using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;
using Cosmos.Build.Common;
using System.IO;
using Cosmos.IL2CPU.X86;
using Cosmos.IL2CPU;
using Microsoft.Win32;
using Cosmos.Build.MSBuild;

namespace Cosmos.Build.Task
{
	class IL2CPUTask
	{
		static int Main(string[] args)
		{
			if(args.Length != 1)
			{
				Console.WriteLine("Except the struct " + typeof(Cosmos.Build.MSBuild.IL2CPUData).FullName + " serialized in XML and this encoded base64.");
				return 1;
			}

			string xXml = Cosmos.Build.MSBuild.IL2CPU.base64Decode(args[0]);
			var xSer = new System.Xml.Serialization.XmlSerializer(typeof(IL2CPUData));
			IL2CPUData parameter;
			using(StringReader xReader = new StringReader(xXml))
			{
				parameter = (IL2CPUData) xSer.Deserialize(xReader);
			}

			IL2CPUTask t = new IL2CPUTask(parameter);
			return t.Execute()? 0 : 1;
		}

		public IL2CPUTask(IL2CPUData parameter)
		{
			this.mParameter = parameter;
		}

		private static bool mFirstTime = true;
		private IL2CPUData mParameter;
		private DebugMode mDebugMode = Cosmos.Build.Common.DebugMode.None;
		private TraceAssemblies mTraceAssemblies = Cosmos.Build.Common.TraceAssemblies.All;

        private static void CheckFirstTime()
        {
            if (mFirstTime)
            {
                mFirstTime = false;
                var xSearchDirs = new List<string>();
                xSearchDirs.Add(Path.GetDirectoryName(typeof(Cosmos.Build.MSBuild.IL2CPU).Assembly.Location));

                using (var xReg = Registry.LocalMachine.OpenSubKey("Software\\Cosmos", false))
                {
                    var xPath = (string)xReg.GetValue(null);
                    xSearchDirs.Add(xPath);
                    xSearchDirs.Add(Path.Combine(xPath, "Kernel"));
                }
                mSearchDirs = xSearchDirs.ToArray();

                AppDomain.CurrentDomain.AssemblyResolve += new ResolveEventHandler(CurrentDomain_AssemblyResolve);
            }
        }

        private static string[] mSearchDirs = new string[0];

        static Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
        {
            var xShortName = args.Name;
            if (xShortName.Contains(','))
            {
                xShortName = xShortName.Substring(0, xShortName.IndexOf(','));
                // TODO: remove following statement if it proves unnecessary
                if (xShortName.Contains(','))
                {
                    throw new Exception("Algo error");
                }
            }
            foreach (var xDir in mSearchDirs)
            {
                var xPath = Path.Combine(xDir, xShortName + ".dll");
                if (File.Exists(xPath))
                {
                    return Assembly.LoadFrom(xPath);
                }
                xPath = Path.Combine(xDir, xShortName + ".exe");
                if (File.Exists(xPath))
                {
                    return Assembly.LoadFrom(xPath);
                }
            }
            if (mStaticLog != null)
            {
                mStaticLog("Assembly '" + args.Name + "' not resolved!");
            }
            return null;
        }

        private static Action<string> mStaticLog = null;

        private bool Initialize()
        {
            CheckFirstTime();            
            // load searchpaths:
            Console.WriteLine("SearchPath: '{0}'", mParameter.References);
			if (mParameter.References != null)
            {
                var xSearchPaths = new List<string>(mSearchDirs);
				foreach (var xName in mParameter.References)
                {
                    var xDir = Path.GetDirectoryName(xName);
                    if (!xSearchPaths.Contains(xDir))
                        xSearchPaths.Insert(0, xDir);
					Assembly.LoadFile(xName);
                }
                mSearchDirs = xSearchPaths.ToArray();
            }
            if (String.IsNullOrEmpty(mParameter.DebugMode))
            {
                mDebugMode = Cosmos.Build.Common.DebugMode.None;
            }
            else
            {
				if (!Enum.GetNames(typeof(DebugMode)).Contains(mParameter.DebugMode, StringComparer.InvariantCultureIgnoreCase))
                {
                    Console.Error.WriteLine("Invalid DebugMode specified");
                    return false;
                }
				mDebugMode = (DebugMode)Enum.Parse(typeof(DebugMode), mParameter.DebugMode);
            }
			if (String.IsNullOrEmpty(mParameter.TraceAssemblies))
            {
                mTraceAssemblies = Cosmos.Build.Common.TraceAssemblies.User;
            }
            else
            {
				if (!Enum.GetNames(typeof(TraceAssemblies)).Contains(mParameter.TraceAssemblies, StringComparer.InvariantCultureIgnoreCase))
				{
					Console.Error.WriteLine("Invalid TraceAssemblies specified");
                    return false;
                }
                mTraceAssemblies = (TraceAssemblies)Enum.Parse(typeof(TraceAssemblies), mParameter.TraceAssemblies);
            }
            return true;
        }

