/*
  MidiSynth, MIDI synthesiser, a repacement for the Acorn MIDI module

  store.c - controls the storage of instrument and bank definitions

  created  01/02/2021
*/

#include <time.h>
#include "main.h"
#include "kbd.h"

// -----  Default Sound Set  -----
// SoundSet.c
extern const char def_name[];                          // name of sound set
extern const unsigned int def_date;                    // creation date/time
extern const ins_t def_instrument[];                   // array of instruments
extern const int num_def_instruments;                  // number of entries in def_instrument[]
extern const bank_t def_bank[];                        // instrument and drum kit banks, array of indexes to instruments[]
extern const int num_def_banks;                        // number of entries in def_bank[]
extern const unsigned char def_banks[MIDI_DATA_RANGE]; // bank selector, indexes to bank[]
extern const unsigned char def_kits[MIDI_DATA_RANGE];  // drum kit selector, indexes to bank[]
extern const harm_t def_wave[];                        // array of waveform harmonic data
extern const int num_def_waves;                        // number of entries in def_wave[]
// -------------------------------

#define NPT (1<<SIN_BITS)
typedef struct fft_data_s // fft data
{
  int xr[NPT]; // real component
  int xi[NPT]; // imaginary component
} fft_data_t;

static fft_data_t fd;

// fft.s
#define INVERSE 0
#define FORWARD 1
void fft(fft_data_t *fd, int dir);

/*
 Sound Set file format
 ---------------------

 A binary file consisting of the following.

 1. File Header, 48 byte
      24 byte: ascii name null padded
      4 byte: (unused)
      4 byte: timestamp
      2 byte: number of instruments
      2 byte: size of each instrument (128)
      2 byte: number of banks
      2 byte: size of each bank       (280)
      2 byte: number of waveforms
      2 byte: size of each waveform   (152)
      4 byte: crc of following data

 2. Instrument data, an array of instruments
    n x 128 byte instrument definitions, of 24 byte name then 104 byte instrument data

 3. Bank data, arrays of banks each, containting indexes to instruments
    n x 280 byte arrays, of 24 byte name then 128 x 2 byte entries

 4. Bank selector data, arrays of indexes to banks,
    2 arrays of 128 bytes, one for melodic instruments, one for percussion drum kits

 5. Waveform's harmonic data array, (optional)
    n x 152 byte waveform definitions, of 24 byte name then 32 x 4 byte harmonic data (2 byte real, 2 byte imaginary)

 All names are ascii null padded strings
*/

//file header
typedef struct InsHdr_s
{
  char name[NAME_LEN];  // ascii string, null padded
  int spare;            // (currently not used)
  unsigned int stamp;   // timestamp, seconds since 1/1/2001
  short int num_instr;  // number of instruments
  short int instr_size; // size of a single instrument
  short int num_banks;  // number of banks
  short int bank_size;  // size of a single bank
  short int num_waves;  // number of waveforms
  short int wave_size;  // total size of the waveforms harmonic data
  unsigned int crc;     // 32 bit crc of the rest of the following data
} InsHdr_t;


/*
 * TimestampToDate
 * ---------------
 * Converts timestamp to date/time structure.
 * We use a timestamp epoch of 1/1/2001.
 * The maths is correct for the whole 400 year Gregorian cycle and
 * hence forever, but a 32 bit timestamp overflows in the year 2137.
 */
#define DAY_ZERO_OFFSET      730792 // number of days from 1/3/0000 to 1/1/2001
void TimestampToDate(unsigned int t, datetime_t *dt)
{
  dt->second = t % 60;
  t /= 60;
  dt->minute = t % 60;
  t /= 60;
  dt->hour = t % 24;
  t /= 24;
  dt->weekday = t % 7;

  t += DAY_ZERO_OFFSET; // relocate from 1/1/2001 to 1/3/0000
  unsigned int a = 4 * t / 146097;
  unsigned int b = t + a - (a / 4);
  unsigned int y = (4 * b - 1) / 1461;
  unsigned int d = b - 365 * y - (y / 4) + 122;
  unsigned int m = d * 100 / 3061;
  dt->day = d - m * 3061 / 100;
  if(--m > 12) // 1/3/xxx0 to 1/1/xxx1 correction
  {
    m -= 12;
    y++;
  }
  dt->month = m;
  dt->year = y;
}


