using System;
using System.Collections.Generic;
using System.Net;
using System.IO;
using System.Text;
using System.Xml;
using System.Threading;
using OpenMetaverse;
using OpenMetaverse.Capabilities;
using OpenMetaverse.Packets;

namespace Simian
{
    public partial class Simian
    {
        // TODO: Don't hard-code these
        public const uint REGION_X = 256000;
        public const uint REGION_Y = 256000;

        public int UDPPort = 9000;
        public int HttpPort = 9000;
        public string DataDir = "SimianData/";

        public HttpServer HttpServer;
        public ulong RegionHandle;

        // Interfaces
        public IAuthenticationProvider Authentication;
        public IAccountProvider Accounts;
        public IUDPProvider UDP;
        public ISceneProvider Scene;
        public IAssetProvider Assets;
        public IAvatarProvider Avatars;
        public IInventoryProvider Inventory;
        public IParcelProvider Parcels;
        public IMeshingProvider Mesher;

        // Persistent extensions
        public List<IPersistable> PersistentExtensions = new List<IPersistable>();

        /// <summary>All of the agents currently connected to this UDP server</summary>
        public Dictionary<UUID, Agent> Agents = new Dictionary<UUID, Agent>();

        public Simian()
        {
        }

        public bool Start(int port, bool ssl)
        {
            HttpPort = port;
            UDPPort = port;

            InitHttpServer(HttpPort, ssl);

            RegionHandle = Helpers.UIntsToLong(REGION_X, REGION_Y);

            // Load all of the extensions
            ExtensionLoader.LoadAllExtensions(AppDomain.CurrentDomain.BaseDirectory, this);

            foreach (ISimianExtension extension in ExtensionLoader.Extensions)
            {
                // Assign to an interface if possible
                TryAssignToInterface(extension);
            }

            foreach (ISimianExtension extension in ExtensionLoader.Extensions)
            {
                // Start persistance providers after all other extensions
                if (!(extension is IPersistenceProvider))
                {
                    Logger.DebugLog("Loading extension " + extension.GetType().Name);
                    extension.Start();
                }
            }

            foreach (ISimianExtension extension in ExtensionLoader.Extensions)
            {
                // Start the persistance provider(s)
                if (extension is IPersistenceProvider)
                {
                    Logger.DebugLog("Loading persistance provider " + extension.GetType().Name);
                    extension.Start();
                }
            }

            if (!CheckInterfaces())
            {
                Logger.Log("Missing interfaces, shutting down", Helpers.LogLevel.Error);
                Stop();
                return false;
            }
            else
            {
                return true;
            }
        }

        public void Stop()
        {
            foreach (ISimianExtension extension in ExtensionLoader.Extensions)
            {
                // Stop persistance providers first
                if (extension is IPersistenceProvider)
                    extension.Stop();
            }

            foreach (ISimianExtension extension in ExtensionLoader.Extensions)
            {
                // Stop all other extensions
                if (!(extension is IPersistenceProvider))
                    extension.Stop();
            }

            HttpServer.Stop();
        }

        void TryAssignToInterface(ISimianExtension extension)
        {
            if (extension is IAuthenticationProvider)
                Authentication = (IAuthenticationProvider)extension;
            else if (extension is IAccountProvider)
                Accounts = (IAccountProvider)extension;
            else if (extension is IUDPProvider)
                UDP = (IUDPProvider)extension;
            else if (extension is ISceneProvider)
                Scene = (ISceneProvider)extension;
            else if (extension is IAssetProvider)
                Assets = (IAssetProvider)extension;
            else if (extension is IAvatarProvider)
                Avatars = (IAvatarProvider)extension;
            else if (extension is IInventoryProvider)
                Inventory = (IInventoryProvider)extension;
            else if (extension is IParcelProvider)
                Parcels = (IParcelProvider)extension;
            else if (extension is IMeshingProvider)
                Mesher = (IMeshingProvider)extension;

