<?php
namespace ILJ\Core\Options;

use ILJ\Helper\Help;
use ILJ\Core\Options as Options;
use ILJ\Core\Options\MultipleKeywords;

/**
 * Option: Links per page
 *
 * @package ILJ\Core\Options
 * @since   1.1.3
 */
class LinksPerPage extends AbstractOption {
	
	/**
	 * Get the unique identifier for the option
	 *
	 * @return string
	 */
	public static function getKey() {
		return self::ILJ_OPTIONS_PREFIX . 'links_per_page';
	}
	
	/**
	 * Get the default value of the option
	 *
	 * @return mixed
	 */
	public static function getDefault() {
		return (int) 0;
	}
	
	/**
	 * Get the frontend label for the option
	 *
	 * @return string
	 */
	public function getTitle() {
		return __('Maximum amount of links per post', 'internal-links');
	}
	
	/**
	 * Get the frontend description for the option
	 *
	 * @return string
	 */
	public function getDescription() {
		return __('For an unlimited number of links, set this value to <code>0</code> .', 'internal-links');
	}
	
	/**
	 * Outputs the options form element for backend administration
	 *
	 * @param  mixed $value
	 * @return mixed
	 */
	public function renderField($value) {
		$multiple_keywords = Options::getOption(MultipleKeywords::getKey());
		$key = self::getKey();

		?>
		<input type="number" name="<?php echo esc_attr($key); ?>" id="<?php echo esc_attr($key); ?>" value="<?php echo esc_attr($value); ?>" min=0 <?php disabled($multiple_keywords); ?> />
		<?php Help::render_options_link('link-countings/', 'links-per-post-amount', 'links per post');
	}
	
	/**
	 * Checks if a value is a valid value for option
	 *
	 * @param  mixed $value The value that gets validated
	 * @return bool
	 */
	public function isValidValue($value) {
		return is_numeric($value);
	}
}