// Copyright 1998-2015 Epic Games, Inc. All Rights Reserved.

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

namespace UnrealBuildTool
{
    class LinuxPlatform : UEBuildPlatform
    {
        /** This is the SDK version we support */
		static private Dictionary<string, string> ExpectedSDKVersions = new Dictionary<string, string>()
		{
			{ "x86_64-unknown-linux-gnu", "v4_clang-3.5.0_ld-2.24_glibc-2.12.2" },
			{ "arm-unknown-linux-gnueabihf", "arm-unknown-linux-gnueabihf_v5_clang-3.5.0-ld-2.23.1-glibc-2.13" },
		};

        /** Platform name (embeds architecture for now) */
        static private string TargetPlatformName = "Linux_x64";

        /** Linux architecture (compiler target triplet) */
		// FIXME: for now switching between architectures is hard-coded
		static private string DefaultArchitecture = "x86_64-unknown-linux-gnu";
		//static private string DefaultArchitecture = "arm-unknown-linux-gnueabihf";

        /** The current architecture */
        public override string GetActiveArchitecture()
        {
            return DefaultArchitecture;
        }

        /**
         * Allow the platform to apply architecture-specific name according to its rules
         */
        public override string ApplyArchitectureName(string BinaryName)
        {
            // Linux ignores architecture-specific names, although it might be worth it to prepend architecture
            return BinaryName;
        }

        /** 
         * Whether platform supports switching SDKs during runtime
         * 
         * @return true if supports
         */
        protected override bool PlatformSupportsAutoSDKs()
        {
            return true;
        }

        /** 
         * Returns platform-specific name used in SDK repository
         * 
         * @return path to SDK Repository
         */
        public override string GetSDKTargetPlatformName()
        {
            return TargetPlatformName;
        }

        /** 
         * Returns SDK string as required by the platform 
         * 
         * @return Valid SDK string
         */
        protected override string GetRequiredSDKString()
        {
			string SDKString;
			if (!ExpectedSDKVersions.TryGetValue(GetActiveArchitecture(), out SDKString))
			{
				throw new BuildException("LinuxPlatform::GetRequiredSDKString: no toolchain set up for architecture '{0}'", GetActiveArchitecture());
			}

			return SDKString;
        }

        protected override String GetRequiredScriptVersionString()
        {
            return "3.0";
        }

        protected override bool PreferAutoSDK()
        {
            // having LINUX_ROOT set (for legacy reasons or for convenience of cross-compiling certain third party libs) should not make UBT skip AutoSDKs
            return true;
        }

        /**
         *	Whether the required external SDKs are installed for this platform
         */
        protected override SDKStatus HasRequiredManualSDKInternal()
        {
            if (BuildHostPlatform.Current.Platform == UnrealTargetPlatform.Linux)
            {
                return SDKStatus.Valid;
            }

            string BaseLinuxPath = Environment.GetEnvironmentVariable("LINUX_ROOT");

            // we don't have an LINUX_ROOT specified
            if (String.IsNullOrEmpty(BaseLinuxPath))
                return SDKStatus.Invalid;

            // paths to our toolchains
            BaseLinuxPath = BaseLinuxPath.Replace("\"", "");
            string ClangPath = Path.Combine(BaseLinuxPath, @"bin\Clang++.exe");
            
            if (File.Exists(ClangPath))
                return SDKStatus.Valid;

            return SDKStatus.Invalid;
        }

		public override bool CanUseXGE()
		{
			// disabled until XGE crash is fixed - it is still happening as of 2014-09-30
			return false;
		}

		/**
		 *	Register the platform with the UEBuildPlatform class
		 */
        protected override void RegisterBuildPlatformInternal()
        {
			if ((ProjectFileGenerator.bGenerateProjectFiles == true) || (HasRequiredSDKsInstalled() == SDKStatus.Valid))
            {
                bool bRegisterBuildPlatform = true;

                string EngineSourcePath = Path.Combine(ProjectFileGenerator.RootRelativePath, "Engine", "Source");
                string LinuxTargetPlatformFile = Path.Combine(EngineSourcePath, "Developer", "Linux", "LinuxTargetPlatform", "LinuxTargetPlatform.Build.cs");

                if (File.Exists(LinuxTargetPlatformFile) == false)
                {
                    bRegisterBuildPlatform = false;
                }

                if (bRegisterBuildPlatform == true)
                {
                    // Register this build platform for Linux
                    if (BuildConfiguration.bPrintDebugInfo)
                    {
                        Console.WriteLine("        Registering for {0}", UnrealTargetPlatform.Linux.ToString());
                    }
                    UEBuildPlatform.RegisterBuildPlatform(UnrealTargetPlatform.Linux, this);
                    UEBuildPlatform.RegisterPlatformWithGroup(UnrealTargetPlatform.Linux, UnrealPlatformGroup.Unix);
                }
            }
        }

