// Copyright Epic Games, Inc. All Rights Reserved.

#include "DesktopPlatformBase.h"
#include "HAL/FileManager.h"
#include "Misc/FileHelper.h"
#include "Misc/Paths.h"
#include "Misc/Guid.h"
#include "Misc/ConfigCacheIni.h"
#include "Misc/FeedbackContext.h"
#include "Misc/App.h"
#include "Misc/EngineVersion.h"
#include "Serialization/JsonTypes.h"
#include "Serialization/JsonReader.h"
#include "Serialization/JsonSerializer.h"
#include "Modules/ModuleManager.h"
#include "DesktopPlatformPrivate.h"
#include "Misc/OutputDeviceRedirector.h"


#define LOCTEXT_NAMESPACE "DesktopPlatform"


FDesktopPlatformBase::FDesktopPlatformBase()
{
	LauncherInstallationTimestamp = FDateTime::MinValue();
}

FString FDesktopPlatformBase::GetEngineDescription(const FString& Identifier)
{
	// Official release versions just have a version number
	if(IsStockEngineRelease(Identifier))
	{
		return Identifier;
	}

	// Otherwise get the path
	FString RootDir;
	if(!GetEngineRootDirFromIdentifier(Identifier, RootDir))
	{
		return FString();
	}

	// Convert it to a platform directory
	FString PlatformRootDir = RootDir;
	FPaths::MakePlatformFilename(PlatformRootDir);

	// Perforce build
	if (IsSourceDistribution(RootDir))
	{
		return FString::Printf(TEXT("Source build at %s"), *PlatformRootDir);
	}
	else
	{
		return FString::Printf(TEXT("Binary build at %s"), *PlatformRootDir);
	}
}

FString FDesktopPlatformBase::GetCurrentEngineIdentifier()
{
	if(CurrentEngineIdentifier.Len() == 0 && !GetEngineIdentifierFromRootDir(FPlatformMisc::RootDir(), CurrentEngineIdentifier))
	{
		CurrentEngineIdentifier.Empty();
	}
	return CurrentEngineIdentifier;
}

void FDesktopPlatformBase::EnumerateLauncherEngineInstallations(TMap<FString, FString> &OutInstallations)
{
	// Cache the launcher install list if necessary
	ReadLauncherInstallationList();

	// We've got a list of launcher installations. Filter it by the engine installations.
	for(TMap<FString, FString>::TConstIterator Iter(LauncherInstallationList); Iter; ++Iter)
	{
		FString AppName = Iter.Key();
		if(AppName.RemoveFromStart(TEXT("UE_"), ESearchCase::CaseSensitive))
		{
			OutInstallations.Add(AppName, Iter.Value());
		}
	}
}

void FDesktopPlatformBase::EnumerateLauncherSampleInstallations(TArray<FString> &OutInstallations)
{
	// Cache the launcher install list if necessary
	ReadLauncherInstallationList();

	// We've got a list of launcher installations. Filter it by the engine installations.
	for(TMap<FString, FString>::TConstIterator Iter(LauncherInstallationList); Iter; ++Iter)
	{
		FString AppName = Iter.Key();
		if(!AppName.StartsWith(TEXT("UE_"), ESearchCase::CaseSensitive))
		{
			OutInstallations.Add(Iter.Value());
		}
	}
}

void FDesktopPlatformBase::EnumerateLauncherSampleProjects(TArray<FString> &OutFileNames)
{
	// Enumerate all the sample installation directories
	TArray<FString> LauncherSampleDirectories;
	EnumerateLauncherSampleInstallations(LauncherSampleDirectories);

	// Find all the project files within them
	for(int32 Idx = 0; Idx < LauncherSampleDirectories.Num(); Idx++)
	{
		TArray<FString> FileNames;
		IFileManager::Get().FindFiles(FileNames, *(LauncherSampleDirectories[Idx] / TEXT("*.uproject")), true, false);
		OutFileNames.Append(FileNames);
	}
}

bool FDesktopPlatformBase::GetEngineRootDirFromIdentifier(const FString &Identifier, FString &OutRootDir)
{
	// Get all the installations
	TMap<FString, FString> Installations;
	EnumerateEngineInstallations(Installations);

	// Find the one with the right identifier
	for (TMap<FString, FString>::TConstIterator Iter(Installations); Iter; ++Iter)
	{
		if (Iter->Key == Identifier)
		{
			OutRootDir = Iter->Value;
			return true;
		}
	}
	return false;
}

bool FDesktopPlatformBase::GetEngineIdentifierFromRootDir(const FString &RootDir, FString &OutIdentifier)
{
	// Get all the installations
	TMap<FString, FString> Installations;
	EnumerateEngineInstallations(Installations);

	// Normalize the root directory
	FString NormalizedRootDir = RootDir;
	FPaths::CollapseRelativeDirectories(NormalizedRootDir);
	FPaths::NormalizeDirectoryName(NormalizedRootDir);

	// Find the label for the given directory
	for (TMap<FString, FString>::TConstIterator Iter(Installations); Iter; ++Iter)
	{
		if (Iter->Value == NormalizedRootDir)
		{
			OutIdentifier = Iter->Key;
			return true;
		}
	}

	// Otherwise just try to add it
	return RegisterEngineInstallation(RootDir, OutIdentifier);
}

bool FDesktopPlatformBase::GetDefaultEngineIdentifier(FString &OutId)
{
	TMap<FString, FString> Installations;
	EnumerateEngineInstallations(Installations);

	bool bRes = false;
	if (Installations.Num() > 0)
	{
		// Default to the first install
		TMap<FString, FString>::TConstIterator Iter(Installations);
		OutId = Iter.Key();
		++Iter;

		// Try to find the most preferred install
		for(; Iter; ++Iter)
		{
			if(IsPreferredEngineIdentifier(Iter.Key(), OutId))
			{
				OutId = Iter.Key();
			}
		}
	}
	return bRes;
}

bool FDesktopPlatformBase::GetDefaultEngineRootDir(FString &OutDirName)
{
	FString Identifier;
	return GetDefaultEngineIdentifier(Identifier) && GetEngineRootDirFromIdentifier(Identifier, OutDirName);
}

bool FDesktopPlatformBase::IsPreferredEngineIdentifier(const FString &Identifier, const FString &OtherIdentifier)
{
	int32 Version = ParseReleaseVersion(Identifier);
	int32 OtherVersion = ParseReleaseVersion(OtherIdentifier);

	if(Version != OtherVersion)
	{
		return Version > OtherVersion;
	}
	else
	{
		return Identifier > OtherIdentifier;
	}
}

bool FDesktopPlatformBase::TryGetEngineVersion(const FString& RootDir, FEngineVersion& OutVersion)
{
	// Read the file to a string
	FString VersionText;
	if(FFileHelper::LoadFileToString(VersionText, *(RootDir / TEXT("Engine/Build/Build.version"))))
	{
		// Deserialize a JSON object from the string
		TSharedPtr< FJsonObject > Object;
		TSharedRef< TJsonReader<> > Reader = TJsonReaderFactory<>::Create(VersionText);
		if(FJsonSerializer::Deserialize(Reader, Object) && Object.IsValid())
		{
			int32 MajorVersion = 0;
			int32 MinorVersion = 0;
			int32 PatchVersion = 0;
			if(Object->TryGetNumberField(TEXT("MajorVersion"), MajorVersion) && Object->TryGetNumberField(TEXT("MinorVersion"), MinorVersion) && Object->TryGetNumberField(TEXT("PatchVersion"), PatchVersion))
			{
				int32 Changelist = 0;
				if(!Object->TryGetNumberField(TEXT("Changelist"), Changelist))
				{
					Changelist = 0;
				}

				int32 IsLicenseeVersion = 0;
				if(!Object->TryGetNumberField(TEXT("IsLicenseeVersion"), IsLicenseeVersion))
				{
					IsLicenseeVersion = 0;
				}

