using Ryujinx.Common.Logging;
using System.IO;
using System.Text;

namespace Ryujinx.HLE.HOS.Services.Lm.LogService
{
    class ILogger : IpcService
    {
        public ILogger() { }

        [CommandHipc(0)]
        // Log(buffer<unknown, 0x21>)
        public ResultCode Log(ServiceCtx context)
        {
            Logger.Guest?.Print(LogClass.ServiceLm, LogImpl(context));

            return ResultCode.Success;
        }

        private string LogImpl(ServiceCtx context)
        {
            (ulong bufPos, ulong bufSize) = context.Request.GetBufferType0x21();

            byte[] logBuffer = new byte[bufSize];

            context.Memory.Read(bufPos, logBuffer);

            using MemoryStream ms = new MemoryStream(logBuffer);

            BinaryReader reader = new BinaryReader(ms);

            long pid = reader.ReadInt64();
            long threadContext = reader.ReadInt64();
            short flags = reader.ReadInt16();
            byte level = reader.ReadByte();
            byte verbosity = reader.ReadByte();
            int payloadLength = reader.ReadInt32();

            StringBuilder sb = new StringBuilder();

            sb.AppendLine($"Guest Log:\n  Log level: {(LmLogLevel)level}");

            while (ms.Position < ms.Length)
            {
                int type = ReadEncodedInt(reader);
                int size = ReadEncodedInt(reader);

                LmLogField field = (LmLogField)type;

                string fieldStr = string.Empty;

                if (field == LmLogField.Start)
                {
                    reader.ReadBytes(size);

                    continue;
                }
                else if (field == LmLogField.Stop)
                {
                    break;
                }
                else if (field == LmLogField.Line)
                {
                    fieldStr = $"{field}: {reader.ReadInt32()}";
                }
                else if (field == LmLogField.DropCount)
                {
                    fieldStr = $"{field}: {reader.ReadInt64()}";
                }
                else if (field == LmLogField.Time)
                {
                    fieldStr = $"{field}: {reader.ReadInt64()}s";
                }
                else if (field < LmLogField.Count)
                {
                    fieldStr = $"{field}: '{Encoding.UTF8.GetString(reader.ReadBytes(size)).TrimEnd()}'";
                }
                else
                {
                    fieldStr = $"Field{field}: '{Encoding.UTF8.GetString(reader.ReadBytes(size)).TrimEnd()}'";
                }

                sb.AppendLine($"    {fieldStr}");
            }

            return sb.ToString();
        }

        private static int ReadEncodedInt(BinaryReader reader)
        {
            int result = 0;
            int position = 0;

            byte encoded;

            do
            {
                encoded = reader.ReadByte();

                result += (encoded & 0x7F) << (7 * position);

                position++;

            } while ((encoded & 0x80) != 0);

            return result;
        }
    }
}