//CLI Midi file player based on libfluidsynth
//Midi file reading module
//Written by Chris Xiong, 2015
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cstdint>
#include <cstdarg>
#include <algorithm>
#include <stdexcept>
#include "qmpmidiplay.hpp"
static const char *GM1SysX = "\xF0\x7E\x7F\x09\x01\xF7";
static const char *GM2SysX = "\xF0\x7E\x7F\x09\x03\xF7";
static const char *GSSysEx = "\xF0\x41\x10\x42\x12\x40\x00\x7F\x00\x41\xF7";
static const char *XGSysEx = "\xF0\x43\x10\x4C\x00\x00\x7E\x00\xF7";
#define assert(x) if(!(x))this->error(false,"assertion failure @ qmpmidiread.cpp:%d",__LINE__)
void CSMFReader::error(int fatal, const char *format, ...)
{
    va_list ap;
    char buf[1024], bufr[1024];
    va_start(ap, format);
    vsnprintf(buf, 1024, format, ap);
    va_end(ap);
    snprintf(bufr, 1024, "%s at %#lx", buf, ftell(f));
    if (fatal)
        throw std::runtime_error(bufr);
    else fprintf(stderr, "CSMFReader W: %s.\n", bufr);
}
uint8_t CSMFReader::read_u8()
{
    uint8_t ret = 0;
    int t = fgetc(f);
    if (!~t)
        error(1, "Unexpected EOF");
    ret = (uint8_t)t;
    return ret;
}
uint16_t CSMFReader::read_u16()
{
    uint16_t ret = 0;
    size_t sz = fread(&ret, 2, 1, f);
    if (sz < 1)
        error(1, "Unexpected EOF");
#if defined(_MSC_VER)&&defined(_WIN32)
    ret = _byteswap_ushort(ret);
#elif __BYTE_ORDER__==__ORDER_LITTLE_ENDIAN__
    ret = __builtin_bswap16(ret);
#endif
    return ret;
}
uint32_t CSMFReader::read_u32()
{
    uint32_t ret = 0;
    size_t sz = fread(&ret, 4, 1, f);
    if (sz < 1)
        error(1, "Unexpected EOF");
#if defined(_MSC_VER)&&defined(_WIN32)
    ret = _byteswap_ulong(ret);
#elif __BYTE_ORDER__==__ORDER_LITTLE_ENDIAN__
    ret = __builtin_bswap32(ret);
#endif
    return ret;
}
uint32_t CSMFReader::read_varlen()
{
    uint32_t ret = 0, c = 0;
    int t;
    do
    {
        t = fgetc(f);
        if (!~t)
            error(1, "Unexpected EOF");
        if (++c > 4)
            error(1, "Variable length type overflow");
        ret <<= 7;
        ret |= (t & 0x7F);
    } while (t & 0x80);
    return ret;
}
int CSMFReader::read_event()//returns 0 if End of Track encountered
{
    uint32_t delta = read_varlen();
    curt += delta;
    uint8_t type = read_u8();
    uint32_t p1, p2;
    static uint8_t lasttype;
    eventdiscarded = false;
    if (!(type & 0x80))
    {
        fseek(f, -1, SEEK_CUR);
        type = lasttype;
    }
    switch (type & 0xF0)
    {
        case 0x80://Note Off
        case 0x90://Note On
        case 0xA0://Note Aftertouch
        case 0xB0://Controller Change
        case 0xE0://Pitch wheel
            p1 = read_u8();
            p2 = read_u8();
            curTrack->appendEvent(SEvent(curid, curt, type, p1, p2));
            break;
        case 0xC0://Patch Change
        case 0xD0://Channel Aftertouch
            p1 = read_u8();
            curTrack->appendEvent(SEvent(curid, curt, type, p1, 0));
            break;
        case 0xF0:
            if ((type & 0x0F) == 0x0F) //Meta Event
            {
                uint8_t metatype = read_u8();
                uint32_t len = read_varlen();
                char *str = nullptr;
                if (len <= 1024 && len > 0)
                    str = new char[len + 8];
                if (str)
                    fread(str, 1, len, f);
                else
                    fseek(f, len, SEEK_CUR);
                std::string sstr;
                if (str)
                {
                    str[len] = '\0';
                    sstr = std::string(str, len);
                }
                switch (metatype)
                {
                    case 0x00://Sequence Number
                        assert(len == 2 || len == 0);
                        break;
                    case 0x20://Channel Prefix
                        assert(len == 1);
                        break;
                    case 0x2F://End of Track
                        assert(len == 0);
                        return 0;
                    case 0x51://Set Tempo
                        assert(len == 3);
                        curTrack->appendEvent(SEvent(curid, curt, type, metatype, 0, sstr));
                        break;
                    case 0x54://SMTPE offset, not handled.
