/*
TShock, a server mod for Terraria
Copyright (C) 2011 The TShock Team

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Security.Cryptography;
using System.Text;
using Terraria;

namespace TShockAPI
{
	public class Utils
	{
		private readonly static int firstItemPrefix = 1;
		private readonly static int lastItemPrefix = 83;
		// Utils is a Singleton
		private static readonly Utils instance = new Utils();
		private Utils() {}
		public static Utils Instance { get { return instance; } }

		public Random Random = new Random();
		//private static List<Group> groups = new List<Group>();

		/// <summary>
		/// Provides the real IP address from a RemoteEndPoint string that contains a port and an IP
		/// </summary>
		/// <param name="mess">A string IPv4 address in IP:PORT form.</param>
		/// <returns>A string IPv4 address.</returns>
		public string GetRealIP(string mess)
		{
			return mess.Split(':')[0];
		}

		/// <summary>
		/// Used for some places where a list of players might be used.
		/// </summary>
		/// <returns>String of players seperated by commas.</returns>
		public string GetPlayers()
		{
			var sb = new StringBuilder();
			foreach (TSPlayer player in TShock.Players)
			{
				if (player != null && player.Active)
				{
					if (sb.Length != 0)
					{
						sb.Append(", ");
					}
					sb.Append(player.Name);
				}
			}
			return sb.ToString();
		}

        /// <summary>
        /// Used for some places where a list of players might be used.
        /// </summary>
        /// <returns>String of players and their id seperated by commas.</returns>
        public string GetPlayersWithIds()
        {
            var sb = new StringBuilder();
            foreach (TSPlayer player in TShock.Players)
            {
                if (player != null && player.Active)
                {
                    if (sb.Length != 0)
                    {
                        sb.Append(", ");
                    }
                    sb.Append(player.Name);
                    string id = "( " + Convert.ToString(TShock.Users.GetUserID(player.UserAccountName)) + " )";
                    sb.Append(id);
                }
            }
            return sb.ToString();
        }

		/// <summary>
		/// Finds a player and gets IP as string
		/// </summary>
		/// <param name="msg">Player name</param>
		public string GetPlayerIP(string playername)
		{
			foreach (TSPlayer player in TShock.Players)
			{
				if (player != null && player.Active)
				{
					if (playername.ToLower() == player.Name.ToLower())
					{
						return player.IP;
					}
				}
			}
			return null;
		}

		/// <summary>
		/// It's a clamp function
		/// </summary>
		/// <typeparam name="T"></typeparam>
		/// <param name="value">Value to clamp</param>
		/// <param name="max">Maximum bounds of the clamp</param>
		/// <param name="min">Minimum bounds of the clamp</param>
		/// <returns></returns>
		public T Clamp<T>(T value, T max, T min)
			where T : IComparable<T>
		{
			T result = value;
			if (value.CompareTo(max) > 0)
				result = max;
			if (value.CompareTo(min) < 0)
				result = min;
			return result;
		}

		/// <summary>
		/// Saves the map data
		/// </summary>
		public void SaveWorld()
		{
			SaveManager.Instance.SaveWorld();
		}

		/// <summary>
		/// Broadcasts a message to all players
		/// </summary>
		/// <param name="msg">string message</param>
		public void Broadcast(string msg)
		{
			Broadcast(msg, Color.Green);
		}

		public void Broadcast(string msg, byte red, byte green, byte blue)
		{
			TSPlayer.All.SendMessage(msg, red, green, blue);
			TSPlayer.Server.SendMessage(msg, red, green, blue);
			Log.Info(string.Format("Broadcast: {0}", msg));
		}

		public void Broadcast(string msg, Color color)
		{
			Broadcast(msg, color.R, color.G, color.B);
		}

