/*---------------------------------------------------------------------------*
  Project:  TwlSDK - SND - demos - seq
  File:     channel.c

  Copyright 2007-2008 Nintendo. All rights reserved.

  These coded instructions, statements, and computer programs contain
  proprietary information of Nintendo of America Inc. and/or Nintendo
  Company Ltd., and are protected by Federal copyright law. They may
  not be disclosed to third parties or copied or duplicated in any form,
  in whole or in part, without the prior written consent of Nintendo.

  $Date:: 2008-09-18#$
  $Rev: 8573 $
  $Author: okubata_ryoma $
 *---------------------------------------------------------------------------*/
#ifdef SDK_TWL
#include <twl.h>
#else
#include <nitro.h>
#endif

#include "smfdefine.h"
#include "channel.h"
#include "piano.g5.pcm16.h"

#define MAX_CHANNEL 16
#define MAX_MIDI_CHANNEL 16

/* Hard channel structure in DS */
typedef struct ChannelEx
{
    u8      playing;                   /* Playback flag */
    u8      midi_ch;                   /* MIDI channel for sound being played back */
    u8      key;                       /* Playback key */
    u8      velocity;                  /* Playback velocity */
}
ChannelEx;

/* MIDI channel structure */
typedef struct MidiChannel
{
    u8      pan;                       /* Pan */
    u8      volume;                    /* Volume */
    u8      expression;                /* Expression */
}
MidiChannel;

ChannelEx channel[MAX_CHANNEL];
MidiChannel midi_ch[MAX_MIDI_CHANNEL];

static void NoteOn(const u8 *midi_data);
static void NoteOff(const u8 *midi_data);


/*---------------------------------------------------------------------------*
  Name:         ChInit

  Description:  Channel initialization.

  Arguments:    None.

  Returns:      None.
 *---------------------------------------------------------------------------*/
void ChInit(void)
{
    int     ch_num;

    /* Locks all channels */
    SND_LockChannel(0xffff, 0);

    for (ch_num = 0; ch_num < MAX_CHANNEL; ch_num++)
    {
        channel[ch_num].playing = FALSE;
    }

    for (ch_num = 0; ch_num < MAX_MIDI_CHANNEL; ch_num++)
    {
        midi_ch[ch_num].volume = 127;
        midi_ch[ch_num].pan = 64;
        midi_ch[ch_num].expression = 127;
    }
}

/*---------------------------------------------------------------------------*
  Name:         ChSetEvent

  Description:  Interprets and runs a MIDI event.

  Arguments:    midi_data: MIDI event data line

  Returns:      None.
 *---------------------------------------------------------------------------*/
void ChSetEvent(const u8 *midi_data)
{
    switch (midi_data[0] & 0xf0)
    {
    case MIDI_NOTEOFF:                /* Note off */
        NoteOff(midi_data);
        break;
    case MIDI_NOTEON:                 /* Note-on. */
        NoteOn(midi_data);
        break;
    case MIDI_CONTROLCHANGE:          /* Control change */
        switch (midi_data[1])
        {
        case MIDI_CC_VOLUME:          /* Channel volume */
            midi_ch[midi_data[0] & 0x0f].volume = midi_data[2];
            break;
        case MIDI_CC_PAN:             /* Channel pan */
            midi_ch[midi_data[0] & 0x0f].pan = midi_data[2];
            break;
        case MIDI_CC_EXPRESSION:      /* Expression */
            midi_ch[midi_data[0] & 0x0f].expression = midi_data[2];
            break;
        default:
            break;
        }
    default:
        /* Other messages are not supported */
        break;
    }
}

/*---------------------------------------------------------------------------*
  Name:         ChAllNoteOff

  Description:  Stops all channels

  Arguments:    None.

  Returns:      None.
 *---------------------------------------------------------------------------*/
void ChAllNoteOff(void)
{
    int     ch_num;

    SND_StopTimer(0xffff, 0, 0, 0);

    for (ch_num = 0; ch_num < MAX_CHANNEL; ch_num++)
    {
        channel[ch_num].playing = FALSE;
    }
}

/*---------------------------------------------------------------------------*
  Name:         NoteOn

  Description:  Executes the note-on operation based on the MIDI event.

  Arguments:    midi_data: MIDI event data line

  Returns:      None.
 *---------------------------------------------------------------------------*/
static void NoteOn(const u8 *midi_data)
{
    int     ch_num;
    ChannelEx *ch;
    s16     db;
    u16     vol;

    for (ch_num = 0; ch_num < MAX_CHANNEL; ch_num++)
    {
        if (!channel[ch_num].playing)
            break;
    }
    if (ch_num == MAX_CHANNEL)
        return;                        /* An open channel was not found */

    ch = &channel[ch_num];
    ch->midi_ch = (u8)(midi_data[0] & 0x0f);
    ch->key = midi_data[1];
    ch->velocity = midi_data[2];

    /* Calculate volume */
    db = SND_CalcDecibel(ch->velocity);
    db += SND_CalcDecibel(midi_ch[ch->midi_ch].volume);
    db += SND_CalcDecibel(midi_ch[ch->midi_ch].expression);
    vol = SND_CalcChannelVolume(db);

    /* Play sound */
    SND_SetupChannelPcm(ch_num,
                        PIANO_G5_PCM16_FORMAT,
                        piano_g5_pcm16,
                        PIANO_G5_PCM16_LOOPFLAG ? SND_CHANNEL_LOOP_REPEAT : SND_CHANNEL_LOOP_1SHOT,
                        PIANO_G5_PCM16_LOOPSTART,
                        PIANO_G5_PCM16_LOOPLEN,
                        vol & 0xff,
                        (SNDChannelDataShift)(vol >> 8),
                        SND_CalcTimer(PIANO_G5_PCM16_TIMER, (int)(ch->key - 67) * 64),
                        midi_ch[ch->midi_ch].pan);
    SND_StartTimer(1U << ch_num, 0, 0, 0);

    ch->playing = TRUE;
}

/*---------------------------------------------------------------------------*
  Name:         NoteOff

  Description:  Executes the note-off operation based on the MIDI event.

  Arguments:    midi_data: MIDI event data line

  Returns:      None.
 *---------------------------------------------------------------------------*/
static void NoteOff(const u8 *midi_data)
{
    int     ch_num;
    ChannelEx *ch;

    for (ch_num = 0; ch_num < MAX_CHANNEL; ch_num++)
    {
        ch = &channel[ch_num];

        if (!ch->playing)
            continue;
        if ((ch->midi_ch == (u8)(midi_data[0] & 0x0f)) && (ch->key == midi_data[1]))
        {
            /* The MIDI channel and key number match and are considered to be the same sound */
            SND_StopTimer(1U << ch_num, 0, 0, 0);
            ch->playing = FALSE;
        }
    }

}