#include <sndfile.hh>
#include "sfizz/Synth.h"
#include "sfizz/MathHelpers.h"
#include "sfizz/SfzHelpers.h"
#include "sfizz/SIMDHelpers.h"
#include "MidiHelpers.h"
#include "cxxopts.hpp"
#include <fmidi/fmidi.h>
#include <iostream>

#define LOG_ERROR(ostream) std::cerr  << ostream << '\n'
#define LOG_INFO(ostream) if (verbose) { std::cout << ostream << '\n'; }
#define ERROR_IF(check, ostream) if ((check)) { LOG_ERROR(ostream); std::exit(-1); }

struct CallbackData {
    sfz::Synth& synth;
    int trackIdx;
    double lastCallTime;
    double blockSizeInSeconds;
    bool finished;
};

void midiCallback(const fmidi_event_t * event, void * cbdata)
{
    auto data = reinterpret_cast<CallbackData*>(cbdata);

    if (event->type != fmidi_event_type::fmidi_event_message)
        return;

    switch (midi::status(event->data[0])) {
        case midi::noteOff:
            data->synth.noteOff(event->delta, event->data[1], event->data[2]);
            break;
        case midi::noteOn:
            data->synth.noteOn(event->delta, event->data[1], event->data[2]);
            break;
        case midi::polyphonicPressure:
            break;
        case midi::controlChange:
            data->synth.cc(event->delta, event->data[1], event->data[2]);
            break;
        case midi::programChange:
            break;
        case midi::channelPressure:
            break;
        case midi::pitchBend:
            data->synth.pitchWheel(event->delta, midi::buildAndCenterPitch(event->data[1], event->data[2]));
            break;
        case midi::systemMessage:
            break;
        }
}

void finishedCallback(void * cbdata)
{
    auto data = reinterpret_cast<CallbackData*>(cbdata);
    data->finished = true;
}

int main(int argc, char** argv)
{
    cxxopts::Options options("sfizz-render", "Render a midi file through an SFZ file using the sfizz library.");

    unsigned blockSize { 1024 };
    int sampleRate { 48000 };
    int trackNumber { -1 };
    bool verbose { false };
    bool help { false };
    bool useEOT { false };
    int oversampling { 1 };

    options.add_options()
        ("sfz", "SFZ file", cxxopts::value<std::string>())
        ("midi", "Input midi file", cxxopts::value<std::string>())
        ("wav", "Output wav file", cxxopts::value<std::string>())
        ("b,blocksize", "Block size for the sfizz callbacks", cxxopts::value(blockSize))
        ("s,samplerate", "Output sample rate", cxxopts::value(sampleRate))
        ("t,track", "Track number to use", cxxopts::value(trackNumber))
        ("oversampling", "Internal oversampling factor", cxxopts::value(oversampling))
        ("v,verbose", "Verbose output", cxxopts::value(verbose))
        ("log", "Produce logs", cxxopts::value<std::string>())
        ("use-eot", "End the rendering at the last End of Track Midi message", cxxopts::value(useEOT))
        ("h,help", "Show help", cxxopts::value(help))
    ;
    auto params = [&]() {
        try { return options.parse(argc, argv); }
        catch (std::exception& e) {
            LOG_ERROR(e.what());
            std::exit(-1);
        }
    }();

    if (help) {
        std::cout << options.help();
        std::exit(0);
    }

    ERROR_IF(params.count("sfz") != 1, "Please specify a single SFZ file using --sfz");
    ERROR_IF(params.count("wav") != 1, "Please specify a single WAV file using --wav");
    ERROR_IF(params.count("midi") != 1, "Please specify a single MIDI file using --midi");

    fs::path sfzPath  = fs::current_path() / params["sfz"].as<std::string>();
    fs::path outputPath  = fs::current_path() / params["wav"].as<std::string>();
    fs::path midiPath  = fs::current_path() / params["midi"].as<std::string>();

    ERROR_IF(!fs::exists(sfzPath) || !fs::is_regular_file(sfzPath),
                    "SFZ file " << sfzPath.string() << " does not exist or is not a regular file");
    ERROR_IF(!fs::exists(midiPath) || !fs::is_regular_file(midiPath),
            "MIDI file " << midiPath.string() << " does not exist or is not a regular file");

    if (fs::exists(outputPath)) {
        LOG_INFO("Output file " << outputPath.string() << " already exists and will be erased.");
    }

