/*
 *  Managed C# wrapper for an extended version of ENet
 *  Copyright (c) 2013 James Bellinger
 *  Copyright (c) 2016 Nate Shoffner
 *  Copyright (c) 2018 Stanislav Denisov
 *
 *  Permission is hereby granted, free of charge, to any person obtaining a copy
 *  of this software and associated documentation files (the "Software"), to deal
 *  in the Software without restriction, including without limitation the rights
 *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *  copies of the Software, and to permit persons to whom the Software is
 *  furnished to do so, subject to the following conditions:
 *
 *  The above copyright notice and this permission notice shall be included in all
 *  copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 *  SOFTWARE.
 */

using System;
using System.Runtime.InteropServices;
using System.Security;
using System.Text;

namespace ENet {
	[Flags]
	public enum PacketFlags {
		None = 0,
		Reliable = 1 << 0,
		Unsequenced = 1 << 1,
		NoAllocate = 1 << 2,
		UnreliableFragment = 1 << 3
	}

	public enum EventType {
		None = 0,
		Connect = 1,
		Disconnect = 2,
		Receive = 3,
		Timeout = 4
	}

	public enum PeerState {
		Uninitialized = -1,
		Disconnected = 0,
		Connecting = 1,
		AcknowledgingConnect = 2,
		ConnectionPending = 3,
		ConnectionSucceeded = 4,
		Connected = 5,
		DisconnectLater = 6,
		Disconnecting = 7,
		AcknowledgingDisconnect = 8,
		Zombie = 9
	}

	[StructLayout(LayoutKind.Sequential)]
	public struct ENetAddress {
		[MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)]
		public byte[] host;
		public ushort port;
	}

	[StructLayout(LayoutKind.Sequential)]
	public struct ENetEvent {
		public EventType type;
		public IntPtr peer;
		public byte channelID;
		public uint data;
		public IntPtr packet;
	}

	[StructLayout(LayoutKind.Sequential)]
	public struct ENetCallbacks {
		[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
		public delegate IntPtr malloc_cb(IntPtr size);
		[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
		public delegate void free_cb(IntPtr memory);
		[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
		public delegate void no_memory_cb();
		public IntPtr malloc, free, no_memory;
	}

	public struct Address {
		private ENetAddress nativeAddress;

		internal ENetAddress NativeData {
			get {
				return nativeAddress;
			}

			set {
				nativeAddress = value;
			}
		}

		public ushort Port {
			get {
				return nativeAddress.port;
			}

			set {
				nativeAddress.port = value;
			}
		}

		public bool SetHost(string hostName) {
			if (hostName == null)
				throw new ArgumentNullException("hostName");

			return Native.enet_address_set_host(ref nativeAddress, Encoding.ASCII.GetBytes(hostName)) == 0;
		}

		public string GetIP() {
			byte[] data = new byte[256];

			if (Native.enet_address_get_host_ip(ref nativeAddress, data, (IntPtr)256) == 0)
				return Encoding.ASCII.GetString(data);
			else
				return String.Empty;
		}

		public string GetName() {
			byte[] data = new byte[256];

			if (Native.enet_address_get_host(ref nativeAddress, data, (IntPtr)256) == 0)
				return Encoding.ASCII.GetString(data);
			else
				return String.Empty;
		}
	}

	public struct Event {
		private ENetEvent nativeEvent;

		internal ENetEvent NativeData {
			get {
				return nativeEvent;
			}

			set {
				nativeEvent = value;
			}
		}

		public Event(ENetEvent @event) {
			nativeEvent = @event;
		}

		public EventType Type {
			get {
				return nativeEvent.type;
			}
		}

		public Peer Peer {
			get {
				return new Peer(nativeEvent.peer);
			}
		}

		public byte ChannelID {
			get {
				return nativeEvent.channelID;
			}
		}

		public uint Data {
			get {
				return nativeEvent.data;
			}
		}

		public Packet Packet {
			get {
				return new Packet(nativeEvent.packet);
			}
		}
	}

	public struct Packet : IDisposable {
		private IntPtr nativePacket;

		internal IntPtr NativeData {
			get {
				return nativePacket;
			}

			set {
				nativePacket = value;
			}
		}

		public Packet(IntPtr packet) {
			nativePacket = packet;
		}

		public void Dispose() {
			if (nativePacket != IntPtr.Zero) {
				Native.enet_packet_destroy(nativePacket);
				nativePacket = IntPtr.Zero;
			}
		}

		public bool IsSet {
			get {
				return nativePacket != IntPtr.Zero;
			}
		}

		internal IntPtr Data {
			get {
				CheckCreated();

				return Native.enet_packet_get_data(nativePacket);
			}
		}

		public int Length {
			get {
				CheckCreated();

				return Native.enet_packet_get_length(nativePacket);
			}
		}

		internal void CheckCreated() {
			if (nativePacket == IntPtr.Zero)
				throw new InvalidOperationException("Packet not created");
		}

		public void Create(byte[] data) {
			if (data == null)
				throw new ArgumentNullException("data");

