/*
 * Mirai. Copyright (C) 2024 Vyn
 * This file is licensed under version 3 of the GNU General Public License (GPL-3.0-only)
 * The license can be found in the LICENSE file or at https://www.gnu.org/licenses/gpl-3.0.txt
 */

#ifndef MIRAI_TODOMD_H
#define MIRAI_TODOMD_H

#include "TaskItem.h"
#include "cpp-utils/debug.h"
#include "cpp-utils/string.h"
#include "mirai-core/DateTime.h"
#include "mirai-core/Day.h"
#include "mirai-core/Event.h"
#include <format>
#include <optional>
#include <sstream>
#include <stdexcept>
#include <string>
#include <vector>

namespace mirai
{

struct MiraiMarkdownFormatParseResult {
	std::string name;
	std::vector<DayData> days;
};

class TodoMdFormat
{
  public:
	static std::string
	stringify(const std::string &name, const std::vector<std::unique_ptr<Day>> &days)
	{
		std::string result = "# " + name + "\n\n";
		std::string currentDate = "";

		for (const auto &day : days) {
			auto &date = day->getDate();
			result += "## " + std::format("{:02d}-{:02d}-{:02d}", date.year, date.month, date.day) +
					  "\n\n";
			for (const auto &event : *(day->events())) {
				auto &start = event->getStartTime();
				auto &end = event->getEndTime();
				result += "> " +
						  std::format(
							  "{:02d}h{:02d}-{:02d}h{:02d} {}", start.hour, start.minute, end.hour,
							  end.minute, event->getText()
						  ) +
						  "\n";
				for (const auto &task : *(event->tasks())) {
					result += taskToString(*task) + '\n';
				}
				result += '\n';
			}
			for (const auto &task : *(day->tasks())) {
				result += taskToString(*task) + '\n';
			}
			result += '\n';
		}

		return result;
	};

	static MiraiMarkdownFormatParseResult parse(const std::string &content)
	{
		cpputils::debug::Timer readMdFormatDuration;
		std::vector<TaskItem> taskItems;
		std::string line;

		std::stringstream contentStream(content);

		if (!std::getline(contentStream, line) || line.substr(0, 2) != "# ") {
			std::cerr << "Couldn't find the task list name" << std::endl;
		}

		std::string name = line.substr(2);
		std::string currentDateString = "";

		std::vector<mirai::DayData> daysData;
		mirai::DayData *currentDay = nullptr;
		mirai::EventData *currentEvent = nullptr;

		cpputils::debug::Timer stringToTaskDuration;
		stringToTaskDuration.reset();
		cpputils::debug::Timer gelinesDuration;
		while (std::getline(contentStream, line)) {
			if (std::string_view{line.data(), 3} == "## ") {
				currentDateString = line.substr(3);
				auto dateOpt = mirai::stringToDate(currentDateString);
				if (!dateOpt.has_value()) {
					throw std::runtime_error("Malformated date");
				}
				daysData.push_back({.date = dateOpt.value()});
				currentDay = &daysData.back();
			} else if (line.starts_with("> ")) {
				auto event = stringToEvent(line, currentDateString);
				if (currentDay) {
					currentDay->events.push_back(event);
					currentEvent = &currentDay->events.back();
				}
			} else if (line.starts_with("- [ ]") || line.starts_with("- [X]")) {
				stringToTaskDuration.start();
				TaskItemData taskItemData = stringToTask(line, currentDateString);
				stringToTaskDuration.stop();
				if (currentEvent) {
					currentEvent->tasks.push_back(taskItemData);
				} else if (currentDay) {
					currentDay->tasks.push_back(taskItemData);
				}
			} else if (cpputils::string::trim(line) == "") {
				currentEvent = nullptr;
			}
		}

		gelinesDuration.printTimeElapsed("getlinesDuration");
		stringToTaskDuration.printTimeElapsed("stringToTaskDuration");
		readMdFormatDuration.printTimeElapsed("Reading MD File duration");
		return {.name = name, .days = daysData};
	}

	static std::string taskToString(const TaskItem &task);
	static TaskItemData stringToTask(const std::string &str, const std::string &date);
	static EventData stringToEvent(const std::string &str, const std::string &date);

  private:
	static std::string fieldWithSpace(const std::string &field);
	static TaskItem parseLine(const std::string &line);
	static Tags extractTagsFromMetadata(std::string metadata);
};
} // namespace mirai

#endif