        /**
         *	Retrieve the CPPTargetPlatform for the given UnrealTargetPlatform
         *
         *	@param	InUnrealTargetPlatform		The UnrealTargetPlatform being build
         *	
         *	@return	CPPTargetPlatform			The CPPTargetPlatform to compile for
         */
        public override CPPTargetPlatform GetCPPTargetPlatform(UnrealTargetPlatform InUnrealTargetPlatform)
        {
            switch (InUnrealTargetPlatform)
            {
                case UnrealTargetPlatform.Linux:
                    return CPPTargetPlatform.Linux;
            }
            throw new BuildException("LinuxPlatform::GetCPPTargetPlatform: Invalid request for {0}", InUnrealTargetPlatform.ToString());
        }

        /**
         *	Get the extension to use for the given binary type
         *	
         *	@param	InBinaryType		The binary type being built
         *	
         *	@return	string				The binary extension (i.e. 'exe' or 'dll')
         */
        public override string GetBinaryExtension(UEBuildBinaryType InBinaryType)
        {
            switch (InBinaryType)
            {
                case UEBuildBinaryType.DynamicLinkLibrary:
                    return ".so";
                case UEBuildBinaryType.Executable:
                    return "";
                case UEBuildBinaryType.StaticLibrary:
                    return ".a";
				case UEBuildBinaryType.Object:
					return ".o";
				case UEBuildBinaryType.PrecompiledHeader:
					return ".gch";
            }
            return base.GetBinaryExtension(InBinaryType);
        }

        /**
         *	Get the extension to use for debug info for the given binary type
         *	
         *	@param	InBinaryType		The binary type being built
         *	
         *	@return	string				The debug info extension (i.e. 'pdb')
         */
        public override string GetDebugInfoExtension(UEBuildBinaryType InBinaryType)
        {
            return "";
        }

        /**
         *	Gives the platform a chance to 'override' the configuration settings 
         *	that are overridden on calls to RunUBT.
         *	
         *	@param	InPlatform			The UnrealTargetPlatform being built
         *	@param	InConfiguration		The UnrealTargetConfiguration being built
         */
        public override void ResetBuildConfiguration(UnrealTargetPlatform InPlatform, UnrealTargetConfiguration InConfiguration)
        {
            ValidateUEBuildConfiguration();
        }

        /**
         *	Validate configuration for this platform
         *	NOTE: This function can/will modify BuildConfiguration!
         *	
         *	@param	InPlatform			The CPPTargetPlatform being built
         *	@param	InConfiguration		The CPPTargetConfiguration being built
         *	@param	bInCreateDebugInfo	true if debug info is getting create, false if not
         */
        public override void ValidateBuildConfiguration(CPPTargetConfiguration Configuration, CPPTargetPlatform Platform, bool bCreateDebugInfo)
        {
            UEBuildConfiguration.bCompileSimplygon = false;
        }

        /**
         *	Validate the UEBuildConfiguration for this platform
         *	This is called BEFORE calling UEBuildConfiguration to allow setting 
         *	various fields used in that function such as CompileLeanAndMean...
         */
        public override void ValidateUEBuildConfiguration()
        {
            if (ProjectFileGenerator.bGenerateProjectFiles && !ProjectFileGenerator.bGeneratingRocketProjectFiles)
            {
                // When generating non-Rocket project files we need intellisense generator to include info from all modules,
                // including editor-only third party libs
                UEBuildConfiguration.bCompileLeanAndMeanUE = false;
            }

            BuildConfiguration.bUseUnityBuild = true;

            // Don't stop compilation at first error...
            BuildConfiguration.bStopXGECompilationAfterErrors = true;

            BuildConfiguration.bUseSharedPCHs = false;
        }

        /**
         *	Whether PDB files should be used
         *	
         *	@param	InPlatform			The CPPTargetPlatform being built
         *	@param	InConfiguration		The CPPTargetConfiguration being built
         *	@param	bInCreateDebugInfo	true if debug info is getting create, false if not
         *	
         *	@return	bool	true if PDB files should be used, false if not
         */
        public override bool ShouldUsePDBFiles(CPPTargetPlatform Platform, CPPTargetConfiguration Configuration, bool bCreateDebugInfo)
        {
            return true;
        }

        /**
         *	Get a list of extra modules the platform requires.
         *	This is to allow undisclosed platforms to add modules they need without exposing information about the platfomr.
         *	
         *	@param	Target						The target being build
         *	@param	BuildTarget					The UEBuildTarget getting build
         *	@param	PlatformExtraModules		OUTPUT the list of extra modules the platform needs to add to the target
         */
        public override void GetExtraModules(TargetInfo Target, UEBuildTarget BuildTarget, ref List<string> PlatformExtraModules)
        {
        }

