/*
 * 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.Xml;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.Reflection;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;
using OpenMetaverse;
using Nini.Config;
using OpenSim.Framework.Servers.HttpServer;
using log4net;

namespace OpenSim.Framework.Console
{
    public class ConsoleConnection
    {
        public int last;
        public long lastLineSeen;
        public bool newConnection = true;
    }

    // A console that uses REST interfaces
    //
    public class RemoteConsole : CommandConsole
    {
        private IHttpServer m_Server = null;
        private IConfigSource m_Config = null;

        private List<string> m_Scrollback = new List<string>();
        private ManualResetEvent m_DataEvent = new ManualResetEvent(false);
        private List<string> m_InputData = new List<string>();
        private long m_LineNumber = 0;
        private Dictionary<UUID, ConsoleConnection> m_Connections =
                new Dictionary<UUID, ConsoleConnection>();
        private string m_UserName = String.Empty;
        private string m_Password = String.Empty;
        private string m_AllowedOrigin = String.Empty;

        public RemoteConsole(string defaultPrompt) : base(defaultPrompt)
        {
        }

        public void ReadConfig(IConfigSource config)
        {
            m_Config = config;

            IConfig netConfig = m_Config.Configs["Network"];
            if (netConfig == null)
                return;

            m_UserName = netConfig.GetString("ConsoleUser", String.Empty);
            m_Password = netConfig.GetString("ConsolePass", String.Empty);
            m_AllowedOrigin = netConfig.GetString("ConsoleAllowedOrigin", String.Empty);
        }

        public void SetServer(IHttpServer server)
        {
            m_Server = server;

            m_Server.AddHTTPHandler("/StartSession/", HandleHttpStartSession);
            m_Server.AddHTTPHandler("/CloseSession/", HandleHttpCloseSession);
            m_Server.AddHTTPHandler("/SessionCommand/", HandleHttpSessionCommand);
        }

        public override void Output(string text, string level)
        {
            lock (m_Scrollback)
            {
                while (m_Scrollback.Count >= 1000)
                    m_Scrollback.RemoveAt(0);
                m_LineNumber++;
                m_Scrollback.Add(String.Format("{0}", m_LineNumber)+":"+level+":"+text);
            }
            FireOnOutput(text.Trim());
            System.Console.WriteLine(text.Trim());
        }

        public override void Output(string text)
        {
            Output(text, "normal");
        }

        public override string ReadLine(string p, bool isCommand, bool e)
        {
            if (isCommand)
                Output("+++"+p);
            else
                Output("-++"+p);

            m_DataEvent.WaitOne();

            string cmdinput;

            lock (m_InputData)
            {
                if (m_InputData.Count == 0)
                {
                    m_DataEvent.Reset();
                    return "";
                }

                cmdinput = m_InputData[0];
                m_InputData.RemoveAt(0);
                if (m_InputData.Count == 0)
                    m_DataEvent.Reset();

            }

            if (isCommand)
            {
                string[] cmd = Commands.Resolve(Parser.Parse(cmdinput));

                if (cmd.Length != 0)
                {
                    int i;

                    for (i=0 ; i < cmd.Length ; i++)
                    {
                        if (cmd[i].Contains(" "))
                            cmd[i] = "\"" + cmd[i] + "\"";
                    }
                    return String.Empty;
                }
            }
            return cmdinput;
        }

        private Hashtable CheckOrigin(Hashtable result)
        {
            if (!string.IsNullOrEmpty(m_AllowedOrigin))
                result["access_control_allow_origin"] = m_AllowedOrigin;
            return result;
        }
        /* TODO: Figure out how PollServiceHTTPHandler can access the request headers
         * in order to use m_AllowedOrigin as a regular expression
        private Hashtable CheckOrigin(Hashtable headers, Hashtable result)
        {
            if (!string.IsNullOrEmpty(m_AllowedOrigin))
            {
                if (headers.ContainsKey("origin"))
                {
                    string origin = headers["origin"].ToString();
                    if (Regex.IsMatch(origin, m_AllowedOrigin))
                        result["access_control_allow_origin"] = origin;
                }
            }
            return result;
        }
        */

        private void DoExpire()
        {
            List<UUID> expired = new List<UUID>();

            lock (m_Connections)
            {
                foreach (KeyValuePair<UUID, ConsoleConnection> kvp in m_Connections)
                {
                    if (System.Environment.TickCount - kvp.Value.last > 500000)
                        expired.Add(kvp.Key);
                }

                foreach (UUID id in expired)
                {
                    m_Connections.Remove(id);
                    CloseConnection(id);
                }
            }
        }

        private Hashtable HandleHttpStartSession(Hashtable request)
        {
            DoExpire();