		/// <summary>
		/// Sends message to all users with 'logs' permission.
		/// </summary>
		/// <param name="log">Message to send</param>
		/// <param name="color">Color of the message</param>
		public void SendLogs(string log, Color color)
		{
			Log.Info(log);
			TSPlayer.Server.SendMessage(log, color);
			foreach (TSPlayer player in TShock.Players)
			{
				if (player != null && player.Active && player.Group.HasPermission(Permissions.logs) && player.DisplayLogs &&
				    TShock.Config.DisableSpewLogs == false)
					player.SendMessage(log, color);
			}
		}

		/// <summary>
		/// The number of active players on the server.
		/// </summary>
		/// <returns>int playerCount</returns>
		public int ActivePlayers()
		{
			return Main.player.Where(p => null != p && p.active).Count();
		}

		/// <summary>
		/// Finds a player ID based on name
		/// </summary>
		/// <param name="ply">Player name</param>
		/// <returns></returns>
		public List<TSPlayer> FindPlayer(string ply)
		{
			var found = new List<TSPlayer>();
			// Avoid errors caused by null search
			if (null == ply)
				return found;
			ply = ply.ToLower();
			foreach (TSPlayer player in TShock.Players)
			{
				if (player == null)
					continue;

				string name = player.Name.ToLower();
				if (name.Equals(ply))
					return new List<TSPlayer> {player};
				if (name.Contains(ply))
					found.Add(player);
			}
			return found;
		}

		/// <summary>
		/// Gets a random clear tile in range
		/// </summary>
		/// <param name="startTileX">Bound X</param>
		/// <param name="startTileY">Bound Y</param>
		/// <param name="tileXRange">Range on the X axis</param>
		/// <param name="tileYRange">Range on the Y axis</param>
		/// <param name="tileX">X location</param>
		/// <param name="tileY">Y location</param>
		public void GetRandomClearTileWithInRange(int startTileX, int startTileY, int tileXRange, int tileYRange,
		                                          out int tileX, out int tileY)
		{
			int j = 0;
			do
			{
				if (j == 100)
				{
					tileX = startTileX;
					tileY = startTileY;
					break;
				}

				tileX = startTileX + Random.Next(tileXRange*-1, tileXRange);
				tileY = startTileY + Random.Next(tileYRange*-1, tileYRange);
				j++;
			} while (TileValid(tileX, tileY) && !TileClear(tileX, tileY));
		}

		/// <summary>
		/// Determines if a tile is valid
		/// </summary>
		/// <param name="tileX">Location X</param>
		/// <param name="tileY">Location Y</param>
		/// <returns>If the tile is valid</returns>
		private bool TileValid(int tileX, int tileY)
		{
			return tileX >= 0 && tileX <= Main.maxTilesX && tileY >= 0 && tileY <= Main.maxTilesY;
		}

		/// <summary>
		/// Clears a tile
		/// </summary>
		/// <param name="tileX">Location X</param>
		/// <param name="tileY">Location Y</param>
		/// <returns>The state of the tile</returns>
		private bool TileClear(int tileX, int tileY)
		{
			return !Main.tile[tileX, tileY].active;
		}

		/// <summary>
		/// Gets a list of items by ID or name
		/// </summary>
		/// <param name="idOrName">Item ID or name</param>
		/// <returns>List of Items</returns>
		public List<Item> GetItemByIdOrName(string idOrName)
		{
			int type = -1;
			if (int.TryParse(idOrName, out type))
			{
				return new List<Item> {GetItemById(type)};
			}
			return GetItemByName(idOrName);
		}

		/// <summary>
		/// Gets an item by ID
		/// </summary>
		/// <param name="id">ID</param>
		/// <returns>Item</returns>
		public Item GetItemById(int id)
		{
			Item item = new Item();
			item.netDefaults(id);
			return item;
		}