				FString BranchName;
				if(!Object->TryGetStringField(TEXT("BranchName"), BranchName))
				{
					BranchName = FString();
				}

				int EncodedChangelist = (IsLicenseeVersion == 0)? Changelist : FEngineVersionBase::EncodeLicenseeChangelist(Changelist);
				OutVersion = FEngineVersion(MajorVersion, MinorVersion, PatchVersion, EncodedChangelist, BranchName);
				return true;
			}
		}
	}

	// Try to read the version file
	FString VersionHeader;
	if(FFileHelper::LoadFileToString(VersionHeader, *(RootDir / TEXT("Engine/Source/Runtime/Launch/Resources/Version.h"))))
	{
		int32 MajorVersion = -1;
		int32 MinorVersion = -1;
		int32 PatchVersion = -1;
		int32 Changelist = 0;
		int32 IsLicenseeVersion = 0;
		FString BranchName;

		// Scan the file for version defines
		const TCHAR* TextPos = *VersionHeader;
		while(*TextPos)
		{
			// Skip over any newlines
			while(FChar::IsWhitespace(*TextPos))
			{
				TextPos++;
			}

			// Buffer up a line of tokens
			TArray<FString> Tokens;
			while(*TextPos != '\n' && *TextPos != 0)
			{
				if(*TextPos == ' ' || *TextPos == '\t' || *TextPos == '\r')
				{
					// Skip over whitespace
					TextPos++;
				}
				else if(FChar::IsIdentifier(*TextPos))
				{
					// Parse an identifier. Exact C rules for an identifier don't really matter; we just need alphanumeric sequences.
					const TCHAR* TokenStart = TextPos++;
					while(FChar::IsIdentifier(*TextPos)) TextPos++;
					Tokens.Add(FString(TextPos - TokenStart, TokenStart));
				}
				else if(*TextPos == '\"')
				{
					// Parse a string
					const TCHAR* TokenStart = TextPos++;
					while(*TextPos != 0 && (TextPos == TokenStart + 1 || *(TextPos - 1) != '\"')) TextPos++;
					Tokens.Add(FString(TextPos - TokenStart, TokenStart));
				}
				else if(*TextPos == '/' && *(TextPos + 1) == '/')
				{
					// Skip a C++ style comment
					TextPos += 2;
					while(*TextPos != '\n' && *TextPos != 0) TextPos++;
				}
				else if(*TextPos == '/' && *(TextPos + 1) == '*' && *(TextPos + 2) != 0 && *(TextPos + 3) != 0)
				{
					// Skip a C-style comment
					TextPos += 4;
					while(*TextPos != 0 && (*(TextPos - 2) != '*' || *(TextPos - 1) != '/')) TextPos++;
				}
				else
				{
					// Take a single symbol character
					Tokens.Add(FString(1, TextPos));
					TextPos++;
				}
			}

			// Check if it matches any version defines
			if(Tokens.Num() >= 4 && Tokens[0] == "#" && Tokens[1] == "define")
			{
				if(FChar::IsDigit(Tokens[3][0]))
				{
					if(Tokens[2] == "ENGINE_MAJOR_VERSION")
					{
						MajorVersion = FCString::Atoi(*Tokens[3]);
					}
					else if(Tokens[2] == "ENGINE_MINOR_VERSION")
					{
						MinorVersion = FCString::Atoi(*Tokens[3]);
					}
					else if(Tokens[2] == "ENGINE_PATCH_VERSION")
					{
						PatchVersion = FCString::Atoi(*Tokens[3]);
					}
					else if(Tokens[2] == "BUILT_FROM_CHANGELIST")
					{
						Changelist = FCString::Atoi(*Tokens[3]);
					}
					else if(Tokens[2] == "ENGINE_IS_LICENSEE_VERSION")
					{
						IsLicenseeVersion = FCString::Atoi(*Tokens[3]);
					}
				}
				else if(Tokens[3].StartsWith("\"") && Tokens[3].EndsWith("\""))
				{
					if(Tokens[2] == "BRANCH_NAME")
					{
						BranchName = Tokens[3].TrimQuotes();
					}
				}
			}
		}

		// If we have everything we need, fill in the version struct
		if(MajorVersion != -1 && MinorVersion != -1 && PatchVersion != -1)
		{
			int EncodedChangelist = (IsLicenseeVersion == 0)? Changelist : FEngineVersionBase::EncodeLicenseeChangelist(Changelist);
			OutVersion = FEngineVersion(MajorVersion, MinorVersion, PatchVersion, EncodedChangelist, BranchName);
			return true;
		}
	}

	return false;
}

bool FDesktopPlatformBase::IsStockEngineRelease(const FString &Identifier)
{
	FGuid Guid;
	return !FGuid::Parse(Identifier, Guid);
}

bool FDesktopPlatformBase::TryParseStockEngineVersion(const FString& Identifier, FEngineVersion& OutVersion)
{
	TCHAR* End;

	uint64 Major = FCString::Strtoui64(*Identifier, &End, 10);
	if (Major > MAX_uint16 || *(End++) != '.')
	{
		return false;
	}

	uint64 Minor = FCString::Strtoui64(End, &End, 10);
	if (Minor > MAX_uint16 || *End != 0)
	{
		return false;
	}

	OutVersion = FEngineVersion(Major, Minor, 0, 0, TEXT(""));
	return true;
}

bool FDesktopPlatformBase::IsSourceDistribution(const FString &EngineRootDir)
{
	// Check for the existence of a SourceBuild.txt file
	FString SourceBuildPath = EngineRootDir / TEXT("Engine/Build/SourceDistribution.txt");
	return (IFileManager::Get().FileSize(*SourceBuildPath) >= 0);
}

bool FDesktopPlatformBase::IsPerforceBuild(const FString &EngineRootDir)
{
	// Check for the existence of a SourceBuild.txt file
	FString PerforceBuildPath = EngineRootDir / TEXT("Engine/Build/PerforceBuild.txt");
	return (IFileManager::Get().FileSize(*PerforceBuildPath) >= 0);
}

bool FDesktopPlatformBase::IsValidRootDirectory(const FString &RootDir)
{
	// Check that there's an Engine\Binaries directory underneath the root
	FString EngineBinariesDirName = RootDir / TEXT("Engine/Binaries");
	FPaths::NormalizeDirectoryName(EngineBinariesDirName);
	if(!IFileManager::Get().DirectoryExists(*EngineBinariesDirName))
	{
		return false;
	}

	// Also check there's an Engine\Build directory. This will filter out anything that has an engine-like directory structure but doesn't allow building code projects - like the launcher.
	FString EngineBuildDirName = RootDir / TEXT("Engine/Build");
	FPaths::NormalizeDirectoryName(EngineBuildDirName);
	if(!IFileManager::Get().DirectoryExists(*EngineBuildDirName))
	{
		return false;
	}

	// Otherwise it's valid
	return true;
}

bool FDesktopPlatformBase::SetEngineIdentifierForProject(const FString &ProjectFileName, const FString &InIdentifier)
{
	// Load the project file
	TSharedPtr<FJsonObject> ProjectFile = LoadProjectFile(ProjectFileName);
	if (!ProjectFile.IsValid())
	{
		return false;
	}

