using System.IO;
using System.Reactive.Subjects;
using System.Threading.Tasks;
using Newtonsoft.Json;
using Wabbajack.Common;
using Wabbajack.Common.IO;
using Wabbajack.Common.Serialization.Json;
using Wabbajack.Lib.Validation;

namespace Wabbajack.Lib.Downloaders
{
    public class ManualDownloader : IDownloader
    {
        private FileSystemWatcher _watcher;
        private Subject<FileEvent> _fileEvents = new Subject<FileEvent>();
        private KnownFolder _downloadfolder;
        public readonly AsyncLock Lock = new AsyncLock();

        class FileEvent
        {
            public string FullPath { get; set; } = string.Empty;
            public string Name { get; set; } = string.Empty;
            public long Size { get; set; }
        }

        public ManualDownloader()
        {
            _downloadfolder = new KnownFolder(KnownFolderType.Downloads);
            _watcher = new FileSystemWatcher(_downloadfolder.Path);
            _watcher.Created += _watcher_Created;
            _watcher.Changed += _watcher_Changed;
        }

        private void _watcher_Changed(object sender, FileSystemEventArgs e)
        {
            PublishEvent(e);
        }
        private void _watcher_Created(object sender, FileSystemEventArgs e)
        {
            PublishEvent(e);
        }

        private void PublishEvent(FileSystemEventArgs e)
        {
            try
            {
                _fileEvents.OnNext(new FileEvent
                {
                    Size = new FileInfo(e.FullPath).Length,
                    Name = e.Name,
                    FullPath = e.FullPath
                });
            }
            catch (IOException)
            {

            }
        }

        public async Task<AbstractDownloadState?> GetDownloaderState(dynamic archiveINI, bool quickMode)
        {
            var url = archiveINI?.General?.manualURL;
            return url != null ? new State(url) : null;
        }

        public async Task Prepare()
        {
        }
        
        [JsonName("ManualDownloader")]
        public class State : AbstractDownloadState
        {
            public string Url { get; }
            
            [JsonIgnore]
            public override object[] PrimaryKey => new object[] { Url };

            public State(string url)
            {
                Url = url;
            }

            public override bool IsWhitelisted(ServerWhitelist whitelist)
            {
                return true;
            }

            public override async Task<bool> Download(Archive a, AbsolutePath destination)
            {
                var (uri, client) = await Utils.Log(await ManuallyDownloadFile.Create(this)).Task;
                var state = new HTTPDownloader.State(uri.ToString()) { Client = client };
                return await state.Download(a, destination);
            }

            public override async Task<bool> Verify(Archive a)
            {
                return true;
            }

            public override IDownloader GetDownloader()
            {
                return DownloadDispatcher.GetInstance<ManualDownloader>();
            }

            public override string GetManifestURL(Archive a)
            {
                return Url;
            }

            public override string[] GetMetaIni()
            {
                return new [] 
                {
                    "[General]",
                    $"manualURL={Url}",
                };
            }
        }
    }
}