/*
 * libADLMIDI is a free MIDI to WAV conversion library with OPL3 emulation
 *
 * Original ADLMIDI code: Copyright (c) 2010-2014 Joel Yliluoma <bisqwit@iki.fi>
 * ADLMIDI Library API:   Copyright (c) 2017 Vitaly Novichkov <admin@wohlnet.ru>
 *
 * Library is based on the ADLMIDI, a MIDI player for Linux and Windows with OPL3 emulation:
 * http://iki.fi/bisqwit/source/adlmidi.html
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "adlmidi_private.hpp"

static const unsigned MaxCards = 100;

/*---------------------------EXPORTS---------------------------*/

ADLMIDI_EXPORT struct ADL_MIDIPlayer *adl_init(long sample_rate)
{
    ADL_MIDIPlayer *midi_device;
    midi_device = (ADL_MIDIPlayer *)malloc(sizeof(ADL_MIDIPlayer));
    midi_device->PCM_RATE = static_cast<unsigned long>(sample_rate);
    midi_device->AdlBank    = 0;
    midi_device->NumFourOps = 7;
    midi_device->NumCards   = 2;
    midi_device->HighTremoloMode   = 0;
    midi_device->HighVibratoMode   = 0;
    midi_device->AdlPercussionMode = 0;
    midi_device->LogarithmicVolumes = 0;
    midi_device->SkipForward = 0;
    midi_device->loopingIsEnabled = 0;
    midi_device->ScaleModulators = 0;
    midi_device->delay = 0.0;
    midi_device->carry = 0.0;
    midi_device->mindelay = 1.0 / (double)midi_device->PCM_RATE;
    midi_device->maxdelay = 512.0 / (double)midi_device->PCM_RATE;
    midi_device->stored_samples = 0;
    midi_device->backup_samples_size = 0;

    MIDIplay *player = new MIDIplay;
    midi_device->adl_midiPlayer = player;
    player->config = midi_device;
    player->opl._parent = midi_device;
    player->opl.NumCards = midi_device->NumCards;
    player->opl.AdlBank = midi_device->AdlBank;
    player->opl.NumFourOps = midi_device->NumFourOps;
    player->opl.LogarithmicVolumes = (midi_device->LogarithmicVolumes != 0);
    player->opl.HighTremoloMode = (midi_device->HighTremoloMode != 0);
    player->opl.HighVibratoMode = (midi_device->HighVibratoMode != 0);
    player->opl.AdlPercussionMode = (midi_device->AdlPercussionMode != 0);
    player->opl.ScaleModulators = (midi_device->ScaleModulators != 0);
    player->ChooseDevice("none");
    adlRefreshNumCards(midi_device);
    return midi_device;
}

ADLMIDI_EXPORT int adl_setNumCards(ADL_MIDIPlayer *device, int numCards)
{
    if(device == NULL)
        return -2;

    device->NumCards = static_cast<unsigned int>(numCards);
    reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->opl.NumCards = device->NumCards;

    if(device->NumCards < 1 || device->NumCards > MaxCards)
    {
        std::stringstream s;
        s << "number of cards may only be 1.." << MaxCards << ".\n";
        ADLMIDI_ErrorString = s.str();
        return -1;
    }

    return adlRefreshNumCards(device);
}

ADLMIDI_EXPORT int adl_setBank(ADL_MIDIPlayer *device, int bank)
{
    #ifdef DISABLE_EMBEDDED_BANKS
    ADL_UNUSED(device);
    ADL_UNUSED(bank);
    ADLMIDI_ErrorString = "This build of libADLMIDI has no embedded banks. Please load bank by using of adl_openBankFile() or adl_openBankData() functions instead of adl_setBank()";
    return -1;
    #else
    const uint32_t NumBanks = static_cast<uint32_t>(maxAdlBanks());
    int32_t bankno = bank;

    if(bankno < 0)
        bankno = 0;