	// Check if the project is a non-foreign project of the given engine installation. If so, blank the identifier 
	// string to allow portability between source control databases. GetEngineIdentifierForProject will translate
	// the association back into a local identifier on other machines or syncs.
	FString Identifier = InIdentifier;
	if(Identifier.Len() > 0)
	{
		FString RootDir;
		if(GetEngineRootDirFromIdentifier(Identifier, RootDir))
		{
			const FUProjectDictionary &Dictionary = GetCachedProjectDictionary(RootDir);
			if(!Dictionary.IsForeignProject(ProjectFileName))
			{
				Identifier.Empty();
			}
		}
	}

	// Set the association on the project and save it
	ProjectFile->SetStringField(TEXT("EngineAssociation"), Identifier);
	return SaveProjectFile(ProjectFileName, ProjectFile);
}

bool FDesktopPlatformBase::GetEngineIdentifierForProject(const FString& ProjectFileName, FString& OutIdentifier)
{
	OutIdentifier.Empty();

	// Load the project file
	TSharedPtr<FJsonObject> ProjectFile = LoadProjectFile(ProjectFileName);
	if(!ProjectFile.IsValid())
	{
		return false;
	}

	// Try to read the identifier from it
	TSharedPtr<FJsonValue> Value = ProjectFile->TryGetField(TEXT("EngineAssociation"));
	if(Value.IsValid() && Value->Type == EJson::String)
	{
		OutIdentifier = Value->AsString();
		if(OutIdentifier.Len() > 0)
		{
			// If it's a path, convert it into an engine identifier
			if(OutIdentifier.Contains(TEXT("/")) || OutIdentifier.Contains("\\"))
			{
				FString EngineRootDir = FPaths::ConvertRelativePathToFull(FPaths::GetPath(ProjectFileName), OutIdentifier);
				if(!GetEngineIdentifierFromRootDir(EngineRootDir, OutIdentifier))
				{
					return false;
				}
			}
			return true;
		}
	}

	// Otherwise scan up through the directory hierarchy to find an installation
	FString ParentDir = FPaths::GetPath(ProjectFileName);
	FPaths::NormalizeDirectoryName(ParentDir);

	// Keep going until we reach the root
	int32 SeparatorIdx;
	while(ParentDir.FindLastChar(TEXT('/'), SeparatorIdx))
	{
		ParentDir.RemoveAt(SeparatorIdx, ParentDir.Len() - SeparatorIdx);
		if(IsValidRootDirectory(ParentDir) && GetEngineIdentifierFromRootDir(ParentDir, OutIdentifier))
		{
			return true;
		}
	}

	// Otherwise check the engine version string for 4.0, in case this project existed before the engine association stuff went in
	FString EngineVersionString;
	if(ProjectFile->TryGetStringField(TEXT("EngineVersion"), EngineVersionString) && EngineVersionString.Len() > 0)
	{
		FEngineVersion EngineVersion;
		if(FEngineVersion::Parse(EngineVersionString, EngineVersion) && EngineVersion.HasChangelist() && EngineVersion.ToString(EVersionComponent::Minor) == TEXT("4.0"))
		{
			OutIdentifier = TEXT("4.0");
			return true;
		}
	}

	return false;
}

bool FDesktopPlatformBase::OpenProject(const FString& ProjectFileName)
{
	FPlatformProcess::LaunchFileInDefaultExternalApplication(*ProjectFileName);
	return true;
}

bool FDesktopPlatformBase::CleanGameProject(const FString& ProjectDir, FString& OutFailPath, FFeedbackContext* Warn)
{
	// Begin a task
	Warn->BeginSlowTask(LOCTEXT("CleaningProject", "Removing stale build products..."), true);

	// Enumerate all the files
	TArray<FString> FileNames;
	TArray<FString> DirectoryNames;
	GetProjectBuildProducts(ProjectDir, FileNames, DirectoryNames);

	// Remove all the files
	for(int32 Idx = 0; Idx < FileNames.Num(); Idx++)
	{
		// Remove the file
		if(!IFileManager::Get().Delete(*FileNames[Idx]))
		{
			OutFailPath = FileNames[Idx];
			Warn->EndSlowTask();
			return false;
		}

		// Update the progress
		Warn->UpdateProgress(Idx, FileNames.Num() + DirectoryNames.Num());
	}

	// Remove all the directories
	for(int32 Idx = 0; Idx < DirectoryNames.Num(); Idx++)
	{
		// Remove the directory
		if(!IFileManager::Get().DeleteDirectory(*DirectoryNames[Idx], false, true))
		{
			OutFailPath = DirectoryNames[Idx];
			Warn->EndSlowTask();
			return false;
		}

		// Update the progress
		Warn->UpdateProgress(Idx + FileNames.Num(), FileNames.Num() + DirectoryNames.Num());
	}

	// End the task
	Warn->EndSlowTask();
	return true;
}

bool FDesktopPlatformBase::CompileGameProject(const FString& RootDir, const FString& ProjectFileName, FFeedbackContext* Warn, ECompilationResult::Type* OutResult)
{
	FModuleManager& ModuleManager = FModuleManager::Get();

	// Build the argument list
	FString Arguments = FString::Printf(TEXT("%s %s"), ModuleManager.GetUBTConfiguration(), FPlatformMisc::GetUBTPlatform());

	// Append the project name if it's a foreign project. Otherwise compile UnrealEditor.
	if ( ProjectFileName.IsEmpty() )
	{
		Arguments = TEXT("UnrealEditor ") + Arguments;
	}
	else
	{
		Arguments += FString::Printf(TEXT(" -Project=\"%s\" -TargetType=Editor"), *IFileManager::Get().ConvertToAbsolutePathForExternalAppForRead(*ProjectFileName));
	}

	// Append any other options
	Arguments += " -Progress -NoEngineChanges -NoHotReloadFromIDE";

	// Run UBT
	int32 ExitCode;
	bool bResult = static_cast<IDesktopPlatform*>(this)->RunUnrealBuildTool(LOCTEXT("CompilingProject", "Compiling project..."), RootDir, Arguments, Warn, ExitCode);
	if (OutResult != nullptr)
	{
		*OutResult = (ECompilationResult::Type)ExitCode;
	}

	// Reset module paths in case they have changed during compilation
	ModuleManager.ResetModulePathsCache();

	return bResult;
}

bool FDesktopPlatformBase::GenerateProjectFiles(const FString& RootDir, const FString& ProjectFileName, FFeedbackContext* Warn, FString LogFilePath)
{
	FString Arguments = TEXT(" -projectfiles");

	// Build the arguments to pass to UBT. If it's a non-foreign project, just build full project files.
	if ( !ProjectFileName.IsEmpty() && GetCachedProjectDictionary(RootDir).IsForeignProject(ProjectFileName) )
	{
		// Figure out whether it's a foreign project
		const FUProjectDictionary &ProjectDictionary = GetCachedProjectDictionary(RootDir);
		if(ProjectDictionary.IsForeignProject(ProjectFileName))
		{
			Arguments += FString::Printf(TEXT(" -project=\"%s\""), *IFileManager::Get().ConvertToAbsolutePathForExternalAppForRead(*ProjectFileName));

			// Always include game source
			Arguments += TEXT(" -game");

			// Determine whether or not to include engine source
			if(IsSourceDistribution(RootDir))
			{
				Arguments += TEXT(" -engine");
			}
			else
			{
				// If this is used within UnrealVersionSelector then we still need to pass
				// -rocket to deal with old versions that don't use Rocket.txt file
				Arguments += TEXT(" -rocket");
			}
		}
	}
	Arguments += TEXT(" -progress");

	if (!LogFilePath.IsEmpty())
	{
		Arguments += FString::Printf(TEXT(" -log=\"%s\""), *LogFilePath);
	}