                        assert(len == 5);
                        break;
                    case 0x58://Time signature
                        assert(len == 4);
                        curTrack->appendEvent(SEvent(curid, curt, type, metatype, 0, sstr));
                        break;
                    case 0x59://Key signature
                        assert(len == 2);
                        curTrack->appendEvent(SEvent(curid, curt, type, metatype, 0, sstr));
                        break;
                    case 0x01:
                    case 0x02:
                    case 0x03:
                    case 0x04:
                    case 0x05:
                    case 0x06:
                    case 0x07:
                    case 0x7F:
                    default://text-like meta
                    {
                        curTrack->appendEvent(SEvent(curid, curt, type, metatype, 0, sstr));
                        if (str && metatype == 0x03 && !ret->title)
                        {
                            ret->title = new char[len + 8];
                            strcpy(ret->title, str);
                        }
                        if (str && metatype == 0x02 && !ret->copyright)
                        {
                            ret->copyright = new char[len + 8];
                            strcpy(ret->copyright, str);
                        }
                    }
                }
                if (str)
                    delete[] str;
            }
            else if ((type & 0x0F) == 0x00 || (type & 0x0F) == 0x07) //SysEx
            {
                uint32_t len = read_varlen();
                char *str = nullptr;
                str = new char[len + 8];
                if ((type & 0x0F) == 0x00)
                {
                    str[0] = char(0xF0);
                    ++len;
                    size_t sz = fread(str + 1, 1, len - 1, f);
                    if (sz < len - 1)
                        error(1, "Unexpected EOF");
                }
                else
                {
                    size_t sz = fread(str, 1, len, f);
                    if (sz < len)
                        error(1, "Unexpected EOF");
                }
                curTrack->appendEvent(SEvent(curid, curt, type, 0, 0, std::string(str, len)));
                if (!strcmp(str, GM1SysX))
                    ret->std = 1;
                if (!strcmp(str, GM2SysX))
                    ret->std = 2;
                if (!strcmp(str, GSSysEx))
                    ret->std = 3;
                if (!strcmp(str, XGSysEx))
                    ret->std = 4;
                delete[] str;
            }
            else
                error(0, "Unknown event type %#x", type);
            break;
        default:
            error(0, "Unknown event type %#x", type);
    }
    lasttype = type;
    ++curid;
    if (curTrack->eventList.size())
    {
        SEvent &le = curTrack->eventList.back();
        CMidiPlayer::getInstance()->callEventReaderCB(le);
    }
    return 1;
}
void CSMFReader::read_track()
{
    ret->tracks.push_back(CMidiTrack());
    curTrack = &ret->tracks.back();
    uint32_t chnklen = read_u32();
    byteread = ftell(f);
    curt = 0;
    curid = 0;
    while (read_event());
    byteread = ftell(f) - byteread;
    if (byteread < chnklen)
    {
        error(0, "Extra bytes after EOT event");
        for (; byteread < chnklen; ++byteread)
            fgetc(f);
    }
    if (byteread > chnklen)
        error(1, "Read past end of track");
}
void CSMFReader::read_header()
{
    uint32_t chnklen = read_u32();
    byteread = ftell(f);
    if (chnklen < 6)