    device->AdlBank = static_cast<uint32_t>(bankno);
    MIDIplay *play = reinterpret_cast<MIDIplay *>(device->adl_midiPlayer);
    play->opl.AdlBank = device->AdlBank;

    if(device->AdlBank >= NumBanks)
    {
        std::stringstream s;
        s << "bank number may only be 0.." << (NumBanks - 1) << ".\n";
        ADLMIDI_ErrorString = s.str();
        return -1;
    }

    return adlRefreshNumCards(device);
    #endif
}

ADLMIDI_EXPORT int adl_getBanksCount()
{
    return maxAdlBanks();
}

ADLMIDI_EXPORT const char *const *adl_getBankNames()
{
    return banknames;
}

ADLMIDI_EXPORT int adl_setNumFourOpsChn(ADL_MIDIPlayer *device, int ops4)
{
    device->NumFourOps = static_cast<unsigned int>(ops4);
    reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->opl.NumFourOps = device->NumFourOps;

    if(device->NumFourOps > 6 * device->NumCards)
    {
        std::stringstream s;
        s << "number of four-op channels may only be 0.." << (6 * (device->NumCards)) << " when " << device->NumCards << " OPL3 cards are used.\n";
        ADLMIDI_ErrorString = s.str();
        return -1;
    }

    return adlRefreshNumCards(device);
}


ADLMIDI_EXPORT void adl_setPercMode(ADL_MIDIPlayer *device, int percmod)
{
    if(!device) return;

    device->AdlPercussionMode = static_cast<unsigned int>(percmod);
    reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->opl.AdlPercussionMode = (device->AdlPercussionMode != 0);
}

ADLMIDI_EXPORT void adl_setHVibrato(ADL_MIDIPlayer *device, int hvibro)
{
    if(!device) return;

    device->HighVibratoMode = static_cast<unsigned int>(hvibro);
    reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->opl.HighVibratoMode = (device->HighVibratoMode != 0);
}

ADLMIDI_EXPORT void adl_setHTremolo(ADL_MIDIPlayer *device, int htremo)
{
    if(!device) return;

    device->HighTremoloMode = static_cast<unsigned int>(htremo);
    reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->opl.HighTremoloMode = (device->HighTremoloMode != 0);
}

ADLMIDI_EXPORT void adl_setScaleModulators(ADL_MIDIPlayer *device, int smod)
{
    if(!device) return;

    device->ScaleModulators = static_cast<unsigned int>(smod);
    reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->opl.ScaleModulators = (device->ScaleModulators != 0);
}

ADLMIDI_EXPORT void adl_setLoopEnabled(ADL_MIDIPlayer *device, int loopEn)
{
    if(!device) return;
    device->loopingIsEnabled = (loopEn != 0);
}

ADLMIDI_EXPORT void adl_setLogarithmicVolumes(struct ADL_MIDIPlayer *device, int logvol)
{
    if(!device) return;

    device->LogarithmicVolumes = static_cast<unsigned int>(logvol);
    reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->opl.LogarithmicVolumes = (device->LogarithmicVolumes != 0);
}

ADLMIDI_EXPORT void adl_setVolumeRangeModel(struct ADL_MIDIPlayer *device, int volumeModel)
{
    if(!device) return;

    device->VolumeModel = volumeModel;
    reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->opl.ChangeVolumeRangesModel(static_cast<ADLMIDI_VolumeModels>(volumeModel));
}

ADLMIDI_EXPORT int adl_openBankFile(struct ADL_MIDIPlayer *device, char *filePath)
{
    ADLMIDI_ErrorString.clear();

    if(device && device->adl_midiPlayer)
    {
        device->stored_samples = 0;
        device->backup_samples_size = 0;

        if(!reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->LoadBank(filePath))
        {
            if(ADLMIDI_ErrorString.empty())
                ADLMIDI_ErrorString = "ADL MIDI: Can't load file";
            return -1;
        }
        else return 0;
    }