	// Compile UnrealBuildTool if it doesn't exist. This can happen if we're just copying source from somewhere.
	bool bRes = true;
	Warn->BeginSlowTask(LOCTEXT("GeneratingProjectFiles", "Generating project files..."), true, true);
	if(!FPaths::FileExists(GetUnrealBuildToolExecutableFilename(RootDir)))
	{
		Warn->StatusUpdate(0, 1, LOCTEXT("BuildingUBT", "Building UnrealBuildTool..."));
		bRes = BuildUnrealBuildTool(RootDir, *Warn);
	}
	if(bRes)
	{
		Warn->StatusUpdate(0, 1, LOCTEXT("GeneratingProjectFiles", "Generating project files..."));
		bRes = RunUnrealBuildTool(LOCTEXT("GeneratingProjectFiles", "Generating project files..."), RootDir, Arguments, Warn);
	}
	Warn->EndSlowTask();
	return bRes;
}

bool FDesktopPlatformBase::IsUnrealBuildToolAvailable()
{
	// If using installed build and the unreal build tool executable exists, then UBT is available. Otherwise check it can be built.
	if (FApp::IsEngineInstalled())
	{
		return FPaths::FileExists(GetUnrealBuildToolExecutableFilename(FPaths::RootDir()));
	}
	else
	{
		return FPaths::FileExists(GetUnrealBuildToolProjectFileName(FPaths::RootDir()));
	}
}

bool FDesktopPlatformBase::InvokeUnrealBuildToolSync(const FString& InCmdLineParams, FOutputDevice &Ar, bool bSkipBuildUBT, int32& OutReturnCode, FString& OutProcOutput)
{
	TRACE_CPUPROFILER_EVENT_SCOPE(FDesktopPlatformBase::InvokeUnrealBuildToolSync);
	void* PipeRead = nullptr;
	void* PipeWrite = nullptr;

	verify(FPlatformProcess::CreatePipe(PipeRead, PipeWrite));

	bool bInvoked = false;
	FProcHandle ProcHandle = InvokeUnrealBuildToolAsync(InCmdLineParams, Ar, PipeRead, PipeWrite, bSkipBuildUBT);
	if (ProcHandle.IsValid())
	{
		// rather than waiting, we must flush the read pipe or UBT will stall if it writes out a ton of text to the console.
		while (FPlatformProcess::IsProcRunning(ProcHandle))
		{
			OutProcOutput += FPlatformProcess::ReadPipe(PipeRead);
			FPlatformProcess::Sleep(0.1f);
		}		
		bInvoked = true;
		bool bGotReturnCode = FPlatformProcess::GetProcReturnCode(ProcHandle, &OutReturnCode);		
		check(bGotReturnCode);
	}
	else
	{
		bInvoked = false;
		OutReturnCode = -1;
		OutProcOutput = TEXT("");
	}


	FPlatformProcess::ClosePipe(PipeRead, PipeWrite);

	return bInvoked;
}

FProcHandle FDesktopPlatformBase::InvokeUnrealBuildToolAsync(const FString& InCmdLineParams, FOutputDevice &Ar, void*& OutReadPipe, void*& OutWritePipe, bool bSkipBuildUBT)
{
	FString CmdLineParams = InCmdLineParams;

	// UnrealBuildTool is currently always located in the Binaries/DotNET folder
	FString ExecutableFileName = GetUnrealBuildToolExecutableFilename(FPaths::RootDir());

	// Installed builds never build UBT, UnrealBuildTool should already exist
	bool bSkipBuild = FApp::IsEngineInstalled() || bSkipBuildUBT;
	if (!bSkipBuild)
	{
		// When not using an installed build, we should attempt to build UBT to make sure it is up to date
		// Only do this if we have not already successfully done it once during this session.
		static bool bSuccessfullyBuiltUBTOnce = false;
		if (!bSuccessfullyBuiltUBTOnce)
		{
			Ar.Log(TEXT("Building UnrealBuildTool..."));
			if (BuildUnrealBuildTool(FPaths::RootDir(), Ar))
			{
				bSuccessfullyBuiltUBTOnce = true;
			}
			else
			{
				// Failed to build UBT
				Ar.Log(TEXT("Failed to build UnrealBuildTool."));
				UE_LOG(LogDesktopPlatform, Warning, TEXT("Failed to compile UnrealBuildTool (project file is '%s', exe path is '%s')"), *GetUnrealBuildToolProjectFileName(FPaths::RootDir()), *ExecutableFileName);
				return FProcHandle();
			}
		}
	}

#if PLATFORM_LINUX
	CmdLineParams += (" -progress");
#endif // PLATFORM_LINUX

	Ar.Logf(TEXT("Launching UnrealBuildTool... [%s %s]"), *ExecutableFileName, *CmdLineParams);

	// Run UnrealBuildTool
	const bool bLaunchDetached = false;
	const bool bLaunchHidden = true;
	const bool bLaunchReallyHidden = bLaunchHidden;

	FProcHandle ProcHandle = FPlatformProcess::CreateProc(*ExecutableFileName, *CmdLineParams, bLaunchDetached, bLaunchHidden, bLaunchReallyHidden, NULL, 0, NULL, OutWritePipe, OutReadPipe);
	if (!ProcHandle.IsValid())
	{
		UE_LOG(LogDesktopPlatform, Warning, TEXT("Failed to launch UnrealBuildTool (exe path is '%s')"), *ExecutableFileName);
		Ar.Logf(TEXT("Failed to launch Unreal Build Tool. (%s)"), *ExecutableFileName);
	}

	return ProcHandle;
}

bool FDesktopPlatformBase::RunUnrealBuildTool(const FText& Description, const FString& RootDir, const FString& Arguments, FFeedbackContext* Warn)
{
	int32 ExitCode;
	return static_cast<IDesktopPlatform*>(this)->RunUnrealBuildTool(Description, RootDir, Arguments, Warn, ExitCode);
}

struct FTargetFileVisitor : IPlatformFile::FDirectoryStatVisitor
{
	TSet<FString>& RemainingTargetNames;
	FDateTime MaxDateTime;
	TArray<FString> SubDirectories;
	bool bSearchSubDirectories;

	FTargetFileVisitor(TSet<FString>& InRemainingTargetNames, FDateTime InMaxDateTime)
		: RemainingTargetNames(InRemainingTargetNames)
		, MaxDateTime(InMaxDateTime)
		, bSearchSubDirectories(false)
	{
	}

	virtual bool Visit(const TCHAR* FileNameOrDirectory, const FFileStatData& StatData) override
	{
		if (StatData.bIsDirectory)
		{
			SubDirectories.Add(FileNameOrDirectory);
			return true;
		}

		int32 Length = FCString::Strlen(FileNameOrDirectory);

		static const TCHAR TargetExt[] = TEXT(".Target.cs");
		static const int32 TargetExtLen = UE_ARRAY_COUNT(TargetExt) - 1;
		if (Length > TargetExtLen && FCString::Stricmp(FileNameOrDirectory + Length - TargetExtLen, TargetExt) == 0)
		{
			FString TargetName = FPaths::GetCleanFilename(FString(Length - TargetExtLen, FileNameOrDirectory));
			return (StatData.ModificationTime < MaxDateTime && RemainingTargetNames.Remove(TargetName) == 1);
		}
		
		static const TCHAR ModuleExt[] = TEXT(".Build.cs");
		static const int32 ModuleExtLen = UE_ARRAY_COUNT(ModuleExt) - 1;
		if (Length > ModuleExtLen && FCString::Stricmp(FileNameOrDirectory + Length - ModuleExtLen, ModuleExt) == 0)
		{
			bSearchSubDirectories = false;
			return true;
		}

		return true;
	}
};

bool IsTargetInfoValid(const TArray<FTargetInfo>& Targets, const FString& SourceDir, const FDateTime& LastModifiedTime)
{
	if (FApp::GetEngineIsPromotedBuild())
	{
		// Promoted builds may not have source code, so we will assume all supplied targets are valid since they will not appear on disk
		return true;
	}