    LOG_INFO("SFZ file:    " << sfzPath.string());
    LOG_INFO("MIDI file:   " << midiPath.string());
    LOG_INFO("Output file: " << outputPath.string());
    LOG_INFO("Block size: " << blockSize);
    LOG_INFO("Sample rate: " << sampleRate);

    sfz::Synth synth;
    synth.setSamplesPerBlock(blockSize);
    synth.setSampleRate(sampleRate);
    synth.enableFreeWheeling();

    if (params.count("log") > 0)
        synth.enableLogging(params["log"].as<std::string>());

    const auto osFactor = [oversampling] {
        switch (oversampling){
        case 1:
            return sfz::Oversampling::x1;
        case 2:
            return sfz::Oversampling::x2;
        case 4:
            return sfz::Oversampling::x4;
        case 5:
            return sfz::Oversampling::x8;
        default:
            LOG_ERROR("Bad oversampling factor: " << oversampling);
            std::exit(-1);
        }
    }();
    synth.setOversamplingFactor(osFactor);

    ERROR_IF(!synth.loadSfzFile(sfzPath), "There was an error loading the SFZ file.");
    LOG_INFO(synth.getNumRegions() << " regions in the SFZ.");

    fmidi_smf_u midiFile { fmidi_smf_file_read(midiPath.c_str()) };
    ERROR_IF(!midiFile, "Can't read " << midiPath);

    const auto* midiInfo = fmidi_smf_get_info(midiFile.get());
    ERROR_IF(!midiInfo, "Can't get info on the midi file");

    LOG_INFO( midiInfo->track_count << " tracks in the SMF.");
    ERROR_IF (trackNumber > midiInfo->track_count, "The track number " <<  trackNumber << " requested does not exist in the SMF file.");

    if (trackNumber >= 0) {
        LOG_INFO("-- Rendering only track number " <<  trackNumber);
    }

    if (useEOT) {
        LOG_INFO("-- Cutting the rendering at the last MIDI End of Track message");
    }

    const auto trackIdx = trackNumber < 1 ? 0 : trackNumber - 1;

    SndfileHandle outputFile (outputPath, SFM_WRITE, SF_FORMAT_WAV | SF_FORMAT_PCM_16, 2, sampleRate);
    ERROR_IF(outputFile.error() != 0, "Error writing out the wav file: " << outputFile.strError());

    auto sampleRateDouble = static_cast<double>(sampleRate);
    double blockSizeInSeconds { blockSize / sampleRateDouble };
    int numFramesWritten { 0 };
    sfz::AudioBuffer<float> audioBuffer { 2, blockSize };
    sfz::Buffer<float> interleavedBuffer { 2 * blockSize };

    fmidi_player_u midiPlayer { fmidi_player_new(midiFile.get()) };
    CallbackData callbackData { synth, trackIdx, 0.0, blockSizeInSeconds, false };
    fmidi_player_event_callback(midiPlayer.get(), &midiCallback, &callbackData);
    fmidi_player_finish_callback(midiPlayer.get(), &finishedCallback, &callbackData);

    fmidi_player_start(midiPlayer.get());
    while (!callbackData.finished) {
        fmidi_player_tick(midiPlayer.get(), blockSizeInSeconds);
        callbackData.lastCallTime += blockSizeInSeconds;
        synth.renderBlock(audioBuffer);
        sfz::writeInterleaved(audioBuffer.getConstSpan(0), audioBuffer.getConstSpan(1), absl::MakeSpan(interleavedBuffer));
        numFramesWritten += outputFile.writef(interleavedBuffer.data(), blockSize);
    }

    if (!useEOT) {
        auto averagePower = sfz::meanSquared<float>(interleavedBuffer);
        while (averagePower > 1e-12f) {
            callbackData.lastCallTime += blockSizeInSeconds;
            synth.renderBlock(audioBuffer);
            sfz::writeInterleaved(audioBuffer.getConstSpan(0), audioBuffer.getConstSpan(1), absl::MakeSpan(interleavedBuffer));
            numFramesWritten += outputFile.writef(interleavedBuffer.data(), blockSize);
            averagePower = sfz::meanSquared<float>(interleavedBuffer);
        }
    }

    outputFile.writeSync();
    LOG_INFO("Wrote " << callbackData.lastCallTime << " seconds of sound data in"
              << outputPath.string() << " (" << numFramesWritten << " frames)");

    return 0;
}