using Avalonia.Metadata;
using Avalonia.Threading;
using CommunityToolkit.Mvvm.ComponentModel;
using Mesen.Config;
using Mesen.Utilities;
using Mesen.ViewModels;
using System;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;

namespace Mesen.ViewModels
{
	public partial class SelectStorageFolderViewModel : ViewModelBase
	{
		[ObservableProperty] public partial bool StoreInUserProfile { get; set; }
		[ObservableProperty] public partial bool IsCopying { get; set; }
		[ObservableProperty] public partial int CopyProgress { get; set; }
		[ObservableProperty] public partial string DestinationFolder { get; private set; } = "";

		public SelectStorageFolderViewModel()
		{
			UpdateDestinationFolder();
		}

		partial void OnStoreInUserProfileChanged(bool value)
		{
			UpdateDestinationFolder();
		}

		private void UpdateDestinationFolder()
		{
			DestinationFolder = StoreInUserProfile ? ConfigManager.DefaultDocumentsFolder : ConfigManager.DefaultPortableFolder;
		}

		private void GetFilesToCopy(string source, string target, List<string> sourceFiles, List<string> targetFiles)
		{
			if(!Directory.Exists(target)) {
				Directory.CreateDirectory(target);
			}

			foreach(string file in Directory.GetFiles(source)) {
				string ext = Path.GetExtension(file).ToLower();
				if(ext != ".exe" && ext != ".dll" && ext != "") {
					sourceFiles.Add(file);
					targetFiles.Add(Path.Combine(target, Path.GetFileName(file)));
				}
			}

			foreach(string subdir in Directory.GetDirectories(source)) {
				GetFilesToCopy(subdir, Path.Combine(target, Path.GetFileName(subdir)), sourceFiles, targetFiles);
			}
		}

		private Task<bool> CopyFiles(string source, string target)
		{
			return Task.Run(() => {
				IsCopying = true;
				try {
					List<string> sourceFiles = new();
					List<string> targetFiles = new();
					GetFilesToCopy(source, target, sourceFiles, targetFiles);
					int fileCount = sourceFiles.Count;
					int filesCopied = 0;
					for(int i = 0; i < sourceFiles.Count; i++) {
						try {
							File.Copy(sourceFiles[i], targetFiles[i], true);
						} catch(Exception ex) {
							Dispatcher.UIThread.Post(() => {
								MesenMsgBox.ShowException(ex);
							});
							return false;
						}
						filesCopied++;
						CopyProgress = filesCopied * 100 / fileCount;
					}

					return true;
				} finally {
					IsCopying = false;
				}
			});
		}

		public async Task<bool> MigrateData()
		{
			string source = ConfigManager.HomeFolder;
			string target = StoreInUserProfile ? ConfigManager.DefaultDocumentsFolder : ConfigManager.DefaultPortableFolder;

			if(string.Compare(source.Trim(), target.Trim(), StringComparison.OrdinalIgnoreCase) == 0) {
				return false;
			}

			ConfigManager.Config.Save();

			if(await CopyFiles(source, target)) {
				try {
					if(File.Exists(Path.Combine(source, "settings.backup.json"))) {
						File.Delete(Path.Combine(source, "settings.backup.json"));
					}
					File.Move(Path.Combine(source, "settings.json"), Path.Combine(source, "settings.backup.json"));
				} catch(Exception ex) {
					Dispatcher.UIThread.Post(() => {
						MesenMsgBox.ShowException(ex);
					});
				}
				ConfigManager.ResetHomeFolder();
				return true;
			} else {
				return false;
			}
		}
	}
}