#include "game.hpp"

#include "engine/data/bounds.hpp"
#include "engine/escape.hpp"
#include "engine/keycodes.hpp"
#include "errors/RLE_reader.hpp"
#include "errors/io.hpp"
#include "util/algorithm.hpp"
#include "util/fs.hpp"
#include "util/string.hpp"

#include <fmt/color.h>
#include <fmt/core.h>

#include <algorithm>
#include <cstdlib>
#include <filesystem>
#include <iostream>
#include <stdexcept>
#include <utility>

Game::Game(
	IStatusLineFactory statusline_factory,
	std::shared_ptr<IScene> scene,
	std::shared_ptr<ICursorController> cursor_controller,
	std::shared_ptr<IGenerationTracker> generation_tracker,
	std::shared_ptr<IStatusManager> status_manager,
	std::shared_ptr<IUserInputObserver> user_input_observer,
	std::shared_ptr<ICellHelper> cell_helper,
	std::shared_ptr<IRLEReader> rle_reader) noexcept
	: _statusline_factory(std::move(statusline_factory)),
	  _scene(std::move(scene)),
	  _cursor_controller(std::move(cursor_controller)),
	  _generation_tracker(std::move(generation_tracker)),
	  _status_manager(std::move(status_manager)),
	  _user_input_observer(std::move(user_input_observer)),
	  _cell_helper(std::move(cell_helper)),
	  _rle_reader(std::move(rle_reader)),
	  _current_mode(Mode::NORMAL),
	  _normal_mode_cursor_style(CursorStyle::SteadyBlock),
	  _command_mode_cursor_style(CursorStyle::SteadyBar),
	  _minimum_cursor_pos_y(0)
{
}

void Game::on_start()
{
	const auto scene_size = _scene->size();

	std::shared_ptr<IStatusLine> statusline =
		_statusline_factory(Bounds({.width = scene_size.get_width(), .height = 1}));

	const auto statusline_section_a_length = 15;
	const auto statusline_section_b_length = 15;
	const auto statusline_section_c_length = 15;
	const auto statusline_section_d_length = 20;
	const auto statusline_section_e_length = 25;
	const auto statusline_section_f_length = 30;
	const auto statusline_section_g_length = 20;
	const auto statusline_section_h_length = 3;

	const auto statusline_section_length_total =
		statusline_section_a_length + statusline_section_b_length +
		statusline_section_c_length + statusline_section_d_length +
		statusline_section_e_length + statusline_section_f_length +
		statusline_section_g_length + statusline_section_h_length;

	if (statusline_section_length_total > scene_size.get_width())
	{
		throw std::runtime_error(
			"To small window terminal size. The statusline doesn't fit");
	}

	statusline->set_section_length(StatusLineSection::A, statusline_section_a_length);
	statusline->set_section_length(StatusLineSection::B, statusline_section_b_length);
	statusline->set_section_length(StatusLineSection::C, statusline_section_c_length);
	statusline->set_section_length(StatusLineSection::D, statusline_section_d_length);
	statusline->set_section_length(StatusLineSection::E, statusline_section_e_length);
	statusline->set_section_length(StatusLineSection::F, statusline_section_f_length);
	statusline->set_section_length(StatusLineSection::G, statusline_section_g_length);
	statusline->set_section_length(StatusLineSection::H, statusline_section_h_length);

	statusline->set_section_style(
		StatusLineSection::A,
		{.bg_color = static_cast<uint32_t>(fmt::color::green),
		 .bold = true,
		 .padding_left = 1U,
		 .padding_right = 1U});

	_scene->register_component(statusline, Vector2({.x = 0, .y = 1}));

	_status_manager->bind(statusline);

	_minimum_cursor_pos_y = 2;

	_status_manager->set_section_title(StatusLineSection::A, "");
	_status_manager->set_section_title(StatusLineSection::B, "X: ");
	_status_manager->set_section_title(StatusLineSection::C, "Y: ");
	_status_manager->set_section_title(StatusLineSection::D, "Paused: ");
	_status_manager->set_section_title(StatusLineSection::E, "Generation: ");
	_status_manager->set_section_title(StatusLineSection::F, "Generation speed: ");
	_status_manager->set_section_title(StatusLineSection::G, "Window size: ");

	const auto center_position = Vector2(
		{.x = static_cast<Vector2::Value>(scene_size.get_width()) / 2,
		 .y = static_cast<Vector2::Value>(scene_size.get_height()) / 2});

