<?php
/**
 * Font Optimizer class.
 *
 * @package SpeedNest
 */

if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

/**
 * Class WPSCO_Font_Optimizer
 *
 * Optimizes Google Fonts loading, adds font-display: swap, preloads critical fonts.
 * Never changes the website's chosen font family.
 */
class WPSCO_Font_Optimizer {

    /**
     * Constructor.
     */
    public function __construct() {
        if ( wpsco_get_setting( 'emergency_disable', false ) ) {
            return;
        }

        // font-display: swap for Google Fonts.
        if ( wpsco_get_setting( 'font_display_swap', false ) ) {
            add_filter( 'style_loader_tag', array( $this, 'add_font_display' ), 10, 4 );
        }

        // Local Google Fonts.
        if ( wpsco_get_setting( 'google_fonts_local', false ) ) {
            add_filter( 'style_loader_tag', array( $this, 'localize_google_fonts' ), 20, 4 );
        }

        // Preload fonts.
        if ( wpsco_get_setting( 'preload_fonts', false ) ) {
            add_action( 'wp_head', array( $this, 'preload_fonts' ), 1 );
        }
    }

    /**
     * Add font-display: swap to Google Fonts.
     *
     * @param string $tag    Link tag.
     * @param string $handle Style handle.
     * @param string $href   Stylesheet href.
     * @param string $media  Media attribute.
     * @return string
     */
    public function add_font_display( $tag, $handle, $href, $media ) {
        if ( strpos( $href, 'fonts.googleapis.com' ) === false ) {
            return $tag;
        }

        // Add display=swap parameter if not already present.
        if ( strpos( $href, 'display=' ) === false ) {
            $new_href = add_query_arg( 'display', 'swap', $href );
            $tag      = str_replace( $href, $new_href, $tag );
        }

        return $tag;
    }

    /**
     * Localize Google Fonts (download and serve locally).
     *
     * @param string $tag    Link tag.
     * @param string $handle Style handle.
     * @param string $href   Stylesheet href.
     * @param string $media  Media attribute.
     * @return string
     */
    public function localize_google_fonts( $tag, $handle, $href, $media ) {
        // Strict opt-in check: never contact external font servers without explicit consent (Guideline 7).
        if ( ! wpsco_get_setting( 'google_fonts_local', false ) ) {
            return $tag;
        }

        if ( strpos( $href, 'fonts.googleapis.com' ) === false ) {
            return $tag;
        }

        $cache_key = 'wpsco_font_' . md5( $href );
        $local_url = get_transient( $cache_key );

        if ( false !== $local_url && file_exists( $this->url_to_path( $local_url ) ) ) {
            return str_replace( $href, $local_url, $tag );
        }

        // Download the Google Fonts CSS.
        $response = wp_remote_get( $href, array(
            'timeout'    => 10,
            'user-agent' => 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
        ) );

        if ( is_wp_error( $response ) ) {
            return $tag; // Serve original on failure.
        }

        $css = wp_remote_retrieve_body( $response );
        if ( empty( $css ) ) {
            return $tag;
        }

        // Download font files and rewrite URLs.
        $font_dir = wpsco_get_cache_dir( 'fonts/' );
        if ( ! is_dir( $font_dir ) ) {
            wp_mkdir_p( $font_dir );
        }

        $css = preg_replace_callback(
            '/url\s*\(\s*([\'"]?)(https?:\/\/fonts\.gstatic\.com\/[^)\'"]+)\1\s*\)/i',
            function ( $matches ) use ( $font_dir ) {
                $font_url   = $matches[2];
                $font_file  = md5( $font_url ) . '.' . pathinfo( wp_parse_url( $font_url, PHP_URL_PATH ), PATHINFO_EXTENSION );
                $local_path = $font_dir . $font_file;

                if ( ! file_exists( $local_path ) ) {
                    $font_response = wp_remote_get( $font_url, array( 'timeout' => 10 ) );
                    if ( ! is_wp_error( $font_response ) ) {
                        wpsco_write_file( $local_path, wp_remote_retrieve_body( $font_response ) );
                    } else {
                        return $matches[0]; // Keep original URL on failure.
                    }
                }

                $local_url = wpsco_get_cache_url( 'fonts/' . $font_file );
                return 'url(' . $matches[1] . $local_url . $matches[1] . ')';
            },
            $css
        );

        // Add font-display: swap if not present.
        if ( strpos( $css, 'font-display' ) === false ) {
            $css = preg_replace( '/(@font-face\s*\{)/', '$1font-display:swap;', $css );
        }

        // Save CSS.
        $css_hash  = md5( $href );
        $css_file  = $font_dir . 'google-fonts-' . substr( $css_hash, 0, 8 ) . '.css';
        $css_url   = wpsco_get_cache_url( 'fonts/google-fonts-' . substr( $css_hash, 0, 8 ) . '.css' );

        wpsco_write_file( $css_file, $css );

        // Cache for 30 days.
        set_transient( $cache_key, $css_url, 30 * DAY_IN_SECONDS );

        return str_replace( $href, $css_url, $tag );
    }

    /**
     * Preload critical fonts.
     */
    public function preload_fonts() {
        if ( is_admin() ) {
            return;
        }

        $font_urls = wpsco_get_setting( 'preload_font_urls', array() );

        if ( empty( $font_urls ) ) {
            return;
        }

        foreach ( $font_urls as $url ) {
            $url = trim( $url );
            if ( empty( $url ) ) {
                continue;
            }

            // Determine type from extension.
            $ext  = strtolower( pathinfo( wp_parse_url( $url, PHP_URL_PATH ), PATHINFO_EXTENSION ) );
            $type = 'font/woff2';
            switch ( $ext ) {
                case 'woff':
                    $type = 'font/woff';
                    break;
                case 'woff2':
                    $type = 'font/woff2';
                    break;
                case 'ttf':
                    $type = 'font/ttf';
                    break;
                case 'otf':
                    $type = 'font/otf';
                    break;
            }

            printf(
                '<link rel="preload" as="font" href="%s" type="%s" crossorigin>' . "\n",
                esc_url( $url ),
                esc_attr( $type )
            );
        }
    }

    /**
     * Convert URL to path.
     *
     * @param string $url URL.
     * @return string|false
     */
    private function url_to_path( $url ) {
        return wpsco_url_to_path( $url );
    }
}