    ADLMIDI_ErrorString = "Can't load file: ADLMIDI is not initialized";
    return -1;
}

ADLMIDI_EXPORT int adl_openBankData(struct ADL_MIDIPlayer *device, void *mem, long size)
{
    ADLMIDI_ErrorString.clear();

    if(device && device->adl_midiPlayer)
    {
        device->stored_samples = 0;
        device->backup_samples_size = 0;

        if(!reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->LoadBank(mem, static_cast<size_t>(size)))
        {
            if(ADLMIDI_ErrorString.empty())
                ADLMIDI_ErrorString = "ADL MIDI: Can't load data from memory";
            return -1;
        }
        else return 0;
    }

    ADLMIDI_ErrorString = "Can't load file: ADL MIDI is not initialized";
    return -1;
}

ADLMIDI_EXPORT int adl_openFile(ADL_MIDIPlayer *device, char *filePath)
{
    ADLMIDI_ErrorString.clear();

    if(device && device->adl_midiPlayer)
    {
        device->stored_samples = 0;
        device->backup_samples_size = 0;

        if(!reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->LoadMIDI(filePath))
        {
            if(ADLMIDI_ErrorString.empty())
                ADLMIDI_ErrorString = "ADL MIDI: Can't load file";

            return -1;
        }
        else return 0;
    }

    ADLMIDI_ErrorString = "Can't load file: ADL MIDI is not initialized";
    return -1;
}

ADLMIDI_EXPORT int adl_openData(ADL_MIDIPlayer *device, void *mem, long size)
{
    ADLMIDI_ErrorString.clear();

    if(device && device->adl_midiPlayer)
    {
        device->stored_samples = 0;
        device->backup_samples_size = 0;

        if(!reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->LoadMIDI(mem, static_cast<size_t>(size)))
        {
            if(ADLMIDI_ErrorString.empty())
                ADLMIDI_ErrorString = "ADL MIDI: Can't load data from memory";

            return -1;
        }
        else return 0;
    }

    ADLMIDI_ErrorString = "Can't load file: ADL MIDI is not initialized";
    return -1;
}


ADLMIDI_EXPORT const char *adl_errorString()
{
    return ADLMIDI_ErrorString.c_str();
}

ADLMIDI_EXPORT const char *adl_getMusicTitle(ADL_MIDIPlayer *device)
{
    if(!device) return "";

    return reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->musTitle.c_str();
}

ADLMIDI_EXPORT void adl_close(ADL_MIDIPlayer *device)
{
    if(device->adl_midiPlayer)
        delete reinterpret_cast<MIDIplay *>(device->adl_midiPlayer);

    device->adl_midiPlayer = NULL;
    free(device);
    device = NULL;
}

ADLMIDI_EXPORT void adl_reset(ADL_MIDIPlayer *device)
{
    if(!device)
        return;

    device->stored_samples = 0;
    device->backup_samples_size = 0;
    reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->opl.Reset();
}

ADLMIDI_EXPORT void adl_positionRewind(struct ADL_MIDIPlayer *device)
{
    if(!device)
        return;
    reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->rewind();
}


inline static void SendStereoAudio(ADL_MIDIPlayer *device,
                                   int      &samples_requested,
                                   ssize_t  &in_size,
                                   short    *_in,
                                   ssize_t   out_pos,
                                   short    *_out)
{
    if(!in_size)
        return;

    device->stored_samples = 0;
    size_t offset       = static_cast<size_t>(out_pos);
    size_t inSamples    = static_cast<size_t>(in_size * 2);
    size_t maxSamples   = static_cast<size_t>(samples_requested) - offset;
    size_t toCopy       = std::min(maxSamples, inSamples);
    std::memcpy(_out + out_pos, _in, toCopy * sizeof(short));

    if(maxSamples < inSamples)
    {
        size_t appendSize = inSamples - maxSamples;
        std::memcpy(device->backup_samples + device->backup_samples_size,
                    maxSamples + _in, appendSize * sizeof(short));
        device->backup_samples_size += (ssize_t)appendSize;
        device->stored_samples += (ssize_t)appendSize;
    }
}


