/*
 * 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 OpenSimulator 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;
using System.Collections.Generic;
using System.Collections.Concurrent;
using System.Reflection;
using System.Threading;
using log4net;
using OpenMetaverse;
using OpenMetaverse.StructuredData;
using OpenSim.Framework.Servers;
using OpenSim.Framework.Servers.HttpServer;

// using OpenSim.Region.Framework.Interfaces;

namespace OpenSim.Framework.Capabilities
{
    /// <summary>
    /// XXX Probably not a particularly nice way of allow us to get the scene presence from the scene (chiefly so that
    /// we can popup a message on the user's client if the inventory service has permanently failed).  But I didn't want
    /// to just pass the whole Scene into CAPS.
    /// </summary>
    public delegate IClientAPI GetClientDelegate(UUID agentID);

    public class Caps : IDisposable
    {
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        private readonly string m_httpListenerHostName;
        private readonly uint m_httpListenPort;

        /// <summary>
        /// This is the uuid portion of every CAPS path.  It is used to make capability urls private to the requester.
        /// </summary>
        private readonly string m_capsObjectPath;
        public string CapsObjectPath { get { return m_capsObjectPath; } }

        private readonly CapsHandlers m_capsHandlers;
        private readonly ConcurrentDictionary<string, PollServiceEventArgs> m_pollServiceHandlers = new ();
        private readonly Dictionary<string, string> m_externalCapsHandlers = new ();

        private readonly IHttpServer m_httpListener;
        private readonly UUID m_agentID;
        private readonly string m_regionName;
        private ManualResetEvent m_capsActive = new(false);
        private readonly string m_baseCapsURL;

        public UUID AgentID
        {
            get { return m_agentID; }
        }

        public string RegionName
        {
            get { return m_regionName; }
        }

        public string HostName
        {
            get { return m_httpListenerHostName; }
        }

        public uint Port
        {
            get { return m_httpListenPort; }
        }

        public IHttpServer HttpListener
        {
            get { return m_httpListener; }
        }

        public bool SSLCaps
        {
            get { return m_httpListener.UseSSL; }
        }

        public string SSLCommonName
        {
            get { return m_httpListener.SSLCommonName; }
        }

        public CapsHandlers CapsHandlers
        {
            get { return m_capsHandlers; }
        }

        public Dictionary<string, string> ExternalCapsHandlers
        {
            get { return m_externalCapsHandlers; }
        }

        [Flags]
        public enum CapsFlags: uint
        {
            None =          0,
            SentSeeds =     1,

            ObjectAnim =    0x100,
            WLEnv =         0x200,
            AdvEnv =        0x400,
            PBR =           0x800,
            ViewerBenefits = 0x1000,
            TPBR =           0x2000
        }

        public CapsFlags Flags { get; set;}

        public Caps(IHttpServer httpServer, string httpListen, uint httpPort, string capsPath,
                    UUID agent, string regionName)
        {
            m_capsObjectPath = capsPath;
            m_httpListener = httpServer;
            m_httpListenerHostName = httpListen;

            m_httpListenPort = httpPort;

            if (httpServer is not null && httpServer.UseSSL)
            {
                m_httpListenPort = httpServer.SSLPort;
                httpListen = httpServer.SSLCommonName;
                httpPort = httpServer.SSLPort;
            }

            m_agentID = agent;
            m_capsHandlers = new CapsHandlers(httpServer, httpListen, httpPort);
            m_regionName = regionName;
            Flags = CapsFlags.None;
            m_capsActive.Reset();
            if (MainServer.Instance.UseSSL)
                m_baseCapsURL = $"https://{MainServer.Instance.SSLCommonName}:{MainServer.Instance.SSLPort}";
            else
            {
                if (MainServer.Instance is null)
                    m_baseCapsURL = $"http://{m_httpListenerHostName}:0";
                else
                    m_baseCapsURL = $"http://{m_httpListenerHostName}:{MainServer.Instance.Port}";
            }
        }

        ~Caps()
        {
            Dispose(false);
        }
        
        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        public void Dispose(bool disposing)
        {
            Flags = CapsFlags.None;
            if (m_capsActive != null)
            {
                DeregisterHandlers();
                m_capsActive.Dispose();
                m_capsActive = null;
            }
        }

