/*****************************************************************************

 * smf.c : Standard MIDI File (.mid) demux module for vlc

 *****************************************************************************

 * Copyright © 2007 Rémi Denis-Courmont

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU Lesser General Public License as published by

 * the Free Software Foundation; either version 2.1 of the License, or

 * (at your option) 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 Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with this program; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.

 *****************************************************************************/

#ifdef HAVE_CONFIG_H

# include "config.h"

#endif

#include <vlc_common.h>

#include <vlc_plugin.h>

#include <vlc_demux.h>

#include <vlc_charset.h>

#include <limits.h>

#include <assert.h>

#define TEMPO_MIN  20

#define TEMPO_MAX 250 /* Beats per minute */

/**

 * Reads MIDI variable length (7, 14, 21 or 28 bits) integer.

 * @return read value, or -1 on EOF/error.

 */

static int32_t ReadVarInt (stream_t *s)

{

    uint32_t val = 0;

    uint8_t byte;

    for (unsigned i = 0; i < 4; i++)

    {

        if (vlc_stream_Read (s, &byte, 1) < 1)

            return -1;

        val = (val << 7) | (byte & 0x7f);

        if ((byte & 0x80) == 0)

            return val;

    }

    return -1;

}

typedef struct smf_track_t

{

    uint64_t next;   /*< Time of next message (in term of pulses) */

    uint64_t start;  /*< Start offset in the file */

    uint32_t length; /*< Bytes length */

    uint32_t offset; /*< Read offset relative to the start offset */

    uint8_t  running_event; /*< Running (previous) event */

} mtrk_t;

/**

 * Reads (delta) time from the next event of a given track.

 * @param s stream to read data from (must be positioned at the right offset)

 */

static int ReadDeltaTime (stream_t *s, mtrk_t *track)

{

    int32_t delta_time;

    assert (vlc_stream_Tell (s) == track->start + track->offset);

    if (track->offset >= track->length)

    {

        /* This track is done */

        track->next = UINT64_MAX;

        return 0;

    }

    delta_time = ReadVarInt (s);

    if (delta_time < 0)

        return -1;

    track->next += delta_time;

    track->offset = vlc_stream_Tell (s) - track->start;

    return 0;

}

typedef struct

{

    es_out_id_t *es;

    date_t       pts; /*< Play timestamp */

    uint64_t     pulse; /*< Pulses counter */

    vlc_tick_t   tick; /*< Last tick timestamp */

    vlc_tick_t   duration; /*< Total duration */

    unsigned     ppqn;   /*< Pulses Per Quarter Note */

    /* by the way, "quarter note" is "noire" in French */

    unsigned     trackc; /*< Number of tracks */

    mtrk_t       trackv[]; /*< Track states */

} demux_sys_t;

/**

 * Non-MIDI Meta events handler

 */

static

int HandleMeta (demux_t *p_demux, mtrk_t *tr)

{

    stream_t *s = p_demux->s;

    demux_sys_t *p_sys = p_demux->p_sys;

    uint8_t *payload;

    uint8_t type;

    int32_t length;

    int ret = 0;

    if (vlc_stream_Read (s, &type, 1) != 1)

        return -1;

    length = ReadVarInt (s);

    if (length < 0)

        return -1;

    payload = malloc (length + 1);

    if ((payload == NULL)

     || (vlc_stream_Read (s, payload, length) != length))

    {

        free (payload);

        return -1;

    }

    payload[length] = '\0';

    switch (type)

    {

        case 0x00: /* Sequence Number */

            break;

        case 0x01: /* Text (comment) */

            EnsureUTF8 ((char *)payload);

            msg_Info (p_demux, "Text      : %s", (char *)payload);

            break;

        case 0x02: /* Copyright */

            EnsureUTF8 ((char *)payload);

            msg_Info (p_demux, "Copyright : %s", (char *)payload);

            break;

        case 0x03: /* Track name */

            EnsureUTF8 ((char *)payload);

            msg_Info (p_demux, "Track name: %s", (char *)payload);

            break;

        case 0x04: /* Instrument name */

            EnsureUTF8 ((char *)payload);

            msg_Info (p_demux, "Instrument: %s", (char *)payload);

            break;

        case 0x05: /* Lyric (one syllable) */

            /*EnsureUTF8 ((char *)payload);*/

            break;

        case 0x06: /* Marker text */

            EnsureUTF8 ((char *)payload);

