felixarntz/theme-boilerplate

<?php
/**
 * Super_Awesome_Theme_Webfont_API class
 *
 * @package Super_Awesome_Theme
 * @license GPL-2.0-or-later
 * @link    https://super-awesome-author.org/themes/super-awesome-theme/
 */

/**
 * Class representing a web font API.
 *
 * @since 1.0.0
 */
abstract class Super_Awesome_Theme_Webfont_API {

    /**
     * Families part of this API.
     *
     * List of font family instances.
     *
     * @since 1.0.0
     * @var array|null
     */
    protected $families = null;

    /**
     * Gets the slug of the web font API.
     *
     * Font families part of this API will be prefixed with that slug and a colon.
     *
     * @since 1.0.0
     *
     * @return string API slug.
     */
    abstract public function get_slug();

    /**
     * Gets the title of the web font API.
     *
     * @since 1.0.0
     *
     * @return string API title.
     */
    abstract public function get_title();

    /**
     * Gets the available font families.
     *
     * @since 1.0.0
     *
     * @return array List of font family instances.
     */
    public function get_families() {
        if ( null === $this->families ) {
            $slug = $this->get_slug();

            $this->families = get_transient( 'super_awesome_theme_' . SUPER_AWESOME_THEME_VERSION . '_' . $slug . '_fonts' );

            if ( false === $this->families ) {
                $this->families = $this->fetch_families();

                if ( ! is_array( $this->families ) ) {
                    $this->families = array();
                }

                set_transient( 'super_awesome_theme_' . SUPER_AWESOME_THEME_VERSION . '_' . $slug . '_fonts', $this->families );
            }

            $this->families = array_filter( array_map( array( $this, 'data_to_object' ), $this->families ) );
        }

        return $this->families;
    }

    /**
     * Loads the fonts by printing out the necessary `<link>` tag or similar.
     *
     * In case of a Customizer preview, the markup needs to be printed even if no fonts are available.
     *
     * @since 1.0.0
     *
     * @param string $id_attr ID attribute to use for the outer tag to print. This has to be used in order
     *                        to support a Customizer partial.
     * @param array  $fonts   List of fonts to load. Each item is an associative arrays containing a `family`
     *                        key with the font family instance, and a `weight` key with the desired font
     *                        weight.
     */
    abstract public function load_fonts( $id_attr, array $fonts );

    /**
     * Fetches the available font families.
     *
     * @since 1.0.0
     *
     * @return array List of font family data.
     */
    abstract protected function fetch_families();

    /**
     * Parses data for a web font family into a web font family object.
     *
     * @since 1.0.0
     *
     * @param array $data Web font family data.
     * @return Super_Awesome_Theme_Webfont_Family Web font family object.
     */
    protected function data_to_object( array $data ) {
        if ( ! isset( $data[ Super_Awesome_Theme_Webfont_Family::PROP_ID ] ) ) {
            return null;
        }

        $id = $this->get_slug() . ':' . $data[ Super_Awesome_Theme_Webfont_Family::PROP_ID ];
        unset( $data[ Super_Awesome_Theme_Webfont_Family::PROP_ID ] );

        $data[ Super_Awesome_Theme_Webfont_Family::PROP_API ] = $this->get_slug();

        return new Super_Awesome_Theme_Webfont_Family( $id, $data );
    }
}