Implement auto-update feature and add UnwrapAsync extension method

Author: IExploitableMan

src/Managers/AutoUpdate.cs

@@ -0,0 +1,76 @@
+using System.Diagnostics;
+using System.Text.Json;
+using HarmonyLib;
+using UnityEngine;
+
+namespace PolyMod.Managers;
+internal static class AutoUpdate
+{
+    [HarmonyPostfix]
+    [HarmonyPatch(typeof(StartScreen), nameof(StartScreen.Start))]
+    private static void StartScreen_Start()
+    {
+        HttpClient client = new();
+        client.DefaultRequestHeaders.Add("User-Agent", "PolyMod");
+        try
+        {
+            var json = JsonDocument.Parse(
+                client.GetAsync("https://api.github.com/repos/PolyModdingTeam/PolyMod/releases/latest").UnwrapAsync()
+                .Content.ReadAsStringAsync().UnwrapAsync()
+            );
+            if (
+                new Version(json.RootElement.GetProperty("tag_name").GetString()!.TrimStart('v'))
+                <= 
+                new Version(Plugin.VERSION)
+            ) return;
+            void Update()
+            {
+                File.WriteAllBytes(
+                    Path.Combine(Plugin.BASE_PATH, "BepInEx", "plugins", "PolyMod.new.dll"),
+                    client.GetAsync(json.RootElement.GetProperty("assets")[0].GetProperty("browser_download_url").GetString()!).UnwrapAsync()
+                    .Content.ReadAsByteArrayAsync().UnwrapAsync()
+                );
+                ProcessStartInfo info = new()
+                {
+                    WorkingDirectory = Path.Combine(Plugin.BASE_PATH, "BepInEx", "plugins"),
+                    CreateNoWindow = true,
+                };
+                if (Application.platform == RuntimePlatform.WindowsPlayer)
+                {
+                    info.FileName = "cmd.exe";
+                    info.Arguments 
+                        = "/C timeout 3 && del /F /Q PolyMod.dll && move /Y PolyMod.new.dll PolyMod.dll && start steam://rungameid/874390";
+                }
+                else
+                {
+                    info.FileName = "/bin/bash";
+                    info.Arguments 
+                    = "-c 'sleep 3 && rm -f PolyMod.dll && mv PolyMod.new.dll PolyMod.dll && xdg-open steam://rungameid/874390'";
+                }
+                Process.Start(info);
+                Application.Quit();
+            }
+            PopupManager.GetBasicPopup(new(
+                Localization.Get("polymod.version.autoupdate"),
+                Localization.Get("polymod.version.autoupdate.description"),
+                new(new PopupBase.PopupButtonData[] {
+                    new(
+                        "buttons.ok",
+                        PopupBase.PopupButtonData.States.None,
+                        (Il2CppSystem.Action)Update,
+                        closesPopup: false
+                    )
+                }))
+            ).Show();
+        }
+        catch (Exception e)
+        {
+            Plugin.logger.LogError($"Failed to check updates: {e.Message}");
+        }
+    }
+
+    internal static void Init()
+    {
+        Harmony.CreateAndPatchAll(typeof(AutoUpdate));
+    }
+}

src/Plugin.cs

@@ -54,6 +54,7 @@ public override void Load()
 		Compatibility.Init();
 
 		Audio.Init();
+		AutoUpdate.Init();
 		Loc.Init();
 		Visual.Init();
 		Hub.Init();

src/Util.cs

@@ -30,6 +30,11 @@ internal static Version Cast(this Il2CppSystem.Version self)
         return new(self.ToString());
     }
 
+    internal static T UnwrapAsync<T>(this Task<T> self)
+    {
+        return self.GetAwaiter().GetResult();
+    }
+
     internal static Version CutRevision(this Version self)
     {
         return new(self.Major, self.Minor, self.Build);