<?php
/**
 * Class containing utility static methods that other SEO tools are relying on.
 *
 * @package automattic/jetpack
 */

use Automattic\Jetpack\Current_Plan as Jetpack_Plan;

/**
 * Class containing utility static methods that other SEO tools are relying on.
 */
class Jetpack_SEO_Utils {
	/**
	 * Site option name used to store front page meta description.
	 */
	const FRONT_PAGE_META_OPTION = 'advanced_seo_front_page_description';

	/**
	 * The LEGACY_META_OPTION is used to support legacy usage on WPcom simple sites (free or paid).
	 * For WPorg JP sites, the JP seo-tools features were made free for all sites (free or paid).
	 */
	const LEGACY_META_OPTION = 'seo_meta_description';

	/**
	 * Used to check whether SEO tools are enabled for given site.
	 *
	 * @return bool True if SEO tools are enabled, false otherwise.
	 */
	public static function is_enabled_jetpack_seo() {
		/**
		 * Can be used by SEO plugin authors to disable the conflicting output of SEO Tools.
		 *
		 * @module seo-tools
		 *
		 * @since 5.0.0
		 *
		 * @param bool True if SEO Tools should be disabled, false otherwise.
		 */
		if ( apply_filters( 'jetpack_disable_seo_tools', false ) ) {
			return false;
		}

		return Jetpack_Plan::supports( 'advanced-seo' );
	}

	/**
	 * Checks if this option was set while it was freely available to all WPcom simple sites.
	 *
	 * @return bool True if we should enable legacy usage, false otherwise.
	 */
	public static function has_legacy_front_page_meta() {
		return ! self::is_enabled_jetpack_seo() && get_option( self::LEGACY_META_OPTION );
	}

	/**
	 * Returns front page meta description for current site.
	 *
	 * @return string Front page meta description string or empty string.
	 */
	public static function get_front_page_meta_description() {
		if ( self::is_enabled_jetpack_seo() ) {
			$front_page_meta = get_option( self::FRONT_PAGE_META_OPTION );
			return $front_page_meta ? $front_page_meta : get_option( self::LEGACY_META_OPTION, '' );
		}

		// Support legacy usage for WPcom simple sites.
		return get_option( self::LEGACY_META_OPTION, '' );
	}

	/**
	 * Sanitizes the custom front page meta description input.
	 *
	 * @param string $value Front page meta string.
	 *
	 * @return string The sanitized string.
	 */
	public static function sanitize_front_page_meta_description( $value ) {
		return wp_strip_all_tags( $value );
	}

	/**
	 * Updates the site option value for front page meta description.
	 *
	 * @param string $value New value for front page meta description.
	 *
	 * @return string Saved value, or empty string if no update was performed.
	 */
	public static function update_front_page_meta_description( $value ) {
		$front_page_description = self::sanitize_front_page_meta_description( $value );

		/**
		 * Can be used to limit the length of front page meta description.
		 *
		 * @module seo-tools
		 *
		 * @since 4.4.0
		 *
		 * @param int Maximum length of front page meta description. Defaults to 300.
		 */
		$description_max_length = apply_filters( 'jetpack_seo_front_page_description_max_length', 300 );

		if ( function_exists( 'mb_substr' ) ) {
			$front_page_description = mb_substr( $front_page_description, 0, $description_max_length );
		} else {
			$front_page_description = substr( $front_page_description, 0, $description_max_length );
		}

		$can_set_meta       = self::is_enabled_jetpack_seo();
		$legacy_meta_option = get_option( self::LEGACY_META_OPTION );
		$has_old_meta       = ! empty( $legacy_meta_option );
		$option_name        = self::has_legacy_front_page_meta() ? self::LEGACY_META_OPTION : self::FRONT_PAGE_META_OPTION;

		$did_update = update_option( $option_name, $front_page_description );

		if ( $did_update && $has_old_meta && $can_set_meta ) {
			// Delete legacy option if user has switched to Business or eCommerce plan and updated the front page meta description.
			delete_option( self::LEGACY_META_OPTION );
		}

		if ( $did_update ) {
			return $front_page_description;
		}

		return '';
	}
}