            Hashtable post = DecodePostString(request["body"].ToString());
            Hashtable reply = new Hashtable();

            reply["str_response_string"] = "";
            reply["int_response_code"] = 401;
            reply["content_type"] = "text/plain";

            if (m_UserName == String.Empty)
                return reply;

            if (post["USER"] == null || post["PASS"] == null)
                return reply;

            if (m_UserName != post["USER"].ToString() ||
                m_Password != post["PASS"].ToString())
            {
                return reply;
            }

            ConsoleConnection c = new ConsoleConnection();
            c.last = System.Environment.TickCount;
            c.lastLineSeen = 0;

            UUID sessionID = UUID.Random();

            lock (m_Connections)
            {
                m_Connections[sessionID] = c;
            }

            string uri = "/ReadResponses/" + sessionID.ToString() + "/";

            m_Server.AddPollServiceHTTPHandler(
                uri, new PollServiceEventArgs(null, HasEvents, GetEvents, NoEvents, sessionID));

            XmlDocument xmldoc = new XmlDocument();
            XmlNode xmlnode = xmldoc.CreateNode(XmlNodeType.XmlDeclaration,
                    "", "");

            xmldoc.AppendChild(xmlnode);
            XmlElement rootElement = xmldoc.CreateElement("", "ConsoleSession",
                    "");

            xmldoc.AppendChild(rootElement);

            XmlElement id = xmldoc.CreateElement("", "SessionID", "");
            id.AppendChild(xmldoc.CreateTextNode(sessionID.ToString()));

            rootElement.AppendChild(id);

            XmlElement prompt = xmldoc.CreateElement("", "Prompt", "");
            prompt.AppendChild(xmldoc.CreateTextNode(DefaultPrompt));

            rootElement.AppendChild(prompt);

            rootElement.AppendChild(MainConsole.Instance.Commands.GetXml(xmldoc));

            reply["str_response_string"] = xmldoc.InnerXml;
            reply["int_response_code"] = 200;
            reply["content_type"] = "text/xml";
            reply = CheckOrigin(reply);

            return reply;
        }

        private Hashtable HandleHttpCloseSession(Hashtable request)
        {
            DoExpire();

            Hashtable post = DecodePostString(request["body"].ToString());
            Hashtable reply = new Hashtable();

            reply["str_response_string"] = "";
            reply["int_response_code"] = 404;
            reply["content_type"] = "text/plain";

            if (post["ID"] == null)
                return reply;

            UUID id;
            if (!UUID.TryParse(post["ID"].ToString(), out id))
                return reply;

            lock (m_Connections)
            {
                if (m_Connections.ContainsKey(id))
                {
                    m_Connections.Remove(id);
                    CloseConnection(id);
                }
            }

            XmlDocument xmldoc = new XmlDocument();
            XmlNode xmlnode = xmldoc.CreateNode(XmlNodeType.XmlDeclaration,
                    "", "");

            xmldoc.AppendChild(xmlnode);
            XmlElement rootElement = xmldoc.CreateElement("", "ConsoleSession",
                    "");

            xmldoc.AppendChild(rootElement);

            XmlElement res = xmldoc.CreateElement("", "Result", "");
            res.AppendChild(xmldoc.CreateTextNode("OK"));

            rootElement.AppendChild(res);

            reply["str_response_string"] = xmldoc.InnerXml;
            reply["int_response_code"] = 200;
            reply["content_type"] = "text/xml";
            reply = CheckOrigin(reply);

            return reply;
        }

        private Hashtable HandleHttpSessionCommand(Hashtable request)
        {
            DoExpire();

            Hashtable post = DecodePostString(request["body"].ToString());
            Hashtable reply = new Hashtable();

            reply["str_response_string"] = "";
            reply["int_response_code"] = 404;
            reply["content_type"] = "text/plain";

            if (post["ID"] == null)
                return reply;

            UUID id;
            if (!UUID.TryParse(post["ID"].ToString(), out id))
                return reply;

            lock (m_Connections)
            {
                if (!m_Connections.ContainsKey(id))
                    return reply;
            }

            if (post["COMMAND"] == null)
                return reply;

            lock (m_InputData)
            {
                m_DataEvent.Set();
                m_InputData.Add(post["COMMAND"].ToString());
            }