            // Track all of the extensions with persistence
            if (extension is IPersistable)
                PersistentExtensions.Add((IPersistable)extension);
        }

        bool CheckInterfaces()
        {
            if (Authentication == null)
                Logger.Log("No IAuthenticationProvider interface loaded", Helpers.LogLevel.Error);
            else if (Accounts == null)
                Logger.Log("No IAccountProvider interface loaded", Helpers.LogLevel.Error);
            else if (UDP == null)
                Logger.Log("No IUDPProvider interface loaded", Helpers.LogLevel.Error);
            else if (Scene == null)
                Logger.Log("No ISceneProvider interface loaded", Helpers.LogLevel.Error);
            else if (Assets == null)
                Logger.Log("No IAssetProvider interface loaded", Helpers.LogLevel.Error);
            else if (Avatars == null)
                Logger.Log("No IAvatarProvider interface loaded", Helpers.LogLevel.Error);
            else if (Inventory == null)
                Logger.Log("No IInventoryProvider interface loaded", Helpers.LogLevel.Error);
            else if (Parcels == null)
                Logger.Log("No IParcelProvider interface loaded", Helpers.LogLevel.Error);
            else if (Mesher == null)
                Logger.Log("No IMeshingProvider interface loaded", Helpers.LogLevel.Error);
            else
                return true;

            return false;
        }

        void InitHttpServer(int port, bool ssl)
        {
            HttpServer = new HttpServer(HttpPort, ssl);

            // Login webpage HEAD request, used to check if the login webpage is alive
            HttpRequestSignature signature = new HttpRequestSignature();
            signature.Method = "head";
            signature.ContentType = String.Empty;
            signature.Path = "/loginpage";
            HttpServer.HttpRequestCallback callback = new HttpServer.HttpRequestCallback(LoginWebpageHeadHandler);
            HttpServer.HttpRequestHandler handler = new HttpServer.HttpRequestHandler(signature, callback);
            HttpServer.AddHandler(handler);

            // Login webpage GET request, gets the login webpage data (purely aesthetic)
            signature.Method = "get";
            signature.ContentType = String.Empty;
            signature.Path = "/loginpage";
            callback = new HttpServer.HttpRequestCallback(LoginWebpageGetHandler);
            handler.Signature = signature;
            handler.Callback = callback;
            HttpServer.AddHandler(handler);

            // Client XML-RPC login
            signature.Method = "post";
            signature.ContentType = "text/xml";
            signature.Path = "/login";
            callback = new HttpServer.HttpRequestCallback(LoginXmlRpcPostHandler);
            handler.Signature = signature;
            handler.Callback = callback;
            HttpServer.AddHandler(handler);

            // Client LLSD login
            signature.Method = "post";
            signature.ContentType = "application/xml";
            signature.Path = "/login";
            callback = new HttpServer.HttpRequestCallback(LoginLLSDPostHandler);
            handler.Signature = signature;
            handler.Callback = callback;
            HttpServer.AddHandler(handler);

            HttpServer.Start();
        }

        void LoginWebpageHeadHandler(HttpRequestSignature signature, ref HttpListenerContext context)
        {
            context.Response.StatusCode = (int)HttpStatusCode.OK;
            context.Response.StatusDescription = "OK";
        }

        void LoginWebpageGetHandler(HttpRequestSignature signature, ref HttpListenerContext context)
        {
            string pageContent = "<html><head><title>Simian</title></head><body><br/><h1>Welcome to Simian</h1></body></html>";
            byte[] pageData = Encoding.UTF8.GetBytes(pageContent);
            context.Response.OutputStream.Write(pageData, 0, pageData.Length);
            context.Response.Close();
        }

        void LoginXmlRpcPostHandler(HttpRequestSignature signature, ref HttpListenerContext context)
        {
            string
                firstName = String.Empty,
                lastName = String.Empty,
                password = String.Empty,
                start = String.Empty,
                version = String.Empty,
                channel = String.Empty;

            try
            {
                // Parse the incoming XML
                XmlReader reader = XmlReader.Create(context.Request.InputStream);

                reader.ReadStartElement("methodCall");
                {
                    string methodName = reader.ReadElementContentAsString("methodName", String.Empty);

                    if (methodName == "login_to_simulator")
                    {
                        reader.ReadStartElement("params");
                        reader.ReadStartElement("param");
                        reader.ReadStartElement("value");
                        reader.ReadStartElement("struct");
                        {
                            while (reader.Name == "member")
                            {
                                reader.ReadStartElement("member");
                                {
                                    string name = reader.ReadElementContentAsString("name", String.Empty);

