#include "audio/synth.h"
#include <assert.h>
#include <math.h>
#include <stdio.h>
#include <string.h>

// A simple floating point comparison with a tolerance
bool is_close(float a, float b, float epsilon = 1e-6f) {
  return fabsf(a - b) < epsilon;
}

void test_registration() {
  synth_init();
  printf("Running test: Registration...\n");

  float spec_buf_a[DCT_SIZE], spec_buf_b[DCT_SIZE];
  Spectrogram spec = {spec_buf_a, spec_buf_b, 1};

  // Fill up all slots
  for (int i = 0; i < MAX_SPECTROGRAMS; ++i) {
    int id = synth_register_spectrogram(&spec);
    assert(id == i);
  }

  // Next one should fail
  int fail_id = synth_register_spectrogram(&spec);
  assert(fail_id == -1);

  // Unregister one
  synth_unregister_spectrogram(5);

  // Now we should be able to register again in the freed slot
  int new_id = synth_register_spectrogram(&spec);
  assert(new_id == 5);

  printf("...Registration test PASSED.\n");
}

void test_render() {
  synth_init();
  printf("Running test: Render...\n");

  float spec_buf_a[DCT_SIZE] = {0};
  Spectrogram spec = {spec_buf_a, nullptr, 1};

  // Create a simple spectrum with one active bin
  spec_buf_a[10] = 1.0f;

  int id = synth_register_spectrogram(&spec);
  assert(id != -1);

  synth_trigger_voice(id, 1.0f, 0.0f);

  float output_buffer[DCT_SIZE * 2] = {0}; // Stereo
  synth_render(output_buffer, DCT_SIZE);

  float total_energy = 0.0f;
  for (int i = 0; i < DCT_SIZE * 2; ++i) {
    total_energy += fabsf(output_buffer[i]);
  }

  // If we rendered a sound, the buffer should not be silent
  assert(total_energy > 0.01f);

  printf("...Render test PASSED.\n");
}

void test_update() {
  synth_init();
  printf("Running test: Update...\n");
  float spec_buf_a[DCT_SIZE] = {0};
  float spec_buf_b[DCT_SIZE] = {0};
  Spectrogram spec = {spec_buf_a, spec_buf_b, 1};

  spec_buf_a[10] = 1.0f; // Original sound
  spec_buf_b[20] = 1.0f; // Updated sound

  int id = synth_register_spectrogram(&spec);

  // Begin update - should get back buffer B
  float *back_buffer = synth_begin_update(id);
  assert(back_buffer == spec_buf_b);

  // We could modify it here, but it's already different.
  // Let's just commit.
  synth_commit_update(id);

  // Now if we trigger a voice, it should play from buffer B.
  // To test this, we'd need to analyze the output, which is complex.
  // For this test, we'll just ensure the mechanism runs and we can
  // begin an update on the *new* back buffer (A).
  back_buffer = synth_begin_update(id);
  assert(back_buffer == spec_buf_a);

  printf("...Update test PASSED.\n");
}

int main() {
  test_registration();
  test_render();
  test_update();

  synth_shutdown();

  printf("\nAll synth tests passed!\n");
  return 0;
}