From db56b2166d3591eb5d16923b1fcf02733c12420b Mon Sep 17 00:00:00 2001
From: Ac_K <Acoustik666@gmail.com>
Date: Fri, 19 Mar 2021 00:04:49 +0100
Subject: [PATCH] ErrorApplet: Implement ApplicationErrorArg (#2123)

This PR implement `ApplicationErrorArg` to the Error Applet. It's used by the guest to throw some specific error messages.
The code was done for (and merged) LDN2 build since long time ago and have been tested a bunch of times because of that! In a way to reduce the differences between LDN and master build it's fine to add it to master.
---
 .../HOS/Applets/Error/ApplicationErrorArg.cs  | 13 ++++++
 Ryujinx.HLE/HOS/Applets/Error/ErrorApplet.cs  | 42 +++++++++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 Ryujinx.HLE/HOS/Applets/Error/ApplicationErrorArg.cs

diff --git a/Ryujinx.HLE/HOS/Applets/Error/ApplicationErrorArg.cs b/Ryujinx.HLE/HOS/Applets/Error/ApplicationErrorArg.cs
new file mode 100644
index 0000000000..931c5912ab
--- /dev/null
+++ b/Ryujinx.HLE/HOS/Applets/Error/ApplicationErrorArg.cs
@@ -0,0 +1,13 @@
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.HLE.HOS.Applets.Error
+{
+    [StructLayout(LayoutKind.Sequential, Pack = 1)]
+    unsafe struct ApplicationErrorArg
+    {
+        public uint       ErrorNumber;
+        public ulong      LanguageCode;
+        public fixed byte MessageText[0x800];
+        public fixed byte DetailsText[0x800];
+    }
+} 
\ No newline at end of file
diff --git a/Ryujinx.HLE/HOS/Applets/Error/ErrorApplet.cs b/Ryujinx.HLE/HOS/Applets/Error/ErrorApplet.cs
index c78cbf3160..c8bdf3e19a 100644
--- a/Ryujinx.HLE/HOS/Applets/Error/ErrorApplet.cs
+++ b/Ryujinx.HLE/HOS/Applets/Error/ErrorApplet.cs
@@ -8,6 +8,7 @@ using Ryujinx.HLE.FileSystem;
 using Ryujinx.HLE.HOS.Services.Am.AppletAE;
 using Ryujinx.HLE.HOS.SystemState;
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Runtime.InteropServices;
@@ -51,6 +52,12 @@ namespace Ryujinx.HLE.HOS.Applets.Error
                     {
                         ParseErrorCommonArg();
 
+                        break;
+                    }
+                case ErrorType.ApplicationErrorArg:
+                    {
+                        ParseApplicationErrorArg();
+
                         break;
                     }
                 default: throw new NotImplementedException($"ErrorApplet type {_errorCommonHeader.Type} is not implemented.");
@@ -163,6 +170,41 @@ namespace Ryujinx.HLE.HOS.Applets.Error
             }
         }
 
+        private void ParseApplicationErrorArg()
+        {
+            ApplicationErrorArg applicationErrorArg = IApplet.ReadStruct<ApplicationErrorArg>(_errorStorage);
+
+            byte[] messageTextBuffer = new byte[0x800];
+            byte[] detailsTextBuffer = new byte[0x800];
+            unsafe
+            {
+                Marshal.Copy((IntPtr)applicationErrorArg.MessageText, messageTextBuffer, 0, 0x800);
+                Marshal.Copy((IntPtr)applicationErrorArg.DetailsText, detailsTextBuffer, 0, 0x800);
+            }
+
+            string messageText = Encoding.ASCII.GetString(messageTextBuffer.TakeWhile(b => !b.Equals(0)).ToArray());
+            string detailsText = Encoding.ASCII.GetString(detailsTextBuffer.TakeWhile(b => !b.Equals(0)).ToArray());
+
+            List<string> buttons = new List<string>();
+
+            // TODO: Handle the LanguageCode to return the translated "OK" and "Details".
+
+            if (detailsText.Trim() != "")
+            {
+                buttons.Add("Details");
+            }
+
+            buttons.Add("OK");
+
+            bool showDetails = _horizon.Device.UiHandler.DisplayErrorAppletDialog($"Error Number: {applicationErrorArg.ErrorNumber}", "\n" + messageText, buttons.ToArray());
+            if (showDetails)
+            {
+                buttons.RemoveAt(0);
+
+                _horizon.Device.UiHandler.DisplayErrorAppletDialog($"Error Number: {applicationErrorArg.ErrorNumber} (Details)", "\n" + detailsText, buttons.ToArray());
+            }
+        }
+
         public ResultCode GetResult()
         {
             return ResultCode.Success;