			Create(data, data.Length);
		}

		public void Create(byte[] data, int length) {
			Create(data, length, PacketFlags.None);
		}

		public void Create(byte[] data, int length, PacketFlags flags) {
			if (data == null)
				throw new ArgumentNullException("data");

			if (length < 0 || length > data.Length)
				throw new ArgumentOutOfRangeException();

			nativePacket = Native.enet_packet_create(data, (IntPtr)length, flags);
		}

		public void CopyTo(byte[] array) {
			if (array == null)
				throw new ArgumentNullException("array");

			CopyTo(array, 0, array.Length);
		}

		public void CopyTo(byte[] array, int offset, int length) {
			if (array == null)
				throw new ArgumentNullException("array");

			if (offset < 0 || length < 0 || length > array.Length - offset)
				throw new ArgumentOutOfRangeException();

			CheckCreated();

			if (length > Length - offset)
				throw new ArgumentOutOfRangeException();

			if (length > 0)
				Marshal.Copy((IntPtr)((Int64)Data + offset), array, offset, length);	
		}
	}

	public class Host : IDisposable {
		private IntPtr nativeHost;

		internal IntPtr NativeData {
			get {
				return nativeHost;
			}

			set {
				nativeHost = value;
			}
		}

		public void Dispose() {
			Dispose(true);
		}

		protected virtual void Dispose(bool disposing) {
			try {
				if (nativeHost != IntPtr.Zero) {
					Native.enet_host_destroy(nativeHost);
					nativeHost = IntPtr.Zero;
				}
			}

			catch { }
		}

		~Host() {
			Dispose(false);
		}

		public bool IsSet {
			get {
				return nativeHost != IntPtr.Zero;
			}
		}

		public uint TransportPacketsSent {
			get {
				return Native.enet_host_get_packets_sent(nativeHost);
			}
		}

		public uint TransportPacketsReceived {
			get {
				return Native.enet_host_get_packets_received(nativeHost);
			}
		}

		public uint TransportBytesSent {
			get {
				return Native.enet_host_get_bytes_sent(nativeHost);
			}
		}

		public uint TransportBytesReceived {
			get {
				return Native.enet_host_get_bytes_received(nativeHost);
			}
		}

		internal void CheckCreated() {
			if (nativeHost == IntPtr.Zero)
				throw new InvalidOperationException("Host not created");
		}

		private void CheckChannelLimit(int channelLimit) {
			if (channelLimit < 0 || channelLimit > Library.maxChannelCount)
				throw new ArgumentOutOfRangeException("channelLimit");
		}

		public void Create(Address? address, int peerLimit) {
			Create(address, peerLimit, 0);
		}

		public void Create(Address? address, int peerLimit, int channelLimit) {
			Create(address, peerLimit, channelLimit, 0, 0);
		}

		public void Create(int peerLimit, int channelLimit, uint incomingBandwidth, uint outgoingBandwidth) {
			Create(null, peerLimit, channelLimit, incomingBandwidth, outgoingBandwidth);
		}

		public void Create(Address? address, int peerLimit, int channelLimit, uint incomingBandwidth, uint outgoingBandwidth) {
			if (nativeHost != IntPtr.Zero)
				throw new InvalidOperationException("Host already created");

			if (peerLimit < 0 || peerLimit > Library.maxPeers)
				throw new ArgumentOutOfRangeException("peerLimit");

			CheckChannelLimit(channelLimit);

			if (address != null) {
				var nativeAddress = address.Value.NativeData;

				nativeHost = Native.enet_host_create(ref nativeAddress, (IntPtr)peerLimit, (IntPtr)channelLimit, incomingBandwidth, outgoingBandwidth);
			} else {
				nativeHost = Native.enet_host_create(IntPtr.Zero, (IntPtr)peerLimit, (IntPtr)channelLimit, incomingBandwidth, outgoingBandwidth);
			}

			if (nativeHost == IntPtr.Zero)
				throw new ENetException(0, "Host creation call failed");
		}

		public void Broadcast(byte channelID, ref Packet packet) {
			CheckCreated();

			packet.CheckCreated();
			Native.enet_host_broadcast(nativeHost, channelID, packet.NativeData);
			packet.NativeData = IntPtr.Zero;
		}

		public int CheckEvents(out Event @event) {
			CheckCreated();