/*
 * crc32
 * -----
 * crc of a number of blocks. For first block, pass 0 for crc.
 *  The polynomial is 0x04C11DB7 or
 *  x32 + x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 + x2 + x1 + 1
 */
static const unsigned int crc32tab[256] =
{
  0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
  0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
  0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
  0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
  0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
  0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
  0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
  0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
  0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
  0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
  0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
  0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
  0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
  0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
  0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
  0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
  0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
  0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
  0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
  0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
  0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
  0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
  0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
  0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
  0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
  0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
  0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
  0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
  0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
  0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
  0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
  0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
};
static unsigned int crc32(const void *buf, int len, unsigned int crc)
{
  while(len--)
    crc = (crc>>8) ^ crc32tab[(crc ^ *(unsigned char *)buf++) & 0xff];

  return crc;
}


/*
 * harm_to_wave
 * ------------
 * converts a harmonic structure to a waveform
 */
void harm_to_wave(const harm_t *h, short int *w)
{
  int i, j;

  // convert harmonic array to waveform
  memset(&fd, 0, sizeof(fd));
  for(i=1; i<=NUM_HARMS; i++)
  {
    fd.xr[i] = h->hrm[i-1].re;
    fd.xi[i] = h->hrm[i-1].im;
    j = (NPT - i) & (NPT - 1);
    fd.xr[j] = fd.xr[i];
    fd.xi[j] = -fd.xi[i];
  }
  fft(&fd, INVERSE);

  // limit data to signed 16 bits and copy to waveform array
  for(i=0; i<NPT; i++)
   if(fd.xr[i] > 0x7fff)
     w[i] = 0x7fff;
   else if(fd.xr[i] < -0x8000)
     w[i] = -0x8000;
   else
     w[i] = fd.xr[i];
}


/*
 * load_defaults
 * -------------
 * Loads the instrument and bank data from the default set programmed in the code.
 */
int load_defaults(ins_data_t* idat)
{
  int max_instruments = num_def_instruments + 100; // allocate extra to allow for editing
  int max_banks = num_def_banks + 10;
  int max_waves = num_def_waves + 5;

  // instruments
  if(idat->instrument)
    free(idat->instrument);
  if((idat->instrument = calloc(max_instruments, sizeof(ins_t))) == NULL)
    return -CANNOT_ALLOCATE_MEMORY;
  memcpy(idat->instrument, &def_instrument, num_def_instruments * sizeof(ins_t));
  idat->num_instruments = num_def_instruments;
  idat->max_instruments = max_instruments;

  // banks
  if(idat->bank)
    free(idat->bank);
  if((idat->bank = calloc(max_banks, sizeof(bank_t))) == NULL)
    return -CANNOT_ALLOCATE_MEMORY;
  memcpy(idat->bank, &def_bank, num_def_banks * sizeof(bank_t));
  idat->num_banks = num_def_banks;
  idat->max_banks = max_banks;

  // selectors
  memcpy(&idat->banks, &def_banks, MIDI_DATA_RANGE);
  memcpy(&idat->kits, &def_kits, MIDI_DATA_RANGE);

  // waveforms
  if(idat->wtbl)
    free(idat->wtbl);
  if((idat->wtbl = calloc(max_waves, sizeof(wave_t))) == NULL)
    return -CANNOT_ALLOCATE_MEMORY;
  if(idat->harm)
    free(idat->harm);
  if((idat->harm = calloc(max_waves, sizeof(harm_t))) == NULL)
    return -CANNOT_ALLOCATE_MEMORY;

  memcpy(idat->harm, &def_wave, num_def_waves * sizeof(harm_t));
  idat->num_waves = num_def_waves;
  idat->max_waves = max_waves;

  int w;
  for(w=0; w<num_def_waves; w++)
    harm_to_wave(&def_wave[w], idat->wtbl[w].wave);

  strncpy(idat->name, def_name, NAME_LEN);
  idat->date = def_date;

  return NO_ERROR_;
}


/*
 * check_filename
 * --------------
 * Sets the top bit of spaces and replaces the first control character with a null.
 */
#define SPC 32
static void check_filename(char *str)
{
  while(*str >= SPC)
  {
    if(*str == SPC)
      *str = SPC | 0x80;
    str++;
  }
  *str = 0;
}