	_cursor_controller->move_to(center_position);

	_status_manager->set_section_body(StatusLineSection::A, "NORMAL");

	_status_manager->set_section_body(
		StatusLineSection::B,
		fmt::format("{}", center_position.get_x()));

	_status_manager->set_section_body(
		StatusLineSection::C,
		fmt::format("{}", center_position.get_y()));

	_status_manager->set_section_body(
		StatusLineSection::D,
		_generation_tracker->get_is_paused() ? "yes" : "no");

	_status_manager->set_section_body(StatusLineSection::E, "0");

	_status_manager->set_section_body(StatusLineSection::F, "0");

	_status_manager->set_section_body(
		StatusLineSection::G,
		fmt::format("{}x{}", scene_size.get_width(), scene_size.get_height()));

	_cursor_controller->set_cursor_style(_normal_mode_cursor_style);

	_commands["open"] = CommandInfo(
		{.option_cnt = 1U,
		 .function = [this](CommandInfo::Options options)
		 {
			 const auto rle_file_path =
				 expand_path_home(std::filesystem::path(options[0]));

			 std::unique_ptr<IMatrix<char>> rle_matrix;

			 try
			 {
				 rle_matrix = _rle_reader->read_RLE_file(rle_file_path);
			 }
			 catch (const InvalidRLEFileError &error)
			 {
				 _show_command_error(fmt::format("Error: {}", error.what()));
				 return;
			 }
			 catch (const IOError &error)
			 {
				 _show_command_error(fmt::format("Error: {}", error.what()));
				 return;
			 }

			 if (rle_matrix == nullptr)
			 {
				 _show_command_error(fmt::format(
					 "A unknown error occurred while reading RLE file with path '{}'",
					 rle_file_path.string()));
				 return;
			 }

			 _return_to_normal_mode();

			 const auto previous_pos = _cursor_controller->where();

			 auto scene_matrix = _scene->get_matrix();

			 for (auto row : *rle_matrix)
			 {
				 for (auto &col : row)
				 {
					 const auto col_pos = _cursor_controller->where();

					 std::cout.put(col);

					 _cursor_controller->move_to(col_pos);

					 scene_matrix->set(col_pos, col);

					 if (!container_has(_living_cell_positions, col_pos))
					 {
						 _living_cell_positions.push_back(col_pos);
					 }

					 _cursor_controller->move(Vector2::right(), 1U);
				 }

				 fmt::print("\n");
				 const auto current_pos = _cursor_controller->where();

				 _cursor_controller->move_to(
					 Vector2({.x = previous_pos.get_x(), .y = current_pos.get_y() - 1}));
			 }

			 std::cout.flush();

			 _cursor_controller->move_to(previous_pos);
		 }});
}

void Game::on_update() noexcept
{
	if (_current_mode == Mode::COMMAND)
	{
		_on_command_mode_update();
		return;
	}

	_on_normal_mode_update();
}

void Game::on_exit() const noexcept
{
	for (auto row : *_scene->get_matrix())
	{
		for (auto &col : row)
		{
			fmt::print("{}", col);
		}

		fmt::print("\n");
	}

	std::cout.flush();
}

void Game::_on_normal_mode_update() noexcept
{
	const auto pressed_key = _user_input_observer->get_currently_pressed_key();

	auto cursor_has_moved = false;
	auto is_generation_stepping = false;

	switch (pressed_key)
	{
	case 'h':
		if (_move_cursor(Vector2::left()))
		{
			cursor_has_moved = true;
		}
		break;

	case 'j':
		if (_move_cursor(Vector2::down()))
		{
			cursor_has_moved = true;
		}
		break;

	case 'k':
		if (_move_cursor(Vector2::up()))
		{
			cursor_has_moved = true;
		}
		break;

	case 'l':
		if (_move_cursor(Vector2::right()))
		{
			cursor_has_moved = true;
		}
		break;

	case 'q':
		std::exit(EXIT_SUCCESS);

	case ':':
		_last_pos_before_command_mode = _cursor_controller->where();

		_cursor_controller->move_to(Vector2({.x = 0, .y = 0}));

		_erase_entire_line();

		std::cout << ":";
		std::cout.flush();

		_cursor_controller->update_position(
			_cursor_controller->where() + Vector2::right());

		_cursor_controller->set_cursor_style(_command_mode_cursor_style);

		_command_mode_input = "";

		_current_mode = Mode::COMMAND;

