// Copyright Epic Games, Inc. All Rights Reserved.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.CodeDom.Compiler;
using Microsoft.CSharp;
using Microsoft.Win32;
using System.Reflection;
using System.Diagnostics;
using UnrealBuildTool;
using EpicGames.Core;
using System.Threading.Tasks;

namespace AutomationTool
{
	/// <summary>
	/// Exception thrown by PreprocessScriptFile.
	/// </summary>
	public class CompilationException : AutomationException
	{
		public CompilationException(string Filename, int StartLine, int StartColumn, int EndLine, int EndColumn, string Message, params string[] Args)
			: base(String.Format("Compilation Failed.\n>{0}({1},{2},{3},{4}): error: {5}", Path.GetFullPath(Filename), StartLine + 1, StartColumn + 1, EndLine + 1, EndColumn + 1,
			String.Format(Message, Args)))
		{
		}
	}

	/// <summary>
	/// Compiles and loads script assemblies.
	/// </summary>
	public static class ScriptCompiler
	{
		private static Dictionary<string, Type> ScriptCommands;
#if DEBUG
		const string BuildConfig = "Debug";
#else
		const string BuildConfig = "Development";
#endif
		const string DefaultScriptsDLLName = "AutomationScripts.Automation.dll";

		/// <summary>
		/// Finds and/or compiles all script files and assemblies.
		/// </summary>
		/// <param name="ScriptsForProjectFileName">Path to the current project. May be null, in which case we compile scripts for all projects.</param>
		/// <param name="AdditionalScriptsFolders">Additional script fodlers to look for source files in.</param>
		public static void FindAndCompileAllScripts(string ScriptsForProjectFileName, List<string> AdditionalScriptsFolders)
		{
			// Find all the project files
			Stopwatch SearchTimer = Stopwatch.StartNew();
			List<FileReference> ProjectFiles = FindAutomationProjects(ScriptsForProjectFileName, AdditionalScriptsFolders);
			Log.TraceLog("Found {0} project files in {1:0.000}s", ProjectFiles.Count, SearchTimer.Elapsed.TotalSeconds);
			foreach(FileReference ProjectFile in ProjectFiles)
			{
				Log.TraceLog("  {0}", ProjectFile);
			}

			// Get the default properties for compiling the projects
			Dictionary<string, string> MsBuildProperties = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
			MsBuildProperties.Add("Platform", "AnyCPU");
			MsBuildProperties.Add("Configuration", BuildConfig);
			MsBuildProperties.Add("EngineDir", CommandUtils.EngineDirectory.FullName);

			// Read all the projects
			Stopwatch ParsingTimer = Stopwatch.StartNew();
			CsProjectInfo[] Projects = new CsProjectInfo[ProjectFiles.Count];
			Parallel.For(0, ProjectFiles.Count, Idx => Projects[Idx] = CsProjectInfo.Read(ProjectFiles[Idx], MsBuildProperties));
			Log.TraceLog("Parsed project files in {0:0.000}s", ParsingTimer.Elapsed.TotalSeconds);

			// Get all the build artifacts
			BuildProducts = new HashSet<FileReference>();

			HashSet<DirectoryReference> OutputDirs = new HashSet<DirectoryReference>();
			OutputDirs.Add(DirectoryReference.Combine(CommandUtils.EngineDirectory, "Binaries", "DotNET")); // Don't want any artifacts from this directory (just AutomationTool.exe and AutomationScripts.dll)

			foreach (CsProjectInfo Project in Projects)
			{
				DirectoryReference OutputDir;
				if (!Project.TryGetOutputDir(out OutputDir))
				{
					throw new AutomationException("Unable to get output directory for {0}", Project.ProjectPath);
				}

				if (OutputDirs.Add(OutputDir))
				{
					if (DirectoryReference.Exists(OutputDir))
					{
						BuildProducts.UnionWith(DirectoryReference.EnumerateFiles(OutputDir));
					}
					else
					{
						Log.TraceLog("Output directory {0} does not exist; ignoring", OutputDir);
					}
				}
			}

