using Cryville.Common.Network;
using Cryville.Common.Unity;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using UnityEngine;
using Logger = Cryville.Common.Logging.Logger;
using ThreadPriority = System.Threading.ThreadPriority;

namespace Cryville.Crtr.Network {
	public class UpdateChecker : MonoBehaviour {
		string _currentVersion;
		void Start() {
			_currentVersion = Application.version;
			new Thread(CheckVersion) { IsBackground = true, Priority = ThreadPriority.BelowNormal }.Start();
		}
		static readonly Uri BaseUri = new Uri("https://www.cryville.world/api/crtr/index");
		List<VersionInfo> _versions;
		public void CheckVersion() {
			try {
				var client = new HttpsClient(BaseUri);
				client.Connect();
				var response = client.Request("GET", new Uri(BaseUri, "versions"));
				var data = Encoding.UTF8.GetString(response.MessageBody.ReadToEnd());
				_versions = JsonConvert.DeserializeObject<List<VersionInfo>>(data, Game.GlobalJsonSerializerSettings);
			}
			catch (Exception ex) {
				Logger.Log("main", 4, "Network", "An error occurred while checking for update: {0}", ex);
				Dialog.Show(null, "Failed to check for update.");
				return;
			}
			var availableVersions = _versions.Where(v => v.platforms.ContainsKey(PlatformConfig.Name)).ToArray();
			var versionIndex = new Dictionary<string, int>(availableVersions.Length);
			for (int i = 0; i < availableVersions.Length; i++) versionIndex.Add(availableVersions[i].name, i);
			var currentVersion = availableVersions.Where(v => v.name == _currentVersion).SingleOrDefault();
			var latestVersion = availableVersions.Last();
			if (currentVersion == null) {
				Dialog.Show(null, string.Format("You are playing an unknown version of Cosmo Resona: {0}\nThe latest version is: {1}", _currentVersion, latestVersion.name));
				return;
			}
			if (latestVersion.name != _currentVersion) {
				var latestResources = latestVersion.platforms[PlatformConfig.Name].resources;
				VersionResourceInfo fullPackage = null;
				if (latestResources != null) {
					fullPackage = (from r in latestResources where r.upstream == null select r).SingleOrDefault();
				}
				if (fullPackage == null) {
					Dialog.Show(null, string.Format("A new version is present: {0}\nUpdate is not available.", latestVersion.name));
					return;
				}
				long totalDiffSize = 0;
				int searchIndex = versionIndex[latestVersion.name], targetIndex = versionIndex[currentVersion.name];
				while (searchIndex != targetIndex) {
					var searchVersion = availableVersions[searchIndex];
					VersionResourceInfo matchedUpstream = null;
					var resources = searchVersion.platforms[PlatformConfig.Name].resources;
					if (resources == null) {
						totalDiffSize = 0;
						break;
					}
					foreach (var r in resources) {
						if (r.upstream == null) continue;
						var upstreamIndex = versionIndex[r.upstream];
						if (upstreamIndex >= targetIndex && upstreamIndex < searchIndex) {
							matchedUpstream = r;
							searchIndex = upstreamIndex;
						}
					}
					if (matchedUpstream != null) {
						if (matchedUpstream.external) {
							totalDiffSize = 0;
							Dialog.ShowAndWait("An error occurred while checking for update.\nPlease report this to the developers.");
							Logger.Log("main", 4, "Network", "Diff package is external, which is not expected");
							break;
						}
						totalDiffSize += matchedUpstream.size;
						if (totalDiffSize >= fullPackage.size) {
							totalDiffSize = 0;
							break;
						}
					}
					else {
						totalDiffSize = 0;
						break;
					}
				}
				if (totalDiffSize == 0 || totalDiffSize >= fullPackage.size) {
					// TODO Check if external
					if (Dialog.ShowAndWait(string.Format("A new version is available: {0}\nYou have to download the full package.\nOpen the download link now?", latestVersion.name), "Yes", "No") == 0) {
						UrlOpener.Open(fullPackage.url);
					}
				}
				else {
					Dialog.ShowAndWait(string.Format("A new version is available: {0}\nDo you want to update?", latestVersion.name), "Yes", "No");
				}
			}
			Logger.Log("main", 0, "Network", "Update checker exited");
		}
		class VersionInfo {
			[JsonRequired]
			public string name;
			public string type;
			public Dictionary<string, PlatformVersionInfo> platforms;
		}
		class PlatformVersionInfo {
			public List<VersionResourceInfo> resources;
		}
		class VersionResourceInfo {
			public bool external;
			public string upstream;
			[JsonRequired]
			public string url;
			[JsonRequired]
			public long size;
		}
	}
}