using System;
using AlicizaX;
using UnityEngine;
using YooAsset;

namespace AlicizaX.Audio.Runtime
{
    internal sealed class AudioClipCacheEntry : IMemory
    {
        private readonly Action<AssetHandle> _completedCallback;

        public AudioService Owner;
        public string Address;
        public AssetHandle Handle;
        public AudioClip Clip;
        public AudioLoadRequest PendingHead;
        public AudioLoadRequest PendingTail;
        public AudioClipCacheEntry LruPrev;
        public AudioClipCacheEntry LruNext;
        public AudioClipCacheEntry AllPrev;
        public AudioClipCacheEntry AllNext;
        public int RefCount;
        public bool Loading;
        public bool Pinned;
        public bool CacheAfterUse;
        public bool InLru;
        public float LastUseTime;

        public AudioClipCacheEntry()
        {
            _completedCallback = OnLoadCompleted;
        }

        public Action<AssetHandle> CompletedCallback => _completedCallback;

        public bool IsLoaded => Clip != null && Handle is { IsValid: true } && !Loading;

        public void Initialize(AudioService owner, string address, bool pinned)
        {
            Owner = owner;
            Address = address;
            Pinned = pinned;
            CacheAfterUse = pinned;
            LastUseTime = Time.realtimeSinceStartup;
        }

        public void AddPending(AudioLoadRequest request)
        {
            request.Next = null;
            if (PendingTail == null)
            {
                PendingHead = request;
                PendingTail = request;
                return;
            }

            PendingTail.Next = request;
            PendingTail = request;
        }

        public int CountPending()
        {
            int count = 0;
            AudioLoadRequest request = PendingHead;
            while (request != null)
            {
                count++;
                request = request.Next;
            }

            return count;
        }

        public void FillDebugInfo(AudioClipCacheDebugInfo info)
        {
            if (info == null)
            {
                return;
            }

            info.Address = Address;
            info.Clip = Clip;
            info.RefCount = RefCount;
            info.PendingCount = CountPending();
            info.Loading = Loading;
            info.Pinned = Pinned;
            info.CacheAfterUse = CacheAfterUse;
            info.InLru = InLru;
            info.IsLoaded = IsLoaded;
            info.HasValidHandle = Handle is { IsValid: true };
            info.LastUseTime = LastUseTime;
        }

        public void Clear()
        {
            if (Handle is { IsValid: true })
            {
                if (Loading)
                {
                    Handle.Completed -= _completedCallback;
                }

                Handle.Dispose();
            }

            AudioLoadRequest request = PendingHead;
            while (request != null)
            {
                AudioLoadRequest next = request.Next;
                MemoryPool.Release(request);
                request = next;
            }

            Owner = null;
            Address = null;
            Handle = null;
            Clip = null;
            PendingHead = null;
            PendingTail = null;
            LruPrev = null;
            LruNext = null;
            AllPrev = null;
            AllNext = null;
            RefCount = 0;
            Loading = false;
            Pinned = false;
            CacheAfterUse = false;
            InLru = false;
            LastUseTime = 0f;
        }

        private void OnLoadCompleted(AssetHandle handle)
        {
            AudioService owner = Owner;
            if (owner != null)
            {
                owner.OnClipLoadCompleted(this, handle);
            }
            else if (handle is { IsValid: true })
            {
                handle.Dispose();
            }
        }
    }
}