#include <iostream>
#include <fstream>
#include <vector>
#include <cmath>
#include <cstdint>
#include <string>

// Simple heightmap generator for testing different world sizes
void generateHeightmap(const std::string& filename, int size, float amplitude = 10.0f) {
    std::vector<float> data(size * size);
    
    // Generate a simple heightmap with some hills
    for (int z = 0; z < size; z++) {
        for (int x = 0; x < size; x++) {
            float fx = (float)x / (size - 1) * 2.0f - 1.0f;
            float fz = (float)z / (size - 1) * 2.0f - 1.0f;
            
            // Create some hills using sine waves
            float height = 0;
            height += sin(fx * 3.14159f * 2.0f) * cos(fz * 3.14159f * 2.0f) * amplitude * 0.5f;
            height += sin(fx * 3.14159f * 4.0f) * sin(fz * 3.14159f * 4.0f) * amplitude * 0.25f;
            
            // Add a central mountain
            float dist = sqrt(fx * fx + fz * fz);
            height += std::max(0.0f, (1.0f - dist) * amplitude);
            
            data[z * size + x] = height;
        }
    }
    
    // Write to binary file
    std::ofstream file(filename, std::ios::binary);
    if (!file) {
        std::cerr << "Failed to open file: " << filename << "\n";
        return;
    }
    
    int32_t fileSize = size;
    file.write(reinterpret_cast<char*>(&fileSize), sizeof(fileSize));
    file.write(reinterpret_cast<char*>(data.data()), data.size() * sizeof(float));
    
    std::cout << "Generated heightmap: " << filename << " (" << size << "x" << size << ")\n";
    std::cout << "World size will be: " << (size-1) << "x" << (size-1) << " units\n";
}

int main(int argc, char* argv[]) {
    if (argc < 3) {
        std::cout << "Usage: " << argv[0] << " <size> <output_file> [amplitude]\n";
        std::cout << "Example: " << argv[0] << " 256 heightmap_256.bin 20.0\n";
        std::cout << "\nCommon sizes:\n";
        std::cout << "  64x64   -> 63x63 unit world (small)\n";
        std::cout << "  128x128 -> 127x127 unit world (medium)\n";
        std::cout << "  256x256 -> 255x255 unit world (large)\n";
        std::cout << "  512x512 -> 511x511 unit world (huge)\n";
        return 1;
    }
    
    int size = std::stoi(argv[1]);
    std::string filename = argv[2];
    float amplitude = (argc > 3) ? std::stof(argv[3]) : 10.0f;
    
    if (size < 2) {
        std::cerr << "Size must be at least 2\n";
        return 1;
    }
    
    generateHeightmap(filename, size, amplitude);
    return 0;
}