/*
* Copyright (c) Contributors, http://www.openmetaverse.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.
* 
*/
/* Original code: Tedd Hansen */
using System;
using System.Collections.Generic;
using System.Text;
using System.Threading;
using System.Reflection;
using OpenSim.Region.Environment.Scenes.Scripting;

namespace OpenSim.Region.ScriptEngine.DotNetEngine
{
    /// <summary>
    /// Loads scripts
    /// Compiles them if necessary
    /// Execute functions for EventQueueManager
    /// </summary>
    class ScriptManager
    {

        private ScriptEngine myScriptEngine;
        public ScriptManager(ScriptEngine _ScriptEngine)
        {
            myScriptEngine = _ScriptEngine;
            myScriptEngine.m_logger.Verbose("ScriptEngine", "ScriptManager Start");
        }


        // Object<string, Script<string, script>>
        internal Dictionary<string, Dictionary<string, OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.LSL_BaseClass>> Scripts = new Dictionary<string, Dictionary<string, OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.LSL_BaseClass>>();


        internal Dictionary<string, OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.LSL_BaseClass>.KeyCollection GetScriptKeys(string ObjectID)
        {
            if (Scripts.ContainsKey(ObjectID) == false)
                return null;

            Dictionary<string, OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.LSL_BaseClass> Obj;
            Scripts.TryGetValue(ObjectID, out Obj);

            return Obj.Keys;

        }

        internal OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.LSL_BaseClass GetScript(string ObjectID, string ScriptID)
        {
            if (Scripts.ContainsKey(ObjectID) == false)
                return null;

            Dictionary<string, OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.LSL_BaseClass> Obj;
            Scripts.TryGetValue(ObjectID, out Obj);
            if (Obj.ContainsKey(ScriptID) == false)
                return null;

            // Get script
            OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.LSL_BaseClass Script;
            Obj.TryGetValue(ScriptID, out Script);

            return Script;

        }
        internal void SetScript(string ObjectID, string ScriptID, OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.LSL_BaseClass Script)
        {
            // Create object if it doesn't exist
            if (Scripts.ContainsKey(ObjectID) == false)
                Scripts.Add(ObjectID, new Dictionary<string, OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.LSL_BaseClass>());

            // Delete script if it exists
            Dictionary<string, OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.LSL_BaseClass> Obj;
            Scripts.TryGetValue(ObjectID, out Obj);
            if (Obj.ContainsKey(ScriptID) == true)
                Obj.Remove(ScriptID);

            // Add to object
            Obj.Add(ScriptID, Script);

        }

        /// <summary>
        /// Fetches, loads and hooks up a script to an objects events
        /// </summary>
        /// <param name="ScriptID"></param>
        /// <param name="ObjectID"></param>
        public void StartScript(string ScriptID, string ObjectID)
        {
            myScriptEngine.m_logger.Verbose("ScriptEngine", "ScriptManager StartScript: ScriptID: " + ScriptID + ", ObjectID: " + ObjectID);

            // We will initialize and start the script.
            // It will be up to the script itself to hook up the correct events.
            string FileName = "";

            try
            {


                // * Fetch script from server
                // DEBUG - ScriptID is an actual filename during debug
                //  (therefore we can also check type by looking at extension)
                FileName = ScriptID;

                // * Does script need compile? Send it to LSL compiler first. (TODO: Use (and clean) compiler cache)
                //myScriptEngine.m_logger.Verbose("ScriptEngine", "ScriptManager Script extension: " + System.IO.Path.GetExtension(FileName).ToLower());
                switch (System.IO.Path.GetExtension(FileName).ToLower())
                {
                    case ".txt":
                    case ".lsl":
                    case ".cs":
                        myScriptEngine.m_logger.Verbose("ScriptEngine", "ScriptManager Script is CS/LSL, compiling to .Net Assembly");
                        // Create a new instance of the compiler (currently we don't want reuse)
                        OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.Compiler LSLCompiler = new OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.Compiler();
                        // Compile
                        FileName = LSLCompiler.Compile(FileName);
                        break;
                    default:
                        throw new Exception("Unknown script type.");
                }



                myScriptEngine.m_logger.Verbose("ScriptEngine", "Compilation done");
                // * Insert yield into code
                FileName = ProcessYield(FileName);

