class-cc-post-republisher-meta-box.php

<?php
/**
 * @package Creative Commons Post Republisher
 */
class CC_Post_Republisher_Meta_Box {
	/**
	 * The global license type.
	 *
	 * @var string
	 */
	private $global_license;

	/**
	 * The fields for the meta box.
	 *
	 * @var array
	 */
	private $fields;

	/**
	 * Class construct method. Adds actions to their respective WordPress hooks.
	 */
	public function __construct() {
		$options              = get_option( 'cc_post_republisher_settings' );
		$this->global_license = isset( $options['license_type'] ) ? $options['license_type'] : 'cc-by';
		$this->fields         = array(
			array(
				'id'      => 'license-type',
				'label'   => 'License Type',
				'type'    => 'radio',
				'default' => 'default',
				'options' => array(
					'default'       => __( 'Default License', 'cc-post-republisher' ),
					'cc-by'         => __( '<strong>CC BY</strong> - Attribution', 'cc-post-republisher' ),
					'cc-by-sa'      => __( '<strong>CC BY-SA</strong> - Attribution-ShareAlike', 'cc-post-republisher' ),
					'cc-by-nd'      => __( '<strong>CC BY-ND</strong> - Attribution-NoDerivs', 'cc-post-republisher' ),
					'cc-by-nc'      => __( '<strong>CC BY-NC</strong> - Attribution-NonCommercial', 'cc-post-republisher' ),
					'cc-by-nc-sa'   => __( '<strong>CC BY-NC-SA</strong> - Attribution-NonCommercial-ShareAlike', 'cc-post-republisher' ),
					'cc-by-nc-nd'   => __( '<strong>CC BY-NC-ND</strong> - Attribution-NonCommercial-NoDerivs', 'cc-post-republisher' ),
					'cc0'           => __( '<strong>CC0</strong> - No Rights Reserved', 'cc-post-republisher' ),
					'pdm'           => __( '<strong>PDM</strong> - Public Domain Mark', 'cc-post-republisher' ),
					'no-cc-license' => __( 'Not Creative Commons Licensed', 'cc-post-republisher' ),
				),
			),
		);

		add_action( 'add_meta_boxes', array( $this, 'add_meta_boxes' ) );
		add_action( 'save_post', array( $this, 'save_post' ) );
	}

	/**
	 * Hooks into WordPress' add_meta_boxes function.
	 * Goes through screens (post types) and adds the meta box.
	 */
	public function add_meta_boxes() {
		$screens    = array();
		$post_types = get_post_types( array( 'public' => true ), 'names' );

		foreach ( $post_types as $post_type ) {
			$screens[] = $post_type;
		}

		foreach ( $screens as $screen ) {
			add_meta_box(
				'creative-commons-post-republisher',
				__( 'Creative Commons', 'cc-post-republisher' ),
				array( $this, 'add_meta_box_callback' ),
				$screen,
				'side',
				'default'
			);
		}
	}

	/**
	 * Generates the HTML for the meta box
	 *
	 * @param object $post WordPress post object
	 */
	public function add_meta_box_callback( $post ) {
		wp_nonce_field( 'creative_commons_post_republisher_data', 'creative_commons_post_republisher_nonce' );

		printf(
			wp_kses(
				/* translators: admin url */
				__( 'Assign a license to this post. If no license is selected, the post will have the default license that is set in the <a href="%s">Creative Commons Post Republisher Settings</a>.', 'cc-post-republisher' ),
				array(
					'a' => array(
						'href' => array(),
					),
				)
			),
			esc_url( admin_url( 'options-general.php?page=cc_post_republisher_settings' ) )
		);

		$this->generate_fields( $post );
	}

	/**
	 * Generates the field's HTML for the meta box.
	 */
	public function generate_fields( $post ) {
		foreach ( $this->fields as $field ) {

			$label    = '<label for="' . esc_attr( $field['id'] ) . '">' . esc_html( $field['label'] ) . '</label>';
			$db_value = get_post_meta( $post->ID, 'creative_commons_post_republisher_' . $field['id'], true );
			if ( empty( $db_value ) ) {
				$db_value = $field['default'];
			}
			$input  = '<fieldset>';
			$input .= '<legend class="screen-reader-text">' . esc_html( $field['label'] ) . '</legend>';
			foreach ( $field['options'] as $key => $value ) {
				$field_value = ! is_numeric( $key ) ? $key : $value;
				// Display what the default global license is set to
				if ( 'default' === $key ) {
					$value .= ' <strong>(' . esc_html( strtoupper( $this->global_license ) ) . ')</strong>';
				}
				$input .= sprintf(
					'<label><input %s id="%s" name="%s" type="radio" value="%s"> %s</label>%s',
					checked( $db_value, $field_value, false ),
					esc_attr( $field['id'] ),
					esc_attr( $field['id'] ),
					esc_attr( $field_value ),
					wp_kses( $value, array( 'strong' => array() ) ),
					'<br>'
				);
			}
			$input .= '</fieldset>';

			echo '<p>' . $input . '</p>';
		}
	}

	/**
	 * Hooks into WordPress' save_post function
	 */
	public function save_post( $post_id ) {
		// Check for nonce
		if ( ! isset( $_POST['creative_commons_post_republisher_nonce'] ) || ! wp_verify_nonce( $_POST['creative_commons_post_republisher_nonce'], 'creative_commons_post_republisher_data' ) ) {
			return $post_id;
		}

		// Check for autosave
		if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
			return $post_id;
		}

		foreach ( $this->fields as $field ) {
			if ( isset( $_POST[ $field['id'] ] ) ) {
				update_post_meta( $post_id, 'creative_commons_post_republisher_' . $field['id'], sanitize_text_field( $_POST[ $field['id'] ] ) );
			}
		}
	}
}
new CC_Post_Republisher_Meta_Box();