			ENetEvent nativeEvent;

			var result = Native.enet_host_check_events(nativeHost, out nativeEvent);

			if (result <= 0) {
				@event = new Event();

				return result;
			}

			@event = new Event(nativeEvent);

			return result;
		}

		public Peer Connect(Address address, int channelLimit, uint data) {
			CheckCreated();
			CheckChannelLimit(channelLimit);

			var nativeAddress = address.NativeData;
			var peer = new Peer(Native.enet_host_connect(nativeHost, ref nativeAddress, (IntPtr)channelLimit, data));

			if (peer.NativeData == IntPtr.Zero)
				throw new ENetException(0, "Host connect call failed");

			return peer;
		}

		public int Service(int timeout) {
			if (timeout < 0)
				throw new ArgumentOutOfRangeException("timeout");

			CheckCreated();

			return Native.enet_host_service(nativeHost, IntPtr.Zero, (uint)timeout);
		}

		public int Service(int timeout, out Event @event) {
			if (timeout < 0)
				throw new ArgumentOutOfRangeException("timeout");

			CheckCreated();

			ENetEvent nativeEvent;

			var result = Native.enet_host_service(nativeHost, out nativeEvent, (uint)timeout);

			if (result <= 0) {
				@event = new Event();

				return result;
			}

			@event = new Event(nativeEvent);

			return result;
		}

		public void SetBandwidthLimit(uint incomingBandwidth, uint outgoingBandwidth) {
			CheckCreated();

			Native.enet_host_bandwidth_limit(nativeHost, incomingBandwidth, outgoingBandwidth);
		}

		public void SetChannelLimit(int channelLimit) {
			CheckCreated();
			CheckChannelLimit(channelLimit);

			Native.enet_host_channel_limit(nativeHost, (IntPtr)channelLimit);
		}

		public void Flush() {
			CheckCreated();

			Native.enet_host_flush(nativeHost);
		}
	}

	public struct Peer {
		private IntPtr nativePeer;

		internal IntPtr NativeData {
			get {
				return nativePeer;
			}

			set {
				nativePeer = value;
			}
		}

		public Peer(IntPtr peer) {
			nativePeer = peer;
		}

		public bool IsSet {
			get {
				return nativePeer != IntPtr.Zero;
			}
		}

		public uint ID {
			get {
				return Native.enet_peer_get_id(nativePeer);
			}
		}

		public Address Address {
			get {
				return Native.enet_peer_get_address(nativePeer);
			}
		}

		public PeerState State {
			get {
				return nativePeer == IntPtr.Zero ? PeerState.Uninitialized : Native.enet_peer_get_state(nativePeer);
			}
		}

		public uint RoundTripTime {
			get {
				return Native.enet_peer_get_rtt(nativePeer);
			}
		}

		public ulong TransportPacketsSent {
			get {
				return Native.enet_peer_get_packets_sent(nativePeer);
			}
		}

		public uint TransportPacketsLost {
			get {
				return Native.enet_peer_get_packets_lost(nativePeer);
			}
		}

		public ulong TransportBytesSent {
			get {
				return Native.enet_peer_get_bytes_sent(nativePeer);
			}
		}

		public ulong TransportBytesReceived {
			get {
				return Native.enet_peer_get_bytes_received(nativePeer);
			}
		}

		internal IntPtr Data {
			get {
				return Native.enet_peer_get_data(nativePeer);
			}

			set {
				Native.enet_peer_set_data(nativePeer, value);
			}
		}

		internal void CheckCreated() {
			if (nativePeer == IntPtr.Zero)
				throw new InvalidOperationException("Peer not created");
		}

		public void ConfigureThrottle(uint interval, uint acceleration, uint deceleration) {
			CheckCreated();

			Native.enet_peer_throttle_configure(nativePeer, interval, acceleration, deceleration);
		}

		public bool Send(byte channelID, byte[] data) {
			if (data == null)
				throw new ArgumentNullException("data");

			return Send(channelID, data, data.Length);
		}

		public bool Send(byte channelID, byte[] data, int length) {
			if (data == null)
				throw new ArgumentNullException("data");

			bool result;

			using (var packet = new Packet()) {
				packet.Create(data, length);
				result = Send(channelID, packet);
			}

			return result;
		}

		public bool Send(byte channelID, Packet packet) {
			return Native.enet_peer_send(nativePeer, channelID, packet.NativeData) >= 0;
		}

		public void Ping() {
			CheckCreated();

			Native.enet_peer_ping(nativePeer);
		}

		public void PingInterval(uint interval) {
			CheckCreated();

