// -*- c++ -*-
// Distributed under the BSD 2-Clause License.
// See accompanying file LICENSE for details.
#include "../../src/util.cc"
#include "../../src/pointerlist.cc"
#include "../../src/execute.cc"

#include <iostream>
#include <string>
#include <filesystem>
#include <thread>
#include <chrono>
#include <sstream>

using namespace std::chrono_literals;

int fail(int value = 1,
         const std::source_location location = std::source_location::current())
{
	std::cout << "*** Failure at line " << location.line() << '\n';
	exit(value);
}

#if _MSC_VER && !__INTEL_COMPILER
const std::string ctor_exe{"ctor.exe"};
const std::string obj_ext{".obj"};
#else
const std::string ctor_exe{"./ctor"};
const std::string obj_ext{".o"};
#endif

void run_ctor(const std::vector<std::string>& args,
	const std::source_location location = std::source_location::current())
{
	ctor::settings settings{.verbose = 2};
	auto ret = execute(settings, ctor_exe, args);
	if(ret != 0)
	{
		fail(ret, location);
	}
}

void assert_not_exists(const std::string& path,
	const std::source_location location = std::source_location::current())
{
	if(std::filesystem::exists(path))
	{
		fail(1, location);
	}
}

void assert_exists(const std::string& path,
	const std::source_location location = std::source_location::current())
{
	if(!std::filesystem::exists(path))
	{
		fail(1, location);
	}
}

void copy_config(std::string cfg)
{
	std::cout << "** ctor_files/ctor.cc." + cfg + "\n";
	std::filesystem::copy("ctor_files/ctor.cc." + cfg, "ctor.cc",
	                      std::filesystem::copy_options::overwrite_existing);
	if(std::filesystem::exists(ctor_exe))
	{
		auto ctor_exe_time = std::filesystem::last_write_time(ctor_exe);
		std::filesystem::last_write_time("ctor.cc",  ctor_exe_time + 1s);
	}
}

class Tracker
{
public:
	Tracker(const std::string& file_) : file(file_)
	{
		capture(); // capture initial value
	}

	void capture()
	{
		changed();
	}

	bool changed()
	{
		auto tmp = readFile(file);
		auto content_changed = tmp != content;
		content = tmp;
		return content_changed;
	}

private:
	std::string file;
	std::string content;
};

void assert_not_changed(Tracker& tracker,
	const std::source_location location = std::source_location::current())
{
	if(tracker.changed())
	{
		fail(1, location);
	}
}

void assert_changed(Tracker& tracker,
	const std::source_location location = std::source_location::current())
{
	if(!tracker.changed())
	{
		fail(1, location);
	}
}

int main()
{
	ctor::settings settings{};
	settings.verbose = 2;
	auto paths = get_paths();

	std::string CXX = "g++";
	get_env("CXX", CXX);
	std::string CTORDIR = "../../build";
	get_env("CTORDIR", CTORDIR);
	std::string BUILDDIR = "build";
	get_env("BUILDDIR", BUILDDIR);
	std::string CXXFLAGS;
	get_env("CXXFLAGS", CXXFLAGS);
	std::string LDFLAGS;
	get_env("LDFLAGS", LDFLAGS);

	// Wipe the board
	std::filesystem::remove_all(BUILDDIR);
#if _MSC_VER && !__INTEL_COMPILER
	std::filesystem::create_directory(BUILDDIR);
#endif
	std::filesystem::remove("configuration.cc");
	std::filesystem::remove("config.h");
	std::filesystem::remove(ctor_exe);