	// Create the state 
	TSet<FString> RemainingTargetNames;
	for (const FTargetInfo& Target : Targets)
	{
		RemainingTargetNames.Add(Target.Name);
	}

	// Loop through all the directories
	TArray<FString> DirectoryNames = { SourceDir };
	for(int Idx = 0; Idx < DirectoryNames.Num(); Idx++)
	{
		FTargetFileVisitor Visitor(RemainingTargetNames, LastModifiedTime);
		if(!IFileManager::Get().IterateDirectoryStat(*DirectoryNames[Idx], Visitor))
		{
			return false;
		}
		if(Visitor.bSearchSubDirectories)
		{
			DirectoryNames += Visitor.SubDirectories;
		}
	}

	// If we found all the previous target files
	return RemainingTargetNames.Num() == 0;
}

const TArray<FTargetInfo>& FDesktopPlatformBase::GetTargetsForProject(const FString& ProjectFile) const
{
	// Normalize the project filename
	FString NormalizedProjectFile = ProjectFile;
	FPaths::NormalizeFilename(NormalizedProjectFile);

	// Check if there's already a cached entry for this project
	const TArray<FTargetInfo>* Targets = ProjectFileToTargets.Find(NormalizedProjectFile);
	if (Targets != nullptr)
	{
		return *Targets;
	}

	// Get the base directory for the project (or the engine directory)
	FString ProjectDir;
	if(ProjectFile.Len() == 0)
	{
		ProjectDir = FPaths::EngineDir();
	}
	else
	{
		ProjectDir = FPaths::GetPath(ProjectFile);
	}

	FString ProjectSourceDir = ProjectDir / TEXT("Source");

	// Get the path to the info filename
	FString InfoFileName = ProjectDir / TEXT("Intermediate/TargetInfo.json");

	// Check if the file already exists
	FFileStatData StatData = IFileManager::Get().GetStatData(*InfoFileName);
	if(StatData.bIsValid)
	{
		// Read it in and check it's still valid
		TArray<FTargetInfo> NewTargets;
		if(ReadTargetInfo(InfoFileName, NewTargets) && IsTargetInfoValid(NewTargets, ProjectSourceDir, StatData.ModificationTime))
		{
			return ProjectFileToTargets.Emplace(MoveTemp(NormalizedProjectFile), MoveTemp(NewTargets));
		}
	}

	// Get the project source directory. If it doesn't exist, there are no targets for this project.
	if (!IFileManager::Get().DirectoryExists(*ProjectSourceDir))
	{
		return ProjectFileToTargets.Add(NormalizedProjectFile, TArray<FTargetInfo>());
	}

	// Otherwise, we'll have to run UBT to update it
	FString Arguments = TEXT("-Mode=QueryTargets");
	if(ProjectFile.Len() > 0)
	{
		Arguments += FString::Printf(TEXT(" -Project=\"%s\""), *IFileManager::Get().ConvertToAbsolutePathForExternalAppForRead(*ProjectFile));
	}
	Arguments += FString::Printf(TEXT(" -Output=\"%s\""), *IFileManager::Get().ConvertToAbsolutePathForExternalAppForRead(*InfoFileName));

	// Run UBT to update the list of targets. Try to run it without building first.
	FString Output;
	int32 ReturnCode = 0;
	if (!FPaths::FileExists(GetUnrealBuildToolExecutableFilename(FPaths::RootDir())) || !const_cast<FDesktopPlatformBase*>(this)->InvokeUnrealBuildToolSync(Arguments, *GLog, true, ReturnCode, Output) || ReturnCode != 0)
	{
		// If that failed, try to build and run again. Build machines should always have an up-to-date copy, and shouldn't build anything without being told to do so.
		if (!GIsBuildMachine)
		{
			const_cast<FDesktopPlatformBase*>(this)->InvokeUnrealBuildToolSync(Arguments, *GLog, false, ReturnCode, Output);
		}
	}

	// Try to read the new targets
	TArray<FTargetInfo> NewTargets;
	if(!ReadTargetInfo(InfoFileName, NewTargets))
	{
		UE_LOG(LogDesktopPlatform, Warning, TEXT("Unable to read target info for %s"), (ProjectFile.Len() == 0)? TEXT("engine") : *ProjectFile);
	}

	// Add it to the cache
	return ProjectFileToTargets.Emplace(MoveTemp(NormalizedProjectFile), MoveTemp(NewTargets));
}

const TArray<FTargetInfo>& FDesktopPlatformBase::GetTargetsForCurrentProject() const
{
	return GetTargetsForProject(FPaths::GetProjectFilePath());
}

FString FDesktopPlatformBase::GetDefaultProjectCreationPath()
{
	// My Documents
	const FString DefaultProjectSubFolder = TEXT("Unreal Projects");
	return FString(FPlatformProcess::UserDir()) + DefaultProjectSubFolder;
}

void FDesktopPlatformBase::ReadLauncherInstallationList()
{
	FString InstalledListFile = FString(FPlatformProcess::ApplicationSettingsDir()) / TEXT("UnrealEngineLauncher/LauncherInstalled.dat");

	// If the file does not exist, manually check for the 4.0 or 4.1 manifest
	FDateTime NewListTimestamp = IFileManager::Get().GetTimeStamp(*InstalledListFile);
	if(NewListTimestamp == FDateTime::MinValue())
	{
		if(LauncherInstallationList.Num() == 0)
		{
			CheckForLauncherEngineInstallation(TEXT("40003"), TEXT("UE_4.0"), LauncherInstallationList);
			CheckForLauncherEngineInstallation(TEXT("1040003"), TEXT("UE_4.1"), LauncherInstallationList);
		}
	}
	else if(NewListTimestamp != LauncherInstallationTimestamp)
	{
		// Read the installation manifest
		FString InstalledText;
		if (FFileHelper::LoadFileToString(InstalledText, *InstalledListFile))
		{
			// Deserialize the object
			TSharedPtr< FJsonObject > RootObject;
			TSharedRef< TJsonReader<> > Reader = TJsonReaderFactory<>::Create(InstalledText);
			if (FJsonSerializer::Deserialize(Reader, RootObject) && RootObject.IsValid())
			{
				// Parse the list of installations
				TArray< TSharedPtr<FJsonValue> > InstallationList = RootObject->GetArrayField(TEXT("InstallationList"));
				for(int32 Idx = 0; Idx < InstallationList.Num(); Idx++)
				{
					TSharedPtr<FJsonObject> InstallationItem = InstallationList[Idx]->AsObject();

