/*
 * Copyright (c) Contributors, http://opensimulator.org/
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the OpenSim Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Reflection;
using System.Text.RegularExpressions;
using System.Threading;
using System.Security.Cryptography.X509Certificates;
using log4net;
using HttpServer;

using HttpListener = HttpServer.HttpListener;

namespace OpenSim.Framework.Servers
{
    /// <sumary>
    /// Any OSHttpHandler must return one of the following results:
    /// <list type = "table">
    ///   <listheader>
    ///     <term>result code</term>
    ///     <description>meaning</description>
    ///   </listheader>
    ///   <item>
    ///     <term>Pass</term>
    ///     <description>handler did not process the request</request>
    ///   </item>
    ///   <item>
    ///     <term>Handled</term>
    ///     <description>handler did process the request, OSHttpServer
    ///       can clean up and close the request</request>
    ///   </item>
    ///   <item>
    ///     <term>Detached</term>
    ///     <description>handler handles the request, OSHttpServer
    ///       can forget about the request and should not touch it as
    ///       the handler has taken control</request>
    ///   </item>
    /// </list>
    /// </summary>
    public enum OSHttpHandlerResult
    {
        Pass,
        Handled,
        Detached,
    }

    public delegate OSHttpHandlerResult OSHttpHandler(OSHttpRequest request);

    /// <summary>
    /// OSHttpServer provides an HTTP server bound to a specific
    /// port. When instantiated with just address and port it uses
    /// normal HTTP, when instantiated with address, port, and X509
    /// certificate, it uses HTTPS.
    /// </summary>
    public class OSHttpServer
    {
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        // underlying HttpServer.HttpListener
        protected HttpListener _listener;
        // underlying core/engine thread
        protected Thread _engine;

        // Queue containing (OS)HttpRequests
        protected OSHttpRequestQueue _queue;

        // OSHttpRequestPumps "pumping" incoming OSHttpRequests
        // upwards
        protected OSHttpRequestPump[] _pumps;

        // thread identifier
        protected string _engineId;
        public string EngineID
        {
            get { return _engineId; }
        }

        /// <summary>
        /// True if this is an HTTPS connection; false otherwise.
        /// </summary>
        protected bool _isSecure;
        public bool IsSecure
        {
            get { return _isSecure; }
        }

        public int QueueSize 
        {
            get { return _pumps.Length; }
        }

        /// <summary>
        /// Instantiate an HTTP server.
        /// </summary>
        public OSHttpServer(IPAddress address, int port, int poolSize)
        {
            _engineId = String.Format("OSHttpServer [HTTP:{0}/ps:{1}]", port, poolSize);
            _isSecure = false;

            _listener = new HttpListener(address, port);
            _queue = new OSHttpRequestQueue();
            _pumps = OSHttpRequestPump.Pumps(this, _queue, poolSize);
        }

        /// <summary>
        /// Instantiate an HTTPS server.
        /// </summary>
        public OSHttpServer(IPAddress address, int port, X509Certificate certificate, int poolSize)
        {
            _engineId = String.Format("OSHttpServer [HTTPS:{0}/ps:{1}]", port, poolSize);
            _isSecure = true;

            _listener = new HttpListener(address, port, certificate);
            _queue = new OSHttpRequestQueue();
            _pumps = OSHttpRequestPump.Pumps(this, _queue, poolSize);
        }

        /// <summary>
        /// Turn an HttpRequest into an OSHttpRequestItem and place it
        /// in the queue. The OSHttpRequestQueue object will pulse the
        /// next available idle pump.
        /// </summary>
        protected void OnHttpRequest(HttpClientContext client, HttpRequest request)
        {
            // turn request into OSHttpRequest
            OSHttpRequest req = new OSHttpRequest(client, request);

            // place OSHttpRequest into _httpRequestQueue, will
            // trigger Pulse to idle waiting pumps
            _queue.Enqueue(req);
        }

        /// <summary>
        /// Start the HTTP server engine.
        /// </summary>
        public void Start()
        {
            _engine = new Thread(new ThreadStart(Engine));
            _engine.Name = _engineId;
            _engine.IsBackground = true;
            _engine.Start();

            ThreadTracker.Add(_engine);
        }

        /// <summary>
        /// Engine keeps the HTTP server running.
        /// </summary>
        private void Engine()
        {
            while (true)
            {
                _listener.RequestHandler += OnHttpRequest;
                _listener.Start(QueueSize);
            }
        }

        protected Dictionary<OSHttpHandler, Regex> Handler2Path = new Dictionary<OSHttpHandler, Regex>();
        protected Dictionary<OSHttpHandler, Dictionary<string, Regex>> Handler2Headers = 
            new Dictionary<OSHttpHandler, Dictionary<string, Regex>>();

        /// <summary>
        /// Add an HTTP request handler.
        /// </summary>
        /// <param name="handler">OSHttpHandler delegate</param>
        /// <param name="path">regex object for path matching</parm>
        /// <param name="headers">dictionary containing header names
        /// and regular expressions to match against header values</param>
        public void AddHandler(OSHttpHandler handler, Regex path, Dictionary<string, Regex> headers)
        {
            lock (Handler2Headers) 
            {
                
            }
        }
        
    }
}