<?php
/**
 * Font Utils class.
 *
 * Provides utility functions for working with font families.
 *
 * @package    WordPress
 * @subpackage Fonts
 * @since      6.5.0
 */

/**
 * A class of utilities for working with the Font Library.
 *
 * These utilities may change or be removed in the future and are intended for internal use only.
 *
 * @since 6.5.0
 * @access private
 */
class WP_Font_Utils {
    /**
     * Adds surrounding quotes to font family names that contain special characters.
     *
     * It follows the recommendations from the CSS Fonts Module Level 4.
     * @link https://www.w3.org/TR/css-fonts-4/#font-family-prop
     *
     * @since 6.5.0
     *
     * @param string $item A font family name.
     * @return string The font family name with surrounding quotes, if necessary.
     */
    private static function maybe_add_quotes( $item ) {
        // Matches strings that are not exclusively alphabetic characters or hyphens, and do not exactly follow the pattern generic(alphabetic characters or hyphens).
        $regex = '/^(?!generic\([a-zA-Z\-]+\)$)(?!^[a-zA-Z\-]+$).+/';
        $item  = trim( $item );
        if ( preg_match( $regex, $item ) ) {
            $item = trim( $item, "\"'" );
            return '"' . $item . '"';
        }
        return $item;
    }

    /**
     * Sanitizes and formats font family names.
     *
     * - Applies `sanitize_text_field`.
     * - Adds surrounding quotes to names containing any characters that are not alphabetic or dashes.
     *
     * It follows the recommendations from the CSS Fonts Module Level 4.
     * @link https://www.w3.org/TR/css-fonts-4/#font-family-prop
     *
     * @since 6.5.0
     * @access private
     *
     * @see sanitize_text_field()
     *
     * @param string $font_family Font family name(s), comma-separated.
     * @return string Sanitized and formatted font family name(s).
     */
    public static function sanitize_font_family( $font_family ) {
        if ( ! $font_family ) {
            return '';
        }

        $output          = sanitize_text_field( $font_family );
        $formatted_items = array();
        if ( str_contains( $output, ',' ) ) {
            $items = explode( ',', $output );
            foreach ( $items as $item ) {
                $formatted_item = self::maybe_add_quotes( $item );
                if ( ! empty( $formatted_item ) ) {
                    $formatted_items[] = $formatted_item;
                }
            }
            return implode( ', ', $formatted_items );
        }
        return self::maybe_add_quotes( $output );
    }

    /**
     * Generates a slug from font face properties, e.g. `open sans;normal;400;100%;U+0-10FFFF`
     *
     * Used for comparison with other font faces in the same family, to prevent duplicates
     * that would both match according the CSS font matching spec. Uses only simple case-insensitive
     * matching for fontFamily and unicodeRange, so does not handle overlapping font-family lists or
     * unicode ranges.
     *
     * @since 6.5.0
     * @access private
     *
     * @link https://drafts.csswg.org/css-fonts/#font-style-matching
     *
     * @param array $settings {
     *     Font face settings.
     *
     *     @type string $fontFamily   Font family name.
     *     @type string $fontStyle    Optional font style, defaults to 'normal'.
     *     @type string $fontWeight   Optional font weight, defaults to 400.
     *     @type string $fontStretch  Optional font stretch, defaults to '100%'.
     *     @type string $unicodeRange Optional unicode range, defaults to 'U+0-10FFFF'.
     * }
     * @return string Font face slug.
     */
    public static function get_font_face_slug( $settings ) {
        $defaults = array(
            'fontFamily'   => '',
            'fontStyle'    => 'normal',
            'fontWeight'   => '400',
            'fontStretch'  => '100%',
            'unicodeRange' => 'U+0-10FFFF',
        );
        $settings = wp_parse_args( $settings, $defaults );
        if ( function_exists( 'mb_strtolower' ) ) {
            $font_family = mb_strtolower( $settings['fontFamily'] );
        } else {
            $font_family = strtolower( $settings['fontFamily'] );
        }
        $font_style    = strtolower( $settings['fontStyle'] );
        $font_weight   = strtolower( $settings['fontWeight'] );
        $font_stretch  = strtolower( $settings['fontStretch'] );
        $unicode_range = strtoupper( $settings['unicodeRange'] );

        // Convert weight keywords to numeric strings.
        $font_weight = str_replace( array( 'normal', 'bold' ), array( '400', '700' ), $font_weight );

        // Convert stretch keywords to numeric strings.
        $font_stretch_map = array(
            'ultra-condensed' => '50%',
            'extra-condensed' => '62.5%',
            'condensed'       => '75%',
            'semi-condensed'  => '87.5%',
            'normal'          => '100%',
            'semi-expanded'   => '112.5%',
            'expanded'        => '125%',
            'extra-expanded'  => '150%',
            'ultra-expanded'  => '200%',
        );
        $font_stretch     = str_replace( array_keys( $font_stretch_map ), array_values( $font_stretch_map ), $font_stretch );