        private void LogTime(string message)
        {
            //
        }

        public bool Execute()
        {
            try
            {
                Console.WriteLine("Executing IL2CPU on assembly");
                if (!Initialize())
                {
                    return false;
                }

                LogTime("Engine execute started");
                // find the kernel's entry point now. we are looking for a public class Kernel, with public static void Boot()
                var xInitMethod = RetrieveEntryPoint();
                if (xInitMethod == null)
                {
                    return false;
                }
				var xOutputFilename = Path.Combine(Path.GetDirectoryName(mParameter.OutputFilename), Path.GetFileNameWithoutExtension(mParameter.OutputFilename));
                if (mDebugMode == Common.DebugMode.None)
                {
                    mParameter.DebugCom = 0;
                }
				var xAsm = new AppAssemblerNasm(mParameter.DebugCom);
                xAsm.DebugMode = mDebugMode;
                xAsm.TraceAssemblies = mTraceAssemblies;
#if OUTPUT_ELF
                xAsm.EmitELF = true;
#endif

                var xNasmAsm = (AssemblerNasm)xAsm.Assembler;
                xAsm.Assembler.Initialize();
                using (var xScanner = new ILScanner(xAsm))
                {
					xScanner.TempDebug += x => Console.WriteLine(x);
                    if(mParameter.EnableLogging)
                    {
                        xScanner.EnableLogging(xOutputFilename + ".log.html");
                    }
                    // TODO: shouldn't be here?
                    xScanner.QueueMethod(xInitMethod.DeclaringType.BaseType.GetMethod("Start"));
                    xScanner.Execute(xInitMethod);

					using (var xOut = new StreamWriter(mParameter.OutputFilename, false))
                    {
						if (mParameter.EmitDebugSymbols)
                        {
                            xNasmAsm.FlushText(xOut);
                            xAsm.WriteDebugSymbols(xOutputFilename + ".cxdb");
                        }
                        else
                        {
                            xAsm.Assembler.FlushText(xOut);
                        }
                    }
                }
                LogTime("Engine execute finished");
                return true;
            }
            catch (Exception E)
			{
				Console.Error.WriteLine(E.Message + ":\r\n" + E.StackTrace);
                //Log.LogErrorFromException(E, true);
                Console.WriteLine("Loaded assemblies: ");
                foreach (var xAsm in AppDomain.CurrentDomain.GetAssemblies())
                {
                    // HACK: find another way to skip dynamic assemblies (which belong to dynamic methods)
                    try
                    {
                       Console.WriteLine(xAsm.Location);
                    }
                    catch
                    {
                    }
                }
                return false;
            }
        }

        private MethodBase RetrieveEntryPoint()
        {
            Type xFoundType = null;
            #region detect entry point method
			foreach (var xFile in mParameter.References)
            {
				if (File.Exists(xFile))
				{
					var xAssembly = Assembly.LoadFile(xFile);
					foreach (var xType in xAssembly.GetExportedTypes())
					{
						if (xType.IsGenericTypeDefinition)
						{
							continue;
						}
						if (xType.IsAbstract)
						{
							continue;
						}
						// FIX THIS: when the kernel class changes, fix the name below
						if (xType.BaseType.FullName == "Cosmos.System.Kernel")
						{
							// found kernel?
							if (xFoundType != null)
							{
								// already a kernel found, which is not supported.
								Console.Error.WriteLine("Two kernels found! '{0}' and '{1}'", xType.AssemblyQualifiedName, xFoundType.AssemblyQualifiedName);
								return null;
							}
							xFoundType = xType;
						}
					}
				}
            }
            #endregion detect entry point method
            if (xFoundType == null)
            {
				Console.Error.WriteLine("No Kernel found!");
                return null;
            }
            var xCtor = xFoundType.GetConstructor(Type.EmptyTypes);
            if (xCtor == null)
            {
				Console.Error.WriteLine("Kernel has no public default constructor");
                return null;
            }
            return xCtor;
        }
	}
}