voice-cat/tests/test_channel_samplerate.cpp

/*
 * test_channel_samplerate — per-channel sample_rate as an Opus bandwidth cap.
 *
 * The codec always runs at 48 kHz internally (docs/voice.md §3); a channel's sample_rate is
 * carried as OPUS_SET_MAX_BANDWIDTH so a low-bitrate / narrowband room can constrain the encoded
 * audio bandwidth without changing the PCM clock. This verifies the cap is actually in effect:
 *
 *   - A channel at sample_rate = 8000 (NARROWBAND, ~4 kHz audio) and a channel at 48000
 *     (FULLBAND) are each fed an identical 7 kHz tone (well above the narrowband edge).
 *   - The narrowband channel's decoded energy must be substantially lower — the only difference
 *     between the two runs is the channel's sample_rate, so a lower energy proves the bandwidth
 *     cap filtered the out-of-band tone.
 *   - vc_get_stream_audio_config reports the channel's configured sample_rate (not 48000).
 */
#include <cstdio>

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

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

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      generic_result_received{false};
    bool      generic_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_GENERIC_RESULT:
            s->generic_result_received = true;
            s->generic_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;
}

// 7 kHz tone — above the NARROWBAND (~4 kHz) edge, within FULLBAND.
static std::vector<int16_t> make_tone(int n, float hz) {
    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 * hz * t) * 16000.0f);
    }
    return pcm;
}

struct SinkData {
    std::mutex              mu;
    std::condition_variable cv;
    std::atomic<int>        call_count{0};
    int64_t  total_energy = 0;
};

static void pcm_sink(void* user, uint32_t, uint32_t,
                     const int16_t* pcm, size_t n, uint32_t channels, uint32_t) {
    auto* d = static_cast<SinkData*>(user);
    std::lock_guard lk(d->mu);
    for (size_t i = 0; i < n * channels; ++i)
        d->total_energy += std::abs(static_cast<int>(pcm[i]));
    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; });
}

static uint32_t make_channel(vc_client* admin, EventStore& evAdmin, const char* name,
                             uint32_t sample_rate) {
    vc_channel_info ch{};
    ch.name                = name;
    ch.audio.codec         = 0;       // OPUS
    ch.audio.mode          = 0;       // mono
    ch.audio.sample_rate   = sample_rate;
    ch.audio.bitrate_bps   = 32000;
    ch.audio.frame_ms      = 20;
    ch.audio.fec           = 1;
    ch.audio.complexity    = 10;

    { std::lock_guard lk(evAdmin.mu); evAdmin.generic_result_received = false; }
    if (vc_create_channel(admin, &ch) != VC_OK) return 0;
    if (!wait_for(evAdmin, [](EventStore& s) { return s.generic_result_received; }, 5000)) return 0;
    { std::lock_guard lk(evAdmin.mu); if (!evAdmin.generic_ok) return 0; }

    vc_channel_list cl{};
    if (vc_list_channels(admin, &cl) != VC_OK) return 0;
    uint32_t id = 0;
    for (size_t i = 0; i < cl.count; ++i)
        if (cl.items[i].name && std::string(cl.items[i].name) == name) { id = cl.items[i].id; break; }
    vc_free_channel_list(&cl);
    return id;
}

// Feed a 7 kHz tone through `channel_id` and return the decoded energy the sink observed.
// Also asserts vc_get_stream_audio_config reports `expect_sr`.
static int64_t run_case(uint16_t port, vc_client* admin, EventStore& evAdmin,
                        uint32_t channel_id, uint32_t expect_sr, const char* tag) {
    EventStore evA, evB;
    vc_client *clientA = nullptr, *clientB = nullptr;
    CHECK(connect_guest(clientA, "SrA", "sr-a", port, evA));
    CHECK(connect_guest(clientB, "SrB", "sr-b", port, evB));
    int64_t energy = -1;
    if (!clientA || !clientB) goto cleanup;

