#include <fstream>
#include <cmath>

const int SAMPLE_RATE = 44100;
const double PI = 3.141592653589793;


void writeWavHeader(std::ofstream& file, int dataSize) {
    file.write("RIFF", 4);
    int chunkSize = 36 + dataSize;
    file.write((char*)&chunkSize, 4);
    file.write("WAVE", 4);

    file.write("fmt ", 4);
    int subChunk1Size = 16;
    short audioFormat = 1;
    short numChannels = 1;
    int byteRate = SAMPLE_RATE * 2;
    short blockAlign = 2;
    short bitsPerSample = 16;

    file.write((char*)&subChunk1Size, 4);
    file.write((char*)&audioFormat, 2);
    file.write((char*)&numChannels, 2);
    file.write((char*)&SAMPLE_RATE, 4);
    file.write((char*)&byteRate, 4);
    file.write((char*)&blockAlign, 2);
    file.write((char*)&bitsPerSample, 2);

    file.write("data", 4);
    file.write((char*)&dataSize, 4);
}


void playNote(std::ofstream& file, double freq, double seconds) {
    int samples = seconds * SAMPLE_RATE;
    for (int i = 0; i < samples; i++) {
        double t = (double)i / SAMPLE_RATE;
        short sample = (short)(30000 * sin(2 * PI * freq * t));
        file.write((char*)&sample, 2);
    }
}

int main() {
    std::ofstream file("jingle_bells.wav", std::ios::binary);

    int totalSamples = SAMPLE_RATE * 4; // approx length
    writeWavHeader(file, totalSamples * 2);

    // Jingle Bells (simplified melody)
    playNote(file, 659.25, 0.4); // E
    playNote(file, 659.25, 0.4);
    playNote(file, 659.25, 0.6);

    playNote(file, 659.25, 0.4);
    playNote(file, 659.25, 0.4);
    playNote(file, 659.25, 0.6);

    playNote(file, 659.25, 0.4);
    playNote(file, 783.99, 0.4); // G
    playNote(file, 523.25, 0.4); // C
    playNote(file, 587.33, 0.4); // D
    playNote(file, 659.25, 0.8); // E

    file.close();
    return EXIT_SUCCESS;
}