        error(1, "Header chunk too short");
    if (chnklen > 6)
        error(0, "Header chunk length longer than expected. Ignoring extra bytes");
    fmt = read_u16();
    trk = read_u16();
    ret->divs = read_u16();
    if (ret->divs & 0x8000)
        error(1, "SMTPE format is not supported");
    for (byteread = ftell(f) - byteread; byteread < chnklen; ++byteread)
        fgetc(f);
}
uint32_t CSMFReader::read_chunk(int is_header)
{
    char hdr[6];
    fread(hdr, 1, 4, f);
    if (feof(f))
        error(1, "Unexpected EOF");
    if (is_header)
    {
        if (!strncmp(hdr, "RIFF", 4))
        {
            fseek(f, 4, SEEK_CUR);
            fread(hdr, 1, 4, f);
            if (strncmp(hdr, "RMID", 4))
                error(1, "Wrong file type in RIFF container");
            fseek(f, 8, SEEK_CUR);
            fread(hdr, 1, 4, f);
        }
        if (strncmp(hdr, "MThd", 4))
            error(1, "Wrong MIDI header.");
        else return read_header(), 0;
    }
    else if (strncmp(hdr, "MTrk", 4))
    {
        error(0, "Wrong track chunk header. Ignoring the entire chunk.");
        uint32_t chnklen = read_u32();
        fseek(f, chnklen, SEEK_CUR);
        return 0;
    }
    else
        return read_track(), 1;
    return 0;
}
CSMFReader::CSMFReader()
{
    f = nullptr;
}
CMidiFile *CSMFReader::readFile(const char *fn)
{
    ret = new CMidiFile;
    ret->title = ret->copyright = nullptr;
    ret->std = 0;
    ret->valid = 1;
    try
    {
        if (!(f = fopen(fn, "rb")))
            throw std::runtime_error("Can't open file");
        read_chunk(1);
        for (uint32_t i = 0; i < trk; i += read_chunk(0));
        fclose(f);
        f = nullptr;
    }
    catch (std::runtime_error &e)
    {
        fprintf(stderr, "CSMFReader E: %s is not a supported file. Cause: %s.\n", fn, e.what());
        ret->valid = 0;
        if (f)
            fclose(f);
        f = nullptr;
    }
    return ret;
}
CSMFReader::~CSMFReader()
{
}

void CSMFReader::discardCurrentEvent()
{
    if (eventdiscarded)
        return;
    eventdiscarded = true;
    curTrack->eventList.pop_back();
}
void CSMFReader::commitEventChange(SEvent d)
{
    curTrack->eventList.back().time = d.time;
    curTrack->eventList.back().type = d.type;
    curTrack->eventList.back().p1 = d.p1;
    curTrack->eventList.back().p2 = d.p2;
}

CMidiFileReaderCollection::CMidiFileReaderCollection()
{
    readers.clear();
    currentReader = nullptr;
    registerReader(new CSMFReader(), "Default SMF Reader");
}
CMidiFileReaderCollection::~CMidiFileReaderCollection()
{
    delete readers[0].first;
}
void CMidiFileReaderCollection::registerReader(qmpFileReader *reader, std::string name)
{
    for (unsigned i = 0; i < readers.size(); ++i)
        if (readers[i].second == name)
            return;
    readers.push_back(std::make_pair(reader, name));
}
void CMidiFileReaderCollection::unregisterReader(std::string name)
{
    for (auto i = readers.begin(); i != readers.end(); ++i)
        if (i->second == name)
        {
            readers.erase(i);
            return;
        }
}
CMidiFile *CMidiFileReaderCollection::readFile(const char *fn)
{
    CMidiFile *file = nullptr;
    for (unsigned i = 0; i < readers.size(); ++i)
    {
        currentReader = readers[i].first;
        CMidiPlayer::getInstance()->notes = 0;
        CMidiFile *t = readers[i].first->readFile(fn);
        if (t->valid)
        {
            file = t;
            break;
        }
        else
            delete t;
    }
    currentReader = nullptr;
    return file;
}
qmpFileReader *CMidiFileReaderCollection::getCurrentReader()
{
    return currentReader;
}