	//////////////////////////////////////////////////////////////////////////////
	// bootstrap
	// TODO: add support for quoted strings with spaces
	{
		auto cxx_prog = locate(CXX, paths);

		std::vector<std::string> args =
#if _MSC_VER && !__INTEL_COMPILER
			{"/nologo", "/MT", "/std:c++20", "/D_X86_", "/EHsc", "/I..\\..\\src",
			 "ctor.cc", "/link", "/LIBPATH:"+CTORDIR, "libctor.lib",
			 "/subsystem:console", "/out:" + ctor_exe};
#else
			{"-pthread", "-std=c++20", "-L", CTORDIR, "-lctor", "-I", "../../src",
			 "ctor.cc", "-o", ctor_exe};
#endif
		if(!CXXFLAGS.empty())
		{
			auto tokens = argsplit(CXXFLAGS);
			for(const auto& token : tokens)
			{
				args.push_back(token);
			}
		}
		if(!LDFLAGS.empty())
		{
			auto tokens = argsplit(LDFLAGS);
			for(const auto& token : tokens)
			{
				args.push_back(token);
			}
		}

		// Compile bootstrap binary
		copy_config("base");
		auto ret = execute(settings, cxx_prog, args);
		if(ret != 0)
		{
			fail(ret);
		}
	}
	//////////////////////////////////////////////////////////////////////////////
	// check if source file changes are tracked
	{
#if _MSC_VER && !__INTEL_COMPILER
#else
		// No build files should have been created yet
		assert_not_exists(BUILDDIR);
#endif

		// capture ctor binary before configure is called
		Tracker ctor_bin(ctor_exe);
		run_ctor(
			{"configure", "--ctor-includedir", "../../src",
			 "--ctor-libdir=" + CTORDIR, "--build-dir=" + BUILDDIR});

		// ctor should be rebuilt at this point, so binary should have changed
		assert_changed(ctor_bin);

		// configuration.cc should have been generated now
		assert_exists("configuration.cc");
		assert_exists("config.h");

		// Shouldn't compile anything yet - only configure
		assert_not_exists(BUILDDIR + "/hello-hello_cc" + obj_ext);

		ctor_bin.capture();

		// Run normally to build project
		run_ctor({"-v"});

		// Compiled object should now exist
		assert_exists(BUILDDIR + "/hello-hello_cc" + obj_ext);

		// ctor should not have been rebuilt, so binary should be the same
		assert_not_changed(ctor_bin);

		std::this_thread::sleep_for(1100ms);

		auto time =
			std::filesystem::last_write_time(BUILDDIR + "/hello-hello_cc" + obj_ext);
		std::filesystem::last_write_time("hello.cc", time + 1s);
		std::this_thread::sleep_for(1100ms);

		// Run normally to rebuild hello.cc
		run_ctor({"-v"});

		// Object file should have been recompiled
		auto time2 =
			std::filesystem::last_write_time(BUILDDIR + "/hello-hello_cc" + obj_ext);
		if(time == time2)
		{
			fail();
		}
	}

	//////////////////////////////////////////////////////////////////////////////
	// check if flags change trigger rebuild
	{
		// Replace -DFOO with -DBAR in foo external.cxxflags
		copy_config("bar");
		Tracker configuration_cc_bin("configuration.cc");
		Tracker ctor_bin(ctor_exe);
		auto time =
			std::filesystem::last_write_time(BUILDDIR + "/hello-hello_cc" + obj_ext);
		std::this_thread::sleep_for(1100ms);

		// Run normally to reconfigure, rebuild ctor and rebuild hello.cc
		run_ctor({"-v"});

		auto time2 =
			std::filesystem::last_write_time(BUILDDIR + "/hello-hello_cc" + obj_ext);
		if(time == time2)
		{
			fail();
		}

		assert_changed(configuration_cc_bin);
		assert_changed(ctor_bin);
	}

	//////////////////////////////////////////////////////////////////////////////
	// check if included files in ctor.cc is tracked for changes
	{
		copy_config("multi");
		Tracker configuration_cc_bin("configuration.cc");
		Tracker ctor_bin(ctor_exe);
		auto time =
			std::filesystem::last_write_time(BUILDDIR + "/hello-hello_cc" + obj_ext);
		std::this_thread::sleep_for(1100ms);