		_status_manager->set_section_body(StatusLineSection::A, "COMMAND");
		return;

	case 'i':
	{
		const auto position = _cursor_controller->where();
		const auto matrix = _scene->get_matrix();

		if (matrix->get(position) == 'x')
		{
			break;
		}

		_set_space(matrix, position, 'x');
		_living_cell_positions.push_back(position);
		break;
	}

	case 'x':
	{
		const auto position = _cursor_controller->where();
		const auto matrix = _scene->get_matrix();

		if (matrix->get(position) == ' ')
		{
			break;
		}

		_set_space(matrix, position, ' ');
		_living_cell_positions.remove(position);
		break;
	}

	case 'p':
	{
		auto onoff = !_generation_tracker->get_is_paused();

		_generation_tracker->set_is_paused(onoff);
		_status_manager->set_section_body(StatusLineSection::D, onoff ? "yes" : "no");

		break;
	}

	case 's':
		is_generation_stepping = true;
		break;

	case '+':
		if (_generations_per_second < MAXIMUM_GENERATIONS_PER_SECOND)
		{
			_generations_per_second++;
		}
		break;

	case '-':
		if (_generations_per_second > 1)
		{
			_generations_per_second--;
		}
		break;

	default:
		break;
	}

	if (cursor_has_moved)
	{
		const auto current_pos = _cursor_controller->where();

		_status_manager->set_section_body(
			StatusLineSection::B,
			fmt::format("{}", current_pos.get_x()));

		_status_manager->set_section_body(
			StatusLineSection::C,
			fmt::format("{}", current_pos.get_y()));
	}

	_status_manager->set_section_body(
		StatusLineSection::F,
		fmt::format("{}/s", _generations_per_second));

	const auto time_now = std::chrono::system_clock::now();

	if (_generation_tracker->get_is_paused() && !is_generation_stepping)
	{
		return;
	}

	const auto time_since_last_gen =
		std::chrono::duration_cast<std::chrono::milliseconds>(
			time_now - _last_gen_update_time);

	if (time_since_last_gen.count() <= MILLIS_IN_SECOND / _generations_per_second)
	{
		return;
	}

	const auto new_current_gen = _generation_tracker->get_current_generation() + 1U;

	_generation_tracker->set_current_generation(new_current_gen);

	_status_manager->set_section_body(
		StatusLineSection::E,
		fmt::format("{}", new_current_gen));

	_last_gen_update_time = time_now;

	auto matrix = _scene->get_matrix();

	const auto dying_cell_positions = container_filter(
		_living_cell_positions,
		[this](const Vector2 &cell_pos)
		{
			return _cell_helper->is_cell_dying(cell_pos);
		});

	auto birth_cell_positions =
		_cell_helper->get_birth_cell_positions(_living_cell_positions);

	for (const auto &dying_cell_pos : dying_cell_positions)
	{
		_set_space(matrix, dying_cell_pos, ' ');

		const auto cell_found = container_find(_living_cell_positions, dying_cell_pos);

		if (cell_found != _living_cell_positions.end())
		{
			_living_cell_positions.erase(cell_found);
		}
	}

	for (const auto &birth_cell_pos : birth_cell_positions)
	{
		if (birth_cell_pos.get_y() >= _minimum_cursor_pos_y)
		{
			_set_space(matrix, birth_cell_pos, 'x');
			_living_cell_positions.push_back(birth_cell_pos);
		}
	}
}

void Game::_on_command_mode_update() noexcept
{
	const auto pressed_key = _user_input_observer->get_currently_pressed_key();

	switch (pressed_key)
	{
	case keycodes::ESCAPE:
		_erase_entire_line();
		_return_to_normal_mode();
		break;

	case keycodes::ENTER:
		if (!_command_mode_input.empty())
		{
			_run_command(_command_mode_input);
		}

		if (_current_mode != Mode::NORMAL)
		{
			_return_to_normal_mode();
		}

		break;

	case keycodes::BACKSPACE:
	{
		const auto position = _cursor_controller->where();

		const auto input_pos_x = static_cast<uint32_t>(position.get_x()) - 1U;

		if (input_pos_x == 0U)
		{
			break;
		}

		_command_mode_input.erase(input_pos_x - 1U, 1U);

		_cursor_controller->move(Vector2::left(), 1U);

		std::cout.put(' ');
		std::cout.flush();

		_cursor_controller->update_position(
			_cursor_controller->where() + Vector2::right());