		/// <summary>
		/// Gets items by name
		/// </summary>
		/// <param name="name">name</param>
		/// <returns>List of Items</returns>
		public List<Item> GetItemByName(string name)
		{
			//Method #1 - must be exact match, allows support for different pickaxes/hammers/swords etc
			for (int i = 1; i < Main.maxItemTypes; i++)
			{
				Item item = new Item();
				item.SetDefaults(name);
				if (item.name == name)
					return new List<Item> {item};
			}
			//Method #2 - allows impartial matching
			var found = new List<Item>();
			for (int i = -24; i < Main.maxItemTypes; i++)
			{
				try
				{
					Item item = new Item();
					item.netDefaults(i);
					if (item.name.ToLower() == name.ToLower())
						return new List<Item> {item};
					if (item.name.ToLower().StartsWith(name.ToLower()))
						found.Add(item);
				}
				catch
				{
				}
			}
			return found;
		}

		/// <summary>
		/// Gets an NPC by ID or Name
		/// </summary>
		/// <param name="idOrName"></param>
		/// <returns>List of NPCs</returns>
		public List<NPC> GetNPCByIdOrName(string idOrName)
		{
			int type = -1;
			if (int.TryParse(idOrName, out type))
			{
				return new List<NPC> {GetNPCById(type)};
			}
			return GetNPCByName(idOrName);
		}

		/// <summary>
		/// Gets an NPC by ID
		/// </summary>
		/// <param name="id">ID</param>
		/// <returns>NPC</returns>
		public NPC GetNPCById(int id)
		{
			NPC npc = new NPC();
			npc.netDefaults(id);
			return npc;
		}

		/// <summary>
		/// Gets a NPC by name
		/// </summary>
		/// <param name="name">Name</param>
		/// <returns>List of matching NPCs</returns>
		public List<NPC> GetNPCByName(string name)
		{
			//Method #1 - must be exact match, allows support for different coloured slimes
			for (int i = -17; i < Main.maxNPCTypes; i++)
			{
				NPC npc = new NPC();
				npc.SetDefaults(name);
				if (npc.name == name)
					return new List<NPC> {npc};
			}
			//Method #2 - allows impartial matching
			var found = new List<NPC>();
			for (int i = 1; i < Main.maxNPCTypes; i++)
			{
				NPC npc = new NPC();
				npc.netDefaults(i);
				if (npc.name.ToLower() == name.ToLower())
					return new List<NPC> {npc};
				if (npc.name.ToLower().StartsWith(name.ToLower()))
					found.Add(npc);
			}
			return found;
		}

		/// <summary>
		/// Gets a buff name by id
		/// </summary>
		/// <param name="id">ID</param>
		/// <returns>name</returns>
		public string GetBuffName(int id)
		{
			return (id > 0 && id < Main.maxBuffs) ? Main.buffName[id] : "null";
		}

		/// <summary>
		/// Gets the description of a buff
		/// </summary>
		/// <param name="id">ID</param>
		/// <returns>description</returns>
		public string GetBuffDescription(int id)
		{
			return (id > 0 && id < Main.maxBuffs) ? Main.buffTip[id] : "null";
		}

		/// <summary>
		/// Gets a list of buffs by name
		/// </summary>
		/// <param name="name">name</param>
		/// <returns>Matching list of buff ids</returns>
		public List<int> GetBuffByName(string name)
		{
			for (int i = 1; i < Main.maxBuffs; i++)
			{
				if (Main.buffName[i].ToLower() == name)
					return new List<int> {i};
			}
			var found = new List<int>();
			for (int i = 1; i < Main.maxBuffs; i++)
			{
				if (Main.buffName[i].ToLower().StartsWith(name.ToLower()))
					found.Add(i);
			}
			return found;
		}

		/// <summary>
		/// Gets a prefix based on its id
		/// </summary>
		/// <param name="id">ID</param>
		/// <returns>Prefix name</returns>
		public string GetPrefixById(int id)
		{
			var item = new Item();
			item.SetDefaults(0);
			item.prefix = (byte) id;
			item.AffixName();
			return item.name.Trim();
		}

