index.php

<?php
/**
 * Plugin Name: Font Weight Options
 * Description: Manage custom font weights for body text, headings, and code elements.
 */

// Prevent direct access.
if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

// Main font weight options class.
class Font_Weight_Options {

    // Constructor.
    public function __construct() {
        add_action( 'admin_menu', array( $this, 'add_admin_menu' ) );
        add_action( 'wp_head', array( $this, 'apply_font_weights_frontend' ) );
        add_action( 'admin_head', array( $this, 'apply_font_weights_admin' ) );
        register_activation_hook( __FILE__, array( $this, 'activate' ) );
    }

    // Plugin activation.
    public function activate() {
        // Set default font weights.
        $default_weights = array(
            'body'     => 400,
            'headings' => 600,
            'code'     => 400,
        );

        if ( ! get_option( 'fwo_font_weights' ) ) {
            add_option( 'fwo_font_weights', $default_weights );
        }
    }

    // Add admin menu.
    public function add_admin_menu() {
        add_theme_page(
            __( 'Font Weight Settings', 'font-weight-options' ),
            __( 'Font Weight', 'font-weight-options' ),
            'manage_options',
            'font-weight-settings',
            array( $this, 'render_admin_page' )
        );
    }

    // Render admin page.
    public function render_admin_page() {
        // Handle form submission.
        if ( isset( $_POST['submit_font_weights'] ) && wp_verify_nonce( $_POST['_wpnonce'], 'fwo_font_weights_nonce' ) ) {
            $font_weights = array(
                'body'     => absint( $_POST['font_weights']['body'] ?? 400 ),
                'headings' => absint( $_POST['font_weights']['headings'] ?? 600 ),
                'code'     => absint( $_POST['font_weights']['code'] ?? 400 ),
            );

            // Validate ranges.
            foreach ( $font_weights as $key => $weight ) {
                if ( $weight < 100 || $weight > 900 ) {
                    $font_weights[ $key ] = ( $key === 'headings' ) ? 600 : 400;
                }
            }

            update_option( 'fwo_font_weights', $font_weights );

            echo '<div class="notice notice-success"><p>' .
                 __( 'Font weights updated successfully!', 'font-weight-options' ) .
                 '</p></div>';
        }

        $saved_weights = get_option( 'fwo_font_weights', array(
            'body'     => 400,
            'headings' => 600,
            'code'     => 400,
        ) );
        ?>
        <div class="wrap">
            <h1><?php _e( 'Font Weight Settings', 'font-weight-options' ); ?></h1>
            <p><?php _e( 'Configure custom font weights for your theme. Enter values between 100–900.', 'font-weight-options' ); ?></p>

            <form method="post" action="">
                <?php wp_nonce_field( 'fwo_font_weights_nonce' ); ?>
                <table class="form-table">
                    <tr>
                        <th scope="row"><?php _e( 'Body Text (Manrope)', 'font-weight-options' ); ?></th>
                        <td>
                            <input type="number" name="font_weights[body]"
                                   value="<?php echo esc_attr( $saved_weights['body'] ); ?>"
                                   min="100" max="900" step="1" />
                            <p class="description"><?php _e( 'Default: 400 (Regular)', 'font-weight-options' ); ?></p>
                        </td>
                    </tr>
                    <tr>
                        <th scope="row"><?php _e( 'Headings (Vollkorn)', 'font-weight-options' ); ?></th>
                        <td>
                            <input type="number" name="font_weights[headings]"
                                   value="<?php echo esc_attr( $saved_weights['headings'] ); ?>"
                                   min="100" max="900" step="1" />
                            <p class="description"><?php _e( 'Default: 600 (Semi Bold)', 'font-weight-options' ); ?></p>
                        </td>
                    </tr>
                    <tr>
                        <th scope="row"><?php _e( 'Code Text (Fira Code)', 'font-weight-options' ); ?></th>
                        <td>
                            <input type="number" name="font_weights[code]"
                                   value="<?php echo esc_attr( $saved_weights['code'] ); ?>"
                                   min="100" max="900" step="1" />
                            <p class="description"><?php _e( 'Default: 400 (Regular)', 'font-weight-options' ); ?></p>
                        </td>
                    </tr>
                </table>

                <?php submit_button( __( 'Save Font Weights', 'font-weight-options' ), 'primary', 'submit_font_weights' ); ?>
            </form>
        </div>
        <?php
    }

    // Apply custom font weights to the frontend.
    public function apply_font_weights_frontend() {
        $this->output_font_weight_css( 'fwo-frontend-styles', false );
    }

    // Apply custom font weights to the editor.
    public function apply_font_weights_admin() {
        $this->output_font_weight_css( 'fwo-admin-styles', true );
    }

    // Generate and output font weight CSS.
    private function output_font_weight_css( $style_id, $include_admin = false ) {
        $font_weights = get_option( 'fwo_font_weights' );
        if ( ! $font_weights ) {
            return;
        }

        $body_weight     = absint( $font_weights['body'] ?? 400 );
        $headings_weight = absint( $font_weights['headings'] ?? 600 );
        $code_weight     = absint( $font_weights['code'] ?? 400 );

        $css = "
            body { font-weight: {$body_weight} !important; }
            h1, h2, h3, h4, h5, h6 { font-weight: {$headings_weight} !important; }
            code, pre { font-weight: {$code_weight} !important; }
        ";

        if ( $include_admin ) {
            $css .= "
                .editor-styles-wrapper body { font-weight: {$body_weight} !important; }
                .editor-styles-wrapper h1,
                .editor-styles-wrapper h2,
                .editor-styles-wrapper h3,
                .editor-styles-wrapper h4,
                .editor-styles-wrapper h5,
                .editor-styles-wrapper h6 { font-weight: {$headings_weight} !important; }
                .editor-styles-wrapper code,
                .editor-styles-wrapper pre { font-weight: {$code_weight} !important; }
            ";
        }

        echo '<style id="' . esc_attr( $style_id ) . '">' . esc_html( $css ) . '</style>';
    }
}

// Initialize the plugin.
new Font_Weight_Options();