            msg_Info (p_demux, "Marker    : %s", (char *)payload);

            break;

        case 0x07: /* Cue point (WAVE filename) */

            EnsureUTF8 ((char *)payload);

            msg_Info (p_demux, "Cue point : %s", (char *)payload);

            break;

        case 0x08: /* Program/Patch name */

            EnsureUTF8 ((char *)payload);

            msg_Info (p_demux, "Patch name: %s", (char *)payload);

            break;

        case 0x09: /* MIDI port name */

            EnsureUTF8 ((char *)payload);

            msg_Dbg (p_demux, "MIDI port : %s", (char *)payload);

            break;

        case 0x2F: /* End of track */

            if (tr->start + tr->length != vlc_stream_Tell (s))

            {

                msg_Err (p_demux, "misplaced end of track");

                ret = -1;

            }

            break;

        case 0x51: /* Tempo */

            if (length == 3)

            {

                uint32_t uspqn = (payload[0] << 16)

                               | (payload[1] << 8) | payload[2];

                unsigned tempo = 60 * 1000000 / (uspqn ? uspqn : 1);

                msg_Dbg (p_demux, "tempo: %uus/qn -> %u BPM",

                         (unsigned)uspqn, tempo);

                if (tempo < TEMPO_MIN)

                {

                    msg_Warn (p_demux, "tempo too slow -> %u BPM", TEMPO_MIN);

                    tempo = TEMPO_MIN;

                }

                else

                if (tempo > TEMPO_MAX)

                {

                    msg_Warn (p_demux, "tempo too fast -> %u BPM", TEMPO_MAX);

                    tempo = TEMPO_MAX;

                }

                date_Change (&p_sys->pts, p_sys->ppqn * tempo, 60);

            }

            else

                ret = -1;

            break;

        case 0x54: /* SMPTE offset */

            if (length == 5)

                msg_Warn (p_demux, "SMPTE offset not implemented");

            else

                ret = -1;

            break;

        case 0x58: /* Time signature */

            if (length == 4)

                ;

            else

                ret = -1;

            break;

        case 0x59: /* Key signature */

            if (length != 2)

                msg_Warn(p_demux, "invalid key signature");

            break;

        case 0x7f: /* Proprietary event */

            msg_Dbg (p_demux, "ignored proprietary SMF Meta Event (%d bytes)",

                     length);

            break;

        default:

            msg_Warn (p_demux, "unknown SMF Meta Event type 0x%02X (%d bytes)",

                      type, length);

    }

    free (payload);

    return ret;

}

static

int HandleMessage (demux_t *p_demux, mtrk_t *tr, es_out_t *out)

{

    stream_t *s = p_demux->s;

    demux_sys_t *sys = p_demux->p_sys;

    block_t *block;

    uint8_t first, event;

    int datalen;

    if (vlc_stream_Seek (s, tr->start + tr->offset)

     || (vlc_stream_Read (s, &first, 1) != 1))

        return -1;

    event = (first & 0x80) ? first : tr->running_event;

    switch (event & 0xf0)

    {

        case 0xF0: /* System Exclusive */

            switch (event)

            {

                case 0xF0: /* System Specific start */

                case 0xF7: /* System Specific continuation */

                {

                    /* Variable length followed by SysEx event data */

                    int32_t len = ReadVarInt (s);

                    if (len == -1)

                        return -1;

                    block = vlc_stream_Block (s, len);

                    if (block == NULL)

                        return -1;

                    block = block_Realloc (block, 1, len);

                    if (block == NULL)

                        return -1;

                    block->p_buffer[0] = event;

                    goto send;

                }

                case 0xFF: /* SMF Meta Event */

                    if (HandleMeta (p_demux, tr))

                        return -1;

                    /* We MUST NOT pass this event forward. It would be

                     * confused as a MIDI Reset real-time event. */

                    goto skip;

                case 0xF1:

                case 0xF3:

                    datalen = 1;

                    break;

                case 0xF2:

                    datalen = 2;

                    break;

                case 0xF4:

                case 0xF5:

                    /* We cannot handle undefined "common" (non-real-time)

                     * events inside SMF, as we cannot differentiate a

                     * one byte delta-time (< 0x80) from event data. */

                default:

                    datalen = 0;

                    break;

            }

            break;

        case 0xC0:

        case 0xD0:

            datalen = 1;

            break;

        default:

            datalen = 2;

            break;

