using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
using UnityEngine;

namespace AssetUpdate
{
    public class AssetCompareAction : IAssetAsyncAction
    {
        public readonly List<AssetDependencyItem> downloadList = new List<AssetDependencyItem>();
        public Dictionary<string, string> streamingPathInfo { get; private set; }
        public bool isEnd { get; private set; }

        public bool UpdateTimeout()
        {
            return isEnd;
        }

        public void Start(AssetDependencyInfo target)
        {
            var streamingText = Resources.Load<TextAsset>(AssetConst.assetPathDataPath.Open(AssetConst.pathFile));
            var formatter = new BinaryFormatter();
            try
            {
                using (var ms = new MemoryStream(streamingText.bytes))
                    streamingPathInfo = formatter.Deserialize(ms) as Dictionary<string, string>;
            }
            catch (Exception e)
            {
                Debug.LogError(e);
            }
            if (streamingPathInfo == null)
                throw new NullReferenceException("Failed to load streamingPathInfo, this is not recoverable!");
            Dictionary<string, string> persist = null;
            var persistTextPath = AssetConst.persistentDataPath.Open(AssetConst.pathFile + AssetConst.bytesExtension);
            if (File.Exists(persistTextPath))
            {
                try
                {
                    using (var fs = File.OpenRead(persistTextPath))
                        persist = formatter.Deserialize(fs) as Dictionary<string, string>;
                }
                catch (Exception e)
                {
                    Debug.LogError(e);
                }
            }
            foreach (var asset in target.assetList)
                if (asset.level >= AssetLevel.onInit)
                {
                    string md5;
                    if (streamingPathInfo.TryGetValue(asset.name, out md5) && md5 == asset.md5)
                        continue;
                    if (persist != null && persist.TryGetValue(asset.name, out md5))
                    {
                        if (md5 != asset.md5)
                        {
#if UNITY_EDITOR
                            Debug.LogWarning(string.Format("Replacing asset {0} with new version!", asset.name));       
#endif
                        }
                        else
                            continue;
                    }
                    downloadList.Add(asset);
                }

            isEnd = true;
        }

        public void Dispose()
        {
        }
    }
}