// Assets/_Project/Scripts/Audio/MusicPlayer.cs
using UnityEngine;

namespace TD.Audio
{
    /// <summary>
    /// Plays a single looping music track for the scene it lives in.
    /// Add to a GameObject in the scene, assign a clip, and it starts on load.
    /// </summary>
    /// <remarks>
    /// Volume is the authored <see cref="volume"/> scaled by the player's music slider
    /// (<see cref="AudioVolumeSettings.MusicScalar"/>). Unlike one-shot SFX, the track is
    /// continuous, so this subscribes to <see cref="AudioVolumeSettings.OnChanged"/> and
    /// re-applies live while the slider is dragged.
    /// </remarks>
    [RequireComponent(typeof(AudioSource))]
    public class MusicPlayer : MonoBehaviour
    {
        [SerializeField] private AudioClip clip;
        [Range(0f, 1f)]
        [SerializeField] private float volume = 1f;

        private AudioSource source;

        private void Awake()
        {
            source = GetComponent<AudioSource>();
        }

        private void OnEnable()
        {
            AudioVolumeSettings.OnChanged += ApplyVolume;
        }

        private void OnDisable()
        {
            AudioVolumeSettings.OnChanged -= ApplyVolume;
        }

        private void Start()
        {
            source.clip        = clip;
            source.loop        = true;
            source.playOnAwake = false;
            ApplyVolume();
            source.Play();
        }

        private void ApplyVolume()
        {
            if (source == null) return;
            source.volume = volume * AudioVolumeSettings.MusicScalar;
        }
    }
}