			// Load everything
			Stopwatch LoadTimer = Stopwatch.StartNew();
			List<Assembly> Assemblies = LoadAutomationAssemblies(Projects);
			Log.TraceLog("Loaded assemblies in {0:0.000}s", LoadTimer.Elapsed.TotalSeconds);

			// Setup platforms
			Platform.InitializePlatforms(Assemblies.ToArray());

			// Instantiate all the automation classes for interrogation
			Log.TraceVerbose("Creating commands.");
			ScriptCommands = new Dictionary<string, Type>(StringComparer.InvariantCultureIgnoreCase);
			foreach (Assembly CompiledScripts in Assemblies)
			{
				try
				{
					foreach (Type ClassType in CompiledScripts.GetTypes())
					{
						if (ClassType.IsSubclassOf(typeof(BuildCommand)) && ClassType.IsAbstract == false)
						{
							if (ScriptCommands.ContainsKey(ClassType.Name) == false)
							{
								ScriptCommands.Add(ClassType.Name, ClassType);
							}
							else
							{
								bool IsSame = string.Equals(ClassType.AssemblyQualifiedName, ScriptCommands[ClassType.Name].AssemblyQualifiedName);

								if (IsSame == false)
								{
									Log.TraceWarning("Unable to add command {0} twice. Previous: {1}, Current: {2}", ClassType.Name,
										ClassType.AssemblyQualifiedName, ScriptCommands[ClassType.Name].AssemblyQualifiedName);
								}
							}
						}
					}
				}
				catch (ReflectionTypeLoadException LoadEx)
				{
					foreach (Exception SubEx in LoadEx.LoaderExceptions)
					{
						Log.TraceWarning("Got type loader exception: {0}", SubEx.ToString());
					}
					throw new AutomationException("Failed to add commands from {0}. {1}", CompiledScripts, LoadEx);
				}
				catch (Exception Ex)
				{
					throw new AutomationException("Failed to add commands from {0}. {1}", CompiledScripts, Ex);
				}
			}
		}

		private static List<FileReference> FindAutomationProjects(string ScriptsForProjectFileName, List<string> AdditionalScriptsFolders)
		{
			// Configure the rules compiler
			// Get all game folders and convert them to build subfolders.
			List<DirectoryReference> AllGameFolders = new List<DirectoryReference>();

			if (ScriptsForProjectFileName == null)
			{
				AllGameFolders = NativeProjects.EnumerateProjectFiles().Select(x => x.Directory).ToList();
			}
			else
			{
				// Project automation scripts currently require source engine builds
				if (!CommandUtils.IsEngineInstalled())
				{
					AllGameFolders = new List<DirectoryReference> { new DirectoryReference(Path.GetDirectoryName(ScriptsForProjectFileName)) };
				}
			}

			List<DirectoryReference> AllAdditionalScriptFolders = AdditionalScriptsFolders.Select(x => new DirectoryReference(x)).ToList();
			foreach (DirectoryReference Folder in AllGameFolders)
			{
				DirectoryReference GameBuildFolder = DirectoryReference.Combine(Folder, "Build");
				if (DirectoryReference.Exists(GameBuildFolder))
				{
					AllAdditionalScriptFolders.Add(GameBuildFolder);
				}
			}

			Log.TraceVerbose("Discovering game folders.");

			List<FileReference> DiscoveredModules = UnrealBuildTool.RulesCompiler.FindAllRulesSourceFiles(UnrealBuildTool.RulesCompiler.RulesFileType.AutomationModule, GameFolders: AllGameFolders, ForeignPlugins: null, AdditionalSearchPaths: AllAdditionalScriptFolders);
			List<FileReference> ModulesToCompile = new List<FileReference>(DiscoveredModules.Count);
			foreach (FileReference ModuleFilename in DiscoveredModules)
			{
				if (HostPlatform.Current.IsScriptModuleSupported(ModuleFilename.GetFileNameWithoutAnyExtensions()))
				{
					ModulesToCompile.Add(ModuleFilename);
				}
				else
				{
					CommandUtils.LogVerbose("Script module {0} filtered by the Host Platform and will not be compiled.", ModuleFilename);
				}
			}

			return ModulesToCompile;
		}

		/// <summary>
		/// Creates a hash collection that represents the state of all modules in this list. If 
		/// a module has no current output or is missing files then a null collection will be returned
		/// </summary>
		/// <param name="Modules"></param>
		/// <returns></returns>
		private static HashCollection HashModules(IEnumerable<string> Modules, bool WarnOnFailure=true)
		{
			HashCollection Hashes = new HashCollection();

			foreach (string Module in Modules)
			{
				// this project is built by the AutomationTool project that the RunUAT script builds so 
				// it will always be newer than was last built
				if (Module.Contains("AutomationUtils.Automation"))
				{
					continue;
				}

