using System.Collections.Generic;
using System.Text;
using UnityEngine;

/// <summary>
///     运行时使用的资源清单，代替Unity的Manifest
/// </summary>
public class AssetDependencyInfo
{
    public AssetDependencyItem[] assetList;
    public int version;

    public static AssetDependencyInfo Create(string path)
    {
        var bundle = AssetBundle.LoadFromFile(path);
        AssetDependencyInfo result = null;
        var textAsset = bundle ? bundle.LoadAsset<TextAsset>(AssetConst.versionFile) : null;
        if (bundle)
            bundle.Unload(false);
        if (!textAsset)
            Debug.LogError(string.Format("Unable to load TextAsset from {0}!", AssetConst.versionFile));
        else
        {
            var text = Encoding.UTF8.GetString(textAsset.bytes);
            int version;
            var lines = AssetUtils.TextToLines(text);
            if (lines.Length < 1)
            {
                Debug.LogError("No data in text to create AssetDependencyInfo!");
            }
            else if (!int.TryParse(lines[0], out version))
            {
                Debug.LogError("No version number in text to create AssetDependencyInfo!");
            }
            else
            {
                var error = false;
                var assetList = new List<AssetDependencyItem>();
                for (var i = 1; i < lines.Length; i++)
                {
                    var line = lines[i];
                    if (!string.IsNullOrEmpty(line))
                    {
                        var assetItem = AssetDependencyItem.Create(line);
                        if (assetItem != null)
                            assetList.Add(assetItem);
                        else
                        {
                            error = true;
                            break;
                        }
                    }
                }

                if (!error)
                {
                    result = new AssetDependencyInfo
                    {
                        version = version,
                        assetList = assetList.ToArray()
                    };
                }
            }
        }
        return result;
    }

    public void Write(StringBuilder builder)
    {
        builder.Append(version);
        foreach (var item in assetList)
        {
            builder.Append('\n');
            item.Write(builder);
        }
    }
}

public class AssetDependencyItem
{
    public const int paramLength = 6;

    // 资源依赖文件
    public string[] dependencies;

    // 资源文件大小
    public int fileSize;

    // 资源后台下载排序参数
    public int importance;

    // 资源等级，对应AssetLevel
    public int level;

    // 资源hash匹配码
    public string md5;

    public string name;

    // 资源版本号
    public int version;

    public static AssetDependencyItem Create(string line)
    {
        AssetDependencyItem result = null;
        // 机器生成的数据，不会出现需要额外Trim的情况
        var segments = line.Split(';');
        if (segments.Length < paramLength)
        {
            Debug.LogError("No enough data in line: " + line);
        }
        else
        {
            // 注：第一位id仅仅用于适配重用的工具的格式
            var name = segments[0];
            var md5 = segments[1];
            int version;
            int level;
            int fileSize;
            int importance;
            if (!int.TryParse(segments[2], out version))
            {
                Debug.LogError("Unable to get asset version from line: " + line);
            }
            else if (!int.TryParse(segments[3], out level))
            {
                Debug.LogError("Unable to get asset level from line: " + line);
            }
            else if (!int.TryParse(segments[4], out fileSize))
            {
                Debug.LogError("Unable to get asset fileSize from line: " + line);
            }
            else if (!int.TryParse(segments[5], out importance))
            {
                Debug.LogError("Unable to get importance from line: " + line);
            }
            else
            {
                var count = segments.Length - paramLength;
                var dependencies = count > 0 ? new string[count] : new string[0];
                for (var i = 0; i < count; i++)
                    dependencies[i] = segments[i + paramLength];
                result = new AssetDependencyItem
                {
                    name = name,
                    md5 = md5,
                    version = version,
                    level = level,
                    fileSize = fileSize,
                    importance = importance,
                    dependencies = dependencies
                };
            }
        }

        return result;
    }

    public void Write(StringBuilder builder)
    {
        builder.Append(name);
        builder.Append(';');
        builder.Append(md5);
        builder.Append(';');
        builder.Append(version);
        builder.Append(';');
        builder.Append(level);
        builder.Append(';');
        builder.Append(fileSize);
        builder.Append(';');
        builder.Append(importance);
        if (dependencies != null)
            foreach (var dependency in dependencies)
            {
                builder.Append(';');
                builder.Append(dependency);
            }
    }
}

public static class AssetLevel
{
    // level：0 = 使用时下载；1 = 后台持续下载；2 = 初始化下载；3 = 首包资源
    public const int onUse = 0;
    public const int onRunning = 1;
    public const int onInit = 2;
    public const int inApk = 3;
}