    }

    /* FIXME: one message per block is very inefficient */

    block = block_Alloc (1 + datalen);

    if (block == NULL)

        goto skip;

    block->p_buffer[0] = event;

    if (first & 0x80)

    {

        if (vlc_stream_Read(s, block->p_buffer + 1, datalen) < datalen)

            goto error;

    }

    else

    {

        if (datalen == 0)

        {   /* implicit running status requires non-empty payload */

            msg_Err (p_demux, "malformatted MIDI event");

            goto error;

        }

        block->p_buffer[1] = first;

        if (datalen > 1

         && vlc_stream_Read(s, block->p_buffer + 2, datalen - 1) < datalen - 1)

            goto error;

    }

send:

    block->i_dts = block->i_pts = date_Get(&sys->pts);

    if (out != NULL)

        es_out_Send(out, sys->es, block);

    else

        block_Release (block);

skip:

    if (event < 0xF8)

        /* If event is not real-time, update running status */

        tr->running_event = event;

    tr->offset = vlc_stream_Tell (s) - tr->start;

    return 0;

error:

    block_Release(block);

    return -1;

}

static int SeekSet0 (demux_t *demux)

{

    stream_t *stream = demux->s;

    demux_sys_t *sys = demux->p_sys;

    /* Default SMF tempo is 120BPM, i.e. half a second per quarter note */

    date_Init (&sys->pts, sys->ppqn * 2, 1);

    date_Set (&sys->pts, VLC_TICK_0);

    sys->pulse = 0;

    sys->tick = VLC_TICK_0;

    for (unsigned i = 0; i < sys->trackc; i++)

    {

        mtrk_t *tr = sys->trackv + i;

        tr->offset = 0;

        tr->next = 0;

        /* Why 0xF6 (Tuning Calibration)?

         * Because it has zero bytes of data, so the parser will detect the

         * error if the first event uses running status. */

        tr->running_event = 0xF6;

        if (vlc_stream_Seek (stream, tr->start)

         || ReadDeltaTime (stream, tr))

        {

            msg_Err (demux, "fatal parsing error");

            return -1;

        }

    }

    return 0;

}

static int ReadEvents (demux_t *demux, uint64_t *restrict pulse,

                       es_out_t *out)

{

    uint64_t cur_pulse = *pulse, next_pulse = UINT64_MAX;

    demux_sys_t *sys = demux->p_sys;

    for (unsigned i = 0; i < sys->trackc; i++)

    {

        mtrk_t *track = sys->trackv + i;

        while (track->next <= cur_pulse)

        {

            if (HandleMessage (demux, track, out)

             || ReadDeltaTime (demux->s, track))

            {

                msg_Err (demux, "fatal parsing error");

                return -1;

            }

        }

        if (next_pulse > track->next)

            next_pulse = track->next;

    }

    if (next_pulse != UINT64_MAX)

        date_Increment (&sys->pts, next_pulse - cur_pulse);

    *pulse = next_pulse;

    return 0;

}

#define TICK VLC_TICK_FROM_MS(10)

/*****************************************************************************

 * Demux: read chunks and send them to the synthesizer

 *****************************************************************************

 * Returns -1 in case of error, 0 in case of EOF, 1 otherwise

 *****************************************************************************/

static int Demux (demux_t *demux)

{

    demux_sys_t *sys = demux->p_sys;

    /* MIDI Tick emulation (ping the decoder every 10ms) */

    if (sys->tick <= date_Get (&sys->pts))

    {

        block_t *tick = block_Alloc (1);

        if (unlikely(tick == NULL))

            return VLC_ENOMEM;

        tick->p_buffer[0] = 0xF9;

        tick->i_dts = tick->i_pts = sys->tick;

        es_out_Send (demux->out, sys->es, tick);

        es_out_SetPCR (demux->out, sys->tick);

        sys->tick += TICK;

        return VLC_DEMUXER_SUCCESS;

    }

    /* MIDI events in chronological order across all tracks */

    uint64_t pulse = sys->pulse;

    if (ReadEvents (demux, &pulse, demux->out))

        return VLC_DEMUXER_EGENERIC;

    if (pulse == UINT64_MAX)

        return VLC_DEMUXER_EOF; /* all tracks are done */

    sys->pulse = pulse;

    return VLC_DEMUXER_SUCCESS;