				CsProjectInfo Proj;

				Dictionary<string, string> Properties = new Dictionary<string, string>();
				Properties.Add("Platform", "AnyCPU");
				Properties.Add("Configuration", "Development");

				FileReference ModuleFile = new FileReference(Module);

				if (!CsProjectInfo.TryRead(ModuleFile, Properties, out Proj))
				{
					if (WarnOnFailure)
					{
						Log.TraceWarning("Failed to read file {0}", ModuleFile);
					}
					return null;
				}

				if (!Hashes.AddCsProjectInfo(Proj, HashCollection.HashType.MetaData))
				{
					if (WarnOnFailure)
					{
						Log.TraceWarning("Failed to hash file {0}", ModuleFile);
					}
					return null;
				}
			}

			return Hashes;
		}

		/// <summary>
		/// Pulls all dependencies from the specified module list, gathers the state of them, and
		/// compares it to the state expressed in the provided file from a previous run
		/// </summary>
		/// <param name="ModuleList"></param>
		/// <param name="DependencyFile"></param>
		/// <returns></returns>
		private static bool AreDependenciesUpToDate(IEnumerable<string> ModuleList, string DependencyFile)
		{
			bool UpToDate = false;

			if (File.Exists(DependencyFile))
			{
				Log.TraceVerbose("Read dependency file at {0}", DependencyFile);

				HashCollection OldHashes = HashCollection.CreateFromFile(DependencyFile);

				if (OldHashes != null)
				{
					HashCollection CurrentHashes = HashModules(ModuleList, false);

					if (OldHashes.Equals(CurrentHashes))
					{
						UpToDate = true;
					}
					else
					{
						if (Log.OutputLevel >= LogEventType.VeryVerbose)
						{
							CurrentHashes.LogDifferences(OldHashes);
						}
					}
				}
				else
				{
					Log.TraceInformation("Failed to read dependency info!");
				}
			}
			else
			{
				Log.TraceVerbose("No dependency file exists at {0}. Will do full build.", DependencyFile);
			}

			return UpToDate;
		}

		/// <summary>
		/// Converts a set of MSBuild properties into command line arguments
		/// </summary>
		/// <param name="Properties">The properties to set</param>
		/// <returns>Command line arguments</returns>
		private static string GetMsBuildPropertyArguments(Dictionary<string, string> Properties)
		{
			return String.Join(" ", Properties.Select(x => String.Format(" /p:{0}={1}", Utils.MakePathSafeToUseWithCommandLine(x.Key), Utils.MakePathSafeToUseWithCommandLine(x.Value))));
		}

		/// <summary>
		/// Compiles all automation projects
		/// </summary>
		/// <param name="Projects">Projects to compile</param>
		/// <param name="MsBuildProperties">Properties to set</param>
		private static void CompileAutomationProjects(List<CsProjectInfo> Projects, Dictionary<string, string> MsBuildProperties)
		{
			Stopwatch Timer = Stopwatch.StartNew();

			string DependencyFile = Path.Combine(CommandUtils.CmdEnv.EngineSavedFolder, "UATModuleHashes.xml");
			if (AreDependenciesUpToDate(Projects.Select(x => x.ProjectPath.FullName), DependencyFile) && !GlobalCommandLine.IgnoreDependencies)
			{
				Log.TraceInformation("Dependencies are up to date ({0:0.000}s). Skipping compile.", Timer.Elapsed.TotalSeconds);
				return;
			}

			Log.TraceInformation("Dependencies are out of date. Compiling scripts....");

			// clean old assemblies
			CleanupScriptsAssemblies();

			string BuildTool = CommandUtils.CmdEnv.MsBuildExe;

