using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using NAudio.Midi;
using System;


public class MidiSong : MonoBehaviour {

    AudioSource audioSource;

    MidiFile midiFile; // midi object
    string midiPath = "/Users/queenjazz/Dropbox/projects/Music/2019/Drafts/make.mid"; // path to midi
    public float timeOffset = 0f; // You can use this to start the song mid-way through
    public float bpm = 88f; // bpm of the song
    int ticksPerSecond; // ticks are the midi's internal timer, this is how many ticks per real-world second
    public bool playing = false;
    float startTime;
    public int soloTrack; // use this for "listening" to a track, the number is the index of the track
    List<NoteOnEvent> noteOns; // to store all the events in the track

    // Use this for initialization
    void Start () {

        audioSource=GetComponent<AudioSource>();

        midiFile = new MidiFile(midiPath);

        ticksPerSecond = midiFile.DeltaTicksPerQuarterNote / 4;

    }

    // Update is called once per frame
    void Update () {
        if (Input.GetKeyDown(KeyCode.G)) {
            Play();
        }

        if (Input.GetKeyDown(KeyCode.H)) {
            Stop();
        }

        if (playing) {

            for (int i = noteOns.Count-1; i >= 0; i--) {
                float noteTime = MidiTickToTime(noteOns[i].AbsoluteTime);
                if ((Time.time - startTime) > noteTime) { // we just go through the list every frame and check if out time is past it yet
                    // do something with soloNoteOns[i];
                    noteOns.RemoveAt(i);
                }
            }
        }
    }

    // midi events use an absoluteTime variable, this function converts it to actual time so you can use it
    public float MidiTickToTime(long absoluteTime) {
        return (60f * absoluteTime) / (bpm * midiFile.DeltaTicksPerQuarterNote);
    }

    // Start playing the song; set the new base time and play the music.
    void Play() {
        audioSource.Play(); // play music
        startTime = Time.time; // set new base time
        startTime -= timeOffset; // if we're starting partway trhough, skip that time
        audioSource.time = timeOffset; // skip the audio too
        playing = true;

        // So we go through the track we're "listening" to, and grab all the events and put em in a list
        noteOns = new List<NoteOnEvent>();
        foreach (MidiEvent me in midiFile.Events[soloTrack]) {
            if (me.CommandCode == MidiCommandCode.NoteOn) { // "NoteOn" is whenever a note starts playing.
                NoteOnEvent noe = (NoteOnEvent) me;
                noteOns.Add(noe); // add it to our list!
            }
        }
    }

    void Stop() {
        GetComponent<AudioSource>().Stop();
    }
}