}

static int Seek (demux_t *demux, vlc_tick_t pts)

{

    demux_sys_t *sys = demux->p_sys;

    /* Rewind if needed */

    if (pts < date_Get (&sys->pts) && SeekSet0 (demux))

        return VLC_EGENERIC;

    /* Fast forward */

    uint64_t pulse = sys->pulse;

    while (pts > date_Get (&sys->pts))

    {

        if (pulse == UINT64_MAX)

            return VLC_SUCCESS; /* premature end */

        if (ReadEvents (demux, &pulse, NULL))

            return VLC_EGENERIC;

    }

    sys->pulse = pulse;

    sys->tick = ((date_Get (&sys->pts) - VLC_TICK_0) / TICK) * TICK + VLC_TICK_0;

    return VLC_SUCCESS;

}

/*****************************************************************************

 * Control:

 *****************************************************************************/

static int Control (demux_t *demux, int i_query, va_list args)

{

    demux_sys_t *sys = demux->p_sys;

    switch (i_query)

    {

        case DEMUX_CAN_SEEK:

            *va_arg (args, bool *) = true;

            break;

        case DEMUX_GET_POSITION:

            if (!sys->duration)

                return VLC_EGENERIC;

            *va_arg (args, double *) = (sys->tick - (double)VLC_TICK_0)

                                     / sys->duration;

            break;

        case DEMUX_SET_POSITION:

            return Seek (demux, va_arg (args, double) * sys->duration);

        case DEMUX_GET_LENGTH:

            *va_arg (args, vlc_tick_t *) = sys->duration;

            break;

        case DEMUX_GET_TIME:

            *va_arg (args, vlc_tick_t *) = sys->tick - VLC_TICK_0;

            break;

        case DEMUX_SET_TIME:

            return Seek (demux, va_arg (args, vlc_tick_t));

        case DEMUX_CAN_PAUSE:

        case DEMUX_SET_PAUSE_STATE:

        case DEMUX_CAN_CONTROL_PACE:

        case DEMUX_GET_PTS_DELAY:

            return demux_vaControlHelper( demux->s, 0, -1, 0, 1, i_query, args );

        default:

            return VLC_EGENERIC;

    }

    return VLC_SUCCESS;

}

/**

 * Probes file format and starts demuxing.

 */

static int Open (vlc_object_t *obj)

{

    demux_t *demux = (demux_t *)obj;

    stream_t *stream = demux->s;

    const uint8_t *peek;

    bool multitrack;

    /* (Try to) parse the SMF header */

    /* Header chunk always has 6 bytes payload */

    if (vlc_stream_Peek (stream, &peek, 14) < 14)

        return VLC_EGENERIC;

    /* Skip RIFF MIDI header if present */

    if (!memcmp (peek, "RIFF", 4) && !memcmp (peek + 8, "RMID", 4))

    {

        uint32_t riff_len = GetDWLE (peek + 4);

        msg_Dbg (demux, "detected RIFF MIDI file (%"PRIu32" bytes)", riff_len);

        if (vlc_stream_Read( stream, NULL, 12 ) != 12 )

            return VLC_EGENERIC;

        /* Look for the RIFF data chunk */

        for (;;)

        {

            char chnk_hdr[8];

            uint32_t chnk_len;

            if ((riff_len < 8)

             || (vlc_stream_Read (stream, chnk_hdr, 8) < 8))

                return VLC_EGENERIC;

            riff_len -= 8;

            chnk_len = GetDWLE (chnk_hdr + 4);

            if (riff_len < chnk_len)

                return VLC_EGENERIC;

            riff_len -= chnk_len;

            if (!memcmp (chnk_hdr, "data", 4))

                break; /* found! */

            if (vlc_stream_Read( stream, NULL, chnk_len ) != chnk_len )

                return VLC_EGENERIC;

        }

        /* Read real SMF header. Assume RIFF data chunk length is proper. */

        if (vlc_stream_Peek (stream, &peek, 14) < 14)

            return VLC_EGENERIC;

    }

    if (memcmp (peek, "MThd\x00\x00\x00\x06", 8))

        return VLC_EGENERIC;

    peek += 8;

    /* First word: SMF type */

    switch (GetWBE (peek))

    {

        case 0:

            multitrack = false;

            break;

        case 1:

            multitrack = true;

            break;

        default:

