/*
 * 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.Generic;
using System.Reflection;
using System.Threading;
using Timer = System.Timers.Timer;

using log4net;
using Nini.Config;
using Mono.Addins;
using OpenMetaverse;

using OpenSim.Region.Framework.Interfaces;
using OpenSim.Region.Framework.Scenes;
using OpenSim.Framework;
using OpenSim.Services.Interfaces;

namespace OpenSim.Region.OptionalModules.World.NPC
{
    [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "NPCModule")]
    public class NPCModule : INPCModule, ISharedRegionModule
    {
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        private readonly Dictionary<UUID, NPCAvatar> m_avatars = new Dictionary<UUID, NPCAvatar>();
        private NPCOptionsFlags m_NPCOptionFlags;

        private int m_MaxNumberNPCperScene = 40;

        public NPCOptionsFlags NPCOptionFlags {get {return m_NPCOptionFlags;}}

        public bool Enabled { get; private set; }

        public void Initialise(IConfigSource source)
        {
            IConfig config = source.Configs["NPC"];

            Enabled = (config != null && config.GetBoolean("Enabled", true));
            m_NPCOptionFlags = NPCOptionsFlags.None;
            if(Enabled)
            {
                if(config.GetBoolean("AllowNotOwned", true))
                    m_NPCOptionFlags |= NPCOptionsFlags.AllowNotOwned;

                if(config.GetBoolean("AllowSenseAsAvatar", true))
                    m_NPCOptionFlags |= NPCOptionsFlags.AllowSenseAsAvatar;

                if(config.GetBoolean("AllowCloneOtherAvatars", true))
                    m_NPCOptionFlags |= NPCOptionsFlags.AllowCloneOtherAvatars;

                if(config.GetBoolean("NoNPCGroup", true))
                    m_NPCOptionFlags |= NPCOptionsFlags.NoNPCGroup;

                m_MaxNumberNPCperScene = config.GetInt("MaxNumberNPCsPerScene", m_MaxNumberNPCperScene);
            }
        }

        public void AddRegion(Scene scene)
        {
            if (Enabled)
                scene.RegisterModuleInterface<INPCModule>(this);
        }

        public void RegionLoaded(Scene scene)
        {
        }

        public void PostInitialise()
        {
        }

        public void RemoveRegion(Scene scene)
        {
            scene.UnregisterModuleInterface<INPCModule>(this);
        }

        public void Close()
        {
        }

        public string Name
        {
            get { return "NPCModule"; }
        }

        public Type ReplaceableInterface { get { return null; } }

        public bool IsNPC(UUID agentId, Scene scene)
        {
            // FIXME: This implementation could not just use the
            // ScenePresence.PresenceType (and callers could inspect that
            // directly).
            ScenePresence sp = scene.GetScenePresence(agentId);
            if (sp == null || sp.IsChildAgent)
                return false;

            lock (m_avatars)
                return m_avatars.ContainsKey(agentId);
        }

        public bool SetNPCAppearance(UUID agentId, AvatarAppearance appearance, Scene scene)
        {
            ScenePresence npc = scene.GetScenePresence(agentId);
            if (npc == null || npc.IsChildAgent)
                return false;

            lock (m_avatars)
                if (!m_avatars.ContainsKey(agentId))
                    return false;

            // Delete existing npc attachments
            if(scene.AttachmentsModule != null)
                scene.AttachmentsModule.DeleteAttachmentsFromScene(npc, false);

            // XXX: We can't just use IAvatarFactoryModule.SetAppearance() yet
            // since it doesn't transfer attachments
            AvatarAppearance npcAppearance = new AvatarAppearance(appearance,
                    true);
            npc.Appearance = npcAppearance;

            // Rez needed npc attachments
            if (scene.AttachmentsModule != null)
                scene.AttachmentsModule.RezAttachments(npc);

            IAvatarFactoryModule module = scene.RequestModuleInterface<IAvatarFactoryModule>();
            module.SendAppearance(npc.UUID);

            return true;
        }

        public UUID CreateNPC(string firstname, string lastname,
                Vector3 position, UUID owner,  bool senseAsAgent, Scene scene,
                AvatarAppearance appearance)
        {
            return CreateNPC(firstname, lastname, position, UUID.Zero, owner, "", UUID.Zero, senseAsAgent, scene, appearance);
        }

        public UUID CreateNPC(string firstname, string lastname,
                Vector3 position, UUID agentID, UUID owner, string groupTitle, UUID groupID, bool senseAsAgent, Scene scene,
                AvatarAppearance appearance)
        {
            if(m_MaxNumberNPCperScene > 0)
            {
                if(scene.GetRootNPCCount() >= m_MaxNumberNPCperScene)
                    return UUID.Zero;
            }

