#include "parser.h"
#include "mix.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>

/* NONE_TYPE is for empty notes. */
/* Since different channels have different time specifications, an
   empty line can only be parsed as an empty note.  So we have to
   explicitly mark a silent note. */

/* A note of type BEAT_DURATION_TYPE stores the new bpm in the secs
   field. */

/* A note of type VOLUME_TYPE stores the new volume in the secs
   field. */

typedef enum {
  NONE_TYPE,
  NOTE_TYPE,
  SILENT_TYPE,
  INSTRUMENT_TYPE,
  BEAT_DURATION_TYPE,
  VOLUME_TYPE
} PType;

struct PNote_s {
  Semitones *tones;
  Beats secs;
  LENT len;
  PType type;

  /* The instrument type, if it is an instrument changing note. */
  InstrumentTypes *name;
};

struct PUnit_s {
  PNote *notes;                 /* the notes of channels */
  LENT len;                     /* the length of channels */
};

/* Helper macro */

#define EMPTY_NOTE ((PNote) { NULL, 0.0, 0, NONE_TYPE, NULL })
#define EMPTY_UNIT ((PUnit) { NULL, 0 })

/* Helper function */

H_ATTR
unsigned char
is_empty_note(PNote *n)
{
  return n->type == NONE_TYPE;
}

/* Destructor */

U_ATTR
void
destroy_sheet(PSheet sh)
{
  for (LENT i = 0; i < sh.len; i++) {
    for (LENT j = 0; j < (sh.data+i)->len; j++) {
      if (((sh.data+i)->notes+j)->tones)
        free(((sh.data+i)->notes+j)->tones);
      if (((sh.data+i)->notes+j)->name)
        free(((sh.data+i)->notes+j)->name);
    }

    free((sh.data+i)->notes);
  }

  free(sh.data);
}

/* For debugging */

U_ATTR
static void
print_note(const PNote note)
{
  switch (note.type) {
  case NONE_TYPE:
    fprintf(stderr, "an empty note\n");
    break;
  case SILENT_TYPE:
    fprintf(stderr, "a silent note with %.3f beats\n",
            note.secs);
    break;
  case NOTE_TYPE:
    fprintf(stderr, "a note with %.3f beats and %lu semitone%s\n",
            note.secs, note.len, (note.len < 2) ? "" : "s");
    fprintf(stderr, "The semitone%s: ",
            (note.len<2) ? " is" : "s are");
    for (LENT i = 0; i < note.len; i++)
      fprintf(stderr, "%.2f%s",
              *(note.tones+i),
              (i==note.len-1) ? "" : ", ");
    fprintf(stderr, "\n");
    break;
  case INSTRUMENT_TYPE:
    fprintf(stderr, "an instrument changing note\n");
    break;
  case BEAT_DURATION_TYPE:
    fprintf(stderr, "a note of the type that changes the bpm to "
            "%.3f beats per minute.\n",
            note.secs);
    break;
  case VOLUME_TYPE:
    fprintf(stderr, "a note of the type that changes the volume to "
            "%.3f times.\n",
            note.secs);
    break;
  }
}

U_ATTR
static void
print_unit(const PUnit u)
{
  fprintf(stderr, "Printing a unit with %lu channel%s\n",
          u.len, (u.len>1) ? "s" : "");
  for (LENT i = 0; i < u.len; i++) {
#ifdef DEBUG
    fprintf(stderr, "The %lu-th note: ", i);
    fprintf(stderr, "%p\n", (u.notes+i));
#endif
    print_note(*(u.notes+i));
    fprintf(stderr, "\n");
  }
}

U_ATTR
void
print_sheet(const PSheet sh)
{
  for (LENT i = 0; i < sh.len;) print_unit(*(sh.data+i++));
}

/* The main read function.

   Warning: A valid sheet file should have a "channel specification"
   in the first line.  A "channel specification" line is a line that
   has no numbers, but just semi-colons.  If there are N channels,
   then there should be N-1 semi-colons in the specification line.
   What if there are no channels?  Why read a sheet without
   channels?