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

        CHECK(vc_move_user(admin, a_uid, channel_id) == VC_OK);
        CHECK(vc_move_user(admin, b_uid, channel_id) == VC_OK);
        std::this_thread::sleep_for(std::chrono::milliseconds(500));

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

        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(400));

        vc_audio_config ac{};
        CHECK(vc_get_stream_audio_config(clientA, a_uid, a_sid, &ac) == VC_OK);
        CHECK(ac.sample_rate == expect_sr);

        auto tone = make_tone(960, 7000.0f);
        for (int i = 0; i < 300; ++i)
            CHECK(vc_stream_feed_pcm(clientA, a_sid, tone.data(), 960, 1) == VC_OK);

        CHECK(sink_wait(sink, 5000));
        std::this_thread::sleep_for(std::chrono::milliseconds(1500));

        energy = sink.total_energy;
        std::printf("test_channel_samplerate[%s]: sr=%u calls=%d energy=%lld\n",
                    tag, expect_sr, sink.call_count.load(), static_cast<long long>(energy));
        CHECK(sink.call_count.load() > 0);

        vc_stream_stop(clientA, a_sid);
    }

cleanup:
    if (clientA) { vc_disconnect(clientA); vc_client_destroy(clientA); }
    if (clientB) { vc_disconnect(clientB); vc_client_destroy(clientB); }
    return energy;
}

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

    {
        voicecat::server::Database db(data_dir + "/voicecat.db");
        std::string err;
        if (!db.open(err) || !db.create_account("admin", "pass", true, err)) {
            std::printf("FAIL: provision admin: %s\n", err.c_str());
            std::filesystem::remove_all(tmp);
            return 1;
        }
    }

    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-ChanSrTest";
    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);
        if (!ready_cv.wait_for(lk, std::chrono::seconds(10), [&] { return ready; })) {
            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("channel_samplerate: server ready on :%u\n", port);

    EventStore evAdmin;
    evAdmin.label = "admin";
    vc_callbacks cbAdmin{on_event, nullptr, &evAdmin};
    vc_config cfgAdmin{"chansr-admin", "0.1", VC_LOG_OFF};
    vc_client* admin = vc_client_create(&cfgAdmin, cbAdmin);
    CHECK(admin != nullptr);
    evAdmin.client = admin;
    CHECK(vc_connect(admin, "127.0.0.1", port) == VC_OK);
    CHECK(vc_authenticate_user(admin, "admin", "pass") == VC_OK);
    CHECK(wait_for(evAdmin, [](EventStore& s) { return s.auth_ok; }, 8000));
    CHECK(wait_for(evAdmin, [](EventStore& s) { return s.channel_list_received; }, 3000));

    uint32_t ch_full   = make_channel(admin, evAdmin, "FullBand",   48000);
    uint32_t ch_narrow = make_channel(admin, evAdmin, "NarrowBand", 8000);
    CHECK(ch_full != 0);
    CHECK(ch_narrow != 0);

    int64_t full_energy   = (ch_full   ? run_case(port, admin, evAdmin, ch_full,   48000, "full")   : -1);
    int64_t narrow_energy = (ch_narrow ? run_case(port, admin, evAdmin, ch_narrow, 8000,  "narrow") : -1);

    // The 7 kHz tone is above the narrowband (~4 kHz) cutoff: the narrowband channel must filter
    // most of it out, so its decoded energy is far below the full-band channel's. Generous margin
    // (< 50%) to stay robust across Opus versions while still proving the cap is in effect.
    CHECK(full_energy > 0);
    CHECK(narrow_energy >= 0);
    std::printf("channel_samplerate: full=%lld narrow=%lld ratio=%.3f\n",
                static_cast<long long>(full_energy), static_cast<long long>(narrow_energy),
                full_energy > 0 ? static_cast<double>(narrow_energy) / static_cast<double>(full_energy)
                                : 0.0);
    CHECK(narrow_energy < full_energy / 2);

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

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