        /**
         *	Modify the newly created module passed in for this platform.
         *	This is not required - but allows for hiding details of a
         *	particular platform.
         *	
         *	@param	InModule		The newly loaded module
         *	@param	Target			The target being build
         */
        public override void ModifyNewlyLoadedModule(UEBuildModule InModule, TargetInfo Target)
        {
            if ((Target.Platform == UnrealTargetPlatform.Win32) || (Target.Platform == UnrealTargetPlatform.Win64))
            {
                if (!UEBuildConfiguration.bBuildRequiresCookedData)
                {
                    if (InModule.ToString() == "Engine")
                    {
                        if (UEBuildConfiguration.bBuildDeveloperTools)
                        {
                            InModule.AddPlatformSpecificDynamicallyLoadedModule("LinuxTargetPlatform");
                            InModule.AddPlatformSpecificDynamicallyLoadedModule("LinuxNoEditorTargetPlatform");
                            InModule.AddPlatformSpecificDynamicallyLoadedModule("LinuxServerTargetPlatform");
                        }
                    }
                }

                // allow standalone tools to use targetplatform modules, without needing Engine
                if (UEBuildConfiguration.bForceBuildTargetPlatforms)
                {
                    InModule.AddPlatformSpecificDynamicallyLoadedModule("LinuxTargetPlatform");
                    InModule.AddPlatformSpecificDynamicallyLoadedModule("LinuxNoEditorTargetPlatform");
                    InModule.AddPlatformSpecificDynamicallyLoadedModule("LinuxServerTargetPlatform");
                }
            }
            else if (Target.Platform == UnrealTargetPlatform.Linux)
            {
                bool bBuildShaderFormats = UEBuildConfiguration.bForceBuildShaderFormats;

                if (!UEBuildConfiguration.bBuildRequiresCookedData)
                {
                    if (InModule.ToString() == "TargetPlatform")
                    {
                        bBuildShaderFormats = true;
                    }
                }

                // allow standalone tools to use target platform modules, without needing Engine
                if (UEBuildConfiguration.bForceBuildTargetPlatforms)
                {
                    InModule.AddDynamicallyLoadedModule("LinuxTargetPlatform");
                    InModule.AddDynamicallyLoadedModule("LinuxNoEditorTargetPlatform");
                    InModule.AddDynamicallyLoadedModule("LinuxServerTargetPlatform");
					InModule.AddDynamicallyLoadedModule("DesktopTargetPlatform");
                }

                if (bBuildShaderFormats)
                {
					// InModule.AddDynamicallyLoadedModule("ShaderFormatD3D");
                    InModule.AddDynamicallyLoadedModule("ShaderFormatOpenGL");
                }
            }
        }

        /**
         *	Setup the target environment for building
         *	
         *	@param	InBuildTarget		The target being built
         */
        public override void SetUpEnvironment(UEBuildTarget InBuildTarget)
        {
            InBuildTarget.GlobalCompileEnvironment.Config.Definitions.Add("PLATFORM_LINUX=1");
            InBuildTarget.GlobalCompileEnvironment.Config.Definitions.Add("LINUX=1");

            InBuildTarget.GlobalCompileEnvironment.Config.Definitions.Add("WITH_DATABASE_SUPPORT=0");		//@todo linux: valid?

            if (GetActiveArchitecture().StartsWith("arm"))
            {
                InBuildTarget.GlobalCompileEnvironment.Config.Definitions.Add("REQUIRES_ALIGNED_INT_ACCESS");
            }

            // link with Linux libraries.
            InBuildTarget.GlobalLinkEnvironment.Config.AdditionalLibraries.Add("pthread");

            // Disable Simplygon support if compiling against the NULL RHI.
            if (InBuildTarget.GlobalCompileEnvironment.Config.Definitions.Contains("USE_NULL_RHI=1"))
            {
                UEBuildConfiguration.bCompileSimplygon = false;
            }
        }

        /**
         *	Whether this platform should create debug information or not
         *	
         *	@param	InPlatform			The UnrealTargetPlatform being built
         *	@param	InConfiguration		The UnrealTargetConfiguration being built
         *	
         *	@return	bool				true if debug info should be generated, false if not
         */
        public override bool ShouldCreateDebugInfo(UnrealTargetPlatform Platform, UnrealTargetConfiguration Configuration)
        {
            switch (Configuration)
            {
                case UnrealTargetConfiguration.Development:
                case UnrealTargetConfiguration.Shipping:
                case UnrealTargetConfiguration.Test:
                case UnrealTargetConfiguration.Debug:
                default:
                    return true;
            };
        }

        /**
         *	Setup the binaries for this specific platform.
         *	
         *	@param	InBuildTarget		The target being built
         */
        public override void SetupBinaries(UEBuildTarget InBuildTarget)
        {
        }
    }
}