        $slug_elements = array( $font_family, $font_style, $font_weight, $font_stretch, $unicode_range );

        $slug_elements = array_map(
            function ( $elem ) {
                // Remove quotes to normalize font-family names, and ';' to use as a separator.
                $elem = trim( str_replace( array( '"', "'", ';' ), '', $elem ) );

                // Normalize comma separated lists by removing whitespace in between items,
                // but keep whitespace within items (e.g. "Open Sans" and "OpenSans" are different fonts).
                // CSS spec for whitespace includes: U+000A LINE FEED, U+0009 CHARACTER TABULATION, or U+0020 SPACE,
                // which by default are all matched by \s in PHP.
                return preg_replace( '/,\s+/', ',', $elem );
            },
            $slug_elements
        );

        return sanitize_text_field( implode( ';', $slug_elements ) );
    }

    /**
     * Sanitizes a tree of data using a schema.
     *
     * The schema structure should mirror the data tree. Each value provided in the
     * schema should be a callable that will be applied to sanitize the corresponding
     * value in the data tree. Keys that are in the data tree, but not present in the
     * schema, will be removed in the sanitized data. Nested arrays are traversed recursively.
     *
     * @since 6.5.0
     *
     * @access private
     *
     * @param array $tree   The data to sanitize.
     * @param array $schema The schema used for sanitization.
     * @return array The sanitized data.
     */
    public static function sanitize_from_schema( $tree, $schema ) {
        if ( ! is_array( $tree ) || ! is_array( $schema ) ) {
            return array();
        }

        foreach ( $tree as $key => $value ) {
            // Remove keys not in the schema or with null/empty values.
            if ( ! array_key_exists( $key, $schema ) ) {
                unset( $tree[ $key ] );
                continue;
            }

            $is_value_array  = is_array( $value );
            $is_schema_array = is_array( $schema[ $key ] ) && ! is_callable( $schema[ $key ] );

            if ( $is_value_array && $is_schema_array ) {
                if ( wp_is_numeric_array( $value ) ) {
                    // If indexed, process each item in the array.
                    foreach ( $value as $item_key => $item_value ) {
                        $tree[ $key ][ $item_key ] = isset( $schema[ $key ][0] ) && is_array( $schema[ $key ][0] )
                            ? self::sanitize_from_schema( $item_value, $schema[ $key ][0] )
                            : self::apply_sanitizer( $item_value, $schema[ $key ][0] );
                    }
                } else {
                    // If it is an associative or indexed array, process as a single object.
                    $tree[ $key ] = self::sanitize_from_schema( $value, $schema[ $key ] );
                }
            } elseif ( ! $is_value_array && $is_schema_array ) {
                // If the value is not an array but the schema is, remove the key.
                unset( $tree[ $key ] );
            } elseif ( ! $is_schema_array ) {
                // If the schema is not an array, apply the sanitizer to the value.
                $tree[ $key ] = self::apply_sanitizer( $value, $schema[ $key ] );
            }

            // Remove keys with null/empty values.
            if ( empty( $tree[ $key ] ) ) {
                unset( $tree[ $key ] );
            }
        }

        return $tree;
    }

    /**
     * Applies a sanitizer function to a value.
     *
     * @since 6.5.0
     *
     * @param mixed    $value     The value to sanitize.
     * @param callable $sanitizer The sanitizer function to apply.
     * @return mixed The sanitized value.
     */
    private static function apply_sanitizer( $value, $sanitizer ) {
        if ( null === $sanitizer ) {
            return $value;

        }
        return call_user_func( $sanitizer, $value );
    }

    /**
     * Returns the expected mime-type values for font files, depending on PHP version.
     *
     * This is needed because font mime types vary by PHP version, so checking the PHP version
     * is necessary until a list of valid mime-types for each file extension can be provided to
     * the 'upload_mimes' filter.
     *
     * @since 6.5.0
     *
     * @access private
     *
     * @return string[] A collection of mime types keyed by file extension.
     */
    public static function get_allowed_font_mime_types() {
        $php_7_ttf_mime_type = PHP_VERSION_ID >= 70300 ? 'application/font-sfnt' : 'application/x-font-ttf';

        return array(
            'otf'   => 'application/vnd.ms-opentype',
            'ttf'   => PHP_VERSION_ID >= 70400 ? 'font/sfnt' : $php_7_ttf_mime_type,
            'woff'  => PHP_VERSION_ID >= 80112 ? 'font/woff' : 'application/font-woff',
            'woff2' => PHP_VERSION_ID >= 80112 ? 'font/woff2' : 'application/font-woff2',
        );
    }
}