using System;
using System.Collections.Generic;
using System.Text;

namespace SharpOSC
{
	public abstract class OscPacket
	{
		public static OscPacket GetPacket(byte[] OscData)
		{
			if (OscData[0] == '#')
				return parseBundle(OscData);
			else
				return parseMessage(OscData);
		}

		public abstract byte[] GetBytes();

		#region Parse OSC packages

		/// <summary>
		/// Takes in an OSC bundle package in byte form and parses it into a more usable OscBundle object
		/// </summary>
		/// <param name="msg"></param>
		/// <returns>Message containing various arguments and an address</returns>
		private static OscMessage parseMessage(byte[] msg)
		{
			int index = 0;
            //Log.Debug("Raw ASCII DATA: " + System.Text.Encoding.ASCII.GetString(msg));
            //Log.Debug("Raw UTF-8 DATA: " + System.Text.Encoding.UTF8.GetString(msg));
			string address = null;
			char[] types = new char[0];
			List<object> arguments = new List<object>();
			List<object> mainArray = arguments; // used as a reference when we are parsing arrays to get the main array back
			// Get address
			address = getAddress(msg, index);
			index += msg.FirstIndexAfter(address.Length, x => x == ',');

			if (index % 4 != 0)
				throw new Exception("Misaligned OSC Packet data. Address string is not padded correctly and does not align to 4 byte interval");

			// Get type tags
			types = getTypes(msg, index);
			index += types.Length;

			while (index % 4 != 0)
				index++;

			bool commaParsed = false;

			foreach (char type in types)
			{
				// skip leading comma
				if (type == ',' && !commaParsed)
				{
					commaParsed = true;
					continue;
				}

				switch(type)
				{
					case ('\0'):
						break;

					case('i'):
						int intVal = getInt(msg, index);
						arguments.Add(intVal);
						index += 4;
						break;
				
					case('f'):
						float floatVal = getFloat(msg, index);
						arguments.Add(floatVal);
						index += 4;
						break;

					case('s'):
						string stringVal = getString(msg, index);
						arguments.Add(stringVal);
						index += stringVal.Length;
						break;
				
					case('b'):
						byte[] blob = getBlob(msg, index);
						arguments.Add(blob);
						index += 4 + blob.Length;
						break;

					case ('h'):
						Int64 hval = getLong(msg, index);
						arguments.Add(hval);
						index += 8;
						break;

					case ('t'):
						UInt64 sval = getULong(msg, index);
						arguments.Add(new Timetag(sval));
						index += 8;
						break;

					case ('d'):
						double dval = getDouble(msg, index);
						arguments.Add(dval);
						index += 8;
						break;

					case ('S'):
						string SymbolVal = getString(msg, index);
						arguments.Add(new Symbol(SymbolVal));
						index += SymbolVal.Length;
						break;

					case ('c'):
						char cval = getChar(msg, index);
						arguments.Add(cval);
						index += 4;
						break;

					case ('r'):
						RGBA rgbaval = getRGBA(msg, index);
						arguments.Add(rgbaval);
						index += 4;
						break;

					case ('m'):
						Midi midival = getMidi(msg, index);
						arguments.Add(midival);
						index += 4;
						break;

					case ('T'):
						arguments.Add(true);
						break;

					case ('F'):
						arguments.Add(false);
						break;

					case ('N'):
						arguments.Add(null);
						break;

					case ('I'):
						arguments.Add(double.PositiveInfinity);
						break;

					case ('['):
						if (arguments != mainArray)
							throw new Exception("SharpOSC does not support nested arrays");
						arguments = new List<object>(); // make arguments point to a new object array
						break;

					case (']'):
						mainArray.Add(arguments); // add the array to the main array
						arguments = mainArray; // make arguments point back to the main array
						break;

					default:
						throw new Exception("OSC type tag '" + type + "' is unknown.");
				}

				while (index % 4 != 0)
					index++;
			}

			return new OscMessage(address, arguments.ToArray());
		}

		/// <summary>
		/// Takes in an OSC bundle package in byte form and parses it into a more usable OscBundle object
		/// </summary>
		/// <param name="bundle"></param>
		/// <returns>Bundle containing elements and a timetag</returns>
		private static OscBundle parseBundle(byte[] bundle)
		{
			UInt64 timetag;
			List<OscMessage> messages = new List<OscMessage>();

