));

        int64_t L = sink.left_energy;
        int64_t R = sink.right_energy;
        uint32_t ch = sink.last_channels;
        std::printf("test_feed_pcm_stereo: channels=%u L_energy=%lld R_energy=%lld\n",
                    ch, static_cast<long long>(L), static_cast<long long>(R));

        CHECK(ch == 2);       // decoder delivered stereo frames
        CHECK(L > 0);         // left channel has signal
        // Opus stereo coding (mid/side): R won't be exactly 0 after decode, but should be
        // substantially quieter than L. Allow up to 30% leakage.
        CHECK(R < L || L == 0);  // L >= R (loud-L / quiet-R)

        vc_stream_stop(clientA, a_sid);
    }

cleanup_st:
    if (clientA) { vc_disconnect(clientA); vc_client_destroy(clientA); }
    if (clientB) { vc_disconnect(clientB); vc_client_destroy(clientB); }
    std::printf("test_feed_pcm_stereo: done\n");
}

// ── test_pcm_sink ─────────────────────────────────────────────────────────────

static void test_pcm_sink(uint16_t port) {
    std::printf("test_pcm_sink: start\n");

    EventStore evA, evB;
    vc_client *clientA = nullptr, *clientB = nullptr;
    CHECK(connect_guest(clientA, "SnkA", "snk-a", port, evA));
    CHECK(connect_guest(clientB, "SnkB", "snk-b", port, evB));
    if (!clientA || !clientB) goto cleanup_sk;

    {
        uint32_t a_uid = 0;
        { std::lock_guard lk(evA.mu); a_uid = evA.self_user_id; }

        SinkData sink;
        CHECK(vc_set_pcm_sink(clientB, pcm_sink, &sink) == VC_OK);

        std::this_thread::sleep_for(std::chrono::milliseconds(500));

        vc_stream_desc desc{};
        desc.kind = VC_STREAM_MIC;
        uint32_t a_sid = 0;
        CHECK(vc_stream_start(clientA, &desc, &a_sid) == VC_OK);

        bool b_saw_a = wait_for(evB, [&](EventStore& s) {
            for (auto& [uid, sid] : s.streams_started)
                if (uid == a_uid) return true;
            return false;
        }, 5000);
        CHECK(b_saw_a);

        // Capture the stream_id that B observed for A's stream.
        uint32_t b_a_sid = 0;
        { std::lock_guard lk(evB.mu);
          for (auto& [uid, sid] : evB.streams_started)
              if (uid == a_uid) { b_a_sid = sid; break; }
        }
        CHECK(b_a_sid != 0);

        std::this_thread::sleep_for(std::chrono::milliseconds(300));

        auto sine = make_sine_mono(960);
        for (int i = 0; i < 250; ++i)
            vc_stream_feed_pcm(clientA, a_sid, sine.data(), 960, 1);

        bool fired = sink_wait(sink, 5000);
        CHECK(fired);

        std::this_thread::sleep_for(std::chrono::milliseconds(1500));

        std::printf("test_pcm_sink: calls=%d user_id=%u stream_id=%u sr=%u energy=%lld\n",
                    sink.call_count.load(),
                    sink.last_user_id, sink.last_stream_id,
                    sink.last_sample_rate,
                    static_cast<long long>(sink.total_energy));

        CHECK(sink.call_count.load() > 0);
        CHECK(sink.total_energy > 0);
        CHECK(sink.last_user_id == a_uid);         // source user matches
        CHECK(sink.last_stream_id == b_a_sid);     // source stream matches
        CHECK(sink.last_sample_rate == 48000);      // always 48000

        // Disable sink — subsequent frames must not reach the callback.
        CHECK(vc_set_pcm_sink(clientB, nullptr, nullptr) == VC_OK);
        int count_before_disable = sink.call_count.load();

        // Feed more frames after disabling.
        for (int i = 0; i < 100; ++i)
            vc_stream_feed_pcm(clientA, a_sid, sine.data(), 960, 1);
        std::this_thread::sleep_for(std::chrono::milliseconds(1000));

        // The count must not have increased (sink was disabled).
        int count_after = sink.call_count.load();
        std::printf("test_pcm_sink: count_before_disable=%d count_after=%d\n",
                    count_before_disable, count_after);
        CHECK(count_after == count_before_disable);

        vc_stream_stop(clientA, a_sid);
    }

cleanup_sk:
    if (clientA) { vc_disconnect(clientA); vc_client_destroy(clientA); }
    if (clientB) { vc_disconnect(clientB); vc_client_destroy(clientB); }
    std::printf("test_pcm_sink: done\n");
}

// ── main ──────────────────────────────────────────────────────────────────────

int main() {
    auto tmp = std::filesystem::temp_directory_path() /
               ("vctest_extpcm_" + std::to_string(
                   std::chrono::steady_clock::now().time_since_epoch().count()));
    std::filesystem::create_directories(tmp);
    std::string data_dir = tmp.string();

    std::atomic<uint16_t> bound_port{0};
    std::mutex ready_mu;
    std::condition_variable ready_cv;
    bool ready{false};

    voicecat::server::Config cfg;
    cfg.data_dir     = data_dir;
    cfg.bind_port    = 0;
    cfg.media_port   = 0;
    cfg.server_name  = "VoiceCat-ExtPcmTest";
    cfg.allow_guests = true;
    cfg.on_ready     = [&](uint16_t p) {
        bound_port.store(p);
        { std::lock_guard lk(ready_mu); ready = true; }
        ready_cv.notify_all();
    };

    voicecat::server::Server server(cfg);
    std::thread server_thread([&] { server.run(); });

    {
        std::unique_lock lk(ready_mu);
        bool ok = ready_cv.wait_for(lk, std::chrono::seconds(10), [&] { return ready; });
        if (!ok) {
            std::printf("FAIL: server did not start\n");
            server.stop(); server_thread.join();
            std::filesystem::remove_all(tmp);
            return 1;
        }
    }

    uint16_t port = bound_port.load();
    std::printf("external_pcm: server ready on :%u\n", port);

    test_feed_pcm_round_trip(port);
    test_feed_pcm_stereo(port);
    test_pcm_sink(port);

    server.stop();
    server_thread.join();
    std::filesystem::remove_all(tmp);

    if (g_failures == 0) {
        std::printf("external_pcm: all checks passed\n");
        return 0;
    }
    std::printf("external_pcm: %d failure(s)\n", g_failures);
    return 1;
}

#else  // !VOICECAT_HAS_NET

int main() {
    std::printf("external_pcm: SKIP (VOICECAT_HAS_NET not defined)\n");
    return 0;
}

#endif  // VOICECAT_HAS_NET