// This file is part of the 64k demo project.
// It tests the procedural generation system.

#include "procedural/generator.h"
#include <cassert>
#include <iostream>
#include <vector>
#include <cmath>

void test_noise() {
  std::cout << "Testing Noise Generator..." << std::endl;
  int w = 64, h = 64;
  std::vector<uint8_t> buffer(w * h * 4);
  float params[] = {12345, 1.0f}; // Seed, Intensity

  // Test with explicit params
  bool res = procedural::gen_noise(buffer.data(), w, h, params, 2);
  assert(res);
  assert(buffer[3] == 255);
  
  // Check that not all pixels are black
  bool nonzero = false;
  for (size_t i = 0; i < buffer.size(); i += 4) {
    if (buffer[i] > 0) {
      nonzero = true;
      break;
    }
  }
  assert(nonzero);

  // Test with default params
  std::fill(buffer.begin(), buffer.end(), 0);
  res = procedural::gen_noise(buffer.data(), w, h, nullptr, 0);
  assert(res);
  assert(buffer[3] == 255); // Alpha should still be set
}

void test_perlin() {
  std::cout << "Testing Perlin Generator..." << std::endl;
  int w = 64, h = 64;
  std::vector<uint8_t> buffer(w * h * 4);
  
  // Test with explicit params
  // Params: Seed, Freq, Amp, Decay, Octaves
  float params[] = {12345, 4.0f, 1.0f, 0.5f, 4.0f};
  bool res = procedural::gen_perlin(buffer.data(), w, h, params, 5);
  assert(res);
  assert(buffer[3] == 255);

  bool nonzero = false;
  for (size_t i = 0; i < buffer.size(); i += 4) {
    if (buffer[i] > 0) {
      nonzero = true;
      break;
    }
  }
  assert(nonzero);

  // Test with default params
  std::fill(buffer.begin(), buffer.end(), 0);
  res = procedural::gen_perlin(buffer.data(), w, h, nullptr, 0);
  assert(res);
  assert(buffer[3] == 255);

  // Test memory allocation failure simulation (large dimensions)
  // This is hard to robustly test without mocking, but we can try an excessively large allocation if desired.
  // For now, we trust the logic path.
}

void test_grid() {
  std::cout << "Testing Grid Generator..." << std::endl;
  int w = 100, h = 100;
  std::vector<uint8_t> buffer(w * h * 4);
  float params[] = {10, 1}; // Size 10, Thickness 1

  // Test with explicit params
  bool res = procedural::gen_grid(buffer.data(), w, h, params, 2);
  assert(res);

  // Pixel (0,0) should be white (on line)
  assert(buffer[0] == 255);
  // Pixel (5,5) should be black (off line, since size=10)
  assert(buffer[(5 * w + 5) * 4] == 0);
  // Pixel (10,0) should be white (on vertical line)
  assert(buffer[(0 * w + 10) * 4] == 255);

  // Test with default params
  res = procedural::gen_grid(buffer.data(), w, h, nullptr, 0);
  assert(res);
  // Default size is 32, thickness 2
  assert(buffer[0] == 255);
  assert(buffer[(0 * w + 32) * 4] == 255);
}

void test_periodic() {
  std::cout << "Testing Periodic Blending..." << std::endl;
  int w = 64, h = 64;
  std::vector<uint8_t> buffer(w * h * 4);

  // Fill with horizontal gradient: left=0, right=255
  for(int y=0; y<h; ++y) {
    for(int x=0; x<w; ++x) {
        int idx = (y*w + x) * 4;
        buffer[idx] = (uint8_t)(x * 255 / (w-1));
        buffer[idx+1] = 0;
        buffer[idx+2] = 0;
        buffer[idx+3] = 255;
    }
  }

  // Pre-check: edges are different
  assert(buffer[0] == 0);
  assert(buffer[(w-1)*4] == 255);

  float params[] = {0.1f}; // Blend ratio 10%
  bool res = procedural::make_periodic(buffer.data(), w, h, params, 1);
  assert(res);

  // Post-check: Left edge (x=0) should now be blended with right edge.
  // Logic: blend right edge INTO left edge. At x=0, we copy from right side.
  // So buffer[0] should be close to 255 (value from right).
  assert(buffer[0] > 200); 

  // Check invalid ratio
  float invalid_params[] = { -1.0f };
  res = procedural::make_periodic(buffer.data(), w, h, invalid_params, 1);
  assert(res); // Should return true but do nothing
}

int main() {
  test_noise();
  test_perlin();
  test_grid();
  test_periodic();
  std::cout << "--- PROCEDURAL TESTS PASSED ---" << std::endl;
  return 0;
}