		/// <summary>
		/// Gets a list of prefixes by name
		/// </summary>
		/// <param name="name">Name</param>
		/// <returns>List of prefix IDs</returns>
		public List<int> GetPrefixByName(string name)
		{
			Item item = new Item();
			item.SetDefaults(0);
			string lowerName = name.ToLower();
			var found = new List<int>();
			for (int i = firstItemPrefix; i <= lastItemPrefix; i++)
			{
				try
				{
					item.prefix = (byte)i;
					string trimmed = item.AffixName().Trim();
					if (trimmed == name)
					{
						// Exact match
						found.Add(i);
						return found;
					}
					else
					{
						string trimmedLower = trimmed.ToLower();
						if (trimmedLower == lowerName)
						{
							// Exact match (caseinsensitive)
							found.Add(i);
							return found;
						}
						else if (trimmedLower.StartsWith(lowerName)) // Partial match
							found.Add(i);
					}
				}
				catch
				{
				}
			}
			return found;
		}

		/// <summary>
		/// Gets a prefix by ID or name
		/// </summary>
		/// <param name="idOrName">ID or name</param>
		/// <returns>List of prefix IDs</returns>
		public List<int> GetPrefixByIdOrName(string idOrName)
		{
			int type = -1;
			if (int.TryParse(idOrName, out type) && type >= firstItemPrefix && type <= lastItemPrefix)
			{
				return new List<int> {type};
			}
			return GetPrefixByName(idOrName);
		}

		/// <summary>
		/// Kicks all player from the server without checking for immunetokick permission.
		/// </summary>
		/// <param name="ply">int player</param>
		/// <param name="reason">string reason</param>
		public void ForceKickAll(string reason)
		{
			foreach (TSPlayer player in TShock.Players)
			{
				if (player != null && player.Active)
				{
					ForceKick(player, reason);
				}
			}
		}

		/// <summary>
		/// Stops the server after kicking all players with a reason message, and optionally saving the world
		/// </summary>
		/// <param name="save">bool perform a world save before stop (default: true)</param>
		/// <param name="reason">string reason (default: "Server shutting down!")</param>
		public void StopServer(bool save = true, string reason = "Server shutting down!")
		{
			ForceKickAll(reason);
			if (save)
				SaveManager.Instance.SaveWorld();

			// Save takes a while so kick again
			ForceKickAll(reason);

			// Broadcast so console can see we are shutting down as well
			TShock.Utils.Broadcast(reason, Color.Red);

			// Disconnect after kick as that signifies server is exiting and could cause a race
			Netplay.disconnect = true;
		}

#if COMPAT_SIGS
		[Obsolete("This method is for signature compatibility for external code only")]
		public bool ForceKick(TSPlayer player, string reason)
		{
			return Kick(player, reason, true, false, string.Empty);
		}
#endif
		/// <summary>
		/// Kicks a player from the server without checking for immunetokick permission.
		/// </summary>
		/// <param name="ply">int player</param>
		/// <param name="reason">string reason</param>
		/// <param name="silent">bool silent (default: false)</param>
		public void ForceKick(TSPlayer player, string reason, bool silent = false)
		{
			Kick(player, reason, true, silent);
		}

#if COMPAT_SIGS
		[Obsolete("This method is for signature compatibility for external code only")]
		public bool Kick(TSPlayer player, string reason, string adminUserName)
		{
			return Kick(player, reason, false, false, adminUserName);
		}
#endif
		/// <summary>
		/// Kicks a player from the server.
		/// </summary>
		/// <param name="ply">int player</param>
		/// <param name="reason">string reason</param>
		/// <param name="force">bool force (default: false)</param>
		/// <param name="silent">bool silent (default: false)</param>
		/// <param name="adminUserName">bool silent (default: null)</param>
		public bool Kick(TSPlayer player, string reason, bool force = false, bool silent = false, string adminUserName = null)
		{
			if (!player.ConnectionAlive)
				return true;
			if (force || !player.Group.HasPermission(Permissions.immunetokick))
			{
				string playerName = player.Name;
				player.SilentKickInProgress = silent;
				player.Disconnect(string.Format("Kicked: {0}", reason));
				Log.ConsoleInfo(string.Format("Kicked {0} for : {1}", playerName, reason));
				string verb = force ? "force " : "";
				if (string.IsNullOrWhiteSpace(adminUserName))
					Broadcast(string.Format("{0} was {1}kicked for {2}", playerName, verb, reason.ToLower()));
				else
					Broadcast(string.Format("{0} {1}kicked {2} for {3}", adminUserName, verb, playerName, reason.ToLower()));
				return true;
			}
			return false;
		}