ADLMIDI_EXPORT int adl_play(ADL_MIDIPlayer *device, int sampleCount, short *out)
{
    if(!device)
        return 0;

    sampleCount -= sampleCount % 2; //Avoid even sample requests

    if(sampleCount < 0)
        return 0;

    ssize_t gotten_len = 0;
    ssize_t n_periodCountStereo = 512;
    //ssize_t n_periodCountPhys = n_periodCountStereo * 2;
    int left = sampleCount;

    while(left > 0)
    {
        if(device->backup_samples_size > 0)
        {
            //Send reserved samples if exist
            ssize_t ate = 0;

            while((ate < device->backup_samples_size) && (ate < left))
            {
                out[ate] = device->backup_samples[ate];
                ate++;
            }

            left -= (int)ate;
            gotten_len += ate;

            if(ate < device->backup_samples_size)
            {
                for(ssize_t j = 0; j < ate; j++)
                    device->backup_samples[(ate - 1) - j] = device->backup_samples[(device->backup_samples_size - 1) - j];
            }

            device->backup_samples_size -= ate;
        }
        else
        {
            const double eat_delay = device->delay < device->maxdelay ? device->delay : device->maxdelay;
            device->delay -= eat_delay;
            device->carry += device->PCM_RATE * eat_delay;
            n_periodCountStereo = static_cast<ssize_t>(device->carry);
            device->carry -= n_periodCountStereo;

            if(device->SkipForward > 0)
                device->SkipForward -= 1;
            else
            {
                MIDIplay *player = reinterpret_cast<MIDIplay *>(device->adl_midiPlayer);

                if((player->atEnd) && (device->delay <= 0.0))
                    break;//Stop to fetch samples at reaching of song end with disabled loop

                //! Count of stereo samples
                ssize_t in_generatedStereo = (n_periodCountStereo > 512) ? 512 : n_periodCountStereo;
                //! Total count of samples
                ssize_t in_generatedPhys = in_generatedStereo * 2;
                //! Unsigned total sample count
                //fill buffer with zeros
                int16_t *out_buf = player->outBuf;
                std::memset(out_buf, 0, static_cast<size_t>(in_generatedPhys) * sizeof(int16_t));

                if(device->NumCards == 1)
                {
                    #ifdef ADLMIDI_USE_DOSBOX_OPL
                    player->opl.cards[0].GenerateArr(out_buf, &in_generatedStereo);
                    in_generatedPhys = in_generatedStereo * 2;
                    #else
                    OPL3_GenerateStream(&player->opl.cards[0], out_buf, static_cast<Bit32u>(in_generatedStereo));
                    #endif
                    /* Process it */
                    SendStereoAudio(device, sampleCount, in_generatedStereo, out_buf, gotten_len, out);
                }
                else if(n_periodCountStereo > 0)
                {
                    /* Generate data from every chip and mix result */
                    for(unsigned card = 0; card < device->NumCards; ++card)
                    {
                        #ifdef ADLMIDI_USE_DOSBOX_OPL
                        player->opl.cards[card].GenerateArrMix(out_buf, &in_generatedStereo);
                        in_generatedPhys = in_generatedStereo * 2;
                        #else
                        OPL3_GenerateStreamMix(&player->opl.cards[card], out_buf, static_cast<Bit32u>(in_generatedStereo));
                        #endif
                    }

                    /* Process it */
                    SendStereoAudio(device, sampleCount, in_generatedStereo, out_buf, gotten_len, out);
                }

                left -= (int)in_generatedPhys;
                gotten_len += (in_generatedPhys) - device->stored_samples;
            }

            device->delay = reinterpret_cast<MIDIplay *>(device->adl_midiPlayer)->Tick(eat_delay, device->mindelay);
        }
    }

    return static_cast<int>(gotten_len);
}