   If there are no specification lines in the beginning, then one
   channel format will be assumed.  But this is prone to errors, and
   not recommended.  */

U_ATTR
PSheet
read_sheet(const char *str, LENT len)
{
  PSheet result = { NULL, 0 };

  Node_t stack = EMPTY_NODE, stack_next = EMPTY_NODE;
  Node_t *stack_pointer = NULL;

  LENT counter = 0, increment = 0, line_count = 0;

  LENT stack_len = 0;

  char current = 0;

  NUMT local = 0.0;

  int channel_num = 0, num_chars_read = 0;
  int num_channels = 0;

  unsigned char first_line = 1, note_used = 0;

  PUnit *unit_pointer = NULL;
  PUnit current_unit = EMPTY_UNIT;

  PUnit *unit_stack = NULL;
  int unit_stack_len = 0;

  /* A note cannot consist of more than 5 semitones.  One more
     semitone will be allocated so that it can store the time
     information. */
  Semitones *st_stack = NULL;
  int st_stack_len = 0;

  InstrumentTypes *ins_pointer = NULL;

  PNote temp_note = EMPTY_NOTE, *notes_pointer = NULL;

  Semitones *st_pointer = NULL;

  /* A note without time information will use the previous beats
     information.  A first note without time information will use 1.0
     as the beats. */

  Beats *beats_channel_array = NULL;

  for (;counter < len;) {
    current = *(str+counter);

    increment = 1;

    switch (current) {
      /* 13 is also a newline character, it seems. */
    case 13:
    case '\n':
      if (!note_used)
        free(current_unit.notes);

      if (first_line) {
        num_channels = channel_num+1;
        current_unit.len = num_channels;
        beats_channel_array = MYALLOC(Beats, num_channels);

        for (int i = 0; i < num_channels; i++) {
          *(beats_channel_array+i) = 1.0;
        }

      } else if (note_used) {
        unit_pointer = MYALLOC(PUnit, 1);
        *unit_pointer = current_unit;
        PUSH_NODE(stack_len, stack_pointer, stack,
                  unit_pointer, v);
        /* Since it is used, we set its pointer to NULL to prevent
           accidental frees. */
        current_unit.notes = NULL;
      }

      notes_pointer = MYALLOC(PNote, num_channels);

      for (int i = 0; i < num_channels;)
        *(notes_pointer+i++) = EMPTY_NOTE;

      current_unit.notes = notes_pointer;

      channel_num = 0;
      first_line = 0;
      line_count++;
      note_used = 0;
      break;
    case '#':
      /* Comments */
      for (;*(str+counter) != '\n' &&
             *(str+counter) != 13;) counter++;
      increment = 2;
      counter -= 2;
      break;
    case ',':
      note_used = 1;
      channel_num++;
      break;
    default:
      /* Limited support for a sheet without channel specifications. */

      if (first_line) {
        num_channels = (channel_num=0)+1;
        current_unit.len = num_channels;

        notes_pointer = MYALLOC(PNote, num_channels);
        beats_channel_array = MYALLOC(Beats, num_channels);

        for (int i = 0; i < num_channels; i++) {
          *(notes_pointer+i) = EMPTY_NOTE;
          *(beats_channel_array+i) = 1.0;
        }

        current_unit.notes = notes_pointer;

        first_line = 0;
      }

      note_used = 1;
      /* fprintf(stderr, "here the char is %c\n", *(str+counter)); */
      if (*(str+counter) == ' ') {
        /* Just skip spaces so that they don't block us reading anchor
           chars. */
      } else if (*(str+counter) == 'v') {
        /* changing volume note */

        counter++;

        for (;*(str+counter) == ' ';) counter++;
        
        if (*(str+counter) != '\n' &&
            *(str+counter) != 13 &&
            sscanf(str+counter, "%lf%n",
                   &local, &num_chars_read) == 1) {
          temp_note = (PNote) {
            NULL, local,
            0, VOLUME_TYPE, NULL
          };

          /* fprintf(stderr, "print a note\n");
           * print_note(temp_note); */

          counter += num_chars_read-1;
        }
        *(current_unit.notes+channel_num) = temp_note;
      } else if (*(str+counter) == 'b') {
        /* changing bpm note */

        counter++;

        for (;*(str+counter) == ' ';) counter++;
        
        if (*(str+counter) != '\n' &&
            *(str+counter) != 13 &&
            sscanf(str+counter, "%lf%n",
                   &local, &num_chars_read) == 1) {
          temp_note = (PNote) {
            NULL, local,
            0, BEAT_DURATION_TYPE, NULL
          };

