prepo: Implement calls of IPrepoService

- Implement `SaveReportOld`, `SaveReportWithUserOld`, `SaveReport`, `SaveReportWithUser` not accurate by RE (except for result codes). It's  here to do something with the data since we will never use the `Play Report` sent by the game. So it's better than just a stub.
- Fix a typo in `ldn` result code.

Close #807

Ryujinx.HLE/HOS/Services/Ldn/ResultCode.cs

@@ -11,6 +11,6 @@ namespace Ryujinx.HLE.HOS.Services.Ldn
         InvalidState    = (32 << ErrorCodeShift) | ModuleId,
         Unknown1        = (48 << ErrorCodeShift) | ModuleId,
         InvalidArgument = (96 << ErrorCodeShift) | ModuleId,
-        InvalidOjbect   = (97 << ErrorCodeShift) | ModuleId,
+        InvalidObject   = (97 << ErrorCodeShift) | ModuleId,
     }
 }

Ryujinx.HLE/HOS/Services/Prepo/IPrepoService.cs

@@ -1,4 +1,9 @@
+using Ryujinx.Common;
 using Ryujinx.Common.Logging;
+using Ryujinx.HLE.Utilities;
+using System.IO;
+using System.Text;
+using System.Text.RegularExpressions;
 
 namespace Ryujinx.HLE.HOS.Services.Prepo
 {
@@ -7,15 +12,153 @@ namespace Ryujinx.HLE.HOS.Services.Prepo
     [Service("prepo:u")]
     class IPrepoService : IpcService
     {
+        private bool _withUserId;
+
         public IPrepoService(ServiceCtx context) { }
 
-        [Command(10101)]
-        // SaveReportWithUser(nn::account::Uid, u64, pid, buffer<u8, 9>, buffer<bytes, 5>)
-        public static ResultCode SaveReportWithUser(ServiceCtx context)
+        [Command(10100)] // 1.0.0-5.1.0
+        // SaveReport(u64, pid, buffer<u8, 9>, buffer<bytes, 5>)
+        public ResultCode SaveReportOld(ServiceCtx context)
         {
-            Logger.PrintStub(LogClass.ServicePrepo);
+            _withUserId = false;
+
+            // We don't care about the differences since we don't use the play report.
+            return SaveReportWithUser(context);
+        }
+
+        [Command(10101)] // 1.0.0-5.1.0
+        // SaveReportWithUserOld(nn::account::Uid, u64, pid, buffer<u8, 9>, buffer<bytes, 5>)
+        public ResultCode SaveReportWithUserOld(ServiceCtx context)
+        {
+            _withUserId = true;
+
+            // We don't care about the differences since we don't use the play report.
+            return SaveReportWithUser(context);
+        }
+
+        [Command(10102)] // 6.0.0+
+        // SaveReport(u64, pid, buffer<u8, 9>, buffer<bytes, 5>)
+        public ResultCode SaveReport(ServiceCtx context)
+        {
+            _withUserId = false;
+
+            // We don't care about the differences since we don't use the play report.
+            return SaveReportWithUser(context);
+        }
+
+        [Command(10103)] // 6.0.0+
+        // SaveReportWithUser(nn::account::Uid, u64, pid, buffer<u8, 9>, buffer<bytes, 5>)
+        public ResultCode SaveReportWithUser(ServiceCtx context)
+        {
+            UInt128 userId   = _withUserId ? new UInt128(context.RequestData.ReadBytes(0x10)) : new UInt128();
+            string  gameRoom = StringUtils.ReadUtf8String(context);
+
+            if (_withUserId)
+            {
+                if (userId.IsNull)
+                {
+                    return ResultCode.InvalidArgument;
+                }
+            }
+
+            if (gameRoom == "")
+            {
+                return ResultCode.InvalidState;
+            }
+
+            long inputPosition = context.Request.SendBuff[0].Position;
+            long inputSize     = context.Request.SendBuff[0].Size;
+
+            if (inputSize == 0)
+            {
+                return ResultCode.InvalidBufferSize;
+            }
+
+            byte[] inputBuffer = context.Memory.ReadBytes(inputPosition, inputSize);
+
+            Logger.PrintInfo(LogClass.ServicePrepo, ReadReportBuffer(inputBuffer, gameRoom, userId));
 
             return ResultCode.Success;
         }
+
+        public string ReadReportBuffer(byte[] buffer, string room, UInt128 userId)
+        {
+            StringBuilder sb = new StringBuilder();
+
+            sb.AppendLine("\nPlayReport log:");
+
+            if (_withUserId)
+            {
+                sb.AppendLine($" UserId: {userId.ToString()}");
+            }
+
+            sb.AppendLine($" Room: {room}");
+
+            using (MemoryStream stream = new MemoryStream(buffer))
+            using (BinaryReader reader = new BinaryReader(stream))
+            {
+                byte  unknown1 = reader.ReadByte();  // Version ?
+                short unknown2 = reader.ReadInt16(); // Size ?
+
+                bool isValue = false;
+
+                string fieldStr = "";
+
+                while (stream.Position != stream.Length)
+                {
+                    byte flag = reader.ReadByte();
+
+                    if (!isValue)
+                    {
+                        byte[] key = reader.ReadBytes(flag - 0xA0);
+
+                        fieldStr = $"  Key: {Encoding.ASCII.GetString(key)}";
+
+                        isValue = true;
+                    }
+                    else
+                    {
+                        if (flag > 0xD0) // Int value.
+                        {
+                            if (flag - 0xD0 == 1)
+                            {
+                                fieldStr += $", Value: {EndianSwap.Swap16(reader.ReadUInt16())}";
+                            }
+                            else if (flag - 0xD0 == 2)
+                            {
+                                fieldStr += $", Value: {EndianSwap.Swap32(reader.ReadInt32())}";
+                            }
+                            else if (flag - 0xD0 == 4)
+                            {
+                                fieldStr += $", Value: {reader.ReadInt64()}";
+                            }
+                            else
+                            {
+                                // Unknown.
+                                break;
+                            }
+                        }
+                        else if (flag > 0xA0 && flag < 0xD0) // String value, max size = 0x20 bytes ?
+                        {
+                            byte[] valueBuffer = reader.ReadBytes(flag - 0xA0);
+                            string value       = Encoding.ASCII.GetString(valueBuffer);
+
+                            // TODO: Find why there is no alpha-numeric value sometimes.
+                            fieldStr += $", Value: {Regex.Replace(value, "[^A-Za-z0-9 -~]", "")}";
+                        }
+                        else // Byte value.
+                        {
+                            fieldStr += $", Value: {flag}";
+                        }
+
+                        sb.AppendLine(fieldStr);
+
+                        isValue = false;
+                    }
+                }
+            }
+
+            return sb.ToString();
+        }
     }
 }

Ryujinx.HLE/HOS/Services/Prepo/ResultCode.cs

@@ -0,0 +1,15 @@
+namespace Ryujinx.HLE.HOS.Services.Prepo
+{
+    enum ResultCode
+    {
+        ModuleId       = 129,
+        ErrorCodeShift = 9,
+
+        Success = 0,
+
+        InvalidArgument   = ( 1 << ErrorCodeShift) | ModuleId,
+        InvalidState      = ( 5 << ErrorCodeShift) | ModuleId,
+        InvalidBufferSize = ( 9 << ErrorCodeShift) | ModuleId,
+        Unknown1          = (90 << ErrorCodeShift) | ModuleId
+    }
+}