		// Run normally to reconfigure, rebuild ctor and rebuild hello.cc
		run_ctor({"-v"});

		auto time2 =
			std::filesystem::last_write_time(BUILDDIR + "/hello-hello_cc" + obj_ext);
		if(time == time2)
		{
			fail();
		}

		assert_changed(configuration_cc_bin);
		assert_changed(ctor_bin);

		// now touching foobar.h, should retrigger re-configuration
		time = std::filesystem::last_write_time(ctor_exe);
		std::filesystem::last_write_time("foobar.h", time + 1s);
		std::this_thread::sleep_for(1100ms);

		// Run normally to reconfigure, rebuild ctor and rebuild hello.cc
		run_ctor({"-v"});

		time2 = std::filesystem::last_write_time(ctor_exe);
		if(time == time2)
		{
			fail();
		}
	}

	//////////////////////////////////////////////////////////////////////////////
	// generated part1: one-to-one generation
	{
		copy_config("generated");
		std::filesystem::remove(BUILDDIR + "/world.cc");
		std::filesystem::remove(BUILDDIR + "/foo.cc");

		Tracker configuration_cc_bin("configuration.cc");
		Tracker ctor_bin(ctor_exe);
		std::this_thread::sleep_for(1100ms);

		// Run normally to reconfigure, rebuild ctor and build world.cc
		run_ctor({"-v", "world"});

		assert_changed(configuration_cc_bin);
		assert_changed(ctor_bin);

		// foo.cc should not be generated at this point
		assert_not_exists(BUILDDIR+"/foo.cc");

		auto time_w = std::filesystem::last_write_time(BUILDDIR + "/world.cc");
		auto time_wo =
			std::filesystem::last_write_time(BUILDDIR + "/" + BUILDDIR+
			                                 "/world-world_cc" + obj_ext);
		std::this_thread::sleep_for(1100ms);

		// now touching hello.cc, should trigger regeneration of world.cc and
		// rebuild
		std::filesystem::last_write_time("hello.cc", time_w + 1s);
		run_ctor({"-v", "world"});

		auto time_w2 = std::filesystem::last_write_time(BUILDDIR + "/world.cc");
		auto time_wo2 =
			std::filesystem::last_write_time(BUILDDIR + "/" + BUILDDIR +
			                                 "/world-world_cc" + obj_ext);
		if(time_w == time_w2)
		{
			fail();
		}
		if(time_wo == time_wo2)
		{
			fail();
		}
	}

	//////////////////////////////////////////////////////////////////////////////
	// generated part2: many-to-one generation
	{
		std::filesystem::remove(BUILDDIR + "/world.cc");
		std::filesystem::remove(BUILDDIR + "/foo.cc");
		std::filesystem::remove(BUILDDIR + "/many_to_one.cc");

		run_ctor({"-v", "many_to_one"});

		// world.cc should not be generated at this point
		assert_not_exists(BUILDDIR+"/world.cc");

		// foo.cc should have been generated at this point
		assert_exists(BUILDDIR+"/foo.cc");

		// many_to_one.cc should have been generated
		assert_exists(BUILDDIR+"/many_to_one.cc");

		auto time = std::filesystem::last_write_time(BUILDDIR + "/many_to_one.cc");
		std::this_thread::sleep_for(1100ms);

		Tracker ctor_bin(ctor_exe);

		// remove "foo.cc" from sources list, so it only contains hello.cc
		copy_config("generated2");

		// rebuild
		run_ctor({"-v", "many_to_one"});

		// Verify that the change resulted in a ctor rebuild
		assert_changed(ctor_bin);

		// Verify that source-list change triggered a new build of many_to_one.cc
		auto time2 =
			std::filesystem::last_write_time(BUILDDIR + "/many_to_one.cc");
		if(time == time2)
		{
			fail();
		}
	}

	return 0;
}