          /* fprintf(stderr, "print a note\n");
           * print_note(temp_note); */

          counter += num_chars_read;
        }
        *(current_unit.notes+channel_num) = temp_note;
      } else if (*(str+counter) == 's') {
        /* a silent note */
        counter++;

        /* skip all spaces that follow */
        for (;*(str+counter) == ' ';) counter++;

        if (*(str+counter) != '\n' &&
            *(str+counter) != 13 &&
            sscanf(str+counter, "%lf%n",
                   &local, &num_chars_read) == 1) {
          *(beats_channel_array+channel_num) = local;
          temp_note = (PNote) {
            NULL, local,
            1, SILENT_TYPE, NULL
          };

          increment = num_chars_read+1;
        } else {
          /* a note without time; use the previous beat instead. */
          temp_note = (PNote) {
            NULL, *(beats_channel_array+channel_num),
            1, SILENT_TYPE, NULL
          };
        }

#ifdef DEBUG
        fprintf(stderr, "print a note while reading\n");
        print_note(temp_note);
        fprintf(stderr, "\n\n\n\n");
#endif

        *(current_unit.notes+channel_num) = temp_note;
        temp_note = EMPTY_NOTE;
        /* subtract one from the increment so that we don't
           unknowingly skip one character. */
        increment--;
      } else if (sscanf(str+counter, "%lf%n",
                        &local, &num_chars_read) == 1) {
        /* a note consisting of one single semitone */
        st_pointer = MYALLOC(Semitones, 1);
        *st_pointer = local;
        counter += num_chars_read;

        /* skip all spaces that follow */
        for (;*(str+counter) == ' ';) counter++;


        if (*(str+counter) != '\n' &&
            *(str+counter) != 13 &&
            sscanf(str+counter, "%lf%n",
                   &local, &num_chars_read) == 1) {
          *(beats_channel_array+channel_num) = local;
          temp_note = (PNote) {
            st_pointer, local,
            1, NOTE_TYPE, NULL
          };

          increment = num_chars_read+1;
        } else {
          /* a note without time; use the previous beat instead. */
          temp_note = (PNote) {
            st_pointer, *(beats_channel_array+channel_num),
            1, NOTE_TYPE, NULL
          };
        }

#ifdef DEBUG
        fprintf(stderr, "print a note while reading\n");
        print_note(temp_note);
        fprintf(stderr, "\n\n\n\n");
#endif

        *(current_unit.notes+channel_num) = temp_note;
        temp_note = EMPTY_NOTE;
        /* subtract one from the increment so that we don't
           unknowingly skip one character. */
        increment--;
      } else if (*(str+counter) == '(') {
        /* a note consisting of multiple semitones */
        st_stack = MYALLOC(Semitones, 10);
        st_stack_len = 0;
        counter++;

        for (;sscanf(str+counter, "%lf %n", &local, &num_chars_read) == 1;
             counter += num_chars_read) {
          *(st_stack+st_stack_len++) = local;
        }

        /* Now skip to the closing parenthesis */
        for (;counter < len && *(str+counter) != ')';) counter++;

        if (st_stack_len>1) {
          st_pointer = MYALLOC(Semitones, st_stack_len-1);

          for (int i = 0; i < st_stack_len-1; i++)
            *(st_pointer+i) = *(st_stack+i);

          *(beats_channel_array+channel_num) =
            *(st_stack+st_stack_len-1);

          temp_note = (PNote) {
            st_pointer, *(st_stack+st_stack_len-1),
            st_stack_len-1, NOTE_TYPE, NULL
          };
        } else if (!st_stack_len) {
          /* empty note */
          temp_note = EMPTY_NOTE;
        } else {
          /* one semitone note */
          st_pointer = MYALLOC(Semitones, 1);
          *st_pointer = *st_stack;

          temp_note = (PNote) {
            st_pointer, *(beats_channel_array+channel_num),
            1, NOTE_TYPE, NULL
          };
        }

        free(st_stack);

