// -*- c++ -*-
// Distributed under the BSD 2-Clause License.
// See accompanying file LICENSE for details.
#include "tasks.h"

#include <filesystem>
#include <deque>
#include <iostream>
#include <algorithm>

#include "settings.h"
#include "libctor.h"
#include "task.h"
#include "task_cc.h"
#include "task_ld.h"
#include "task_ar.h"
#include "task_so.h"
#include "rebuild.h"
#include "configure.h"

const std::deque<Target>& getTargets(const Settings& settings,
                                     bool resolve_externals)
{
	static bool initialised{false};
	static std::deque<Target> targets;
	if(!initialised)
	{
		const auto& externals = configuration().externals;
		for(std::size_t i = 0; i < numConfigFiles; ++i)
		{
			std::string path =
				std::filesystem::path(configFiles[i].file).parent_path().string();
			if(settings.verbose > 1)
			{
				std::cout << configFiles[i].file << " in path " << path << "\n";
			}
			auto configs = configFiles[i].cb();
			for(auto& config : configs)
			{
				if(resolve_externals)
				{
					// Resolv config externals
					for(const auto& external : config.externals)
					{
						if(externals.find(external) == externals.end())
						{
							std::cout << "External '" << external <<
								"' not found in cache - run configure.\n";
							exit(1);
						}
						const auto& flags = externals.at(external);
						config.flags.cflags.insert(config.flags.cflags.end(),
						                           flags.cflags.begin(),
						                           flags.cflags.end());
						config.flags.cxxflags.insert(config.flags.cxxflags.end(),
						                             flags.cxxflags.begin(),
						                             flags.cxxflags.end());
						config.flags.ldflags.insert(config.flags.ldflags.end(),
						                            flags.ldflags.begin(),
						                            flags.ldflags.end());
						config.flags.asmflags.insert(config.flags.asmflags.end(),
						                             flags.asmflags.begin(),
						                             flags.asmflags.end());
						//config.libs.insert(config.libs.end(),
						//                   libs.begin(),
						//                   libs.end());
					}
				}

				targets.push_back({config, path});
			}
		}
		initialised = true;
	}

	return targets;
}

std::list<std::shared_ptr<Task>> taskFactory(const BuildConfiguration& config,
                                             const Settings& settings,
                                             const std::string& sourceDir)
{
	std::filesystem::path targetFile(config.target);

	TargetType target_type{config.type};
	if(target_type == TargetType::Auto)
	{
		if(targetFile.extension() == ".a")
		{
			target_type = TargetType::StaticLibrary;
		}
		else if(targetFile.extension() == ".so")
		{
			target_type = TargetType::DynamicLibrary;
		}
		else if(targetFile.extension() == "")
		{
			target_type = TargetType::Executable;
		}
		else
		{
			std::cerr << "Could not deduce target type from target " <<
				targetFile.string() << " please specify.\n";
			exit(1);
		}
	}

	std::vector<std::string> objects;
	std::list<std::shared_ptr<Task>> tasks;
	for(const auto& file : config.sources)
	{
		tasks.emplace_back(std::make_shared<TaskCC>(config, settings,
		                                            sourceDir, file));
		objects.push_back(tasks.back()->target());
	}

	switch(target_type)
	{
	case TargetType::Auto:
		// The target_type cannot be Auto
		break;

	case TargetType::StaticLibrary:
		tasks.emplace_back(std::make_shared<TaskAR>(config, settings, config.target,
		                                            objects, sourceDir));
		break;
#ifndef BOOTSTRAP
	case TargetType::DynamicLibrary:
		// TODO: Use C++20 starts_with
		if(targetFile.stem().string().substr(0, 3) != "lib")
		{
			std::cerr << "Dynamic library target must have 'lib' prefix\n";
			exit(1);
		}
		tasks.emplace_back(std::make_shared<TaskSO>(config, settings, config.target,
		                                            objects, sourceDir));
		break;

	case TargetType::Executable:
	case TargetType::UnitTest:
		tasks.emplace_back(std::make_shared<TaskLD>(config, settings, config.target,
		                                            objects, sourceDir));
		break;

	case TargetType::Object:
		break;
#else
	default:
		break;
#endif
	}

	return tasks;
}

std::shared_ptr<Task> getNextTask(const std::list<std::shared_ptr<Task>>& allTasks,
                                  std::list<std::shared_ptr<Task>>& dirtyTasks)
{
	for(auto dirtyTask = dirtyTasks.begin();
	    dirtyTask != dirtyTasks.end();
	    ++dirtyTask)
	{
		//std::cout << "Examining target " << (*dirtyTask)->target() << "\n";
		if((*dirtyTask)->ready())
		{
			dirtyTasks.erase(dirtyTask);
			return *dirtyTask;
		}
	}

	//std::cout << "No task ready ... \n";
	return nullptr;
}

std::list<std::shared_ptr<Task>> getTasks(const Settings& settings,
                                          const std::vector<std::string> names,
                                          bool resolve_externals)
{
	auto& targets = getTargets(settings, resolve_externals);
	std::list<std::shared_ptr<Task>> tasks;
	for(const auto& target : targets)
	{
		if(names.empty() ||
		   std::find(std::begin(names), std::end(names), target.config.target) != std::end(names))
		{
			std::vector<std::string> objects;
			auto t = taskFactory(target.config, settings, target.path);
			tasks.insert(tasks.end(), t.begin(), t.end());
		}
	}

	return tasks;
}