            NPCAvatar npcAvatar = null;
            string born = DateTime.UtcNow.ToString();

            try
            {
                if (agentID.IsZero())
                    npcAvatar = new NPCAvatar(firstname, lastname, position,
                            owner, senseAsAgent, scene);
                else
                    npcAvatar = new NPCAvatar(firstname, lastname, agentID, position,
                        owner, senseAsAgent, scene);
            }
            catch (Exception e)
            {
                m_log.Info("[NPC MODULE]: exception creating NPC avatar: " + e.ToString());
                return UUID.Zero;
            }

            agentID = npcAvatar.AgentId;
            uint circuit = (uint)Random.Shared.Next(0, int.MaxValue);
            npcAvatar.CircuitCode = circuit;

            //m_log.DebugFormat(
            //    "[NPC MODULE]: Creating NPC {0} {1} {2}, owner={3}, senseAsAgent={4} at {5} in {6}",
            //    firstname, lastname, npcAvatar.AgentId, owner, senseAsAgent, position, scene.RegionInfo.RegionName);

            AgentCircuitData acd = new AgentCircuitData()
            {
                circuitcode = circuit,
                AgentID = agentID,
                firstname = firstname,
                lastname = lastname,
                ServiceURLs = new Dictionary<string, object>(),
                Appearance = new AvatarAppearance(appearance, true)
            };

            /*
            for (int i = 0;
                    i < acd.Appearance.Texture.FaceTextures.Length; i++)
            {
                m_log.DebugFormat(
                        "[NPC MODULE]: NPC avatar {0} has texture id {1} : {2}",
                        acd.AgentID, i,
                        acd.Appearance.Texture.FaceTextures[i]);
            }
            */

            lock (m_avatars)
            {
                scene.AuthenticateHandler.AddNewCircuit(acd);
                scene.AddNewAgent(npcAvatar, PresenceType.Npc);

                if (scene.TryGetScenePresence(agentID, out ScenePresence sp))
                {
                    npcAvatar.Born = born;
                    npcAvatar.ActiveGroupId = groupID;
                    sp.CompleteMovement(npcAvatar, false);
                    sp.Grouptitle = groupTitle;
                    m_avatars.Add(agentID, npcAvatar);
                    //m_log.DebugFormat("[NPC MODULE]: Created NPC {0} {1}", npcAvatar.AgentId, sp.Name);
                }
            }

//            m_log.DebugFormat("[NPC MODULE]: Created NPC with id {0}", npcAvatar.AgentId);

            return agentID;
        }

        public bool MoveToTarget(UUID agentID, Scene scene, Vector3 pos,
                bool noFly, bool landAtTarget, bool running)
        {
            lock (m_avatars)
            {
                if (m_avatars.ContainsKey(agentID))
                {
                    ScenePresence sp;
                    if (scene.TryGetScenePresence(agentID, out sp))
                    {
                        if (sp.IsSatOnObject || sp.SitGround)
                            return false;

                    //m_log.DebugFormat(
                    //        "[NPC MODULE]: Moving {0} to {1} in {2}, noFly {3}, landAtTarget {4}",
                    //        sp.Name, pos, scene.RegionInfo.RegionName,
                    //        noFly, landAtTarget);

                        sp.MoveToTarget(pos, noFly, landAtTarget, running);

                        return true;
                    }
                }
            }

            return false;
        }

        public bool StopMoveToTarget(UUID agentID, Scene scene)
        {
            lock (m_avatars)
            {
                if (m_avatars.ContainsKey(agentID))
                {
                    ScenePresence sp;
                    if (scene.TryGetScenePresence(agentID, out sp))
                    {
                        sp.Velocity = Vector3.Zero;
                        sp.ResetMoveToTarget();