			Native.enet_peer_ping_interval(nativePeer, interval);
		}

		public void Disconnect(uint data) {
			CheckCreated();

			Native.enet_peer_disconnect(nativePeer, data);
		}

		public void DisconnectNow(uint data) {
			CheckCreated();

			Native.enet_peer_disconnect_now(nativePeer, data);
		}

		public void DisconnectLater(uint data) {
			CheckCreated();

			Native.enet_peer_disconnect_later(nativePeer, data);
		}

		public void Reset() {
			CheckCreated();

			Native.enet_peer_reset(nativePeer);
		}
	}

	public class ENetException : Exception {
		public ENetException(int code, string message) : base(message) {
			Code = code;
		}

		public int Code {
			get; private set;
		}
	}

	public static class Library {
		public const int maxChannelCount = 0xFF;
		public const int maxPeers = 0xFFF;
		public const uint version = (2 << 16) | (0 << 8) | (3);

		public static int Initialize() {
			return Native.enet_initialize();
		}

		public static void Deinitialize() {
			Native.enet_deinitialize();
		}

		public static uint Time {
			get {
				return Native.enet_time_get();
			}
		}
	}

	[SuppressUnmanagedCodeSecurity]
	internal static class Native {
		private const string nativeLibrary = "enet";

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern int enet_initialize();

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_deinitialize();

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern uint enet_time_get();

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern int enet_initialize_with_callbacks(uint version, ref ENetCallbacks inits);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern int enet_address_get_host(ref ENetAddress address, byte[] hostName, IntPtr nameLength);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern int enet_address_set_host(ref ENetAddress address, byte[] hostName);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern int enet_address_get_host_ip(ref ENetAddress address, byte[] hostIP, IntPtr ipLength);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern IntPtr enet_packet_create(byte[] data, IntPtr dataLength, PacketFlags flags);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern IntPtr enet_packet_get_data(IntPtr packet);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern int enet_packet_get_length(IntPtr packet);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_packet_destroy(IntPtr packet);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern IntPtr enet_host_create(IntPtr address, IntPtr peerLimit, IntPtr channelLimit, uint incomingBandwidth, uint outgoingBandwidth);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern IntPtr enet_host_create(ref ENetAddress address, IntPtr peerLimit, IntPtr channelLimit, uint incomingBandwidth, uint outgoingBandwidth);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern IntPtr enet_host_connect(IntPtr host, ref ENetAddress address, IntPtr channelCount, uint data);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_host_broadcast(IntPtr host, byte channelID, IntPtr packet);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern int enet_host_service(IntPtr host, IntPtr @event, uint timeout);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern int enet_host_service(IntPtr host, out ENetEvent @event, uint timeout);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern int enet_host_check_events(IntPtr host, out ENetEvent @event);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_host_channel_limit(IntPtr host, IntPtr channelLimit);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_host_bandwidth_limit(IntPtr host, uint incomingBandwidth, uint outgoingBandwidth);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern uint enet_host_get_packets_sent(IntPtr host);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern uint enet_host_get_packets_received(IntPtr host);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern uint enet_host_get_bytes_sent(IntPtr host);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern uint enet_host_get_bytes_received(IntPtr host);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_host_flush(IntPtr host);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_host_destroy(IntPtr host);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_peer_throttle_configure(IntPtr peer, uint interval, uint acceleration, uint deceleration);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern uint enet_peer_get_id(IntPtr peer);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern Address enet_peer_get_address(IntPtr peer);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern PeerState enet_peer_get_state(IntPtr peer);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern uint enet_peer_get_rtt(IntPtr peer);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern ulong enet_peer_get_packets_sent(IntPtr peer);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern uint enet_peer_get_packets_lost(IntPtr peer);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern ulong enet_peer_get_bytes_sent(IntPtr peer);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern ulong enet_peer_get_bytes_received(IntPtr peer);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern IntPtr enet_peer_get_data(IntPtr peer);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_peer_set_data(IntPtr peer, IntPtr data);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern int enet_peer_send(IntPtr peer, byte channelID, IntPtr packet);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_peer_ping(IntPtr peer);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_peer_ping_interval(IntPtr peer, uint pingInterval);
	
		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_peer_disconnect(IntPtr peer, uint data);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_peer_disconnect_now(IntPtr peer, uint data);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_peer_disconnect_later(IntPtr peer, uint data);

		[DllImport(nativeLibrary, CallingConvention = CallingConvention.Cdecl)]
		internal static extern void enet_peer_reset(IntPtr peer);
	}
}