#include <stdio.h>
#include <string.h>

#define SOKOL_IMPL
#include "sokol_app.h"
#include "sokol_audio.h"
#include "sokol_log.h"

#include "glad/src/glad.c"

#define STFU_MAIN
#include "../config.h"
#include "../envelope.c"
#include "../oscillators.c"
#include "../phaser.c"

#include "../Instruments/Trojka/trojka.c"

static struct stfu_trojka synth = {0};

// todo: Separate to playback.c, generic for Player and Maker
#define CROSSFADE_RING_RANGE                                                   \
  (STFU_CROSSFADE_BUFFER_FRAMES * STFU_AUDIO_CHANNEL_COUNT)
static float crossfade_ring[CROSSFADE_RING_RANGE] = {0};
static size_t crossfade_ring_needle = 0;
static unsigned int crossfade_frames_left = 0;

// 1.0 is with A at 440
static float octave = 0.5;

static void stream(float *buffer, int num_frames, int num_channels) {
  /* Fade away */
  for (size_t i = 0; crossfade_frames_left > 0;
       crossfade_frames_left--, i += 2) {
    crossfade_ring[(crossfade_ring_needle + i) % CROSSFADE_RING_RANGE] *=
        (float)crossfade_frames_left / STFU_CROSSFADE_BUFFER_FRAMES;
    crossfade_ring[(crossfade_ring_needle + i + 1) % CROSSFADE_RING_RANGE] *=
        (float)crossfade_frames_left / STFU_CROSSFADE_BUFFER_FRAMES;
  }

  /* Drive the ring buffer */
  // todo: Use memcpy for left and right side of the ring.
  while (num_frames--) {
    buffer[0] = crossfade_ring[crossfade_ring_needle % CROSSFADE_RING_RANGE];
    buffer[1] =
        crossfade_ring[(crossfade_ring_needle + 1) % CROSSFADE_RING_RANGE];
    synth = stfu_sample_trojka(synth, &crossfade_ring[crossfade_ring_needle % CROSSFADE_RING_RANGE]);
    buffer = &buffer[2];
    crossfade_ring_needle += 2;
  }
}

static void init(void) {
  gladLoadGL();

  saudio_setup(&(saudio_desc){
      .sample_rate = STFU_AUDIO_FRAME_RATE,
      .num_channels = STFU_AUDIO_CHANNEL_COUNT,
      // .stream_cb = stream,
  });

  synth.freq_scales[0] = 1.0;
  synth.freq_scales[1] = 0.25;
  synth.freq_scales[2] = 2.0;

  synth.indices[0] = 2.0;
  synth.indices[1] = 10.0;

  synth.feedback_gain = 0.25;

  for (int i = 0; i < STFU_TROJKA_OP_COUNT; ++i) {
    synth.envelopes[i] = stfu_init_envelope(
        (struct stfu_envelope_point[]){[0] = {.dur = 0.02, .vol = 1.0},
                                       [1] = {.dur = 0.5, .vol = 0.33},
                                       [2] = {.dur = 1.0, .vol = 0}},
        3);
    synth.gains[i] = 1.0;
  }
}

static void cleanup(void) { saudio_shutdown(); }

static void event(const sapp_event *e) {
  switch (e->type) {
  case SAPP_EVENTTYPE_KEY_DOWN: {
    if (e->key_repeat)
      break;

    bool key_was_pressed = false;

    switch (e->key_code) {
    case SAPP_KEYCODE_Z:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[0] * octave);
      break;
    case SAPP_KEYCODE_X:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[1] * octave);
      break;
    case SAPP_KEYCODE_C:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[2] * octave);
      break;
    case SAPP_KEYCODE_V:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[3] * octave);
      break;
    case SAPP_KEYCODE_B:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[4] * octave);
      break;
    case SAPP_KEYCODE_N:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[5] * octave);
      break;
    case SAPP_KEYCODE_M:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[6] * octave);
      break;
    case SAPP_KEYCODE_COMMA:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[7] * octave);
      break;
    case SAPP_KEYCODE_PERIOD:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[8] * octave);
      break;
    case SAPP_KEYCODE_SLASH:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[9] * octave);
      break;

    case SAPP_KEYCODE_A:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[0] * (octave * 2));
      break;
    case SAPP_KEYCODE_S:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[1] * (octave * 2));
      break;
    case SAPP_KEYCODE_D:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[2] * (octave * 2));
      break;
    case SAPP_KEYCODE_F:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[3] * (octave * 2));
      break;
    case SAPP_KEYCODE_G:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[4] * (octave * 2));
      break;
    case SAPP_KEYCODE_H:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[5] * (octave * 2));
      break;
    case SAPP_KEYCODE_J:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[6] * (octave * 2));
      break;
    case SAPP_KEYCODE_K:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[7] * (octave * 2));
      break;
    case SAPP_KEYCODE_L:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[8] * (octave * 2));
      break;
    case SAPP_KEYCODE_SEMICOLON:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[9] * (octave * 2));
      break;
    case SAPP_KEYCODE_APOSTROPHE:
      key_was_pressed = true;
      synth = stfu_press_trojka(synth, STFU_SCALE[10] * (octave * 2));
      break;

    default:
      break;
    }

    if (key_was_pressed) {
      crossfade_frames_left = STFU_CROSSFADE_BUFFER_FRAMES;
    }

    break;
  }
  default:
    break;
  }
}

static void frame(void) {
  int frames = (int)(sapp_frame_duration() * (float)STFU_AUDIO_FRAME_RATE);
  int expected = saudio_expect();
  frames = frames > expected ? expected : frames;
  // todo: Prevent drifting apart.
  static float buffer[STFU_AUDIO_FRAME_RATE * STFU_AUDIO_CHANNEL_COUNT];
  while (frames > 0) {
    int now = frames > STFU_AUDIO_FRAME_RATE ? STFU_AUDIO_FRAME_RATE : frames;
    stream(buffer, now, STFU_AUDIO_CHANNEL_COUNT);
    saudio_push(buffer, now);
    frames -= now;
  }
}

sapp_desc sokol_main(int argc, char *argv[]) {
  return (sapp_desc){
      .width = 640,
      .height = 480,
      .init_cb = init,
      .frame_cb = frame,
      .cleanup_cb = cleanup,
      .event_cb = event,
      .logger.func = slog_func,
      // .gl_major_version = 2,
      // .gl_minor_version = 0,
      // .swap_interval = 0,
      .window_title = "stfu-maker",
  };
}