			int index = 0;

			var bundleTag = Encoding.UTF8.GetString(bundle.SubArray(0, 8));
			index += 8;

			timetag = getULong(bundle, index);
			index += 8;

			if (bundleTag != "#bundle\0")
				throw new Exception("Not a bundle");

			while (index < bundle.Length)
			{
				int size = getInt(bundle, index);
				index += 4;

				byte[] messageBytes = bundle.SubArray(index, size);
				var message = parseMessage(messageBytes);

				messages.Add(message);

				index += size;
				while (index % 4 != 0)
					index++;
			}

			OscBundle output = new OscBundle(timetag, messages.ToArray());
			return output;
		}

		#endregion

		#region Get arguments from byte array
		
		private static string getAddress(byte[] msg, int index)
		{
			int i = index;
			string address = "";
			for (; i < msg.Length; i += 4)
			{
				if (msg[i] == ',')
				{
					if (i == 0)
						return "";

					address = Encoding.UTF8.GetString(msg.SubArray(index, i - 1));
					break;
				}
			}

			if (i >= msg.Length && address == null)
				throw new Exception("no comma found");

			return address.Replace("\0", "");
		}

		private static char[] getTypes(byte[] msg, int index)
		{
			int i = index + 4;
			char[] types = null;

			for (; i < msg.Length; i += 4)
			{
				if (msg[i - 1] == 0)
				{
					types = Encoding.UTF8.GetChars(msg.SubArray(index, i - index));
					break;
				}
			}

            if (types == null)
            {
                byte[] term = { 0 };
                types = Encoding.UTF8.GetChars(term);
            }

			if (i >= msg.Length && types == null)
				throw new Exception("No null terminator after type string");

			return types;
		}

		private static int getInt(byte[] msg, int index)
		{
			int val = (msg[index] << 24) + (msg[index + 1] << 16) + (msg[index + 2] << 8) + (msg[index + 3] << 0);
			return val;
		}

		private static float getFloat(byte[] msg, int index)
		{
			byte[] reversed = new byte[4];
			reversed[3] = msg[index];
			reversed[2] = msg[index+1];
			reversed[1] = msg[index+2];
			reversed[0] = msg[index + 3];
			float val = System.BitConverter.ToSingle(reversed, 0);
			return val;
		}

		private static string getString(byte[] msg, int index)
		{
			string output = null;
			int i = index + 4;
			for (; (i-1) < msg.Length; i += 4)
			{
				if (msg[i - 1] == 0)
				{
					output = Encoding.UTF8.GetString(msg.SubArray(index, i - index));
					break;
				}
			}
            if (output == null)
            {
                byte[] term = { 0 };
                output = Encoding.UTF8.GetString(term);
            }
            if (i >= msg.Length && output == null)
				throw new Exception("No null terminator after type string");

			return output.Replace("\0", "");
		}

		private static byte[] getBlob(byte[] msg, int index)
		{
			int size = getInt(msg, index);
			return msg.SubArray(index + 4, size);
		}

		private static UInt64 getULong(byte[] msg, int index)
		{
			UInt64 val = ((UInt64)msg[index] << 56) + ((UInt64)msg[index + 1] << 48) + ((UInt64)msg[index + 2] << 40) + ((UInt64)msg[index + 3] << 32)
					+ ((UInt64)msg[index + 4] << 24) + ((UInt64)msg[index + 5] << 16) + ((UInt64)msg[index + 6] << 8) + ((UInt64)msg[index + 7] << 0);
			return val;
		}

		private static Int64 getLong(byte[] msg, int index)
		{
			byte[] var = new byte[8];
			var[7] = msg[index];
			var[6] = msg[index+1];
			var[5] = msg[index+2];
			var[4] = msg[index+3];
			var[3] = msg[index+4];
			var[2] = msg[index+5];
			var[1] = msg[index+6];
			var[0] = msg[index+7];

