using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;

using Microsoft.Dnx.Runtime.Common.CommandLine;
using Microsoft.DotNet.Cli.Utils;
using Microsoft.DotNet.Tools.Common;

namespace Microsoft.DotNet.Tools.Compiler.Native
{
	public class WindowsLinkStep : IPlatformNativeStep
	{
		private readonly string LinkerName = "link.exe";
		private readonly string LinkerOutputExtension = ".exe";
        private readonly string VSBin = "..\\..\\VC\\bin\\amd64";

        private readonly string InputExtension = ".obj";

        private static readonly Dictionary<BuildConfiguration, string> ConfigurationLinkerOptionsMap = new Dictionary<BuildConfiguration, string>
		{
			{ BuildConfiguration.debug, "/NOLOGO /ERRORREPORT:PROMPT /MANIFEST /MANIFESTUAC:\"level='asInvoker' uiAccess='false'\" /manifest:embed /Debug /SUBSYSTEM:CONSOLE /TLBID:1 /DYNAMICBASE /NXCOMPAT" },
			{ BuildConfiguration.release, "/NOLOGO /ERRORREPORT:PROMPT /INCREMENTAL:NO /OPT:REF /OPT:ICF /LTCG:incremental /MANIFEST /MANIFESTUAC:\"level='asInvoker' uiAccess='false'\" /manifest:embed /Debug /SUBSYSTEM:CONSOLE /TLBID:1 /DYNAMICBASE /NXCOMPAT" }
		};

        private static readonly Dictionary<NativeIntermediateMode, string[]> ModeLibMap = new Dictionary<NativeIntermediateMode, string[]>
        {
            { NativeIntermediateMode.cpp, new string[] { "PortableRuntime.lib", "bootstrappercpp.lib" } },
            { NativeIntermediateMode.ryujit, new string[] { "Runtime.lib", "bootstrapper.lib" } }
        };

        private static readonly string[] ConstantLinkLibs = new string[]
        {
            "kernel32.lib",
            "user32.lib",
            "gdi32.lib",
            "winspool.lib",
            "comdlg32.lib",
            "advapi32.lib",
            "shell32.lib",
            "ole32.lib",
            "oleaut32.lib",
            "uuid.lib",
            "odbc32.lib",
            "odbccp32.lib"
        };

        private static readonly Dictionary<BuildConfiguration, string[]> ConfigurationLinkLibMap = new Dictionary<BuildConfiguration, string[]>()
        {
        	{ BuildConfiguration.debug , new string[] { "msvcrtd" } },
        	{ BuildConfiguration.release , new string[] { "msvcrt" } }
        };
		
		private string ArgStr { get; set; }
		private NativeCompileSettings config;
		
		public WindowsLinkStep(NativeCompileSettings config)
		{
			this.config = config;
			InitializeArgs(config);
		}
		
		public int Invoke()
		{
			var result = WindowsCommon.SetVCVars();
			if (result != 0)
			{
				Reporter.Error.WriteLine("vcvarsall.bat invocation failed.");
				return result;
			}
			
			result = InvokeLinker();
			if (result != 0)
			{
                Reporter.Error.WriteLine("Linking of intermediate files failed.");
			}
			return result;
		}
		
		public bool CheckPreReqs()
		{
            var vcInstallDir = Environment.GetEnvironmentVariable("VS140COMNTOOLS");
            return !string.IsNullOrEmpty(vcInstallDir);
        }
		
		private void InitializeArgs(NativeCompileSettings config)
		{
			var argsList = new List<string>();
			
			// Configuration Based Linker Options 
			argsList.Add(ConfigurationLinkerOptionsMap[config.BuildType]);
			
			//Output
			var outFile = DetermineOutputFile(config);
			argsList.Add($"/out:\"{outFile}\"");
			
			// Constant Libs
			argsList.Add(string.Join(" ", ConstantLinkLibs));

            // SDK Libs
            var SDKLibs = ModeLibMap[config.NativeMode];
			foreach (var lib in SDKLibs)
			{
				argsList.Add(Path.Combine(config.IlcPath, lib));
			}

			// Configuration Based Libs
			var configLibs = ConfigurationLinkLibMap[config.BuildType];
			foreach (var lib in configLibs)
			{
				argsList.Add(lib);
			}

			// Link Libs
			foreach(var path in config.LinkLibPaths){
				argsList.Add($"\"{path}\"");
			}
			
			//arch
			argsList.Add($"/MACHINE:{config.Architecture}");

            //Input Obj file
            var inputFile = DetermineInputFile(config);
			argsList.Add($"\"{inputFile}\"");
			
			this.ArgStr = string.Join(" ", argsList);
		}
		
		private int InvokeLinker()
		{
			var vcInstallDir = Environment.GetEnvironmentVariable("VS140COMNTOOLS");
			var linkerPath = Path.Combine(vcInstallDir, VSBin, LinkerName);
			
			var result = Command.Create(linkerPath, ArgStr)
				.ForwardStdErr()
				.ForwardStdOut()
				.Execute();
			
			return result.ExitCode;
		}
		
		public string DetermineOutputFile(NativeCompileSettings config)
		{
			var outputDirectory = config.OutputDirectory;
			
			var filename = Path.GetFileNameWithoutExtension(config.InputManagedAssemblyPath);
		
			var outFile = Path.Combine(outputDirectory, filename + LinkerOutputExtension);
			
			return outFile;
		}

        private string DetermineInputFile(NativeCompileSettings config)
        {
            var intermediateDirectory = config.IntermediateDirectory;

            var filename = Path.GetFileNameWithoutExtension(config.InputManagedAssemblyPath);

            var infile = Path.Combine(intermediateDirectory, filename + InputExtension);

            return infile;
        }
		
	}
}