/**
	GDC compiler support.
 
	Copyright: © 2013-2013 rejectedsoftware e.K.
	License: Subject to the terms of the MIT license, as written in the included LICENSE.txt file.
	Authors: Sönke Ludwig
*/
module dub.compilers.gdc;
 
import dub.compilers.compiler;
import dub.compilers.utils;
import dub.internal.utils;
import dub.internal.vibecompat.core.file;
import dub.internal.vibecompat.inet.path;
import dub.internal.logging;
 
import std.algorithm;
import std.array;
import std.exception;
import std.process : execute;
import std.typecons;
 
 
class GDCCompiler : Compiler {
	private static immutable s_options = [
		tuple(BuildOption.debugMode, ["-fdebug"]),
		tuple(BuildOption.releaseMode, ["-frelease"]),
		tuple(BuildOption.coverage, ["-fprofile-arcs", "-ftest-coverage"]),
		tuple(BuildOption.debugInfo, ["-g"]),
		tuple(BuildOption.debugInfoC, ["-g"]),
		//tuple(BuildOption.alwaysStackFrame, ["-X"]),
		//tuple(BuildOption.stackStomping, ["-X"]),
		tuple(BuildOption.inline, ["-finline-functions"]),
		tuple(BuildOption.noBoundsCheck, ["-fno-bounds-check"]),
		tuple(BuildOption.optimize, ["-O2"]),
		tuple(BuildOption.profile, ["-pg"]),
		tuple(BuildOption.unittests, ["-funittest"]),
		tuple(BuildOption.verbose, ["-v"]),
		tuple(BuildOption.ignoreUnknownPragmas, ["-fignore-unknown-pragmas"]),
		tuple(BuildOption.syntaxOnly, ["-fsyntax-only"]),
		tuple(BuildOption.warnings, ["-Wall"]),
		tuple(BuildOption.warningsAsErrors, ["-Werror", "-Wall"]),
		tuple(BuildOption.ignoreDeprecations, ["-Wno-deprecated"]),
		tuple(BuildOption.deprecationWarnings, ["-Wdeprecated"]),
		tuple(BuildOption.deprecationErrors, ["-Werror", "-Wdeprecated"]),
		tuple(BuildOption.property, ["-fproperty"]),
		//tuple(BuildOption.profileGC, ["-?"]),
		tuple(BuildOption.betterC, ["-fno-druntime"]),
		tuple(BuildOption.color, ["-fdiagnostics-color=always"]),
 
		tuple(BuildOption._docs, ["-fdoc-dir=docs"]),
		tuple(BuildOption._ddox, ["-Xfdocs.json", "-fdoc-file=__dummy.html"]),
	];
 
	@property string name() const { return "gdc"; }
 
	string determineVersion(string compiler_binary, string verboseOutput)
	{
		const result = execute([
			compiler_binary,
			"-dumpfullversion",
			"-dumpversion"
		]);
 
		return result.status == 0 ? result.output : null;
	}
 
	BuildPlatform determinePlatform(ref BuildSettings settings, string compiler_binary, string arch_override)
	{
		string[] arch_flags;
		switch (arch_override) {
			default: throw new UnsupportedArchitectureException(arch_override);
			case "": break;
			case "arm": arch_flags = ["-marm"]; break;
			case "arm_thumb": arch_flags = ["-mthumb"]; break;
			case "x86": arch_flags = ["-m32"]; break;
			case "x86_64": arch_flags = ["-m64"]; break;
		}
		settings.addDFlags(arch_flags);
 
		return probePlatform(
			compiler_binary,
			arch_flags ~ ["-fsyntax-only", "-v"],
			arch_override
		);
	}
 
	void prepareBuildSettings(ref BuildSettings settings, const scope ref BuildPlatform platform, BuildSetting fields = BuildSetting.all) const
	{
		enforceBuildRequirements(settings);
 
		// Keep the current dflags at the end of the array so that they will overwrite other flags.
		// This allows user $DFLAGS to modify flags added by us.
		const dflagsTail = settings.dflags;
		settings.dflags = [];
 
		if (!(fields & BuildSetting.options)) {
			foreach (t; s_options)
				if (settings.options & t[0])
					settings.addDFlags(t[1]);
		}
 
		if (!(fields & BuildSetting.versions)) {
			settings.addDFlags(settings.versions.map!(s => "-fversion="~s)().array());
			settings.versions = null;
		}
 
		if (!(fields & BuildSetting.debugVersions)) {
			settings.addDFlags(settings.debugVersions.map!(s => "-fdebug="~s)().array());
			settings.debugVersions = null;
		}
 
		if (!(fields & BuildSetting.importPaths)) {
			settings.addDFlags(settings.importPaths.map!(s => "-I"~s)().array());
			settings.importPaths = null;
		}
 
		if (!(fields & BuildSetting.cImportPaths)) {
			settings.addDFlags(settings.cImportPaths.map!(s => "-I"~s)().array());
			settings.cImportPaths = null;
		}
 
		if (!(fields & BuildSetting.stringImportPaths)) {
			settings.addDFlags(settings.stringImportPaths.map!(s => "-J"~s)().array());
			settings.stringImportPaths = null;
		}
 
		if (!(fields & BuildSetting.sourceFiles)) {
			settings.addDFlags(settings.sourceFiles);
			settings.sourceFiles = null;
		}
 
		if (!(fields & BuildSetting.libs)) {
			resolveLibs(settings, platform);
			settings.addDFlags(settings.libs.map!(l => "-l"~l)().array());
		}
 
