#include <vector>
#include <string>
#include <filesystem>
#include <iostream>
#include <utility>
#include <list>
#include <chrono>
#include <thread>
#include <memory>
#include <algorithm>
#include <list>
#include <array>
#include <deque>
#include <fstream>
#include <cstdlib>
#include <set>
#include <future>

#include <getoptpp/getoptpp.hpp>

#include "libcppbuild.h"
#include "settings.h"
#include "configure.h"
#include "rebuild.h"
#include "tasks.h"

using namespace std::chrono_literals;

int main(int argc, char* argv[])
{
	if(argc > 1 && std::string(argv[1]) == "configure")
	{
		return configure(argc, argv);
	}

	Settings settings{};

	settings.builddir = getConfiguration(cfg::builddir, "build");
	settings.parallel_processes =
		std::max(1u, std::thread::hardware_concurrency() * 2 - 1);
	settings.verbose = 0;

	bool write_compilation_database{false};
	std::string compilation_database;
	bool print_configure_cmd{false};
	bool print_configure_db{false};
	std::vector<std::string> add_files;
	std::vector<std::string> remove_files;
	bool list_files{false};

	dg::Options opt;
	int key{128};

	opt.add("jobs", required_argument, 'j',
	        "Number of parallel jobs. (default: cpucount * 2 - 1 )",
	        [&]() {
		        try
		        {
			        settings.parallel_processes = std::stoi(optarg);
		        }
		        catch(...)
		        {
			        std::cerr << "Not a number\n";
			        return 1;
		        }
		        return 0;
	        });

	opt.add("build-dir", required_argument, 'b',
	        "Overload output directory for build files (default: '" +
	        settings.builddir + "').",
	        [&]() {
		        settings.builddir = optarg;
		        return 0;
	        });

	opt.add("verbose", no_argument, 'v',
	        "Be verbose. Add multiple times for more verbosity.",
	        [&]() {
		        settings.verbose++;
		        return 0;
	        });

	opt.add("add", required_argument, 'a',
	        "Add specified file to the build configurations.",
	        [&]() {
		        add_files.push_back(optarg);
		        return 0;
	        });

	opt.add("remove", required_argument, 'r',
	        "Remove specified file from the build configurations.",
	        [&]() {
		        remove_files.push_back(optarg);
		        return 0;
	        });

	opt.add("list", no_argument, 'l',
	        "List files in the build configurations.",
	        [&]() {
		        list_files = true;
		        return 0;
	        });

	opt.add("configure-cmd", no_argument, key++,
	        "Print commandline for last configure.",
	        [&]() {
		        print_configure_cmd = true;
		        return 0;
	        });

	opt.add("configure-db", no_argument, key++,
	        "Print entire configure parameter database.",
	        [&]() {
		        print_configure_db = true;
		        return 0;
	        });

	opt.add("database", required_argument, 'd',
	        "Write compilation database json file.",
	        [&]() {
		        write_compilation_database = true;
		        compilation_database = optarg;
		        return 0;
	        });

	opt.add("help", no_argument, 'h',
	        "Print this help text.",
	        [&]() {
		        std::cout << "usage stuff\n";
		        opt.help();
		        exit(0);
		        return 0;
	        });

	opt.process(argc, argv);

	auto verbose_env = std::getenv("V");
	if(verbose_env)
	{
		settings.verbose = std::atoi(verbose_env);
	}

	if(list_files)
	{
		std::set<std::string> files;
		for(std::size_t i = 0; i < numConfigFiles; ++i)
		{
			files.insert(configFiles[i].file);
		}

		for(const auto& file : files)
		{
			std::cout << file << "\n";
		}

		return 0;
	}

	if(!add_files.empty() || !remove_files.empty())
	{
		for(const auto& add_file : add_files)
		{
			reg(add_file.data(), [](){ return std::vector<BuildConfiguration>{};});
		}

		for(const auto& remove_file : remove_files)
		{
			unreg(remove_file.data());
		}

		// Force rebuild if files were added
		recompileCheck(settings, 1, argv, true);
	}

	recompileCheck(settings, argc, argv);

	std::filesystem::path builddir(settings.builddir);
	std::filesystem::create_directories(builddir);

	auto tasks = getTasks(settings);

	if(write_compilation_database)
	{
		std::ofstream istr(compilation_database);
		istr << "[";
		bool first{true};
		for(auto task : tasks)
		{
			auto s = task->toJSON();
			if(!s.empty())
			{
				if(!first)
				{
					istr << ",\n";
				}
				else
				{
					istr << "\n";
				}
				first = false;
				istr << s;
			}
		}
		istr << "\n]\n";
	}

	if(print_configure_cmd)
	{
		std::cout << getConfiguration("cmd") << "\n";
		return 0;
	}

	if(print_configure_db)
	{
		const auto& c = configuration();
		for(const auto& config : c)
		{
			std::cout << config.first << ": " << config.second << "\n";
		}
		return 0;
	}

	for(auto task : tasks)
	{
		if(task->registerDepTasks(tasks))
		{
			return 1;
		}
	}

	std::list<std::shared_ptr<Task>> dirtyTasks;
	for(auto task : tasks)
	{
		if(task->dirty())
		{
			dirtyTasks.push_back(task);
		}
	}

	for(auto const &arg : opt.arguments())
	{
		if(arg == "clean")
		{
			std::cout << "Cleaning\n";
			for(auto& task : tasks)
			{
				if(task->clean() != 0)
				{
					return 1;
				}
			}

			return 0;
		}

		if(arg == "configure")
		{
			std::cerr << "The 'configure' target must be the first argument.\n";
			return 1;
		}
	}

	if(dirtyTasks.empty())
	{
		return 0;
	}

	std::cout << "Building\n";
	std::list<std::future<int>> processes;

	// Start all tasks
	bool done{false};
	while(!done)
	{
		bool started_one{false};
		while(processes.size() < settings.parallel_processes)
		{
			if(dirtyTasks.empty())
			{
				done = true;
				break;
			}

			auto task = getNextTask(tasks, dirtyTasks);
			if(task == nullptr)
			{
				break;
				//return 1;
			}

			processes.emplace_back(
				std::async(std::launch::async,
				           [task]()
				           {
					           return task->run();
				           }));
			started_one = true;
			std::this_thread::sleep_for(2ms);
		}

		for(auto process = processes.begin();
		    process != processes.end();
		    ++process)
		{
			if(process->valid())
			{
				if(process->get() != 0)
				{
					return 1;
				}
				processes.erase(process);
				break;
			}
		}

		if(started_one)
		{
			std::this_thread::sleep_for(2ms);
		}
		else
		{
			std::this_thread::sleep_for(200ms);
		}
	}

	for(auto process = processes.begin();
	    process != processes.end();
	    ++process)
	{
		process->wait();
		auto ret = process->get();
		if(ret != 0)
		{
			return 1;
		}
	}

	return 0;
}