                                    reader.ReadStartElement("value");
                                    {
                                        switch (name)
                                        {
                                            case "first":
                                                firstName = reader.ReadElementContentAsString("string", String.Empty);
                                                break;
                                            case "last":
                                                lastName = reader.ReadElementContentAsString("string", String.Empty);
                                                break;
                                            case "passwd":
                                                password = reader.ReadElementContentAsString("string", String.Empty);
                                                break;
                                            case "start":
                                                start = reader.ReadElementContentAsString("string", String.Empty);
                                                break;
                                            case "version":
                                                version = reader.ReadElementContentAsString("string", String.Empty);
                                                break;
                                            case "channel":
                                                channel = reader.ReadElementContentAsString("string", String.Empty);
                                                break;
                                            default:
                                                if (reader.Name == "string")
                                                    Console.WriteLine(String.Format("Ignore login xml value: name={0}, value={1}", name, reader.ReadInnerXml()));
                                                else
                                                    Console.WriteLine(String.Format("Unknown login xml: name={0}, value={1}", name, reader.ReadInnerXml()));
                                                break;
                                        }
                                    }
                                    reader.ReadEndElement();
                                }
                                reader.ReadEndElement();
                            }
                        }
                        reader.ReadEndElement();
                        reader.ReadEndElement();
                        reader.ReadEndElement();
                        reader.ReadEndElement();
                    }
                }
                reader.ReadEndElement();
                reader.Close();

                LoginResponseData responseData = HandleLogin(firstName, lastName, password, start, version, channel);
                XmlWriter writer = XmlWriter.Create(context.Response.OutputStream);
                responseData.ToXmlRpc(writer);
                writer.Close();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }

        void LoginLLSDPostHandler(HttpRequestSignature signature, ref HttpListenerContext context)
        {
            string body = String.Empty;

            using (StreamReader reader = new StreamReader(context.Request.InputStream, context.Request.ContentEncoding))
            {
                body = reader.ReadToEnd();
            }

            Console.WriteLine(body);
        }

        LoginResponseData HandleLogin(string firstName, string lastName, string password, string start, string version, string channel)
        {
            LoginResponseData response = new LoginResponseData();
            Agent agent;

            UUID agentID = Authentication.Authenticate(firstName, lastName, password);
            if (agentID != UUID.Zero)
            {
                // Authentication successful, create a login instance of this agent
                agent = Accounts.CreateInstance(agentID);

                if (agent != null)
                {
                    // Assign a circuit code and insert the agent into the unassociatedAgents dictionary
                    agent.CircuitCode = UDP.CreateCircuit(agent);

                    agent.TickLastPacketReceived = Environment.TickCount;
                    agent.LastLoginTime = Utils.DateTimeToUnixTime(DateTime.Now);

                    // Get this machine's IP address
                    IPHostEntry addresses = Dns.GetHostByName(Dns.GetHostName());
                    IPAddress simIP = addresses.AddressList.Length > 0 ? addresses.AddressList[0] : IPAddress.Loopback;

                    response.AgentID = agent.AgentID;
                    response.SecureSessionID = agent.SecureSessionID;
                    response.SessionID = agent.SessionID;
                    response.CircuitCode = agent.CircuitCode;
                    response.AgentAccess = agent.AccessLevel;
                    response.BuddyList = null; // FIXME:
                    response.FirstName = agent.FirstName;
                    response.HomeLookAt = agent.HomeLookAt;
                    response.HomePosition = agent.HomePosition;
                    response.HomeRegion = agent.HomeRegionHandle;
                    response.InventoryRoot = agent.InventoryRoot;
                    response.InventorySkeleton = null; // FIXME:
                    response.LastName = agent.LastName;
                    response.LibraryOwner = agent.InventoryLibraryOwner;
                    response.LibraryRoot = agent.InventoryLibraryRoot;
                    response.LibrarySkeleton = null; // FIXME:
                    response.LookAt = agent.CurrentLookAt;
                    response.Message = "Welcome to Simian";
                    response.Reason = String.Empty;

                    uint regionX, regionY;
                    Helpers.LongToUInts(agent.CurrentRegionHandle, out regionX, out regionY);
                    response.RegionX = regionX;
                    response.RegionY = regionY;

                    response.SecondsSinceEpoch = DateTime.Now;
                    // FIXME: Actually generate a seed capability
                    response.SeedCapability = String.Format("http://{0}:{1}/seed_caps", simIP, HttpPort);
                    response.SimIP = simIP;
                    response.SimPort = (ushort)UDPPort;
                    response.StartLocation = "last"; // FIXME:
                    response.Success = true;
                }
                else
                {
                    // Something went wrong creating an agent instance, return a fail response
                    response.AgentID = agentID;
                    response.FirstName = firstName;
                    response.LastName = lastName;
                    response.Message = "Failed to create an account instance";
                    response.Reason = "account";
                    response.Success = false;
                }
            }
            else
            {
                // Authentication failed, return a fail response
                response.AgentID = agentID;
                response.FirstName = firstName;
                response.LastName = lastName;
                response.Message = "Authentication failed";
                response.Reason = "key";
                response.Success = false;
            }

            return response;
        }
    }
}