#include "synth_common.h"
#include "osc.h"

#include <sndfile.h>
#include <stdlib.h>
#include <stddef.h>


float
osc_interpolate(float offset, float start, float end) {
  // linear interpolation between start and end
  float m = (end - start) / (1 - 0);
  float b = start /* + m * 0 */;

  // the value to pick
  float x = offset - (int)offset;

  return m * x + b;
}

/**
 * Takes a floating-point position (offset) in the oscillator/buffer.
 * Wraps it so it stays between osc->start and osc->len - 1 (cyclically).
 * Converts it to an integer index.
 * Returns the next index, wrapping back to osc->start if it reaches the end.
 */
int
osc_next_index(osc_t * osc, float offset)
{
  if (offset >= osc->len) offset = fmodf(osc->start + offset, osc->len - osc->start);
  if (offset < osc->start) offset = osc->start + fmodf(osc->start + offset, osc->len - osc->start);

  int current_index = (int)offset;
  return current_index + 1 >= osc->len ? osc->start : current_index + 1;
}
// TODO same from AI: check it
/* int */
/* osc_next_index(osc_t *osc, float offset) { */
/*     float range = osc->len - osc->start; */

/*     // Wrap offset into the [start, len) range */
/*     offset = osc->start + fmodf(offset - osc->start + range, range); */

/*     // Get integer index and advance */
/*     int next = (int)offset + 1; */
/*     return (next >= osc->len) ? osc->start : next; */
/* } */

float
osc_next_offset(osc_t * osc, float f, float offset)
{
  if (offset >= osc->len) offset = fmodf(osc->start + offset, osc->len - osc->start);
  if (offset < osc->start) offset = osc->start + fmodf(osc->start + offset, osc->len - osc->start);

  if (osc->type == SAMPLE) {
    // this makes A2 be the base ???
    // A2 = 220.0 Hz is base ???
    // get this from osc*
    f = f / (16.35160 * pow(2, (2 + 5 / 12.0)));
  }

  float step = f * ((osc->len - osc->start)  / (float)SAMPLE_RATE);

  offset += step;
  if (offset >= osc->len) {
    offset -= osc->len;
  }

  return offset;
}

/* static inline float wrap_offset(float x, float start, float len) { */
/*     float range = len - start; */
/*     x -= start; */
/*     x -= range * floorf(x / range); // efficient wrap to [0, range) */
/*     return start + x; */
/* } */

/* float osc_next_offset(osc_t * osc, float f, float offset) */
/* { */
/*     // Wrap once at the start */
/*     if (offset < osc->start || offset >= osc->len) { */
/*         offset = wrap_offset(offset, osc->start, osc->len); */
/*     } */

/*     if (osc->type == SAMPLE) { */
/*         // Precomputed constant for (16.35160 * 2^(2 + 5/12)) */
/*         // = base frequency for A2 mapping */
/*         #define BASE_A2_FACTOR  220.00000f */
/*         f /= BASE_A2_FACTOR; */
/*     } */

/*     // Precompute conversion factor */
/*     float step = f * ((osc->len - osc->start) / (float)SAMPLE_RATE); */

/*     offset += step; */

/*     // Single wrap without fmodf (branchless for most cases) */
/*     if (offset >= osc->len) { */
/*         offset -= osc->len; */
/*     } */

/*     return offset; */
/* } */

int
osc_load_wav(osc_t * osc, const char * path)
{
  SNDFILE* file;
  SF_INFO fileInfo;
  int numSamplesRead = 0;

  // Open the WAV file
  file = sf_open(path, SFM_READ, &fileInfo);
  if (!file) {
    printf("Failed to open the WAV file: %s\n", sf_strerror(NULL));
    return -1;
  }
  
  /* printf("Opened %s: \n", path); */
  /* printf("frames: %ld sr: %d chan: %d format: %d sections: %d seekable: %d\n", fileInfo.frames, fileInfo.samplerate, fileInfo.channels, fileInfo.format, fileInfo.sections, fileInfo.seekable); */

  // Ensure the WAV file has only one channel
  if (fileInfo.channels != 1) {
    printf("Only mono WAV files are supported.\n");
    sf_close(file);
    return -1;
  }

  osc->len = fileInfo.frames;
  osc->data = (float *) malloc(sizeof(float) * fileInfo.frames);

  // Read the WAV file into the buffer
  numSamplesRead = sf_readf_float(file, osc->data, fileInfo.frames);
  (void)numSamplesRead;
  
  /* float max = -1000; */
  /* float min = 1000; */
  /* for (int i = 0; i < numSamplesRead; i++) { */
  /*   float s = osc_sound_data[i]; */
  /*   //    printf("Sample %d: %f\n", i, s); */
  /*   if (s < min) min = s; */
  /*   if (s > max) max = s; */
  /* } */
  /* printf("Min: %f Max: %f\n", min, max); */
  
  // Close the WAV file
  sf_close(file);
  return 0;
}