        /// <summary>
        /// Register a handler.  This allows modules to register handlers.
        /// </summary>
        /// <param name="capName"></param>
        /// <param name="handler"></param>
        public void RegisterHandler(string capName, IRequestHandler handler)
        {
            //m_log.DebugFormat("[CAPS]: Registering handler for \"{0}\": path {1}", capName, handler.Path);
            m_capsHandlers[capName] = handler;
        }

        public void RegisterSimpleHandler(string capName, ISimpleStreamHandler handler, bool addToListener = true)
        {
            //m_log.DebugFormat("[CAPS]: Registering handler for \"{0}\": path {1}", capName, handler.Path);
            m_capsHandlers.AddSimpleHandler(capName, handler, addToListener);
        }

        public void RegisterPollHandler(string capName, PollServiceEventArgs pollServiceHandler)
        {
            //m_log.DebugFormat(
            //    "[CAPS]: Registering handler with name {0}, url {1} for {2}",
            //    capName, pollServiceHandler.Url, m_agentID, m_regionName);

            if(!m_pollServiceHandlers.TryAdd(capName, pollServiceHandler))
            {
                m_log.ErrorFormat(
                    "[CAPS]: Handler with name {0} already registered (ulr {1}, agent {2}, region {3}",
                    capName, pollServiceHandler.Url, m_agentID, m_regionName);
                return;
            }

            m_httpListener.AddPollServiceHTTPHandler(pollServiceHandler);

            //uint port = (MainServer.Instance == null) ? 0 : MainServer.Instance.Port;
            //string protocol = "http";
            //string hostName = m_httpListenerHostName;

            //if (MainServer.Instance.UseSSL)
            //{
            //    hostName = MainServer.Instance.SSLCommonName;
            //    port = MainServer.Instance.SSLPort;
            //    protocol = "https";
            //}

            //RegisterHandler(
            //   capName, String.Format("{0}://{1}:{2}{3}", protocol, hostName, port, pollServiceHandler.Url));
        }

        /// <summary>
        /// Register an external handler. The service for this capability is somewhere else
        /// given by the URL.
        /// </summary>
        /// <param name="capsName"></param>
        /// <param name="url"></param>
        public void RegisterHandler(string capsName, string url)
        {
            m_externalCapsHandlers.Add(capsName, url);
        }

        /// <summary>
        /// Remove all CAPS service handlers.
        /// </summary>
        public void DeregisterHandlers()
        {
            foreach (string capsName in m_capsHandlers.Caps)
            {
                m_capsHandlers.Remove(capsName);
            }

            foreach (PollServiceEventArgs handler in m_pollServiceHandlers.Values)
            {
                m_httpListener.RemovePollServiceHTTPHandler(handler.Url);
            }
            m_pollServiceHandlers.Clear();
        }
        public bool TryGetPollHandler(string name, out PollServiceEventArgs pollHandler)
        {
            return m_pollServiceHandlers.TryGetValue(name, out pollHandler);
        }

        public Dictionary<string, PollServiceEventArgs> GetPollHandlers()
        {
            return new Dictionary<string, PollServiceEventArgs>(m_pollServiceHandlers);
        }

        /// <summary>
        /// Return an LLSD-serializable Hashtable describing the
        /// capabilities and their handler details.
        /// </summary>
        /// <param name="excludeSeed">If true, then exclude the seed cap.</param>
        public Hashtable GetCapsDetails(bool excludeSeed, List<string> requestedCaps)
        {
            Hashtable caps = CapsHandlers.GetCapsDetails(excludeSeed, requestedCaps);

            lock (m_pollServiceHandlers)
            {
                foreach (KeyValuePair<string, PollServiceEventArgs> kvp in m_pollServiceHandlers)
                {
                    if (!requestedCaps.Contains(kvp.Key))
                        continue;

                    string hostName = m_httpListenerHostName;
                    uint port = (MainServer.Instance is null) ? 0 : MainServer.Instance.Port;
                    string protocol = "http";

                    if (MainServer.Instance.UseSSL)
                    {
                        hostName = MainServer.Instance.SSLCommonName;
                        port = MainServer.Instance.SSLPort;
                        protocol = "https";
                    }
                    caps[kvp.Key] = string.Format("{0}://{1}:{2}{3}", protocol, hostName, port, kvp.Value.Url);
                }
            }

            // Add the external too
            foreach (KeyValuePair<string, string> kvp in ExternalCapsHandlers)
            {
                if (!requestedCaps.Contains(kvp.Key))
                    continue;

                caps[kvp.Key] = kvp.Value;
            }


            return caps;
        }

        public void GetCapsDetailsLLSDxml(HashSet<string> requestedCaps, osUTF8 sb)
        {

            CapsHandlers.GetCapsDetailsLLSDxml(requestedCaps, sb);

            lock (m_pollServiceHandlers)
            {
                foreach (KeyValuePair<string, PollServiceEventArgs> kvp in m_pollServiceHandlers)
                {
                    if (requestedCaps.Contains(kvp.Key))
                        LLSDxmlEncode2.AddElem(kvp.Key, m_baseCapsURL + kvp.Value.Url, sb);
                }
            }

            // Add the external too
            foreach (KeyValuePair<string, string> kvp in ExternalCapsHandlers)
            {
                if (requestedCaps.Contains(kvp.Key))
                    LLSDxmlEncode2.AddElem(kvp.Key, kvp.Value, sb);
            }
        }

        public void Activate()
        {
            m_capsActive.Set();
        }

        public bool WaitForActivation()
        {
            // Wait for 30s. If that elapses, return false and run without caps
            return m_capsActive.WaitOne(120000);
        }
    }
}