#if COMPAT_SIGS
		[Obsolete("This method is for signature compatibility for external code only")]
		public bool Ban(TSPlayer player, string reason, string adminUserName)
		{
			return Ban(player, reason, false, adminUserName);
		}
#endif
		/// <summary>
		/// Bans and kicks a player from the server.
		/// </summary>
		/// <param name="ply">int player</param>
		/// <param name="reason">string reason</param>
		/// <param name="force">bool force (default: false)</param>
		/// <param name="adminUserName">bool silent (default: null)</param>
		public bool Ban(TSPlayer player, string reason, bool force = false, string adminUserName = null)
		{
			if (!player.ConnectionAlive)
				return true;
			if (force || !player.Group.HasPermission(Permissions.immunetoban))
			{
				string ip = player.IP;
				string playerName = player.Name;
				TShock.Bans.AddBan(ip, playerName, reason);
				player.Disconnect(string.Format("Banned: {0}", reason));
				Log.ConsoleInfo(string.Format("Banned {0} for : {1}", playerName, reason));
				string verb = force ? "force " : "";
				if (string.IsNullOrWhiteSpace(adminUserName))
					Broadcast(string.Format("{0} was {1}banned for {1}", playerName, verb, reason.ToLower()));
				else
					Broadcast(string.Format("{0} {1}banned {1} for {2}", adminUserName, verb, playerName, reason.ToLower()));
				return true;
			}
			return false;
		}

		/// <summary>
		/// Shows a file to the user.
		/// </summary>
		/// <param name="ply">int player</param>
		/// <param name="file">string filename reletave to savedir</param>
		//Todo: Fix this
		public void ShowFileToUser(TSPlayer player, string file)
		{
			string foo = "";
			using (var tr = new StreamReader(Path.Combine(TShock.SavePath, file)))
			{
				while ((foo = tr.ReadLine()) != null)
				{
					foo = foo.Replace("%map%", Main.worldName);
					foo = foo.Replace("%players%", GetPlayers());
					//foo = SanitizeString(foo);
					if (foo.Substring(0, 1) == "%" && foo.Substring(12, 1) == "%") //Look for a beginning color code.
					{
						string possibleColor = foo.Substring(0, 13);
						foo = foo.Remove(0, 13);
						float[] pC = {0, 0, 0};
						possibleColor = possibleColor.Replace("%", "");
						string[] pCc = possibleColor.Split(',');
						if (pCc.Length == 3)
						{
							try
							{
								player.SendMessage(foo, (byte) Convert.ToInt32(pCc[0]), (byte) Convert.ToInt32(pCc[1]),
								                   (byte) Convert.ToInt32(pCc[2]));
								continue;
							}
							catch (Exception e)
							{
								Log.Error(e.ToString());
							}
						}
					}
					player.SendMessage(foo);
				}
			}
		}

		/// <summary>
		/// Returns a Group from the name of the group
		/// </summary>
		/// <param name="ply">string groupName</param>
		public Group GetGroup(string groupName)
		{
			//first attempt on cached groups
			for (int i = 0; i < TShock.Groups.groups.Count; i++)
			{
				if (TShock.Groups.groups[i].Name.Equals(groupName))
				{
					return TShock.Groups.groups[i];
				}
			}
			return new Group(TShock.Config.DefaultGuestGroupName);
		}

