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

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

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;
}