		_cursor_controller->move(Vector2::left(), 1U);

		_erase_line_from_cursor();

		std::cout << _command_mode_input.substr(input_pos_x - 1U);
		std::cout.flush();

		_cursor_controller->move_to(position);
		_cursor_controller->move(Vector2::left(), 1U);

		break;
	}

	case keycodes::LEFT_ARROW:
		if (_cursor_controller->where().get_x() >= 2)
		{
			_cursor_controller->move(Vector2::left(), 1U);
		}
		break;

	case keycodes::RIGHT_ARROW:
		if (static_cast<uint32_t>(_cursor_controller->where().get_x()) - 1U <
			_command_mode_input.size())
		{
			_cursor_controller->move(Vector2::right(), 1U);
		}
		break;

	case keycodes::UP_ARROW:
	case keycodes::DOWN_ARROW:
	case 0:
		break;

	default:
		const auto position = _cursor_controller->where();

		const auto input_pos_x = static_cast<uint32_t>(position.get_x()) - 1U;

		if (input_pos_x < _command_mode_input.length())
		{
			_command_mode_input.insert(input_pos_x, 1, pressed_key);

			_erase_line_from_cursor();

			std::cout << pressed_key << _command_mode_input.substr(input_pos_x + 1U);
			std::cout.flush();

			_cursor_controller->move_to(position + Vector2::right());
			break;
		}

		_command_mode_input += pressed_key;

		std::cout << pressed_key;
		std::cout.flush();

		_cursor_controller->update_position(
			_cursor_controller->where() + Vector2::right());

		break;
	}
}

void Game::_return_to_normal_mode() noexcept
{
	_cursor_controller->move_to(_last_pos_before_command_mode.value_or(
		Vector2({.x = CURSOR_FALLBACK_POS_X, .y = CURSOR_FALLBACK_POS_Y})));

	_cursor_controller->set_cursor_style(_normal_mode_cursor_style);

	_current_mode = Mode::NORMAL;

	_status_manager->set_section_body(StatusLineSection::A, "NORMAL");
}

void Game::_run_command(const std::string &command) noexcept
{
	const auto split_command = split_string<std::vector<std::string>>(command, ' ');

	if (split_command.size() == 1)
	{
		if (!_commands.contains(command))
		{
			_show_command_error(fmt::format("Error: Not a command: {}", command));
			return;
		}

		if (_commands.at(command).option_cnt != 0U)
		{
			_show_command_error(
				fmt::format("Error: Insufficient arguments for command: {}", command));
			return;
		}
	}

	const auto &command_name = split_command[0];

	if (!_commands.contains(command_name))
	{
		_show_command_error(fmt::format("Error: Not a command: {}", command));
		return;
	}

	const auto &command_info = _commands.at(command_name);

	const auto args =
		decltype(split_command)(split_command.begin() + 1, split_command.end());

	command_info.function(args);
}

void Game::_show_command_error(const std::string_view &error_message) noexcept
{
	_erase_entire_line();

	const auto position = _cursor_controller->where();

	_cursor_controller->move_to(Vector2({.x = 0, .y = position.get_y()}));

	fmt::print(fmt::fg(fmt::color::red), "{}", error_message);
}

auto Game::_move_cursor(const Vector2 &direction) noexcept -> bool
{
	const auto current_position = _cursor_controller->where();

	const auto dest_position = current_position + direction;

	const auto scene_size = _scene->size();

	if (scene_size.validate_coords(dest_position) != CoordsValidation::VALID)
	{
		return false;
	}

	if (dest_position.get_y() < _minimum_cursor_pos_y)
	{
		return false;
	}

	_cursor_controller->move_to(dest_position);

	return true;
}

void Game::_set_space(
	const std::shared_ptr<IMatrix<IScene::MatrixElement>> &matrix,
	const Vector2 &position,
	char character) noexcept
{
	const auto prev_position = _cursor_controller->where();

	_cursor_controller->move_to(position);

	std::cout.put(character);
	std::cout.flush();

	matrix->set(position, character);

	_cursor_controller->move_to(prev_position);
}

void Game::_erase_entire_line() noexcept
{
	fmt::print(ERASE_ENTIRE_LINE, fmt::arg("esc", ESC));
	std::cout.flush();
}

void Game::_erase_line_from_cursor() noexcept
{
	fmt::print(ERASE_LINE_FROM_CURSOR, fmt::arg("esc", ESC));
	std::cout.flush();
}