					FString AppName = InstallationItem->GetStringField(TEXT("AppName"));
					FString InstallLocation = InstallationItem->GetStringField(TEXT("InstallLocation"));
					if(AppName.Len() > 0 && InstallLocation.Len() > 0)
					{
						FPaths::NormalizeDirectoryName(InstallLocation);
						LauncherInstallationList.Add(AppName, InstallLocation);
					}
				}
			}
			LauncherInstallationTimestamp = NewListTimestamp;
		}
	}
}

void FDesktopPlatformBase::CheckForLauncherEngineInstallation(const FString &AppId, const FString &Identifier, TMap<FString, FString> &OutInstallations)
{
	FString ManifestText;
	FString ManifestFileName = FString(FPlatformProcess::ApplicationSettingsDir()) / FString::Printf(TEXT("UnrealEngineLauncher/Data/Manifests/%s.manifest"), *AppId);

	if (FFileHelper::LoadFileToString(ManifestText, *ManifestFileName))
	{
		TSharedPtr< FJsonObject > RootObject;
		TSharedRef< TJsonReader<> > Reader = TJsonReaderFactory<>::Create(ManifestText);
		if (FJsonSerializer::Deserialize(Reader, RootObject) && RootObject.IsValid())
		{
			TSharedPtr<FJsonObject> CustomFieldsObject = RootObject->GetObjectField(TEXT("CustomFields"));
			if (CustomFieldsObject.IsValid())
			{
				FString InstallLocation = CustomFieldsObject->GetStringField("InstallLocation");
				if (InstallLocation.Len() > 0)
				{
					OutInstallations.Add(Identifier, InstallLocation);
				}
			}
		}
	}
}

int32 FDesktopPlatformBase::ParseReleaseVersion(const FString &Version)
{
	TCHAR *End;

	uint64 Major = FCString::Strtoui64(*Version, &End, 10);
	if (Major >= MAX_int16 || *(End++) != '.')
	{
		return INDEX_NONE;
	}

	uint64 Minor = FCString::Strtoui64(End, &End, 10);
	if (Minor >= MAX_int16 || *End != 0)
	{
		return INDEX_NONE;
	}

	return (Major << 16) + Minor;
}

TSharedPtr<FJsonObject> FDesktopPlatformBase::LoadProjectFile(const FString &FileName)
{
	FString FileContents;

	if (!FFileHelper::LoadFileToString(FileContents, *FileName))
	{
		return TSharedPtr<FJsonObject>(NULL);
	}

	TSharedPtr< FJsonObject > JsonObject;
	TSharedRef< TJsonReader<> > Reader = TJsonReaderFactory<>::Create(FileContents);
	if (!FJsonSerializer::Deserialize(Reader, JsonObject) || !JsonObject.IsValid())
	{
		return TSharedPtr<FJsonObject>(NULL);
	}

	return JsonObject;
}

bool FDesktopPlatformBase::SaveProjectFile(const FString &FileName, TSharedPtr<FJsonObject> Object)
{
	FString FileContents;

	TSharedRef< TJsonWriter<> > Writer = TJsonWriterFactory<>::Create(&FileContents);
	if (!FJsonSerializer::Serialize(Object.ToSharedRef(), Writer))
	{
		return false;
	}

	if (!FFileHelper::SaveStringToFile(FileContents, *FileName))
	{
		return false;
	}

	return true;
}

const FUProjectDictionary &FDesktopPlatformBase::GetCachedProjectDictionary(const FString& RootDir)
{
	FString NormalizedRootDir = RootDir;
	FPaths::NormalizeDirectoryName(NormalizedRootDir);

	FUProjectDictionary *Dictionary = CachedProjectDictionaries.Find(NormalizedRootDir);
	if(Dictionary == NULL)
	{
		Dictionary = &CachedProjectDictionaries.Add(RootDir, FUProjectDictionary(RootDir));
	}
	return *Dictionary;
}

void FDesktopPlatformBase::GetProjectBuildProducts(const FString& ProjectDir, TArray<FString> &OutFileNames, TArray<FString> &OutDirectoryNames)
{
	FString NormalizedProjectDir = ProjectDir;
	FPaths::NormalizeDirectoryName(NormalizedProjectDir);

	// Find all the build roots
	TArray<FString> BuildRootDirectories;
	BuildRootDirectories.Add(NormalizedProjectDir);

	// Add all the plugin directories
	TArray<FString> PluginFileNames;
	IFileManager::Get().FindFilesRecursive(PluginFileNames, *(NormalizedProjectDir / TEXT("Plugins")), TEXT("*.uplugin"), true, false);
	for(int32 Idx = 0; Idx < PluginFileNames.Num(); Idx++)
	{
		BuildRootDirectories.Add(FPaths::GetPath(PluginFileNames[Idx]));
	}

	// Add all the intermediate directories
	for(int32 Idx = 0; Idx < BuildRootDirectories.Num(); Idx++)
	{
		OutDirectoryNames.Add(BuildRootDirectories[Idx] / TEXT("Intermediate"));
	}

	// Add the files in the cleaned directories to the output list
	for(int32 Idx = 0; Idx < OutDirectoryNames.Num(); Idx++)
	{
		IFileManager::Get().FindFilesRecursive(OutFileNames, *OutDirectoryNames[Idx], TEXT("*"), true, false, false);
	}
}

FString FDesktopPlatformBase::GetEngineSavedConfigDirectory(const FString& Identifier)
{
	// Get the game agnostic config dir
	const FString UserDir = GetUserDir(Identifier);
	if (!UserDir.IsEmpty())
	{
		return UserDir / TEXT("Saved/Config") / ANSI_TO_TCHAR(FPlatformProperties::PlatformName());
	}

	return FString();
}

bool FDesktopPlatformBase::EnumerateProjectsKnownByEngine(const FString &Identifier, bool bIncludeNativeProjects, TArray<FString> &OutProjectFileNames)
{
	// Get the engine root directory
	FString RootDir;
	if (!GetEngineRootDirFromIdentifier(Identifier, RootDir))
	{
		return false;
	}

	FString GameAgnosticConfigDir = GetEngineSavedConfigDirectory(Identifier);
	if (GameAgnosticConfigDir.Len() == 0)
	{
		return false;
	}

	// Find all the created project directories. Start with the default project creation path.
	TArray<FString> SearchDirectories;
	SearchDirectories.AddUnique(GetDefaultProjectCreationPath());

	UE_LOG(LogDesktopPlatform, Log, TEXT("Enumerating Projects From Engine Ver: %s"), *Identifier);

	UE_LOG(LogDesktopPlatform, Log, TEXT("Looking for directories to scan from : %s"), *GameAgnosticConfigDir);
	// Load the config file
	FConfigFile GameAgnosticConfig;
	if (!FConfigCacheIni::LoadExternalIniFile(GameAgnosticConfig, TEXT("EditorSettings"), NULL, *GameAgnosticConfigDir, false))
	{
		FString PreviousConfigDir = MoveTemp(GameAgnosticConfigDir);

		// Load from the legacy path. Most likely a pre-UE5 engine install
		GameAgnosticConfigDir = GetLegacyEngineSavedConfigDirectory(Identifier);

		UE_LOG(LogDesktopPlatform, Log, TEXT("%s not found, looking for directories in %s"), *PreviousConfigDir , *GameAgnosticConfigDir);

		FConfigCacheIni::LoadExternalIniFile(GameAgnosticConfig, TEXT("EditorSettings"), NULL, *GameAgnosticConfigDir, false);
	}

	// Find the editor game-agnostic settings
	FConfigSection* Section = GameAgnosticConfig.Find(TEXT("/Script/UnrealEd.EditorSettings"));

	if (Section == NULL)
	{
		FConfigCacheIni::LoadExternalIniFile(GameAgnosticConfig, TEXT("EditorGameAgnostic"), NULL, *GameAgnosticConfigDir, false);
		Section = GameAgnosticConfig.Find(TEXT("/Script/UnrealEd.EditorGameAgnosticSettings"));
	}

	if (GameAgnosticConfig.IsEmpty())
	{
		UE_LOG(LogDesktopPlatform, Log, TEXT("Config not found"));
	}

	if(Section != NULL)
	{
		UE_LOG(LogDesktopPlatform, Log, TEXT("Searching for previously created project directories..."));