		if (!(fields & BuildSetting.lflags)) {
			settings.addDFlags(lflagsToDFlags(settings.lflags));
			settings.lflags = null;
		}
 
		if (settings.options & BuildOption.pic)
			settings.addDFlags("-fPIC");
 
		settings.addDFlags(dflagsTail);
 
		assert(fields & BuildSetting.dflags);
		assert(fields & BuildSetting.copyFiles);
	}
 
	void extractBuildOptions(ref BuildSettings settings) const
	{
		Appender!(string[]) newflags;
		next_flag: foreach (f; settings.dflags) {
			foreach (t; s_options)
				if (t[1].canFind(f)) {
					settings.options |= t[0];
					continue next_flag;
				}
			if (f.startsWith("-fversion=")) settings.addVersions(f[10 .. $]);
			else if (f.startsWith("-fdebug=")) settings.addDebugVersions(f[8 .. $]);
			else newflags ~= f;
		}
		settings.dflags = newflags.data;
	}
 
	string getTargetFileName(in BuildSettings settings, in BuildPlatform platform)
	const {
		assert(settings.targetName.length > 0, "No target name set.");
		final switch (settings.targetType) {
			case TargetType.autodetect: assert(false, "Configurations must have a concrete target type.");
			case TargetType.none: return null;
			case TargetType.sourceLibrary: return null;
			case TargetType.executable:
				if (platform.isWindows())
					return settings.targetName ~ ".exe";
				else return settings.targetName.idup;
			case TargetType.library:
			case TargetType.staticLibrary:
				return "lib" ~ settings.targetName ~ ".a";
			case TargetType.dynamicLibrary:
				if (platform.isWindows())
					return settings.targetName ~ ".dll";
				else if (platform.platform.canFind("darwin"))
					return "lib" ~ settings.targetName ~ ".dylib";
				else return "lib" ~ settings.targetName ~ ".so";
			case TargetType.object:
				if (platform.isWindows())
					return settings.targetName ~ ".obj";
				else return settings.targetName ~ ".o";
		}
	}
 
	void setTarget(ref BuildSettings settings, in BuildPlatform platform, string tpath = null) const
	{
		const targetFileName = getTargetFileName(settings, platform);
 
		final switch (settings.targetType) {
			case TargetType.autodetect: assert(false, "Invalid target type: autodetect");
			case TargetType.none: assert(false, "Invalid target type: none");
			case TargetType.sourceLibrary: assert(false, "Invalid target type: sourceLibrary");
			case TargetType.executable: break;
			case TargetType.library:
			case TargetType.staticLibrary:
			case TargetType.object:
				settings.addDFlags("-c");
				break;
			case TargetType.dynamicLibrary:
				settings.addDFlags("-shared", "-fPIC");
				addDynamicLibName(settings, platform, targetFileName);
				break;
		}
 
		if (tpath is null)
			tpath = (NativePath(settings.targetPath) ~ targetFileName).toNativeString();
		settings.addDFlags("-o", tpath);
	}
 
	void invoke(in BuildSettings settings, in BuildPlatform platform, void delegate(int, string) output_callback, NativePath cwd)
	{
		auto res_file = getTempFile("dub-build", ".rsp");
		writeFile(res_file, join(settings.dflags.map!(s => escape(s)), "\n"));
 
		logDiagnostic("%s %s", platform.compilerBinary, join(cast(string[])settings.dflags, " "));
		string[string] env;
		foreach (aa; [settings.environments, settings.buildEnvironments])
			foreach (k, v; aa)
				env[k] = v;
		invokeTool([platform.compilerBinary, "@"~res_file.toNativeString()], output_callback, cwd, env);
	}
 
	void invokeLinker(in BuildSettings settings, in BuildPlatform platform, string[] objects, void delegate(int, string) output_callback, NativePath cwd)
	{
		import std.string;
		string[] args;
		// As the user is supposed to call setTarget prior to invoke, -o target is already set.
		if (settings.targetType == TargetType.staticLibrary || settings.targetType == TargetType.staticLibrary) {
			auto tpath = extractTarget(settings.dflags);
			assert(tpath !is null, "setTarget should be called before invoke");
			args = [ "ar", "rcs", tpath ] ~ objects;
		} else {
			args = platform.compilerBinary ~ objects ~ settings.sourceFiles ~ settings.lflags ~ settings.dflags.filter!(f => isLinkageFlag(f)).array;
			if (platform.platform.canFind("linux"))
				args ~= "-L--no-as-needed"; // avoids linker errors due to libraries being specified in the wrong order
		}
		logDiagnostic("%s", args.join(" "));
		string[string] env;
		foreach (aa; [settings.environments, settings.buildEnvironments])
			foreach (k, v; aa)
				env[k] = v;
		invokeTool(args, output_callback, cwd, env);
	}
 
	string[] lflagsToDFlags(const string[] lflags) const
	{
		string[] dflags;
		foreach( f; lflags )
		{
            if ( f == "") {
                continue;
            }
			dflags ~= "-Xlinker";
			dflags ~= f;
		}
 
		return  dflags;
	}
}
 
private string extractTarget(const string[] args) { auto i = args.countUntil("-o"); return i >= 0 ? args[i+1] : null; }
 
private bool isLinkageFlag(string flag) {
	switch (flag) {
		case "-c":
			return false;
		default:
			return true;
	}
}
 
private string escape(string str)
{
	auto ret = appender!string();
	foreach (char ch; str) {
		switch (ch) {
			default: ret.put(ch); break;
			case '\\': ret.put(`\\`); break;
			case ' ': ret.put(`\ `); break;
		}
	}
	return ret.data;
}