/*
 * load_file
 * ---------
 * Loads the instrument and bank data from the given file
 */
int load_file(ins_data_t* idat, char *filename)
{
  #define BUFF_SIZE 32
  unsigned char buff[BUFF_SIZE];
  int err = NO_ERROR_, len, crc = 0, n;
  FILE *f;
  InsHdr_t hdr;

  check_filename(filename);
  if((f = fopen(filename, "rb")) == NULL)
    return -PROBLEM_OPENING_FILE;

  if(fread(&hdr, sizeof(InsHdr_t), 1, f) != 1) // read header
    err = -INVALID_DATA;

  else if((hdr.instr_size != sizeof(ins_t)) ||
          (hdr.bank_size != sizeof(bank_t)) ||
          (hdr.wave_size != sizeof(harm_t)))    // check that data sizes agree with ours
    err = -INVALID_SIZE;

  else
  {
    // length of remainder of file
    len = hdr.num_instr * sizeof(ins_t) +
          hdr.num_banks * sizeof(bank_t) +
          MIDI_DATA_RANGE + MIDI_DATA_RANGE;
    if(hdr.num_waves > 0)
      len += hdr.num_waves * sizeof(harm_t);

    // check validity of data
    while((len > 0) && (err >= NO_ERROR_))
    {
      n = (len > BUFF_SIZE) ? BUFF_SIZE : len;
      if(fread(buff, 1, n, f) != n)
        err = -PROBLEM_READING_FILE;
      else
        crc = crc32(buff, n, crc);
      len -= n;
    }
    if(err >= NO_ERROR_)
    {
      if(crc != hdr.crc)
        err = -INVALID_CRC;
      else // data valid
      {
        fseek(f, sizeof(hdr), SEEK_SET);

        int max_instruments = hdr.num_instr + 100; // allocate extra to allow for editing
        int max_banks = hdr.num_banks + 10;
        int max_waves = hdr.num_waves + 5;

        // instruments
        if(idat->instrument)
          free(idat->instrument);
        if((idat->instrument = calloc(max_instruments, sizeof(ins_t))) == NULL)
          err = -CANNOT_ALLOCATE_MEMORY;
        else
        {
          fread(idat->instrument, sizeof(ins_t), hdr.num_instr, f);
          idat->num_instruments = hdr.num_instr;
          idat->max_instruments = max_instruments;

          // banks
          if(idat->bank)
            free(idat->bank);
          if((idat->bank = calloc(max_banks, sizeof(bank_t))) == NULL)
            err = -CANNOT_ALLOCATE_MEMORY;
          else
          {
            fread(idat->bank, sizeof(bank_t), hdr.num_banks, f);
            idat->num_banks = hdr.num_banks;
            idat->max_banks = max_banks;

            // selectors
            fread(&idat->banks, MIDI_DATA_RANGE, 1, f);
            fread(&idat->kits, MIDI_DATA_RANGE, 1, f);

            // waveforms
            if(hdr.num_waves > 0)
            {
              if(idat->wtbl)
                free(idat->wtbl);
              if((idat->wtbl = calloc(max_waves, sizeof(wave_t))) == NULL)
                err = -CANNOT_ALLOCATE_MEMORY;
              else
              {
                if(idat->harm)
                  free(idat->harm);
                if((idat->harm = calloc(max_waves, sizeof(harm_t))) == NULL)
                  err = -CANNOT_ALLOCATE_MEMORY;
                else
                {
                  fread(idat->harm, sizeof(harm_t), hdr.num_waves, f);
                  idat->num_waves = hdr.num_waves;
                  idat->max_waves = max_waves;

                  // create waveforms from the harmonic data
                  int w;
                  for(w=0; w<hdr.num_waves; w++)
                    harm_to_wave(&idat->harm[w], idat->wtbl[w].wave);
                }
              }
            }
          }
        }
      }
    }
  }
  fclose(f);

  if(err >= NO_ERROR_)
  {
    strncpy(idat->name, hdr.name, NAME_LEN);
    idat->date = hdr.stamp;
  }

  return err;
}