		/// <summary>
		/// Returns an IPv4 address from a DNS query
		/// </summary>
		/// <param name="hostname">string ip</param>
		public string GetIPv4Address(string hostname)
		{
			try
			{
				//Get the ipv4 address from GetHostAddresses, if an ip is passed it will return that ip
				var ip = Dns.GetHostAddresses(hostname).FirstOrDefault(i => i.AddressFamily == AddressFamily.InterNetwork);
				//if the dns query was successful then return it, otherwise return an empty string
				return ip != null ? ip.ToString() : "";
			}
			catch (SocketException)
			{
			}
			return "";
		}

        public string HashAlgo = "sha512";

		public readonly Dictionary<string, Func<HashAlgorithm>> HashTypes = new Dictionary<string, Func<HashAlgorithm>>
		                                                                    	{
		                                                                    		{"sha512", () => new SHA512Managed()},
		                                                                    		{"sha256", () => new SHA256Managed()},
		                                                                    		{"md5", () => new MD5Cng()},
		                                                                    		{"sha512-xp", () => SHA512.Create()},
		                                                                    		{"sha256-xp", () => SHA256.Create()},
		                                                                    		{"md5-xp", () => MD5.Create()},
		                                                                    	};

		/// <summary>
		/// Returns a Sha256 string for a given string
		/// </summary>
		/// <param name="bytes">bytes to hash</param>
		/// <returns>string sha256</returns>
		public string HashPassword(byte[] bytes)
		{
			if (bytes == null)
				throw new NullReferenceException("bytes");
			Func<HashAlgorithm> func;
			if (!HashTypes.TryGetValue(HashAlgo.ToLower(), out func))
				throw new NotSupportedException("Hashing algorithm {0} is not supported".SFormat(HashAlgo.ToLower()));

			using (var hash = func())
			{
				var ret = hash.ComputeHash(bytes);
				return ret.Aggregate("", (s, b) => s + b.ToString("X2"));
			}
		}

		/// <summary>
		/// Returns a Sha256 string for a given string
		/// </summary>
		/// <param name="bytes">bytes to hash</param>
		/// <returns>string sha256</returns>
		public string HashPassword(string password)
		{
			if (string.IsNullOrEmpty(password) || password == "non-existant password")
				return "non-existant password";
			return HashPassword(Encoding.UTF8.GetBytes(password));
		}

		/// <summary>
		/// Checks if the string contains any unprintable characters
		/// </summary>
		/// <param name="str">String to check</param>
		/// <returns>True if the string only contains printable characters</returns>
		public bool ValidString(string str)
		{
			foreach (var c in str)
			{
				if (c < 0x20 || c > 0xA9)
					return false;
			}
			return true;
		}

		/// <summary>
		/// Checks if world has hit the max number of chests
		/// </summary>
		/// <returns>True if the entire chest array is used</returns>
		public bool MaxChests()
		{
			for (int i = 0; i < Main.chest.Length; i++)
			{
				if (Main.chest[i] == null)
					return false;
			}
			return true;
		}

		/// <summary>
		/// Searches for a projectile by identity and owner
		/// </summary>
		/// <param name="identity">identity</param>
		/// <param name="owner">owner</param>
		/// <returns>projectile ID</returns>
		public int SearchProjectile(short identity, int owner)
		{
			for (int i = 0; i < Main.maxProjectiles; i++)
			{
				if (Main.projectile[i].identity == identity && Main.projectile[i].owner == owner)
					return i;
			}
			return 1000;
		}

		/// <summary>
		/// Sanitizes input strings
		/// </summary>
		/// <param name="str">string</param>
		/// <returns>sanitized string</returns>
		public string SanitizeString(string str)
		{
			var returnstr = str.ToCharArray();
			for (int i = 0; i < str.Length; i++)
			{
				if (!ValidString(str[i].ToString()))
					returnstr[i] = ' ';
			}
			return new string(returnstr);
		}
	}
}