            XmlDocument xmldoc = new XmlDocument();
            XmlNode xmlnode = xmldoc.CreateNode(XmlNodeType.XmlDeclaration,
                    "", "");

            xmldoc.AppendChild(xmlnode);
            XmlElement rootElement = xmldoc.CreateElement("", "ConsoleSession",
                    "");

            xmldoc.AppendChild(rootElement);

            XmlElement res = xmldoc.CreateElement("", "Result", "");
            res.AppendChild(xmldoc.CreateTextNode("OK"));

            rootElement.AppendChild(res);

            reply["str_response_string"] = xmldoc.InnerXml;
            reply["int_response_code"] = 200;
            reply["content_type"] = "text/xml";
            reply = CheckOrigin(reply);

            return reply;
        }

        private Hashtable DecodePostString(string data)
        {
            Hashtable result = new Hashtable();

            string[] terms = data.Split(new char[] {'&'});

            foreach (string term in terms)
            {
                string[] elems = term.Split(new char[] {'='});
                if (elems.Length == 0)
                    continue;

                string name = System.Web.HttpUtility.UrlDecode(elems[0]);
                string value = String.Empty;

                if (elems.Length > 1)
                    value = System.Web.HttpUtility.UrlDecode(elems[1]);
                
                result[name] = value;
            }

            return result;
        }

        public void CloseConnection(UUID id)
        {
            try
            {
                string uri = "/ReadResponses/" + id.ToString() + "/";

                m_Server.RemovePollServiceHTTPHandler("", uri);
            }
            catch (Exception)
            {
            }
        }

        private bool HasEvents(UUID RequestID, UUID sessionID)
        {
            ConsoleConnection c = null;

            lock (m_Connections)
            {
                if (!m_Connections.ContainsKey(sessionID))
                    return false;
                c = m_Connections[sessionID];
            }
            c.last = System.Environment.TickCount;
            if (c.lastLineSeen < m_LineNumber)
                return true;
            return false;
        }

        private Hashtable GetEvents(UUID RequestID, UUID sessionID, string request)
        {
            ConsoleConnection c = null;

            lock (m_Connections)
            {
                if (!m_Connections.ContainsKey(sessionID))
                    return NoEvents(RequestID, UUID.Zero);
                c = m_Connections[sessionID];
            }
            c.last = System.Environment.TickCount;
            if (c.lastLineSeen >= m_LineNumber)
                return NoEvents(RequestID, UUID.Zero);

            Hashtable result = new Hashtable();

            XmlDocument xmldoc = new XmlDocument();
            XmlNode xmlnode = xmldoc.CreateNode(XmlNodeType.XmlDeclaration,
                    "", "");

            xmldoc.AppendChild(xmlnode);
            XmlElement rootElement = xmldoc.CreateElement("", "ConsoleSession",
                    "");

            if (c.newConnection)
            {
                c.newConnection = false;
                Output("+++" + DefaultPrompt);
            }

            lock (m_Scrollback)
            {
                long startLine = m_LineNumber - m_Scrollback.Count;
                long sendStart = startLine;
                if (sendStart < c.lastLineSeen)
                    sendStart = c.lastLineSeen;

                for (long i = sendStart ; i < m_LineNumber ; i++)
                {
                    XmlElement res = xmldoc.CreateElement("", "Line", "");
                    long line = i + 1;
                    res.SetAttribute("Number", line.ToString());
                    res.AppendChild(xmldoc.CreateTextNode(m_Scrollback[(int)(i - startLine)]));

                    rootElement.AppendChild(res);
                }
            }
            c.lastLineSeen = m_LineNumber;

            xmldoc.AppendChild(rootElement);

            result["str_response_string"] = xmldoc.InnerXml;
            result["int_response_code"] = 200;
            result["content_type"] = "application/xml";
            result["keepalive"] = false;
            result["reusecontext"] = false;
            result = CheckOrigin(result);

            return result;
        }

        private Hashtable NoEvents(UUID RequestID, UUID id)
        {
            Hashtable result = new Hashtable();

            XmlDocument xmldoc = new XmlDocument();
            XmlNode xmlnode = xmldoc.CreateNode(XmlNodeType.XmlDeclaration,
                    "", "");

            xmldoc.AppendChild(xmlnode);
            XmlElement rootElement = xmldoc.CreateElement("", "ConsoleSession",
                    "");

            xmldoc.AppendChild(rootElement);

            result["str_response_string"] = xmldoc.InnerXml;
            result["int_response_code"] = 200;
            result["content_type"] = "text/xml";
            result["keepalive"] = false;
            result["reusecontext"] = false;
            result = CheckOrigin(result);

            return result;
        }
    }
}
