// Copyright 1998-2016 Epic Games, Inc. All Rights Reserved.

/*=============================================================================
	LinuxTargetDevice.cpp: Implements the LinuxTargetDevice class.
=============================================================================*/

#include "LinuxTargetPlatformPrivatePCH.h"

#include "LinuxTargetDevice.h"

#if PLATFORM_LINUX
	#include <signal.h> // for process termination
	#include <pwd.h> // for getting uid/gid
#endif // PLATFORM_LINUX

/* ITargetDevice interface
*****************************************************************************/

bool FLinuxTargetDevice::Deploy( const FString& SourceFolder, FString& OutAppId )
{
#if PLATFORM_LINUX	// if running natively, support simplified, local deployment	
	OutAppId = TEXT("");

	FString PlatformName = TEXT("Linux");
	FString DeploymentDir = FPaths::EngineIntermediateDir() / TEXT("Devices") / PlatformName;

	// delete previous build
	IFileManager::Get().DeleteDirectory(*DeploymentDir, false, true);

	// copy files into device directory
	TArray<FString> FileNames;

	IFileManager::Get().FindFilesRecursive(FileNames, *SourceFolder, TEXT("*.*"), true, false);

	for (int32 FileIndex = 0; FileIndex < FileNames.Num(); ++FileIndex)
	{
		const FString& SourceFilePath = FileNames[FileIndex];
		FString DestFilePath = DeploymentDir + SourceFilePath.RightChop(SourceFolder.Len());

		IFileManager::Get().Copy(*DestFilePath, *SourceFilePath);
	}

	return true;
#else
	// @todo: support deployment to a remote machine
	STUBBED("FLinuxTargetDevice::Deploy");
	return false;
#endif // PLATFORM_LINUX
}

int32 FLinuxTargetDevice::GetProcessSnapshot( TArray<FTargetDeviceProcessInfo>& OutProcessInfos )
{
	STUBBED("FLinuxTargetDevice::GetProcessSnapshot");
	return 0;
}

bool FLinuxTargetDevice::Launch( const FString& AppId, EBuildConfigurations::Type BuildConfiguration, EBuildTargets::Type BuildTarget, const FString& Params, uint32* OutProcessId )
{
#if PLATFORM_LINUX	// if running natively, support launching in place
	// build executable path
	FString PlatformName = TEXT("Linux");
	FString ExecutablePath = FPaths::EngineIntermediateDir() / TEXT("Devices") / PlatformName / TEXT("Engine") / TEXT("Binaries") / PlatformName;

	if (BuildTarget == EBuildTargets::Game)
	{
		ExecutablePath /= TEXT("UE4Game");
	}
	else if (BuildTarget == EBuildTargets::Server)
	{
		ExecutablePath /= TEXT("UE4Server");
	}
	else if (BuildTarget == EBuildTargets::Editor)
	{
		ExecutablePath /= TEXT("UE4Editor");
	}

	if (BuildConfiguration != EBuildConfigurations::Development)
	{
		ExecutablePath += FString::Printf(TEXT("-%s-%s"), *PlatformName, EBuildConfigurations::ToString(BuildConfiguration));
	}

	// launch the game
	FProcHandle ProcessHandle = FPlatformProcess::CreateProc(*ExecutablePath, *Params, true, false, false, OutProcessId, 0, NULL, NULL);
	if (ProcessHandle.IsValid())
	{
		FPlatformProcess::CloseProc(ProcessHandle);
		return true;
	}
	return false;
#else
	// @todo: support launching on a remote machine
	STUBBED("FLinuxTargetDevice::Launch");
	return false;
#endif // PLATFORM_LINUX
}

bool FLinuxTargetDevice::Reboot( bool bReconnect)
{
	STUBBED("FLinuxTargetDevice::Reboot");
	return false;
}

bool FLinuxTargetDevice::Run( const FString& ExecutablePath, const FString& Params, uint32* OutProcessId )
{
#if PLATFORM_LINUX	// if running natively, support simplified, local deployment	
	FProcHandle ProcessHandle = FPlatformProcess::CreateProc(*ExecutablePath, *Params, true, false, false, OutProcessId, 0, NULL, NULL);
	if (ProcessHandle.IsValid())
	{
		FPlatformProcess::CloseProc(ProcessHandle);
		return true;
	}
	return false;
#else
	// @todo: support remote run
	STUBBED("FLinuxTargetDevice::Run");
	return false;
#endif // PLATFORM_LINUX
}

bool FLinuxTargetDevice::SupportsFeature( ETargetDeviceFeatures Feature ) const
{
	switch (Feature)
	{
		case ETargetDeviceFeatures::MultiLaunch:
			return true;

		// @todo to be implemented
		case ETargetDeviceFeatures::PowerOff:
			return false;

		// @todo to be implemented turning on remote PCs (wake on LAN)
		case ETargetDeviceFeatures::PowerOn:
			return false;

		// @todo to be implemented
		case ETargetDeviceFeatures::ProcessSnapshot:
			return false;

		// @todo to be implemented
		case ETargetDeviceFeatures::Reboot:
			return false;
	}

	return false;
}

bool FLinuxTargetDevice::SupportsSdkVersion( const FString& VersionString ) const
{
	STUBBED("FLinuxTargetDevice::SupportsSdkVersion");
	return true;
}

void FLinuxTargetDevice::SetUserCredentials( const FString& InUserName, const FString& InUserPassword )
{
	STUBBED("FLinuxTargetDevice::SetUserCredentials");
	UserName = InUserName;
	UserPassword = InUserPassword;
}

bool FLinuxTargetDevice::GetUserCredentials( FString& OutUserName, FString& OutUserPassword )
{
	STUBBED("FLinuxTargetDevice::GetUserCredentials");
	OutUserName = UserName;
	OutUserPassword = UserPassword;
	return true;
}

bool FLinuxTargetDevice::TerminateProcess( const int32 ProcessId )
{
#if PLATFORM_LINUX // if running natively, just terminate the local process
	// get process path from the ProcessId
	const int32 ReadLinkSize = 1024;
	char ReadLinkCmd[ReadLinkSize] = {0};
	FCStringAnsi::Sprintf(ReadLinkCmd, "/proc/%d/exe", ProcessId);
	char ProcessPath[ MAX_PATH + 1 ] = {0};
	int32 Ret = readlink(ReadLinkCmd, ProcessPath, ARRAY_COUNT(ProcessPath) - 1);
	if (Ret != -1)
	{
		struct stat st;
		uid_t euid;
		stat(ProcessPath, &st);
		euid = geteuid(); // get effective uid of current application, as this user is asking to kill a process

		// now check if we own the process
		if (st.st_uid == euid)
		{
			// terminate it (will this terminate children as well because we set their pgid?)
			kill(ProcessId, SIGTERM);
			sleep(2); // sleep in case process still remains then send a more strict signal
			kill(ProcessId, SIGKILL);
			return true;
		}
	}
#else
	// @todo: support remote termination
	STUBBED("FLinuxTargetDevice::TerminateProcess");
#endif // PLATFORM_LINUX
	return false;
}