using System;
using System.Collections.Generic;
using System.IO;
using Godot;
using Zio;

namespace TBL.GodotSharp.Content.Package
{
    /// <summary>
    /// 基于文件系统的抽象内容包
    /// <para>会在内部自动检索配置文件来获取描述符和依赖项信息</para>
    /// </summary>
    public class FileSystemPackage : PackageNode
    {
        public override IFileSystem SelfFileSystem { get; }
        
        public sealed override Info SelfInfo { get; }
        
        public sealed override IEnumerable<DependencyInfo> Dependencies { get; }

        public FileSystemPackage(IFileSystem fileSystem)
        {
            Dependencies = null;
            var iniFound = false;
            foreach (var iniPath in fileSystem.EnumeratePaths(UPath.Root, "*.ini", SearchOption.TopDirectoryOnly, SearchTarget.File))
            {
                var ini = new ConfigFile();
                var err = ini.Parse(fileSystem.ReadAllText(iniPath));
                if (err != Error.Ok)
                    throw new GodotException(err);

                iniFound = true;

                if (SelfInfo.Name.Empty() && ini.HasSection(nameof(SelfInfo)))
                {
                    SelfInfo = new Info(
                        ini.GetValue(nameof(SelfInfo), nameof(SelfInfo.Name)) as string,
                        ini.GetValue(nameof(SelfInfo), nameof(SelfInfo.AuthorInfo)) as string,
                        ini.GetValue(nameof(SelfInfo), nameof(SelfInfo.VersionInfo)) as string
                        );
                }

                if (Dependencies == null && ini.HasSection(nameof(Dependencies)))
                {
                    var dependencies = new List<DependencyInfo>();
                    foreach (var dependencyName in ini.GetSectionKeys(nameof(Dependencies)))
                    {
                        var info = ini.GetValue(nameof(Dependencies), dependencyName) as Godot.Collections.Array;
                        if (info == null || info.Count < 2)
                            continue;
                        var flags = DependencyInfo.FlagsEnum.None;
                        if (info.Count > 2 && info[2] is string flagsInfo)
                        {
                            foreach (var flagInfo in flagsInfo.Split(';'))
                                if (Enum.TryParse<DependencyInfo.FlagsEnum>(flagInfo.Trim(), out var flag))
                                    flags |= flag;
                        }
                        var dependency = new DependencyInfo(new Info(dependencyName, info[0] as string, info[1] as string), flags);
                        dependencies.Add(dependency);
                    }
                    Dependencies = dependencies;
                }

                if (!SelfInfo.Name.Empty() &&
                    Dependencies != null)
                {
                    break;
                }
            }

            if (!iniFound)
            {
                QueueFree();
                throw new GodotException(Error.FileNotFound);
            }
            
            SelfFileSystem = fileSystem;
        }
    }
}