add_action(
	'init',
	function() {
		register_post_type(
			'demo',
			[
				'labels'   => [ 'name' => 'Demos' ],
				'public'   => false,
				'show_ui'  => true,
				'supports' => [ 'title' ],
			]
		);
	}
);

add_action(
	'fm_post_demo',
	function() {
		// Make a big array of sample data.
		$options = range(1, 100);
		$modules = [];
		foreach ( $options as $option ) {
			$modules[ $option ] = new Fieldmanager_Group( get_panel_args( $option ) );
		}

		$fm = new Fieldmanager_Group([
			'name' => 'modules',
			'label' => 'Modules',
			'children' => [
				'module' => new Fieldmanager_Group([
					'label' => 'New Module',
					'label_macro' => [ 'Module: %s', 'module_name' ],
					'limit' => 0,
					'add_more_label' => 'Add another module',
					'collapsible' => true,
					'collapsed' => true,
					'sortable' => true,
					'starting_count' => 1,
					'extra_elements' => 0,
					'children' => array_merge(
						[
							'type' => new Fieldmanager_Select([
								'label' => 'Module Type',
								'options' => $options,
							]),
							'module_name' => new Fieldmanager_TextField([
								'label' => 'Module Name',
							]),
						],
						$modules
					),
				]),
			],
		]);
		$fm->add_meta_box( 'Page Modules', ['demo']);
	}
);

function get_panel_args( $key ) {
	return [
		'label' => $key,
		'display_if' => [
			'src' => 'type',
			'value' => $key,
		],
		'children' => [
			'intro' => new Fieldmanager_RichTextArea('Intro'),
			'items' => new Fieldmanager_Group([
				'label' => 'Item',
				'label_macro' => [ 'Item: %s', 'name' ],
				'limit' => 0,
				'add_more_label' =>  'Add another item',
				'collapsible' => true,
				'collapsed' => true,
				'sortable' => true,
				'starting_count' => 1,
				'extra_elements' => 0,
				'children' => [
					'name' => new Fieldmanager_TextField('Name'),
					'type' => new Fieldmanager_Select([
						'label' => 'Type',
						'type_ahead' => true,
						'first_empty' => true,
						'options' => [
							'nested1' => 'Nested 1',
							'nested2' => 'Nested 2',
						],
					]),
				],
			]),
		],
	];
}