			// msbuild (standard on windows, in mono >=5.0 is preferred due to speed and parallel compilation)
			bool UseParallelMsBuild = Path.GetFileNameWithoutExtension(BuildTool).ToLower() == "msbuild";
			if (UseParallelMsBuild)
			{
				string ProjectsList = string.Join(";", Projects.Select(x => x.ProjectPath));

				// Mono has an issue where arugments with semicolons or commas can't be passed through to
				// as arguments so we need to manually construct a temp file with the list of modules
				// see (https://github.com/Microsoft/msbuild/issues/471)
				string UATProjTemplate = CommandUtils.CombinePaths(CommandUtils.CmdEnv.LocalRoot, @"Engine\Source\Programs\AutomationTool\Scripts\UAT.proj");
				string UATProjFile = Path.Combine(CommandUtils.CmdEnv.EngineSavedFolder, "UATTempProj.proj");

				string ProjContents = File.ReadAllText(UATProjTemplate);
				ProjContents = ProjContents.Replace("$(Modules)", ProjectsList);

				Directory.CreateDirectory(Path.GetDirectoryName(UATProjFile));
				File.WriteAllText(UATProjFile, ProjContents);
				
				string MsBuildVerbosity = Log.OutputLevel >= LogEventType.Verbose ? "minimal" : "quiet";

				string CmdLine = String.Format("\"{0}\" {1} /verbosity:{2} /nologo", UATProjFile, GetMsBuildPropertyArguments(MsBuildProperties), MsBuildVerbosity);
				// suppress the run command because it can be long and intimidating, making the logs around this code harder to read.
				IProcessResult Result = CommandUtils.Run(BuildTool, CmdLine, Options: CommandUtils.ERunOptions.Default | CommandUtils.ERunOptions.NoLoggingOfRunCommand | CommandUtils.ERunOptions.LoggingOfRunDuration);
				if (Result.ExitCode != 0)
				{
					throw new AutomationException(String.Format("Failed to build \"{0}\":{1}{2}", UATProjFile, Environment.NewLine, Result.Output));
				}
			}
			else
			{
				// Make sure DefaultScriptsDLLName is compiled first
				string DefaultScriptsProjName = Path.ChangeExtension(DefaultScriptsDLLName, "csproj");

				// Primary modules must be built first
				List<CsProjectInfo> PrimaryProjects = Projects.Where(M => M.ProjectPath.FullName.IndexOf(DefaultScriptsProjName, StringComparison.InvariantCultureIgnoreCase) >= 0).ToList();
				foreach (CsProjectInfo PrimaryProject in PrimaryProjects)
				{
					Log.TraceInformation("Building script module: {0}", PrimaryProject.ProjectPath);
					try
					{
						CompileAutomationProject(PrimaryProject.ProjectPath, MsBuildProperties);
					}
					catch (Exception Ex)
					{
						throw new AutomationException(Ex, "Failed to compile module {0}", PrimaryProject.ProjectPath);
					}
					break;
				}

				// Second pass, compile everything else
				List<CsProjectInfo> SecondaryProjects = Projects.Where(M => !PrimaryProjects.Contains(M)).ToList();

				// Non-parallel method
				foreach (CsProjectInfo SecondaryProject in SecondaryProjects)
				{
					Log.TraceInformation("Building script module: {0}", SecondaryProject.ProjectPath);
					try
					{
						CompileAutomationProject(SecondaryProject.ProjectPath, MsBuildProperties);
					}
					catch (Exception Ex)
					{
						throw new AutomationException(Ex, "Failed to compile module {0}", SecondaryProject.ProjectPath);
					}
				}
			}			
			
			Log.TraceInformation("Compiled {0} modules in {1:0.000} secs", Projects.Count, Timer.Elapsed.TotalSeconds);

			HashCollection NewHashes = HashModules(Projects.Select(x => x.ProjectPath.FullName));

			if (NewHashes == null)
			{
				Log.TraceWarning("Failed to save dependency info!");
			}
			else
			{
				NewHashes.SaveToFile(DependencyFile);
				Log.TraceVerbose("Wrote dependencies to {0}", DependencyFile);
			}
		}