        *(current_unit.notes+channel_num) = temp_note;
        temp_note = EMPTY_NOTE;
      } else if (*(str+counter) == 'i') {
        /* an instrument changing unit */
        /* Just piano for now */
        ins_pointer = MYALLOC(InstrumentTypes, 1);
        *ins_pointer = PIANO;
        *(current_unit.notes+channel_num) = (PNote) {
          NULL, 0, 0, INSTRUMENT_TYPE, ins_pointer
        };
      } else {
        /* invalid input */
        fprintf(stderr, "Invalid input in the sheet.\n"
                "channel = %d, line = %lu\n",
                channel_num, line_count);
      }

      break;
    }

    counter += increment;
  }

  free(current_unit.notes);
  free(beats_channel_array);

  /* Then fill the variables up with the data we have read. */

  LENT total_len = stack_len;

  unit_stack = MYALLOC(PUnit, total_len);

  for (LENT i = 0; i < total_len; i++) {
    POP_NODE(stack_len, unit_pointer, stack, stack_next, v);
    *(unit_stack+total_len-1-(unit_stack_len++)) =
      *unit_pointer;
    free(unit_pointer);
  }

  result.data = unit_stack;
  result.len = total_len;

  return result;
}

/* Get the number of note_type notes in a sheet.

   Also calculate the number of notes per channel and store in
   nums_per_channel, which is assumed to be already allocated. */

U_ATTR
static LENT
sheet_note_num(const PSheet sh, LENT *nums_per_channel)
{
  LENT note_num = 0;

  for (LENT i = 0; i < (sh.data)->len;)
    *(nums_per_channel+i++) = 0;

  for (LENT i = 0; i < sh.len; i++) {
    PUnit pu = *(sh.data+i);

    for (LENT j = 0; j < pu.len; j++)
      if ((pu.notes+j)->type == NOTE_TYPE ||
          (pu.notes+j)->type == SILENT_TYPE) {
        note_num++;
        *(nums_per_channel+j) += 1;
      }
  }

  return note_num;
}

H_ATTR
static WaveFrag
silent_note(Beats b, NUMT dur)
{
  WaveFrag w;

  LENT sample_num = (LENT) floor(SAMPLE_RATE * b * dur);

  w.w = MYALLOC(Pulse, sample_num);
  w.n = sample_num;

  for (LENT i = 0; i < sample_num; i++)
    *(w.w+i) = 0.0;

  return w;
}

U_ATTR
WaveFrag
play_sheet(const PSheet sh, const Volume v)
{
  WaveFrag wf = (WaveFrag) { NULL, 0 };

  /* If there is not unit or if the channel number is zero then we
     return an empty wave fragment. */

  if (!(sh.len) || !(sh.data->len)) return wf;

  Instrument *piano = make_piano();
  Instrument *violin = make_violin();
  Instrument *inst = piano;

  /* For mixing sounds in notes */
  WaveFrag *war = NULL;
  WaveFrag **temp = NULL;
  LENT *channel_num_array = NULL;
  /* For mixing semitones */
  WaveFrag *st_temp = MYALLOC(WaveFrag, 10);

  LENT total_len = 0, channel_num = sh.data->len;

  LENT *num_notes_per_channel = MYALLOC(LENT, channel_num);

  Beats dur = BEAT_DUR; 

  /* Each channel can specify its sound. */
  
  Volume *volume_per_channel = MYALLOC(Volume, channel_num);;

#ifdef DEBUG
  fprintf(stderr, "before finding num\n");
#endif

  total_len = sheet_note_num(sh, num_notes_per_channel);

  /* for (LENT i = 0; i < sh.len;)
   *   total_len += (sh.data+i++)->len; */

  /* Allocate spaces */

  temp = MYALLOC(WaveFrag*, channel_num);
  channel_num_array = MYALLOC(LENT, channel_num);

  for (LENT i = 0; i < channel_num; i++) {

#ifdef DEBUG
    fprintf(stderr, "num_notes_per_channel + %lu = %lu\n",
            i, *(num_notes_per_channel+i));
#endif

