/*
 * author: mark joshwel
 * date: 29/5/2024
 * description: audio manager for handling audio in the game
 */

using System;
using UnityEngine;

/// <summary>
///     singleton class for handling audio in the game
/// </summary>
public class AudioManager : MonoBehaviour
{
    /// <summary>
    ///     enum for available audio channels in the game
    /// </summary>
    public enum AudioChannel
    {
        Music,
        SoundEffects
    }

    /// <summary>
    ///     singleton pattern: define instance field for accessing the singleton elsewhere
    /// </summary>
    public static AudioManager Instance;

    /// <summary>
    ///     music audio source
    /// </summary>
    [SerializeField] private AudioSource musicSource;

    /// <summary>
    ///     sound effects (sfx) audio source
    /// </summary>
    [SerializeField] private AudioSource sfxSource;

    /// <summary>
    ///     music source default volume
    /// </summary>
    [SerializeField] private float musicSourceDefaultVolume = 0.6f;

    /// <summary>
    ///     sound effects (sfx) source default volume
    /// </summary>
    [SerializeField] private float sfxSourceDefaultVolume = 0.6f;

    /// <summary>
    ///     enforces singleton behaviour; sets doesn't destroy on load and checks for multiple instances
    /// </summary>
    private void Awake()
    {
        // check if instance hasn't been set yet
        if (Instance == null)
        {
            Debug.Log("awake as singleton instance, setting self as the forever-alive instance");
            Instance = this;
            DontDestroyOnLoad(gameObject);
        }
        // check if instance is already set and it's not this instance
        else if (Instance != null && Instance != this)
        {
            Debug.Log("awake as non-singleton instance, destroying self");
            Destroy(gameObject);
        }
    }

    /// <summary>
    ///     function to set default volumes for the audio sources
    /// </summary>
    public void Start()
    {
        // set the default volume for the music source
        musicSource.volume = musicSourceDefaultVolume;

        // set the default volume for the sfx source
        sfxSource.volume = sfxSourceDefaultVolume;
    }

    /// <summary>
    ///     plays the audio clip once on a given channel
    /// </summary>
    /// <param name="clip">the audio clip to play</param>
    /// <param name="channel">the audio channel to play the clip on</param>
    public void PlayClipOnChannel(AudioClip clip, AudioChannel channel)
    {
        switch (channel)
        {
            case AudioChannel.Music:
                musicSource.PlayOneShot(clip);
                break;
            case AudioChannel.SoundEffects:
                sfxSource.PlayOneShot(clip);
                break;
            default:
                Debug.LogError($"invalid channel '{channel}'");
                break;
        }
    }

    /// <summary>
    ///     gets the volume of a given audio channel
    /// </summary>
    /// <param name="channel">the AudioManager.AudioChannel to get the volume of</param>
    /// <returns>volume float value of the channel, from 0.0f-1.0f</returns>
    public float GetChannelVolume(AudioChannel channel)
    {
        switch (channel)
        {
            case AudioChannel.Music:
                return musicSource.volume;
            case AudioChannel.SoundEffects:
                return sfxSource.volume;
            default:
                Debug.LogError($"invalid channel '{channel}'");
                return 0f;
        }
    }

    /// <summary>
    ///     sets the pure volume value of a given audio channel
    /// </summary>
    /// <param name="volume">volume float value for the channel, from 0.0f-1.0f</param>
    /// <param name="channel">the AudioManager.AudioChannel to set the volume of</param>
    public void SetChannelVolumeReal(float volume, AudioChannel channel)
    {
        switch (channel)
        {
            case AudioChannel.Music:
                musicSource.volume = Math.Min(volume, 1.0f);
                break;
            case AudioChannel.SoundEffects:
                sfxSource.volume = Math.Min(volume, 1.0f);
                break;
            default:
                Debug.LogError($"invalid channel '{channel}'");
                break;
        }
    }

    /// <summary>
    ///     sets the volume value of a given audio channel based on a logarithmic scale
    ///     for human perception (e.g. 0.5f is half volume, 0.1f is very quiet)
    /// </summary>
    /// <param name="volume">volume float value for the channel, from 0.0f-1.0f</param>
    /// <param name="channel">the AudioManager.AudioChannel to set the volume of</param>
    public void SetChannelVolumeLog(float volume, AudioChannel channel)
    {
        switch (channel)
        {
            case AudioChannel.Music:
                musicSource.volume = Mathf.Log10(Mathf.Max(volume, 0.0001f)) * 20;
                break;
            case AudioChannel.SoundEffects:
                sfxSource.volume = Mathf.Log10(Mathf.Max(volume, 0.0001f)) * 20;
                break;
            default:
                Debug.LogError($"invalid channel '{channel}'");
                break;
        }
    }
}