/**
 * @copyright 2019 Christoph Wurst <christoph@winzerhof-wurst.at>
 *
 * @author 2019 Christoph Wurst <christoph@winzerhof-wurst.at>
 *
 * @license GNU AGPL version 3 or any later version
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * Parses a URL query string into a JS map
 * @param {string} queryString query string in the format param1=1234&param2=abcde&param3=xyz
 * @returns {Object.<string, string>} map containing key/values matching the URL parameters
 */
export const parse = queryString => {
	let pos
	let components
	const result = {}
	let key
	if (!queryString) {
		return null
	}
	pos = queryString.indexOf('?')
	if (pos >= 0) {
		queryString = queryString.substr(pos + 1)
	}
	const parts = queryString.replace(/\+/g, '%20').split('&')
	for (let i = 0; i < parts.length; i++) {
		// split on first equal sign
		const part = parts[i]
		pos = part.indexOf('=')
		if (pos >= 0) {
			components = [
				part.substr(0, pos),
				part.substr(pos + 1),
			]
		} else {
			// key only
			components = [part]
		}
		if (!components.length) {
			continue
		}
		key = decodeURIComponent(components[0])
		if (!key) {
			continue
		}
		// if equal sign was there, return string
		if (components.length > 1) {
			result[key] = decodeURIComponent(components[1])
		} else {
			// no equal sign => null value
			result[key] = null
		}
	}
	return result
}

/**
 * Builds a URL query from a JS map.
 * @param {Object.<string, string>} params map containing key/values matching the URL parameters
 * @returns {string} String containing a URL query (without question) mark
 */
export const build = params => {
	if (!params) {
		return ''
	}
	return $.map(params, function(value, key) {
		let s = encodeURIComponent(key)
		if (value !== null && typeof (value) !== 'undefined') {
			s += '=' + encodeURIComponent(value)
		}
		return s
	}).join('&')
}