            /* We don't implement SMF2 (as do many) */

            msg_Err (demux, "unsupported SMF file type %u", GetWBE (peek));

            return VLC_EGENERIC;

    }

    peek += 2;

    /* Second word: number of tracks */

    unsigned tracks = GetWBE (peek);

    peek += 2;

    if (!multitrack && (tracks != 1))

    {

        msg_Err (demux, "invalid SMF type 0 file");

        return VLC_EGENERIC;

    }

    msg_Dbg (demux, "detected Standard MIDI File (type %u) with %u track(s)",

             multitrack, tracks);

    /* Third/last word: timing */

    unsigned ppqn = GetWBE (peek);

    if (ppqn & 0x8000)

    {   /* FIXME */

        msg_Err (demux, "SMPTE timestamps not implemented");

        return VLC_EGENERIC;

    }

    else

    {

        if (ppqn == 0)

        {

            msg_Err(demux, "invalid SMF file PPQN: %u", ppqn);

            return VLC_EGENERIC;

        }

        msg_Dbg (demux, " %u pulses per quarter note", ppqn);

    }

    demux_sys_t *sys = malloc (sizeof (*sys) + (sizeof (mtrk_t) * tracks));

    if (unlikely(sys == NULL))

        return VLC_ENOMEM;

    /* We've had a valid SMF header - now skip it*/

    if (vlc_stream_Read( stream, NULL, 14 ) != 14 )

        goto error;

    demux->p_sys = sys;

    sys->duration = 0;

    sys->ppqn = ppqn;

    sys->trackc = tracks;

    /* Prefetch track offsets */

    for (unsigned i = 0; i < tracks; i++)

    {

        mtrk_t *tr = sys->trackv + i;

        uint8_t head[8];

        /* Seeking screws streaming up, but there is no way around this, as

         * SMF1 tracks are performed simultaneously.

         * Not a big deal as SMF1 are usually only a few kbytes anyway. */

        if (i > 0 && vlc_stream_Seek (stream, tr[-1].start + tr[-1].length))

        {

            msg_Err (demux, "cannot build SMF index (corrupted file?)");

            goto error;

        }

        for (;;)

        {

            if (vlc_stream_Read (stream, head, 8) < 8)

            {

                /* FIXME: don't give up if we have at least one valid track */

                msg_Err (demux, "incomplete SMF chunk, file is corrupted");

                goto error;

            }

            if (memcmp (head, "MTrk", 4) == 0)

                break;

            uint_fast32_t chunk_len = GetDWBE(head + 4);

            msg_Dbg(demux, "skipping unknown SMF chunk (%"PRIuFAST32" bytes)",

                    chunk_len);

            if (vlc_stream_Seek(stream, vlc_stream_Tell(stream) + chunk_len))

                goto error;

        }

        tr->start = vlc_stream_Tell (stream);

        tr->length = GetDWBE (head + 4);

    }

    bool b;

    if (vlc_stream_Control (stream, STREAM_CAN_FASTSEEK, &b) == 0 && b)

    {

        if (SeekSet0 (demux))

            goto error;

        for (uint64_t pulse = 0; pulse != UINT64_MAX;)

             if (ReadEvents (demux, &pulse, NULL))

                 break;

        sys->duration = date_Get (&sys->pts);

    }

    if (SeekSet0 (demux))

        goto error;

    es_format_t  fmt;

    es_format_Init (&fmt, AUDIO_ES, VLC_CODEC_MIDI);

    fmt.audio.i_channels = 2;

    fmt.audio.i_rate = 44100; /* dummy value */

    fmt.i_id = 0;

    sys->es = es_out_Add (demux->out, &fmt);

    if( unlikely(!sys->es) )

        goto error;

    demux->pf_demux = Demux;

    demux->pf_control = Control;

    return VLC_SUCCESS;

error:

    free (sys);

    return VLC_EGENERIC;

}

/**

 * Releases allocate resources.

 */

static void Close (vlc_object_t * p_this)

{

    demux_t *p_demux = (demux_t *)p_this;

    demux_sys_t *p_sys = p_demux->p_sys;

    free (p_sys);

}

vlc_module_begin ()

    set_description (N_("SMF demuxer"))

    set_subcategory (SUBCAT_INPUT_DEMUX)

    set_capability ("demux", 20)

    set_callbacks (Open, Close)

    add_file_extension("kar")

    add_file_extension("mid")

    add_file_extension("rmi")

vlc_module_end ()