Interview Fields

class Interview_Information {

	public function __construct() {

		if ( is_admin() ) {
			add_action( 'load-post.php',     array( $this, 'init_metabox' ) );
			add_action( 'load-post-new.php', array( $this, 'init_metabox' ) );
		}

	}

	public function init_metabox() {

		add_action( 'add_meta_boxes',        array( $this, 'add_metabox' )         );
		add_action( 'save_post',             array( $this, 'save_metabox' ), 10, 2 );

	}

	public function add_metabox() {

		add_meta_box(
			'interview_information',
			__( 'Interview Information', 'hcw' ),
			array( $this, 'interview_info_render_metabox' ),
			'speakers',
			'normal',
			'high'
		);

	}

	public function interview_info_render_metabox( $post ) {

		// Retrieve an existing value from the database.
		$hcw_interview_title = get_post_meta( $post->ID, 'hcw_interview_title', true );
		$hcw_interview_summary = get_post_meta( $post->ID, 'hcw_interview_summary', true );
		$hcw_interview_embed_code = get_post_meta( $post->ID, 'hcw_interview_embed_code', true );
		$hcw_interview_download_link = get_post_meta( $post->ID, 'hcw_interview_download_link', true );

		// Set default values.
		if( empty( $hcw_interview_title ) ) $hcw_interview_title = '';
		if( empty( $hcw_interview_summary ) ) $hcw_interview_summary = '';
		if( empty( $hcw_interview_embed_code ) ) $hcw_interview_embed_code = '';
		if( empty( $hcw_interview_download_link ) ) $hcw_interview_download_link = '';

		// Form fields.
		echo '<table class="form-table">';

		echo '	<tr>';
		echo '		<th><label for="hcw_interview_title" class="hcw_interview_title_label">' . __( 'Interview Title', 'hcw' ) . '</label></th>';
		echo '		<td>';
		echo '			<input type="text" id="hcw_interview_title" name="hcw_interview_title" class="hcw_interview_title_field" placeholder="' . esc_attr__( '', 'hcw' ) . '" value="' . esc_attr( $hcw_interview_title ) . '">';
		echo '		</td>';
		echo '	</tr>';

		echo '	<tr>';
		echo '		<th><label for="hcw_interview_summary" class="hcw_interview_summary_label">' . __( 'Interview Summary', 'hcw' ) . '</label></th>';
		echo '		<td>';
		echo '			<textarea id="hcw_interview_summary" name="hcw_interview_summary" class="hcw_interview_summary_field" placeholder="' . esc_attr__( '', 'hcw' ) . '">' . $hcw_interview_summary . '</textarea>';
		echo '		</td>';
		echo '	</tr>';

		echo '	<tr>';
		echo '		<th><label for="hcw_interview_embed_code" class="hcw_interview_embed_code_label">' . __( 'Interview Embed Code', 'hcw' ) . '</label></th>';
		echo '		<td>';
		echo '			<textarea id="hcw_interview_embed_code" name="hcw_interview_embed_code" class="hcw_interview_embed_code_field" placeholder="' . esc_attr__( '', 'hcw' ) . '">' . $hcw_interview_embed_code . '</textarea>';
		echo '		</td>';
		echo '	</tr>';

		echo '	<tr>';
		echo '		<th><label for="hcw_interview_download_link" class="hcw_interview_download_link_label">' . __( 'Interview Download Link', 'hcw' ) . '</label></th>';
		echo '		<td>';
		echo '			<input type="url" id="hcw_interview_download_link" name="hcw_interview_download_link" class="hcw_interview_download_link_field" placeholder="' . esc_attr__( '', 'hcw' ) . '" value="' . esc_attr( $hcw_interview_download_link ) . '">';
		echo '		</td>';
		echo '	</tr>';

		echo '</table>';

	}

	public function save_metabox( $post_id, $post ) {

		// Check if it's not an autosave.
		if ( wp_is_post_autosave( $post_id ) )
			return;

		// Check if it's not a revision.
		if ( wp_is_post_revision( $post_id ) )
			return;

		// Sanitize user input.
		$hcw_new_interview_title = isset( $_POST[ 'hcw_interview_title' ] ) ? sanitize_text_field( $_POST[ 'hcw_interview_title' ] ) : '';
		$hcw_new_interview_summary = isset( $_POST[ 'hcw_interview_summary' ] ) ? sanitize_text_field( $_POST[ 'hcw_interview_summary' ] ) : '';
		$hcw_new_interview_embed_code = isset( $_POST[ 'hcw_interview_embed_code' ] ) ? sanitize_text_field( $_POST[ 'hcw_interview_embed_code' ] ) : '';
		$hcw_new_interview_download_link = isset( $_POST[ 'hcw_interview_download_link' ] ) ? esc_url( $_POST[ 'hcw_interview_download_link' ] ) : '';

		// Update the meta field in the database.
		update_post_meta( $post_id, 'hcw_interview_title', $hcw_new_interview_title );
		update_post_meta( $post_id, 'hcw_interview_summary', $hcw_new_interview_summary );
		update_post_meta( $post_id, 'hcw_interview_embed_code', $hcw_new_interview_embed_code );
		update_post_meta( $post_id, 'hcw_interview_download_link', $hcw_new_interview_download_link );

	}

}

new Interview_Information;