                // * Find next available AppDomain to put it in
                AppDomain FreeAppDomain = GetFreeAppDomain();

                // * Load and start script, for now with dummy host
                
                //OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSO.LSL_BaseClass Script = LoadAndInitAssembly(FreeAppDomain, FileName);
                OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.LSL_BaseClass Script = LoadAndInitAssembly(FreeAppDomain, FileName, new NullScriptHost() );
                string FullScriptID = ScriptID + "." + ObjectID;                               
                // Add it to our temporary active script keeper
                //Scripts.Add(FullScriptID, Script);
                SetScript(ObjectID, ScriptID, Script);
                // We need to give (untrusted) assembly a private instance of BuiltIns
                //  this private copy will contain Read-Only FullScriptID so that it can bring that on to the server whenever needed.
                //OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL_BuiltIn_Commands_Interface LSLB = new OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL_BuiltIn_Commands_TestImplementation(FullScriptID);

                // Start the script - giving it BuiltIns
                //myScriptEngine.m_logger.Verbose("ScriptEngine", "ScriptManager initializing script, handing over private builtin command interface");
                
                Script.Start(myScriptEngine.World, ScriptID);

            }
            catch (Exception e)
            {
                myScriptEngine.m_logger.Error("ScriptEngine", "Exception loading script \"" + FileName + "\": " + e.ToString());
            }


        }
        private string ProcessYield(string FileName)
        {
            // TODO: Create a new assembly and copy old but insert Yield Code
            return FileName;
        }

        private AppDomain GetFreeAppDomain()
        {
            // TODO: Find an available AppDomain - if none, create one and add default security
            return Thread.GetDomain();
        }

        /// <summary>
        /// Does actual loading and initialization of script Assembly
        /// </summary>
        /// <param name="FreeAppDomain">AppDomain to load script into</param>
        /// <param name="FileName">FileName of script assembly (.dll)</param>
        /// <returns></returns>
        private OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.LSL_BaseClass LoadAndInitAssembly(AppDomain FreeAppDomain, string FileName, IScriptHost host)
        {
            //myScriptEngine.m_logger.Verbose("ScriptEngine", "ScriptManager Loading Assembly " + FileName);
            // Load .Net Assembly (.dll)
            // Initialize and return it

            // TODO: Add error handling
            // Script might not follow our rules since users can upload -anything-

            Assembly a;
            //try
            //{


            // Load to default appdomain (temporary)
            a = Assembly.LoadFrom(FileName);
            // Load to specified appdomain
            // TODO: Insert security
            //a = FreeAppDomain.Load(FileName);
            //}
            //catch (Exception e)
            //{
            //}


            //foreach (Type _t in a.GetTypes())
            //{
            //    Console.WriteLine("Type: " + _t.ToString());
            //}

            Type t;
            //try
            //{
            t = a.GetType("SecondLife.Script", true);
            //}
            //catch (Exception e)
            //{
            //}

            object[] args = new object[] { host };
            
            return (OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.LSL_BaseClass)Activator.CreateInstance(t, args );


        }

        internal void ExecuteFunction(string ObjectID, string ScriptID, string FunctionName, object[] args)
        {
            myScriptEngine.m_logger.Verbose("ScriptEngine", "Executing Function ObjectID: " + ObjectID + ", ScriptID: " + ScriptID + ", FunctionName: " + FunctionName);
            OpenSim.Region.ScriptEngine.DotNetEngine.Compiler.LSL.LSL_BaseClass Script = myScriptEngine.myScriptManager.GetScript(ObjectID, ScriptID);

            Type type = Script.GetType();


            myScriptEngine.m_logger.Verbose("ScriptEngine", "Invoke: \"" + Script.State + "_event_" + FunctionName + "\"");

            try
            {
                type.InvokeMember(Script.State + "_event_" + FunctionName, BindingFlags.InvokeMethod, null, Script, args);
            }
            catch (Exception e)
            {
                myScriptEngine.m_logger.Error("ScriptEngine", "Exception attempting to executing script function: " + e.ToString());
            }


            //foreach (MemberInfo mi in type.GetMembers())
            //{
            //    Common.SendToDebug("Member found: " + mi.ToString());
            //}

        }

    }
}