// Crest Ocean System

// Copyright 2020 Wave Harmonic Ltd

using System.Collections;
using UnityEngine;

namespace Crest.Examples
{
    [RequireComponent(typeof(AudioSource))]
    public class DemoMusic : MonoBehaviour
    {
        [SerializeField] float _stopTime = 175f;

        public static DemoMusic Instance { get; private set; }

        AudioSource _src;

        private void Awake()
        {
            if (Instance != null)
            {
                Destroy(gameObject);
                return;
            }

            Instance = this;

            _src = GetComponent<AudioSource>();

            DontDestroyOnLoad(gameObject);
        }

        void Update()
        {
            if (_src.time > _stopTime)
            {
                _src.Stop();
            }
        }

        public void Play()
        {
            _src.Play();
        }

        public void FadeOut()
        {
            StartCoroutine(FadeOutMusic(_src, 2f));
        }

        private static IEnumerator FadeOutMusic(AudioSource a, float duration)
        {
            float startVolume = a.volume;

            while (a.volume > 0f)
            {
                a.volume -= startVolume * Time.deltaTime / duration;
                yield return new WaitForEndOfFrame();
            }

            Destroy(a.gameObject);
        }
    }
}