		// Add in every path that the user has ever created a project file. This is to catch new projects showing up in the user's project folders
		TArray<FString> AdditionalDirectories;
		Section->MultiFind(TEXT("CreatedProjectPaths"), AdditionalDirectories);
		for(int Idx = 0; Idx < AdditionalDirectories.Num(); Idx++)
		{
			FPaths::NormalizeDirectoryName(AdditionalDirectories[Idx]);

			UE_LOG(LogDesktopPlatform, Log, TEXT("Found directory: \"%s\""), *AdditionalDirectories[Idx]);
			SearchDirectories.AddUnique(AdditionalDirectories[Idx]);
		}

		// Also add in all the recently opened projects
		TArray<FString> RecentlyOpenedFiles;
		Section->MultiFind(TEXT("RecentlyOpenedProjectFiles"), RecentlyOpenedFiles);
		for(int Idx = 0; Idx < RecentlyOpenedFiles.Num(); Idx++)
		{
			FPaths::NormalizeFilename(RecentlyOpenedFiles[Idx]);

			UE_LOG(LogDesktopPlatform, Log, TEXT("Found project \"%s\" in recently opened files"), *RecentlyOpenedFiles[Idx]);

			OutProjectFileNames.AddUnique(RecentlyOpenedFiles[Idx]);
		}		
	}

	// Find all the other projects that are in the search directories
	for(int Idx = 0; Idx < SearchDirectories.Num(); Idx++)
	{
		TArray<FString> ProjectFolders;
		IFileManager::Get().FindFiles(ProjectFolders, *(SearchDirectories[Idx] / TEXT("*")), false, true);

		for(int32 FolderIdx = 0; FolderIdx < ProjectFolders.Num(); FolderIdx++)
		{
			TArray<FString> ProjectFiles;
			IFileManager::Get().FindFiles(ProjectFiles, *(SearchDirectories[Idx] / ProjectFolders[FolderIdx] / TEXT("*.uproject")), true, false);

			for(int32 FileIdx = 0; FileIdx < ProjectFiles.Num(); FileIdx++)
			{
				FString ProjName = SearchDirectories[Idx] / ProjectFolders[FolderIdx] / ProjectFiles[FileIdx];

				UE_LOG(LogDesktopPlatform, Log, TEXT("Found project \"%s\" in previously created project directory"), *ProjName);

				OutProjectFileNames.AddUnique(MoveTemp(ProjName));
			}
		}
	}

	UE_LOG(LogDesktopPlatform, Log, TEXT("Searcing for projects in .uprojectdirs"));

	// Find all the native projects, and either add or remove them from the list depending on whether we want native projects
	const FUProjectDictionary &Dictionary = GetCachedProjectDictionary(RootDir);
	if(bIncludeNativeProjects)
	{
		TArray<FString> NativeProjectPaths = Dictionary.GetProjectPaths();
		for(int Idx = 0; Idx < NativeProjectPaths.Num(); Idx++)
		{
			if(!NativeProjectPaths[Idx].Contains(TEXT("/Templates/")))
			{
				UE_LOG(LogDesktopPlatform, Log, TEXT("Found project \"%s\" in .uprojectdirs"), *NativeProjectPaths[Idx]);

				OutProjectFileNames.AddUnique(NativeProjectPaths[Idx]);
			}
		}
	}
	else
	{
		TArray<FString> NativeProjectPaths = Dictionary.GetProjectPaths();
		for(int Idx = 0; Idx < NativeProjectPaths.Num(); Idx++)
		{
			OutProjectFileNames.Remove(NativeProjectPaths[Idx]);
		}
	}

	return true;
}

#if PLATFORM_WINDOWS

#include "Windows/WindowsHWrapper.h"
#include "Windows/AllowWindowsPlatformTypes.h"
#include <ShlObj.h>
#include "Windows/HideWindowsPlatformTypes.h"

static bool TryReadMsBuildInstallPath(HKEY RootKey, const TCHAR* KeyName, const TCHAR* ValueName, const TCHAR* MsBuildRelativePath, FString& OutMsBuildPath)
{
	FString Value;
	if (!FWindowsPlatformMisc::QueryRegKey(RootKey, KeyName, ValueName, Value))
	{
		return false;
	}

	FString Result = Value / MsBuildRelativePath;
	if (!FPaths::FileExists(Result))
	{
		return false;
	}

	OutMsBuildPath = Result;
	return true;
}

static bool TryReadMsBuildInstallPath(const TCHAR* KeyRelativeName, const TCHAR* ValueName, const TCHAR* MsBuildRelativePath, FString& OutMsBuildPath)
{
	if (TryReadMsBuildInstallPath(HKEY_CURRENT_USER, *(FString("SOFTWARE\\") + KeyRelativeName), ValueName, MsBuildRelativePath, OutMsBuildPath))
	{
		return true;
	}
	if (TryReadMsBuildInstallPath(HKEY_LOCAL_MACHINE, *(FString("SOFTWARE\\") + KeyRelativeName), ValueName, MsBuildRelativePath, OutMsBuildPath))
	{
		return true;
	}
	if (TryReadMsBuildInstallPath(HKEY_CURRENT_USER, *(FString("SOFTWARE\\Wow6432Node\\") + KeyRelativeName), ValueName, MsBuildRelativePath, OutMsBuildPath))
	{
		return true;
	}
	if (TryReadMsBuildInstallPath(HKEY_LOCAL_MACHINE, *(FString("SOFTWARE\\Wow6432Node\\") + KeyRelativeName), ValueName, MsBuildRelativePath, OutMsBuildPath))
	{
		return true;
	}
	return false;
}

static bool TryReadMsBuildInstallPath(FString& OutPath)
{
	// Try to get the MSBuild 14.0 path directly (see https://msdn.microsoft.com/en-us/library/hh162058(v=vs.120).aspx)
	TCHAR ProgramFilesX86[MAX_PATH];
	if (SUCCEEDED(SHGetFolderPath(NULL, CSIDL_PROGRAM_FILES | CSIDL_FLAG_CREATE, NULL, SHGFP_TYPE_CURRENT, ProgramFilesX86)))
	{
		FString ToolPath = FString(ProgramFilesX86) / TEXT("MSBuild/14.0/bin/MSBuild.exe");
		if (FPaths::FileExists(ToolPath))
		{
			OutPath = ToolPath;
			return true;
		}
	}

	// Try to get the MSBuild 14.0 path from the registry
	if (TryReadMsBuildInstallPath(TEXT("Microsoft\\MSBuild\\ToolsVersions\\14.0"), TEXT("MSBuildToolsPath"), TEXT("MSBuild.exe"), OutPath))
	{
		return true;
	}

	// Check for MSBuild 15. This is installed alongside Visual Studio 2017, so we get the path relative to that.
	if (TryReadMsBuildInstallPath(TEXT("Microsoft\\VisualStudio\\SxS\\VS7"), TEXT("15.0"), TEXT("MSBuild\\15.0\\bin\\MSBuild.exe"), OutPath))
	{
		return true;
	}

	// Check for older versions of MSBuild. These are registered as separate versions in the registry.
	if (TryReadMsBuildInstallPath(TEXT("Microsoft\\MSBuild\\ToolsVersions\\12.0"), TEXT("MSBuildToolsPath"), TEXT("MSBuild.exe"), OutPath))
	{
		return true;
	}
	if (TryReadMsBuildInstallPath(TEXT("Microsoft\\MSBuild\\ToolsVersions\\4.0"), TEXT("MSBuildToolsPath"), TEXT("MSBuild.exe"), OutPath))
	{
		return true;
	}

	return false;
}
#endif

bool FDesktopPlatformBase::BuildUnrealBuildTool(const FString& RootDir, FOutputDevice& Ar)
{
	Ar.Logf(TEXT("Building UnrealBuildTool in %s..."), *RootDir);

