<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle 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, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Class representing a named selector that can be used in Behat tests.
 *
 * @package    core
 * @category   test
 * @copyright  2019 Andrew Nicols <andrew@nicols.co.uk>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

/**
 * Class representing a named selector that can be used in Behat tests.
 *
 * Named selectors are what make Behat steps like
 *   Then I should see "Useful text" in the "General" "fieldset"
 * Here, "fieldset" is the named selector, and "General" is the locator.
 *
 * Selectors can either be exact, in which case the locator needs to
 * match exactly, or can be partial, for example the way
 *   When I click "Save" "button"
 * will trigger a "Save changes" button.
 *
 * Instances of this class get returned by the get_exact_named_selectors()
 * and get_partial_named_selectors() methods in classes like behat_mod_mymod.
 * The code that makes the magic work is in the trait behat_named_selector
 * used by both behat_exact_named_selector and behat_partial_named_selector.
 *
 * @package    core
 * @category   test
 * @copyright  2019 Andrew Nicols <andrew@nicols.co.uk>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class behat_component_named_selector {
    /** @var string */
    protected $alias;

    /** @var array List of xpaths */
    protected $xpaths;

    /** @var string */
    protected $istextselector;

    /**
     * Create the selector definition.
     *
     * As an example, if you define
     *   new behat_component_named_selector('Message',
     *           [".//*[@data-conversation-id]//img[contains(@alt, %locator%)]/.."])
     * in get_partial_named_selectors in behat_message in
     * message/tests/behat/behat_message.php, then steps like
     *   When "Group 1" "core_message > Message" should exist
     * will work.
     *
     * Text selectors are things that contain other things (e.g. some particular text), e.g.
     *   Then I can see "Some text" in the "Whatever" "text_selector"
     * whereas non-text selectors are atomic things, like
     *   When I click the "Whatever" "widget".
     *
     * @param string $alias The 'friendly' name of the thing. This will be prefixed with the component name.
     *      For example, if the mod_mymod plugin, says 'Thingy', then "mod_mymod > Thingy" becomes a selector.
     * @param array $xpaths A list of xpaths one or more XPaths that the selector gets transformed into.
     * @param bool $istextselector Whether this selector can also be used as a text selector.
     */
    public function __construct(string $alias, array $xpaths, bool $istextselector = true) {
        $this->alias = $alias;
        $this->xpaths = $xpaths;
        $this->istextselector = $istextselector;
    }

    /**
     * Whether this is a text selector.
     *
     * @return bool
     */
    public function is_text_selector(): bool {
        return $this->istextselector;
    }

    /**
     * Get the name of the selector.
     * This is a back-end feature and contains a namespaced md5 of the human-readable name.
     *
     * @param string $component
     * @return string
     */
    public function get_name(string $component): string {
        return implode('_', [$component, md5($this->alias)]);
    }

    /**
     * Get the alias of the selector.
     * This is the human-readable name that you would typically interact with.
     *
     * @param string $component
     * @return string
     */
    public function get_alias(string $component): string {
        return implode(" > ", [$component, $this->alias]);;
    }

    /**
     * Get the list of combined xpaths.
     *
     * @return string The list of xpaths combined with the xpath | (OR) operator
     */
    public function get_combined_xpath(): string {
        return implode(' | ', $this->xpaths);
    }
}