		/// <summary>
		/// Starts compiling the provided project file and returns the process. Caller should check HasExited
		/// or call WaitForExit() to get results
		/// </summary>
		/// <param name="ProjectFile"></param>
		/// <returns></returns>
		private static bool CompileAutomationProject(FileReference ProjectFile, Dictionary<string, string> Properties)
		{
			if (!ProjectFile.HasExtension(".csproj"))
			{
				throw new AutomationException(String.Format("Unable to build Project {0}. Not a valid .csproj file.", ProjectFile));
			}
			if (!FileReference.Exists(ProjectFile))
			{
				throw new AutomationException(String.Format("Unable to build Project {0}. Project file not found.", ProjectFile));
			}

			string CmdLine = String.Format("\"{0}\" /verbosity:quiet /nologo /target:Build {1} /p:TreatWarningsAsErrors=false /p:NoWarn=\"612,618,672,1591\" /p:BuildProjectReferences=true",
				ProjectFile, GetMsBuildPropertyArguments(Properties));

			// Compile the project
			IProcessResult Result = CommandUtils.Run(CommandUtils.CmdEnv.MsBuildExe, CmdLine);

			if (Result.ExitCode != 0)
			{
				throw new AutomationException(String.Format("Failed to build \"{0}\":{1}{2}", ProjectFile, Environment.NewLine, Result.Output));
			}
			else
			{
				// Remove .Automation.csproj and copy to target dir
				Log.TraceVerbose("Successfully compiled {0}", ProjectFile);
			}
			return Result.ExitCode == 0;
		}

		/// <summary>
		/// Loads all precompiled assemblies (DLLs that end with *Scripts.dll).
		/// </summary>
		/// <param name="Projects">Projects to load</param>
		/// <returns>List of compiled assemblies</returns>
		private static List<Assembly> LoadAutomationAssemblies(IEnumerable<CsProjectInfo> Projects)
		{
			List<Assembly> Assemblies = new List<Assembly>();
			foreach (CsProjectInfo Project in Projects)
			{
				// Get the output assembly name
				FileReference AssemblyLocation;
				if (!Project.TryGetOutputFile(out AssemblyLocation))
				{
					throw new AutomationException("Unable to get output file for {0}", Project.ProjectPath);
				}

				// Load the assembly into our app domain
				CommandUtils.LogLog("Loading script DLL: {0}", AssemblyLocation);
				try
				{
					AssemblyUtils.AddFileToAssemblyCache(AssemblyLocation.FullName);
					Assembly Assembly = AppDomain.CurrentDomain.Load(AssemblyName.GetAssemblyName(AssemblyLocation.FullName));
					Assemblies.Add(Assembly);
				}
				catch (Exception Ex)
				{
					throw new AutomationException("Failed to load script DLL: {0}: {1}", AssemblyLocation, Ex.Message);
				}
			}
			return Assemblies;
		}

		private static void CleanupScriptsAssemblies()
		{
			if (!CommandUtils.IsEngineInstalled())
			{
				CommandUtils.LogVerbose("Cleaning up script DLL folder");
				CommandUtils.DeleteDirectory(GetScriptAssemblyFolder());

				// Bug in PortalPublishingTool caused these DLLs to be copied into Engine/Binaries/DotNET. Delete any files left over.
				DirectoryReference BinariesDir = DirectoryReference.Combine(CommandUtils.RootDirectory, "Engine", "Binaries", "DotNET");
				foreach (FileReference FileToDelete in DirectoryReference.EnumerateFiles(BinariesDir, "*.automation.dll"))
				{
					CommandUtils.DeleteFile(FileToDelete.FullName);
				}
				foreach (FileReference FileToDelete in DirectoryReference.EnumerateFiles(BinariesDir, "*.automation.pdb"))
				{
					CommandUtils.DeleteFile(FileToDelete.FullName);
				}
			}
		}

		private static DirectoryReference GetScriptAssemblyFolder()
		{
			return DirectoryReference.Combine(CommandUtils.EngineDirectory, "Binaries", "DotNET", "AutomationScripts");
		}

		public static Dictionary<string, Type> Commands
		{
			get { return ScriptCommands; }
		}

		public static HashSet<FileReference> BuildProducts
		{
			get;
			private set;
		}
	}
}