const fs = require('fs');
const { Midi } = require('@tonejs/midi');

const midiData = fs.readFileSync('song.mid');
const midi = new Midi(midiData);

const sampleRate = 44100;
let notesByteCode = [];

function midiToFrequency(n) {
    return 440 * Math.pow(2, (n - 69) / 12);
}

function getADSRCode(startT, endT) {
    const attack = 50;  
    const release = 50; 
    return `(t<${startT}+${attack}?((t-${startT})/${attack}):t>${endT}-${release}?(${endT}-t)/${release}:1)`;
}

function getByteCode(note) {
    const startT = Math.round(note.time * sampleRate);
    const endT = Math.round((note.time + note.duration) * sampleRate);
    const freq = midiToFrequency(note.midi);
    const velocity = note.velocity || 1; 

    const adsr = getADSRCode(startT, endT);

    return `(t>=${startT}&&t<${endT}?(${velocity}*${adsr}*Math.sin(2*Math.PI*${freq}*t/${sampleRate})*127 + 128):0)`;
}

midi.tracks.forEach(track => {
    track.notes.forEach(note => {
        notesByteCode.push(getByteCode(note));
    });
});

const result = `Math.max(${notesByteCode.join(',')})`;

fs.writeFileSync('result.txt', result);