			Int64 val = BitConverter.ToInt64(var, 0);
			return val;
		}

		private static double getDouble(byte[] msg, int index)
		{
			byte[] var = new byte[8];
			var[7] = msg[index];
			var[6] = msg[index + 1];
			var[5] = msg[index + 2];
			var[4] = msg[index + 3];
			var[3] = msg[index + 4];
			var[2] = msg[index + 5];
			var[1] = msg[index + 6];
			var[0] = msg[index + 7];

			double val = BitConverter.ToDouble(var, 0);
			return val;
		}

		private static char getChar(byte[] msg, int index)
		{
			return (char)msg[index + 3];
		}

		private static RGBA getRGBA(byte[] msg, int index)
		{
			return new RGBA(msg[index], msg[index + 1], msg[index + 2], msg[index + 3]);
		}

		private static Midi getMidi(byte[] msg, int index)
		{
			return new Midi(msg[index], msg[index + 1], msg[index + 2], msg[index + 3]);
		}

		#endregion

		#region Create byte arrays for arguments

		protected static byte[] setInt(int value)
		{
			byte[] msg = new byte[4];

			var bytes = BitConverter.GetBytes(value);
			msg[0] = bytes[3];
			msg[1] = bytes[2];
			msg[2] = bytes[1];
			msg[3] = bytes[0];

			return msg;
		}

		protected static byte[] setFloat(float value)
		{
			byte[] msg = new byte[4];

			var bytes = BitConverter.GetBytes(value);
			msg[0] = bytes[3];
			msg[1] = bytes[2];
			msg[2] = bytes[1];
			msg[3] = bytes[0];

			return msg;
		}

		protected static byte[] setString(string value)
		{
            var bytes = Encoding.UTF8.GetBytes(value);
            int len = bytes.Length + (4 - bytes.Length % 4);
			if (len <= bytes.Length) len = len + 4;

			byte[] msg = new byte[len];
			bytes.CopyTo(msg, 0);

			return msg;
		}

		protected static byte[] setBlob(byte[] value)
		{
			int len = value.Length + 4;
			len = len + (4 - len % 4);

			byte[] msg = new byte[len];
			byte[] size = setInt(value.Length);
			size.CopyTo(msg, 0);
			value.CopyTo(msg, 4);
			return msg;
		}

		protected static byte[] setLong(Int64 value)
		{
			byte[] rev = BitConverter.GetBytes(value);
			byte[] output = new byte[8];
			output[0] = rev[7];
			output[1] = rev[6];
			output[2] = rev[5];
			output[3] = rev[4];
			output[4] = rev[3];
			output[5] = rev[2];
			output[6] = rev[1];
			output[7] = rev[0];
			return output;
		}

		protected static byte[] setULong(UInt64 value)
		{
			byte[] rev = BitConverter.GetBytes(value);
			byte[] output = new byte[8];
			output[0] = rev[7];
			output[1] = rev[6];
			output[2] = rev[5];
			output[3] = rev[4];
			output[4] = rev[3];
			output[5] = rev[2];
			output[6] = rev[1];
			output[7] = rev[0];
			return output;
		}

		protected static byte[] setDouble(double value)
		{
			byte[] rev = BitConverter.GetBytes(value);
			byte[] output = new byte[8];
			output[0] = rev[7];
			output[1] = rev[6];
			output[2] = rev[5];
			output[3] = rev[4];
			output[4] = rev[3];
			output[5] = rev[2];
			output[6] = rev[1];
			output[7] = rev[0];
			return output;
		}

		protected static byte[] setChar(char value)
		{
			byte[] output = new byte[4];
			output[0] = 0;
			output[1] = 0;
			output[2] = 0;
			output[3] = (byte)value;
			return output;
		}

		protected static byte[] setRGBA(RGBA value)
		{
			byte[] output = new byte[4];
			output[0] = value.R;
			output[1] = value.G;
			output[2] = value.B;
			output[3] = value.A;
			return output;
		}

		protected static byte[] setMidi(Midi value)
		{
			byte[] output = new byte[4];
			output[0] = value.Port;
			output[1] = value.Status;
			output[2] = value.Data1;
			output[3] = value.Data2;
			return output;
		}

		#endregion
	}
}