using System.Collections.Generic;
using UnityEngine;

namespace Game.Common.Audio
{
    public class AudioPooling : MonoBehaviour
    {
        /// <summary>
        /// Init Count of Audio Sources (how much audioclips can be played simultaneously)
        /// </summary>
        [SerializeField] private int _initCountOfAudioSources;

        private List<AudioSource> _audioSources;

        private AudioRolloffMode _defaultRolloffMode;
        private bool _defaultLoop;
        private int _defaultPriority;

        #region Singleton staff

        private static AudioPooling _instance;

        public static AudioPooling Instance
        {
            get
            {
                if (_instance == null)
                {
                    _instance = FindObjectOfType<AudioPooling>();

                    if (_instance == null)
                    {
                        // Create gameObject and add component
                        _instance = (new GameObject("AudioPooling")).AddComponent<AudioPooling>();
                    }
                }

                return _instance;
            }
        }

        #endregion

        private void Start()
        {
            _defaultRolloffMode = AudioRolloffMode.Linear;
            _defaultLoop = false;
            _defaultPriority = 128;

            InitAudioSources();
        }

        /// <summary>
        /// Initialize list of Audio Sources
        /// </summary>
        private void InitAudioSources()
        {
            for (int i = 0; i < _initCountOfAudioSources; i++)
            {
                CreateAudioSource();
            }
        }

        /// <summary>
        /// Create new AudioSource
        /// </summary>
        /// <returns>new AudioSource</returns>
        private AudioSource CreateAudioSource()
        {
            // create new GameObject
            var audioSourceGameObject = new GameObject();

            // add to new GameObject AudioSource component
            var audioSource = audioSourceGameObject.AddComponent<AudioSource>();

            // set parent
            audioSourceGameObject.transform.parent = Instance.gameObject.transform;

            _audioSources.Add(audioSource);

            return audioSource;
        }

        /// <summary>
        /// Set AudioSource properties
        /// </summary>
        /// <param name="position">Position for AudioSource</param>
        /// <param name="maxDistance">Max Distance</param>
        /// <param name="volume">Volume</param>
        /// <returns>AudioSource</returns>
        public AudioSource SetAudioSourceProperties(Vector3 position, float maxDistance, float volume = 1f)
        {
            var audioSource = GetAudioSourceFromPool();

            audioSource.transform.position = position;
            audioSource.maxDistance = maxDistance;
            audioSource.volume = Mathf.Clamp01(volume);
            audioSource.rolloffMode = _defaultRolloffMode;

// ?? may be the following properties will already be by default
            audioSource.priority = _defaultPriority;
            audioSource.loop = _defaultLoop;
            audioSource.playOnAwake = false;

            return audioSource;
        }

        /// <summary>
        /// Get AudioSource
        /// </summary>
        /// <remarks>if there is not free AudioSource, return a new AudioSource</remarks>
        /// <returns>AudioSource</returns>
        private AudioSource GetAudioSourceFromPool()
        {
            for (int i = 0; i < _audioSources.Count; i++)
            {
                if(_audioSources[i].isPlaying == false)
                {
                    return _audioSources[i];
                }
            }

            return CreateAudioSource();
        }
    }
}