#ifdef _WIN32
    #include <winsock2.h>
#endif

#include "manager.hpp"
#include <array>
#define MINIAUDIO_IMPLEMENTATION
#include <miniaudio.h>
#include <opus.h>
#include <cstring>

const uint8_t *StripRTPExtensionHeader(const uint8_t *buf, int num_bytes, size_t &outlen) {
    if (buf[0] == 0xbe && buf[1] == 0xde && num_bytes > 4) {
        uint64_t offset = 4 + 4 * ((buf[2] << 8) | buf[3]);

        outlen = num_bytes - offset;
        return buf + offset;
    }
    outlen = num_bytes;
    return buf;
}

void data_callback(ma_device *pDevice, void *pOutput, const void *pInput, ma_uint32 frameCount) {
    AudioManager *mgr = reinterpret_cast<AudioManager *>(pDevice->pUserData);
    if (mgr == nullptr) return;
    std::lock_guard<std::mutex> _(mgr->m_mutex);

    auto *pOutputF32 = static_cast<float *>(pOutput);
    for (auto &[ssrc, pair] : mgr->m_sources) {
        auto &buf = pair.first;
        const size_t n = std::min(buf.size(), frameCount * 2ULL);
        for (size_t i = 0; i < n; i++) {
            pOutputF32[i] += buf[i] / 32768.F;
        }
        buf.erase(buf.begin(), buf.begin() + n);
    }
}

AudioManager::AudioManager() {
    m_ok = true;

    m_device_config = ma_device_config_init(ma_device_type_playback);
    m_device_config.playback.format = ma_format_f32;
    m_device_config.playback.channels = 2;
    m_device_config.sampleRate = 48000;
    m_device_config.dataCallback = data_callback;
    m_device_config.pUserData = this;

    if (ma_device_init(nullptr, &m_device_config, &m_device) != MA_SUCCESS) {
        puts("open playabck fail");
        m_ok = false;
        return;
    }

    if (ma_device_start(&m_device) != MA_SUCCESS) {
        puts("failed to start playback");
        ma_device_uninit(&m_device);
        m_ok = false;
        return;
    }
}

AudioManager::~AudioManager() {
    ma_device_uninit(&m_device);
    for (auto &[ssrc, pair] : m_sources) {
        opus_decoder_destroy(pair.second);
    }
}

void AudioManager::FeedMeOpus(uint32_t ssrc, const std::vector<uint8_t> &data) {
    size_t payload_size = 0;
    const auto *opus_encoded = StripRTPExtensionHeader(data.data(), static_cast<int>(data.size()), payload_size);
    static std::array<opus_int16, 120 * 48 * 2> pcm;
    if (m_sources.find(ssrc) == m_sources.end()) {
        int err;
        auto *decoder = opus_decoder_create(48000, 2, &err);
        m_sources.insert(std::make_pair(ssrc, std::make_pair(std::deque<int16_t> {}, decoder)));
    }
    int decoded = opus_decode(m_sources.at(ssrc).second, opus_encoded, static_cast<opus_int32>(payload_size), pcm.data(), 120 * 48, 0);
    if (decoded <= 0) {
    } else {
        m_mutex.lock();
        auto &buf = m_sources.at(ssrc).first;
        buf.insert(buf.end(), pcm.begin(), pcm.begin() + decoded * 2);
        m_mutex.unlock();
    }
}

bool AudioManager::OK() const {
    return m_ok;
}