    *(temp+i) = MYALLOC(WaveFrag, *(num_notes_per_channel+i));
    
    *(channel_num_array+i) = 0;
    
    *(volume_per_channel+i) = 1.0;
  }

  war = MYALLOC(WaveFrag, channel_num);

#ifdef DEBUG
  fprintf(stderr, "before for loop\n");
#endif

  for (LENT i = 0; i < sh.len; i++) {
    PUnit pu = *(sh.data+i);

    if (pu.len != channel_num) {
      fprintf(stderr, "Every unit should have the same number of channels.\n"
              "But unit %lu has %lu channels\n",
              i, pu.len);
      exit(1);
    }

    for (LENT j = 0; j < channel_num; j++) {
      PNote pn = *(pu.notes+j);

      if (pn.type != NOTE_TYPE &&
          pn.type != SILENT_TYPE &&
          pn.type != BEAT_DURATION_TYPE &&
          pn.type != VOLUME_TYPE) continue;

      if (pn.len >= 10) {
        fprintf(stderr, "A note cannot have more than 10 semitones together.\n");
        fprintf(stderr, "node %lu and number = %lu\n", j, pn.len);
        exit(1);
      }

#ifdef DEBUG
      fprintf(stderr, "i = %lu, j = %lu\n", i, j);
#endif

      switch (pn.type) {
      case NOTE_TYPE:
        for (LENT k = 0; k < pn.len; k++) {
          *(st_temp+k) = make_sound(inst, v * *(volume_per_channel+j),
                                    stoh(*(pn.tones+k)), pn.secs * dur);
        }
        break;
      case BEAT_DURATION_TYPE:
        dur = 60.0 / pn.secs;
        break;
      case VOLUME_TYPE:
        *(volume_per_channel+j) = pn.secs;
        break;
      case SILENT_TYPE:
        *(st_temp) = silent_note(pn.secs, dur);
        break;
      default:
        /* Not goint to happen */
        fprintf(stderr, "something weird happens in play_sheet.\n");
        exit(1);
        break;
      }

#ifdef DEBUG
      fprintf(stderr, "after making sound\n");
      if (j==1) {
        print_note(pn);
        fprintf(stderr, "channel num + 1 = %lu\n", *(channel_num_array+1));
      }
#endif

      *(*(temp+j)+*(channel_num_array+j)) =
        mix_waves(st_temp, pn.len);

#ifdef DEBUG
      fprintf(stderr, "after mixing\n");
#endif

      *(channel_num_array+j) = *(channel_num_array+j) + 1;
      /* *(temp + i*channel_num + j) = mix_waves(st_temp, pn.len); */

      for (int k = 0; k < pn.len; k++)
        free((st_temp+k)->w);
    }
  }

#ifdef DEBUG
  fprintf(stderr, "after for loop\n");
#endif

  free(st_temp);

  /* Now all the waves are produced.  We just need to merge and mix
     them. */

  /* Note: merge_waves free the waves in the input. */

  for (LENT j = 0; j < channel_num; j++)
    *(war+j) = merge_waves(inst, *(temp+j),
                           *(num_notes_per_channel+j),
                           1);
  free(temp);
  free(num_notes_per_channel);
  free(channel_num_array);
  free(volume_per_channel);

#ifdef DEBUG
  fprintf(stderr, "after merging\n");
#endif

  wf = mix_waves(war, channel_num);

  for (LENT i = 0; i < channel_num;) free((war+i++)->w);

  free(war);
  destroy_piano(piano);
  destroy_violin(violin);

#ifdef DEBUG
  fprintf(stderr, "after mixing\n");
#endif

  return wf;
}

/* An embedded test function */

#ifdef TEST
int
main(int argc, char **argv)
{
  char *file_content = MYALLOC(char, 512);

  LENT len = read_entire_file("test.txt", &file_content);

  PSheet sh = read_sheet(file_content, len);

  print_sheet(sh);

  WaveFrag wf = play_sheet(sh, 0.3);

  destroy_sheet(sh);

  printf("w.n = %lu\n", wf.n);
  printf("some sound is %lf\n", *(wf.w+10));

  free(wf.w);

  free(file_content);

  return 0;
}
#endif