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// This file is part of the 64k demo project.
// It tests the DCT implementation for correctness and coverage.

#include "audio/dct.h"
#include <cassert>
#include <cmath>
#include <cstdlib>
#include <iostream>
#include <vector>

void test_fdct_idct() {
  float input[DCT_SIZE];
  float freq[DCT_SIZE];
  float output[DCT_SIZE];

  // Initialize with random data
  srand(12345); // Fixed seed for reproducibility
  for (int i = 0; i < DCT_SIZE; ++i) {
    input[i] = (float)rand() / RAND_MAX * 2.0f - 1.0f;
  }

  fdct_512(input, freq);
  idct_512(freq, output);

  // Verify reconstruction
  float max_error = 0.0f;
  for (int i = 0; i < DCT_SIZE; ++i) {
    float err = std::abs(input[i] - output[i]);
    if (err > max_error)
      max_error = err;
  }
  std::cout << "Max reconstruction error: " << max_error << std::endl;

  // Allow some error due to float precision and iterative sum
  // 512 sums can accumulate error.
  assert(max_error < 1e-4f);
}

int main() {
  std::cout << "Running DCT tests..." << std::endl;
  test_fdct_idct();
  std::cout << "DCT tests PASSED" << std::endl;
  return 0;
}