                        return true;
                    }
                }
            }

            return false;
        }

        public bool Say(UUID agentID, Scene scene, string text)
        {
            return Say(agentID, scene, text, 0);
        }

        public bool Say(UUID agentID, Scene scene, string text, int channel)
        {
            lock (m_avatars)
            {
                if (m_avatars.ContainsKey(agentID))
                {
                    m_avatars[agentID].Say(channel, text);

                    return true;
                }
            }

            return false;
        }

        public bool Shout(UUID agentID, Scene scene, string text, int channel)
        {
            lock (m_avatars)
            {
                if (m_avatars.ContainsKey(agentID))
                {
                    m_avatars[agentID].Shout(channel, text);

                    return true;
                }
            }

            return false;
        }

        public bool Sit(UUID agentID, UUID partID, Scene scene)
        {
            lock (m_avatars)
            {
                if (m_avatars.ContainsKey(agentID))
                {
                    ScenePresence sp;
                    if (scene.TryGetScenePresence(agentID, out sp))
                    {
                        sp.HandleAgentRequestSit(m_avatars[agentID], agentID, partID, Vector3.Zero);

                        return true;
                    }
                }
            }

            return false;
        }

        public bool Whisper(UUID agentID, Scene scene, string text,
                int channel)
        {
            lock (m_avatars)
            {
                if (m_avatars.ContainsKey(agentID))
                {
                    m_avatars[agentID].Whisper(channel, text);

                    return true;
                }
            }

            return false;
        }

        public bool Stand(UUID agentID, Scene scene)
        {
            lock (m_avatars)
            {
                if (m_avatars.ContainsKey(agentID))
                {
                    ScenePresence sp;
                    if (scene.TryGetScenePresence(agentID, out sp))
                    {
                        sp.StandUp();

                        return true;
                    }
                }
            }

            return false;
        }

        public bool Touch(UUID agentID, UUID objectID)
        {
            lock (m_avatars)
            {
                if (m_avatars.ContainsKey(agentID))
                    return m_avatars[agentID].Touch(objectID);

                return false;
            }
        }

        public UUID GetOwner(UUID agentID)
        {
            lock (m_avatars)
            {
                NPCAvatar av;
                if (m_avatars.TryGetValue(agentID, out av))
                    return av.OwnerID;
            }

            return UUID.Zero;
        }

        public INPC GetNPC(UUID agentID, Scene scene)
        {
            lock (m_avatars)
            {
                if (m_avatars.ContainsKey(agentID))
                    return m_avatars[agentID];
                else
                    return null;
            }
        }

        public bool DeleteNPC(UUID agentID, Scene scene)
        {
            bool doRemove = false;
            NPCAvatar av;
            lock (m_avatars)
            {
                if (m_avatars.TryGetValue(agentID, out av))
                {
                    /*
                    m_log.DebugFormat("[NPC MODULE]: Found {0} {1} to remove",
                            agentID, av.Name);
                    */
                    doRemove = true;
                }
            }

            if (doRemove)
            {
                scene.CloseAgent(agentID, false);
                lock (m_avatars)
                {
                    m_avatars.Remove(agentID);
                }
                m_log.DebugFormat("[NPC MODULE]: Removed NPC {0} {1}",
                        agentID, av.Name);
                return true;
            }
            /*
            m_log.DebugFormat("[NPC MODULE]: Could not find {0} to remove",
                    agentID);
            */
            return false;
        }

        public bool CheckPermissions(UUID npcID, UUID callerID)
        {
            lock (m_avatars)
            {
                NPCAvatar av;
                if (m_avatars.TryGetValue(npcID, out av))
                {
                    if (npcID == callerID)
                        return true;
                    return CheckPermissions(av, callerID);
                }
                else
                {
                    return false;
                }
            }
        }

        /// <summary>
        /// Check if the caller has permission to manipulate the given NPC.
        /// </summary>
        /// <remarks>
        /// A caller has permission if
        ///   * The caller UUID given is UUID.Zero.
        ///   * The avatar is unowned (owner is UUID.Zero).
        ///   * The avatar is owned and the owner and callerID match.
        ///   * The avatar is owned and the callerID matches its agentID.
        /// </remarks>
        /// <param name="av"></param>
        /// <param name="callerID"></param>
        /// <returns>true if they do, false if they don't.</returns>
        private bool CheckPermissions(NPCAvatar av, UUID callerID)
        {
            return callerID.IsZero() || av.OwnerID.IsZero() ||
                av.OwnerID.Equals(callerID)  || av.AgentId.Equals(callerID);
        }
    }
}