/**

 * ShaderShark

 * Copyright © 2023 František Kučera (Frantovo.cz, GlobalCode.info)

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, version 3 of the License.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program. If not, see <http://www.gnu.org/licenses/>.

 */

#pragma once

#include <vector>

#include <string>

#include "Configuration.h"

class CLIParser {

private:

	static const std::string OPTION_TEXTURE;

	static const std::string OPTION_SHADER;

	static const std::string OPTION_BACKGROUND_COLOR;

	static const std::string OPTION_ROOT_WINDOW;

	const std::string

	readNext(const std::vector<std::string>& arguments, int& i) {

		if (i < arguments.size()) return arguments[i++];

		else throw std::logic_error("Missing CLI argument"

				+ (i > 0 ? (" after " + arguments[i - 1]) : ""));

	}

	bool parseBoolean(const std::string& value) {

		if (value == "true") return true;

		else if (value == "false") return false;

		else throw std::logic_error("Unable to parse boolean value: "

				+ value + " (expecting true or false)");

	}

	unsigned long

	parseHexColor(const std::string& hex) {

		size_t count;

		unsigned long rgb = std::stoul(hex, &count, 16);

		if (count == 6 || count == 8 && hex.starts_with("0x")) return rgb;

		else throw std::logic_error("Invalid hex color string");

		// the input should be (0x)?[0-9a-fA-F]{6}, however:

		// values like 0x0123 are also accepted and interpreted as 000123

		// values like +0x012 are also accepted and interpreted as 000012

	}

	unsigned long

	parseUL(const std::string& str) {

		int base = str.starts_with("0x") ? 16 : 10;

		return std::stoul(str, nullptr, base);

	}

public:

	const Configuration parse(const std::vector<std::string>& arguments) {

		Configuration c;

		for (int i = 0; i < arguments.size();) {

			const std::string& option = readNext(arguments, i);

			if (option == OPTION_TEXTURE) {

				Configuration::Texture tex;

				tex.fileName = readNext(arguments, i);

				c.textures.push_back(tex);

			} else if (option == OPTION_SHADER) {

				const auto type = readNext(arguments, i);

				const auto file = readNext(arguments, i);

				c.shaders.push_back({file, type});

			} else if (option == OPTION_BACKGROUND_COLOR) {

				c.backgroundColor = parseHexColor(readNext(arguments, i));

			} else if (option == OPTION_ROOT_WINDOW) {

				c.rootWindow = parseUL(readNext(arguments, i));

			} else throw std::logic_error("Unsupported CLI option: " + option);

		}

		return c;

	}

};

const std::string CLIParser::OPTION_TEXTURE = "--texture";

const std::string CLIParser::OPTION_SHADER = "--shader";

const std::string CLIParser::OPTION_BACKGROUND_COLOR = "--background-color";

const std::string CLIParser::OPTION_ROOT_WINDOW = "--root-window";