/*
TShock, a server mod for Terraria
Copyright (C) 2011-2012 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.Linq;
using System.Net;
using HttpServer;

namespace Rests
{
	/// <summary>
	/// 
	/// </summary>
	/// <param name="username">Username to verify</param>
	/// <param name="password">Password to verify</param>
	/// <returns>Returning a restobject with a null error means a successful verification.</returns>
	public delegate RestObject VerifyD(string username, string password);

	public class SecureRest : Rest
	{
		public Dictionary<string, object> Tokens { get; protected set; }
		public event VerifyD Verify;

		public SecureRest(IPAddress ip, int port)
			: base(ip, port)
		{
			Tokens = new Dictionary<string, object>();
			Register(new RestCommand("/token/create/{username}/{password}", NewToken) {RequiresToken = false});
			Register(new RestCommand("/v2/token/create/{password}", NewTokenV2) { RequiresToken = false });
			Register(new RestCommand("/token/destroy/{token}", DestroyToken) {RequiresToken = true});
			foreach (KeyValuePair<string, string> t in TShockAPI.TShock.RESTStartupTokens)
			{
				Tokens.Add(t.Key, t.Value);
			}
		}

		private object DestroyToken(RestVerbs verbs, IParameterCollection parameters)
		{
			var token = verbs["token"];
			try
			{
				Tokens.Remove(token);
			}
			catch (Exception)
			{
				return new Dictionary<string, string>
				       	{{"status", "400"}, {"error", "The specified token queued for destruction failed to be deleted."}};
			}
			return new Dictionary<string, string>
			       	{{"status", "200"}, {"response", "Requested token was successfully destroyed."}};
		}

		private object NewTokenV2(RestVerbs verbs, IParameterCollection parameters)
		{
			var user = parameters["username"];
			var pass = verbs["password"];

			RestObject obj = null;
			if (Verify != null)
				obj = Verify(user, pass);

			if (obj == null)
				obj = new RestObject("401") { Error = "Invalid username/password combination provided. Please re-submit your query with a correct pair." };

			if (obj.Error != null)
				return obj;

			string hash;
			var rand = new Random();
			var randbytes = new byte[32];
			do
			{
				rand.NextBytes(randbytes);
				hash = randbytes.Aggregate("", (s, b) => s + b.ToString("X2"));
			} while (Tokens.ContainsKey(hash));

			Tokens.Add(hash, user);

			obj["token"] = hash;
			return obj;
		}

		private object NewToken(RestVerbs verbs, IParameterCollection parameters)
		{
			var user = verbs["username"];
			var pass = verbs["password"];

			RestObject obj = null;
			if (Verify != null)
				obj = Verify(user, pass);

			if (obj == null)
				obj = new RestObject("401")
				      	{Error = "Invalid username/password combination provided. Please re-submit your query with a correct pair."};

			if (obj.Error != null)
				return obj;

			string hash;
			var rand = new Random();
			var randbytes = new byte[32];
			do
			{
				rand.NextBytes(randbytes);
				hash = randbytes.Aggregate("", (s, b) => s + b.ToString("X2"));
			} while (Tokens.ContainsKey(hash));

			Tokens.Add(hash, user);

			obj["token"] = hash;
			obj["deprecated"] = "This method will be removed from TShock in 3.6.";
			return obj;
		}


		protected override object ExecuteCommand(RestCommand cmd, RestVerbs verbs, IParameterCollection parms)
		{
			if (cmd.RequiresToken)
			{
				var strtoken = parms["token"];
				if (strtoken == null)
					return new Dictionary<string, string>
					       	{{"status", "401"}, {"error", "Not authorized. The specified API endpoint requires a token."}};

				object token;
				if (!Tokens.TryGetValue(strtoken, out token))
					return new Dictionary<string, string>
					       	{
					       		{"status", "403"},
					       		{
					       			"error",
					       			"Not authorized. The specified API endpoint requires a token, but the provided token was not valid."
					       			}
					       	};
			}
			return base.ExecuteCommand(cmd, verbs, parms);
		}
	}
}