<?php
namespace ILJ\Helper;

/**
 * Regex Custom Field Rule
 *
 * This class represents a single regex rule used in both custom field for post and custom fields for term
 * option
 *
 * @package ILJ\Helper
 * @since   2.23.5
 */
class Regex_Custom_Field {

	private const STARTS_WITH_PREFIX = 'starts_with:';
	private const ENDS_WITH_PREFIX = 'ends_with:';
	private const CONTAINS_PREFIX = 'contains:';

	/**
	 * This denotes the type of the rule.
	 *
	 * @var string Indicates the type of rule, possible values are {@link STARTS_WITH_PREFIX},
	 * {@link ENDS_WITH_PREFIX}, {@link CONTAINS_PREFIX}
	 */
	private $type;

	/**
	 * The name of the regex field rule.
	 *
	 * @var string Name of the post meta field.
	 */
	private $value;

	private function __construct($type, $value) {
		$this->type = $type;
		$this->value = $value;
	}

	/**
	 * Returns starts with label for displaying on ui, also used by javascript
	 *
	 * @return string
	 */
	public static function get_starts_with_label_template() {
		/* translators: %s: Custom Field Name */
		return __('Custom field name starts with \'%s\'', 'internal-links');
	}

	/**
	 * Returns ends with label for displaying on ui, also used by javascript
	 *
	 * @return string
	 */
	public static function get_ends_with_label_template() {
		/* translators: %s: Custom Field Name */
		return __('Custom field name ends with \'%s\'', 'internal-links');
	}

	/**
	 * Returns contains label for displaying on ui, also used by javascript
	 *
	 * @return string
	 */
	public static function get_contains_label_template() {
		/* translators: %s: Custom Field Name */
		return __('Custom field name contains \'%s\'', 'internal-links');
	}

	/**
	 * Return a label for the regex field, this is for displaying it on ui.
	 *
	 * @return string
	 */
	public function get_label() {
		switch ($this->type) {
			case self::STARTS_WITH_PREFIX:
				return sprintf(self::get_starts_with_label_template(), $this->value);
			case self::ENDS_WITH_PREFIX:
				return sprintf(self::get_ends_with_label_template(), $this->value);
			case self::CONTAINS_PREFIX:
				return sprintf(self::get_contains_label_template(), $this->value);
		}
		return '';
	}

	/**
	 * Returns to the format which can be stored in option, for example
	 * starts_with:foo
	 *
	 * @return string
	 */
	public function to_option_value() {
		return $this->type . $this->value;
	}


	/**
	 * Determines if the regex field data is valid. It is recommended to invoke this method before
	 * trying to construct the instance using any builder methods.
	 *
	 * @param string $item
	 *
	 * @return bool
	 */
	public static function is_valid_rule($item) {
		return strpos($item, self::STARTS_WITH_PREFIX) === 0 || strpos($item, self::ENDS_WITH_PREFIX) === 0
			   || strpos($item, self::CONTAINS_PREFIX) === 0;
	}


	/**
	 * Generates a {@link Regex_Custom_Field} instance from option, Its recommended to invoke {@link Regex_Custom_Field::is_valid_rule()}
	 * before calling this function.
	 *
	 * @param string $option_value
	 *
	 * @return Regex_Custom_Field
	 */
	public static function from($option_value) {
		$data = explode(':', $option_value);
		return new Regex_Custom_Field($data[0] . ':', $data[1]);
	}

	/**
	 * Method to determine if the given meta key matches the rule.
	 *
	 * @param string $meta_key
	 *
	 * @return boolean
	 */
	public function meta_key_matches_rule($meta_key) {
		switch ($this->type) {
			case self::STARTS_WITH_PREFIX:
				return strpos($meta_key, $this->value) === 0;
			case self::ENDS_WITH_PREFIX:
				return substr($meta_key, -strlen($this->value)) === $this->value;
			case self::CONTAINS_PREFIX:
				return strpos($meta_key, $this->value) !== false;
			default:
				return false;
		}

	}

	/**
	 * Return the sql like clause value for the regex custom field, for example %apple, apple%, %apple%
	 * based on the type.
	 *
	 * @return string
	 */
	public function get_escaped_sql_like_clause() {
		global $wpdb;
		if (self::STARTS_WITH_PREFIX === $this->type) {
			return $wpdb->esc_like($this->value).'%';
		}
		if (self::ENDS_WITH_PREFIX === $this->type) {
			return '%'.$wpdb->esc_like($this->value);
		}
		if (self::CONTAINS_PREFIX === $this->type) {
			return '%'.$wpdb->esc_like($this->value).'%';
		}
		return '';
	}
}