	// Check the project file exists
	FString CsProjLocation = GetUnrealBuildToolProjectFileName(RootDir);
	if (!FPaths::FileExists(CsProjLocation))
	{
		Ar.Logf(TEXT("Project file not found at %s"), *CsProjLocation);
		return false;
	}

	FString CompilerExecutableFilename;
	FString CmdLineParams;

	if (PLATFORM_WINDOWS)
	{
#if PLATFORM_WINDOWS
		if (!TryReadMsBuildInstallPath(CompilerExecutableFilename))
		{
			Ar.Logf(TEXT("Couldn't find MSBuild installation; skipping."));
			return false;
		}
#endif
		CmdLineParams = FString::Printf(TEXT("/nologo /verbosity:quiet \"%s\" /property:Configuration=Development /property:Platform=AnyCPU"), *CsProjLocation);
	}
	else if (PLATFORM_MAC)
	{
		FString ScriptPath = FPaths::ConvertRelativePathToFull(RootDir / TEXT("Engine/Build/BatchFiles/Mac/RunXBuild.sh"));
		CompilerExecutableFilename = TEXT("/bin/sh");
		CmdLineParams = FString::Printf(TEXT("\"%s\" /property:Configuration=Development %s"), *ScriptPath, *CsProjLocation);
	}
	else if (PLATFORM_LINUX)
	{
		FString ScriptPath = FPaths::ConvertRelativePathToFull(RootDir / TEXT("Engine/Build/BatchFiles/Linux/RunXBuild.sh"));
		CompilerExecutableFilename = TEXT("/bin/bash");
		CmdLineParams = FString::Printf(TEXT("\"%s\" /property:Configuration=Development %s"), *ScriptPath, *CsProjLocation);
	}
	else
	{
		Ar.Log(TEXT("Unknown platform, unable to build UnrealBuildTool."));
		return false;
	}

	// Spawn the compiler
	Ar.Logf(TEXT("Running: %s %s"), *CompilerExecutableFilename, *CmdLineParams);
	const bool bLaunchDetached = false;
	const bool bLaunchHidden = true;
	const bool bLaunchReallyHidden = bLaunchHidden;

	void* PipeRead = nullptr;
	void* PipeWrite = nullptr;

	verify(FPlatformProcess::CreatePipe(PipeRead, PipeWrite));

	FProcHandle ProcHandle = FPlatformProcess::CreateProc(*CompilerExecutableFilename, *CmdLineParams, bLaunchDetached, bLaunchHidden, bLaunchReallyHidden, NULL, 0, NULL, PipeWrite, PipeRead);
	if (!ProcHandle.IsValid())
	{
		Ar.Log(TEXT("Failed to start process."));
		return false;
	}
	FPlatformProcess::WaitForProc(ProcHandle);
	FPlatformProcess::CloseProc(ProcHandle);
	FPlatformProcess::ClosePipe(PipeRead, PipeWrite);

	// If the executable appeared where we expect it, then we were successful
	FString UnrealBuildToolExePath = GetUnrealBuildToolExecutableFilename(RootDir);
	if (!FPaths::FileExists(UnrealBuildToolExePath))
	{
		Ar.Logf(TEXT("Missing %s after build"), *UnrealBuildToolExePath);
		return false;
	}

	return true;
}

bool FDesktopPlatformBase::ReadTargetInfo(const FString& FileName, TArray<FTargetInfo>& Targets)
{
	// Read the file to a string
	FString Contents;
	if (!FFileHelper::LoadFileToString(Contents, *FileName))
	{
		return false;
	}

	// Deserialize a JSON object from the string
	TSharedPtr<FJsonObject> ObjectPtr;
	TSharedRef<TJsonReader<>> Reader = TJsonReaderFactory<>::Create(Contents);
	if (!FJsonSerializer::Deserialize(Reader, ObjectPtr) || !ObjectPtr.IsValid())
	{
		return false;
	}

	// Get the targets array
	const TArray<TSharedPtr<FJsonValue>>* TargetArray;
	if (!ObjectPtr->TryGetArrayField(TEXT("Targets"), TargetArray))
	{
		return false;
	}

	// Presize the output array
	Targets.SetNum(TargetArray->Num());

	// Parse the entries
	for (int Idx = 0; Idx < TargetArray->Num(); Idx++)
	{
		const FJsonValue& TargetValue = *(*TargetArray)[Idx].Get();
		if (TargetValue.Type != EJson::Object)
		{
			return false;
		}

		const FJsonObject& TargetObject = *TargetValue.AsObject();
		if(!TargetObject.TryGetStringField(TEXT("Name"), Targets[Idx].Name) || !TargetObject.TryGetStringField(TEXT("Path"), Targets[Idx].Path))
		{
			return false;
		}

		FString Type;
		if (!TargetObject.TryGetStringField(TEXT("Type"), Type))
		{
			return false;
		}
		if(!LexTryParseString(Targets[Idx].Type, *Type) || Targets[Idx].Type == EBuildTargetType::Unknown)
		{
			return false;
		}
	}

	return true;
}

FString FDesktopPlatformBase::GetUserDir(const FString& Identifier)
{
	// Get the engine root directory
	FString RootDir;
	if (!GetEngineRootDirFromIdentifier(Identifier, RootDir))
	{
		return FString();
	}

	// Get the path to the game agnostic settings
	FString UserDir;
	if (IsStockEngineRelease(Identifier))
	{
		UserDir = FPaths::Combine(FPlatformProcess::UserSettingsDir(), *FApp::GetEpicProductIdentifier(), *Identifier);
	}
	else
	{
		UserDir = FPaths::Combine(*RootDir, TEXT("Engine"));
	}

	return UserDir;
}

FString FDesktopPlatformBase::GetLegacyEngineSavedConfigDirectory(const FString& Identifier)
{
	const FString UserDir = GetUserDir(Identifier);
	if (!UserDir.IsEmpty())
	{
		return UserDir / TEXT("Saved/Config") / ANSI_TO_TCHAR(FPlatformProperties::IniPlatformName());
	}

	return FString();
}

FString FDesktopPlatformBase::GetUnrealBuildToolProjectFileName(const FString& RootDir) const
{
	return FPaths::ConvertRelativePathToFull(RootDir / TEXT("Engine/Source/Programs/UnrealBuildTool/UnrealBuildTool.csproj"));
}

FString FDesktopPlatformBase::GetUnrealBuildToolExecutableFilename(const FString& RootDir) const
{
	FConfigFile Config;
	if (FConfigCacheIni::LoadExternalIniFile(Config, TEXT("Engine"), *FPaths::Combine(RootDir, TEXT("Engine/Config/")), *FPaths::Combine(RootDir, TEXT("Engine/Config/")), true, NULL, false, /*bWriteDestIni*/ false))
	{
		FString Entry;
		if( Config.GetString( TEXT("PlatformPaths"), TEXT("UnrealBuildTool"), Entry ))
		{
			FString NewPath = FPaths::ConvertRelativePathToFull(RootDir / Entry);
			return NewPath;
		}
	}
	

	return FPaths::ConvertRelativePathToFull(RootDir / TEXT("Engine/Binaries/DotNET/UnrealBuildTool/UnrealBuildTool.exe"));
}

#undef LOCTEXT_NAMESPACE