// Assets/_Project/Scripts/Audio/AudioManager.cs
using System.Collections.Generic;
using UnityEngine;

namespace TD.Audio
{
    public class AudioManager : MonoBehaviour
    {
        [System.Serializable]
        public struct CategoryConfig
        {
            public AudioCategory category;
            public int           maxVoices;

            // NOTE: currently inert. It seeds each pooled AudioSource at init, but every
            // Play() call overwrites src.volume with (per-sound volume × SFX slider), so
            // this value never reaches the mix. Left as-is rather than "fixed" because
            // multiplying it in would halve every existing sound (authored scenes use 0.5).
            // Wire it up only alongside a pass to re-level the per-sound volumes.
            [Range(0f, 1f)]
            public float         volume;
        }

        public static AudioManager Instance { get; private set; }

        [SerializeField] private CategoryConfig[] categories;

        private Dictionary<AudioCategory, AudioSource[]> pools;
        private Dictionary<AudioCategory, int>           indices;

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

        private void OnDestroy()
        {
            if (Instance == this) Instance = null;
        }

        private void InitializePools()
        {
            pools   = new Dictionary<AudioCategory, AudioSource[]>();
            indices = new Dictionary<AudioCategory, int>();

            foreach (var config in categories)
            {
                var pool = new AudioSource[config.maxVoices];
                for (int i = 0; i < config.maxVoices; i++)
                {
                    var src = gameObject.AddComponent<AudioSource>();
                    src.playOnAwake = false;
                    src.volume      = config.volume;
                    pool[i]         = src;
                }
                pools[config.category]   = pool;
                indices[config.category] = 0;
            }
        }

        /// <summary>
        /// Plays a one-shot on the given category's voice pool. <paramref name="volume"/> is
        /// the per-sound authored level; it's scaled by the player's SFX slider
        /// (<see cref="AudioVolumeSettings.SfxScalar"/>) on the way in.
        /// </summary>
        /// <remarks>
        /// The scalar is sampled at play time, so a sound already in flight keeps the volume
        /// it started with when the slider moves. Every SFX here is short, so that's
        /// imperceptible and avoids having to track live voices.
        /// </remarks>
        public void Play(AudioClip clip, AudioCategory category, float pitch = 1f, float volume = 1f)
        {
            if (clip == null) return;
            if (!pools.TryGetValue(category, out var pool)) return;

            int idx           = indices[category];
            var src           = pool[idx % pool.Length];
            src.pitch         = pitch;
            src.volume        = volume * AudioVolumeSettings.SfxScalar;
            src.clip          = clip;
            src.Play();
            indices[category] = idx + 1;
        }
    }
}