#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sndfile.h>
#include <math.h>
#include <vector>

#include "banner.h"
#include "fft.h"
using namespace std;

static constexpr int ORDER = 8;
static constexpr int TAPS  = (1 << ORDER);
static constexpr int HALF  = TAPS >> 1;
static constexpr int OFS   = 20;

static CFFT fft (ORDER);
static vector<double> mono;
static bool odd = false;

void cputs (const char * s) {
  odd = ! odd;
  const complex plus (0.0, 256.0), minus (0.0, -256.0);
  complex data [TAPS];
  memset (&data,0, TAPS * sizeof(complex));
  int n = 0;
  while (true) {
    const char c = s [n];
    if (c == '\0') break;
    if (c == '#' ) {
      const bool sign = (n & 1) xor odd;
      // Střídání fáze 0/180 dost potlačí rozmazání spektra.
      const complex fill = sign ? plus : minus;
      const int k = n + OFS;
      data[k]        = fill;
      data[TAPS - k] = fill;
    }
    putchar(c);
    n += 1;
  }
  //printf("\tlen=%d\n", n);
  fft.Inverse(data, false);
  for (int i=0; i<TAPS; i++) {
    mono.push_back (data[i].im());
  }
}
static bool WriteSound (const char * filename = "output.vaw") {
  printf("len=%zd\n", mono.size());
  double min = 1.0e100, max = -1.0e100;
  for (double e: mono) {
    if (e < min) min = e;
    if (e > max) max = e;
  }
  printf("min=%g, max=%g\n", min, max);
  double z = abs(min) > abs(max) ? abs(min) : abs(max);
  z = 32000.0 / z;
  vector<short> data (mono.size());
  int n = 0;
  for (double e: mono) {
    data[n] = ::lround (e * z);
    n += 1;
  }
  
  SF_INFO info;
  memset (&info, 0, sizeof(SF_INFO));
  info.channels = 1;
  info.format   = SF_FORMAT_WAV | SF_FORMAT_PCM_16;
  info.samplerate = 8000;
  if (sf_format_check (&info) == SF_FALSE) {
    fprintf(stderr, "bad output format\n");
    return false;
  }
  SNDFILE * outfile = sf_open (filename, SFM_WRITE, &info);
  if (!outfile) {
    fprintf(stderr, "cannot open output file \"%s\"\n", filename);
    return false;
  }
  sf_write_short (outfile, data.data(), data.size());
  sf_close (outfile);
  return true;
}
int main (int argc, char *argv[]) {
  if (argc < 2) {
    printf("Usage:\n\t%s \"Text to spectrogram\"\n", argv[0]);
    return 0;
  }
  const char * buffer = argv[1];
  for (const char * p = buffer; *p; p++) {
    banchr (*p);
  }
  WriteSound ("test.vaw");
  return 0;
}