Term Meta (Date)

class Custom_Term_Meta {

	public function __construct() {

		if ( is_admin() ) {

			add_action( 'issue_add_form_fields',  array( $this, 'create_screen_fields'), 10, 1 );
			add_action( 'issue_edit_form_fields', array( $this, 'edit_screen_fields' ),  10, 2 );

			add_action( 'created_issue', array( $this, 'save_data' ), 10, 1 );
			add_action( 'edited_issue',  array( $this, 'save_data' ), 10, 1 );

			add_action( 'admin_enqueue_scripts', array( $this, 'load_scripts_styles' ) );
			add_action( 'admin_footer',          array( $this, 'add_admin_js' )        );

		}

	}

	public function create_screen_fields( $taxonomy ) {

		// Set default values.
		$custom_ = '';

		// Form fields.
		echo '<div class="form-field term-custom_-wrap">';
		echo '	<label for="custom_">' . __( 'Issue Date', 'mch-core' ) . '</label>';
		echo '	<input type="text" id="custom_" name="custom_" class="widefat custom_date_picker" placeholder="' . esc_attr__( '07/15/2018', 'mch-core' ) . '" value="' . esc_attr( $custom_ ) . '">';
		echo '	<p class="description">' . __( 'Enter the date of Issue', 'mch-core' ) . '</p>';
		echo '</div>';

	}

	public function edit_screen_fields( $term, $taxonomy ) {

		// Retrieve an existing value from the database.
		$custom_ = get_term_meta( $term->term_id, 'custom_', true );

		// Set default values.
		if( empty( $custom_ ) ) $custom_ = '';

		// Form fields.
		echo '<tr class="form-field term-custom_-wrap">';
		echo '<th scope="row">';
		echo '	<label for="custom_">' . __( 'Issue Date', 'mch-core' ) . '</label>';
		echo '</th>';
		echo '<td>';
		echo '	<input type="text" id="custom_" name="custom_" class="widefat custom_date_picker" placeholder="' . esc_attr__( '07/15/2018', 'mch-core' ) . '" value="' . esc_attr( $custom_ ) . '">';
		echo '	<p class="description">' . __( 'Enter the date of Issue', 'mch-core' ) . '</p>';
		echo '</td>';
		echo '</tr>';

	}

	public function save_data( $term_id ) {

		// Sanitize user input.
		$custom_new_ = isset( $_POST[ 'custom_' ] ) ? sanitize_text_field( $_POST[ 'custom_' ] ) : '';

		// Update the meta field in the database.
		update_term_meta( $term_id, 'custom_', $custom_new_ );

	}

	public function load_scripts_styles() {

		// Date picker
		wp_enqueue_script( 'jquery-ui' );
		wp_enqueue_script( 'jquery-ui-datepicker' );
		wp_enqueue_style( 'jquery-ui-datepicker', 'http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.2/themes/smoothness/jquery-ui.css' );

	}

	public function add_admin_js() {

		// Print js only once per page
		if ( did_action( 'Custom_Term_Meta_js' ) >= 1 ) {
			return;
		}

		?>
		<script type="text/javascript">
			jQuery(document).ready(function($){
				$('.custom_date_picker').datepicker();
			});
		</script>
		<?php

		do_action( 'Custom_Term_Meta_js', $this );

	}

}

new Custom_Term_Meta;