#include "sound.hpp"
#include "bfsk.hpp"
#include "config.hpp"
#include "x25519_handshake.hpp"

#include <iostream>
#include <thread>
#include <atomic>
#include <vector>
#include <cmath>

#include <portaudio.h> 

extern "C" {
#include "monocypher.h"
}

constexpr int CAPTURE_SECONDS = 3;

static std::atomic<bool> gSoundActive{false};
static std::thread gSoundThread;

static std::vector<float> gInputBuffer;
static size_t gWritePos = 0;

static std::vector<float> gOutputBuffer;
static size_t gReadPos = 0;

static int audioCallback(const void *input,
                         void *output,
                         unsigned long frameCount,
                         const PaStreamCallbackTimeInfo* timeInfo,
                         PaStreamCallbackFlags statusFlags,
                         void *userData)
{
    (void)timeInfo; (void)statusFlags; (void)userData;
    const float *in  = static_cast<const float*>(input);   
    float *out       = static_cast<float*>(output);        

    for (unsigned long i = 0; i < frameCount; i++) {
        if (gWritePos < gInputBuffer.size()) {
            gInputBuffer[gWritePos++] = in ? in[i] : 0.0f;
        }

        float sample = 0.0f;
        if (gReadPos < gOutputBuffer.size()) {
            sample = gOutputBuffer[gReadPos++];
        }
        out[i*2 + 0] = sample; 
        out[i*2 + 1] = sample; 
    }

    return paContinue;
}

static void soundThreadFunc(AppConfig config) {
    PaError err = Pa_Initialize();
    if (err != paNoError) {
        std::cerr << CLR_RED "[sound] Pa_Initialize error: " << Pa_GetErrorText(err) << CLR_RESET "\n";
        return;
    }

    PaStreamParameters inParams, outParams;

    inParams.device = Pa_GetDefaultInputDevice();
    if (inParams.device == paNoDevice) {
        std::cerr << CLR_RED "[sound] Нет устройства ввода.\n" CLR_RESET;
        Pa_Terminate();
        return;
    }
    inParams.channelCount = 1;
    inParams.sampleFormat = paFloat32;
    inParams.suggestedLatency = Pa_GetDeviceInfo(inParams.device)->defaultLowInputLatency;
    inParams.hostApiSpecificStreamInfo = nullptr;

    outParams.device = Pa_GetDefaultOutputDevice();
    if (outParams.device == paNoDevice) {
        std::cerr << CLR_RED "[sound] Нет устройства вывода.\n" CLR_RESET;
        Pa_Terminate();
        return;
    }
    outParams.channelCount = 2; 
    outParams.sampleFormat = paFloat32;
    outParams.suggestedLatency = Pa_GetDeviceInfo(outParams.device)->defaultLowOutputLatency;
    outParams.hostApiSpecificStreamInfo = nullptr;

    PaStream *stream = nullptr; 

    err = Pa_OpenStream(&stream,
                        &inParams,
                        &outParams,
                        SAMPLE_RATE,
                        256,  
                        paNoFlag,
                        audioCallback,
                        nullptr);
    if (err != paNoError) {
        std::cerr << CLR_RED "[sound] Pa_OpenStream error: " << Pa_GetErrorText(err) << CLR_RESET "\n";
        Pa_Terminate();
        return;
    }

    err = Pa_StartStream(stream);
    if (err != paNoError) {
        std::cerr << CLR_RED "[sound] Pa_StartStream error: " << Pa_GetErrorText(err) << CLR_RESET "\n";
        Pa_CloseStream(stream);
        Pa_Terminate();
        return;
    }

    std::cout << CLR_BLUE "[sound] Старт записи/воспроизведения (3 сек)...\n" CLR_RESET;
    Pa_Sleep(CAPTURE_SECONDS * 1000);

    Pa_StopStream(stream);
    Pa_CloseStream(stream);
    Pa_Terminate();

    std::cout << CLR_BLUE "[sound] Остановка аудиопотока...\n" CLR_RESET;

    auto received = bfskDemodulate(gInputBuffer);
    if (!received.empty()) {
        if (received.size() >= 33 && received[0] == 'E') {
            uint8_t otherPub[32];
            std::memcpy(otherPub, received.data() + 1, 32);

            x25519ComputeShared(config, otherPub);
            std::cout << CLR_GREEN "[x25519] Общий сеансовый ключ вычислен!\n" CLR_RESET;
        } else {
            std::cout << CLR_YELLOW "[sound] Получены " << received.size()
                      << " байт, но не формат 'E' + 32 байта.\n" CLR_RESET;
        }
    } else {
        std::cout << CLR_YELLOW "[sound] Ничего не демодулировано.\n" CLR_RESET;
    }

    gSoundActive = false;
}

void soundFind(AppConfig &config) {
    if (config.soundExchangeActive) {
        std::cout << CLR_YELLOW "[sound] Уже идёт процесс.\n" CLR_RESET;
        return;
    }
    config.soundExchangeActive = true;
    gSoundActive = true;

    x25519GenerateEphemeral(config);

    std::vector<unsigned char> packet;
    packet.push_back('E');
    packet.insert(packet.end(), config.ephemeralPub, config.ephemeralPub + 32);

    gOutputBuffer = bfskModulate(packet);
    gReadPos = 0;

    gInputBuffer.clear();
    gInputBuffer.resize(SAMPLE_RATE * CAPTURE_SECONDS, 0.0f);
    gWritePos = 0;

    gSoundThread = std::thread(soundThreadFunc, config);

    std::cout << CLR_GREEN "[sound] Отправляем свой публичный ключ X25519 и слушаем!\n" CLR_RESET;
}

void soundLose(AppConfig &config) {
    if (!config.soundExchangeActive) {
        std::cout << CLR_YELLOW "[sound] Процесс не активен.\n" CLR_RESET;
        return;
    }
    config.soundExchangeActive = false;

    if (gSoundActive) {
        gSoundActive = false;
    }
    if (gSoundThread.joinable()) {
        gSoundThread.join();
    }
    std::cout << CLR_GREEN "[sound] Процесс остановлен.\n" CLR_RESET;
}