<?php
/**
 * Settings API wiring.
 *
 * @package MM_Post_Grid
 */

namespace MM_Post_Grid\Admin;

use MM_Post_Grid\Settings;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Registers the option, the sections and every field.
 *
 * Field types come from the setting schema, this class only adds the labels,
 * the help text and the grouping.
 *
 * @since 0.1
 */
final class Settings_Fields {

	/**
	 * Hooks the registration.
	 *
	 * @since 0.1
	 * @return void
	 */
	public function register() {
		add_action( 'admin_init', array( $this, 'register_settings' ) );
	}

	/**
	 * Returns the sections, grouped per tab and in display order.
	 *
	 * @since 0.1
	 * @return array<string, array<string, array<string, string>>>
	 */
	public static function sections() {
		return array(
			'general'  => array(
				'query'  => array(
					'title'       => __( 'Posts', 'mm-post-grid' ),
					'description' => __( 'What a grid queries when the shortcode has no attributes.', 'mm-post-grid' ),
				),
				'layout' => array(
					'title'       => __( 'Layout', 'mm-post-grid' ),
					'description' => __( 'Column counts apply per screen size. Below 1024px the tablet value is used, below 640px the mobile value.', 'mm-post-grid' ),
				),
			),
			'content'  => array(
				'elements' => array(
					'title'       => __( 'Card elements', 'mm-post-grid' ),
					'description' => __( 'Turn off anything the cards should not show.', 'mm-post-grid' ),
				),
				'text'     => array(
					'title'       => __( 'Text', 'mm-post-grid' ),
					'description' => '',
				),
			),
			'styling'  => array(
				'card'  => array(
					'title'       => __( 'Card', 'mm-post-grid' ),
					'description' => __( 'These values become CSS custom properties, so the grid keeps the fonts of your theme and only the values below change. Start from a template on the Templates tab, then fine-tune here.', 'mm-post-grid' ),
				),
				'image' => array(
					'title'       => __( 'Image', 'mm-post-grid' ),
					'description' => '',
				),
				'type'  => array(
					'title'       => __( 'Typography and colours', 'mm-post-grid' ),
					'description' => __( 'In the overlay layout the text is always light, so it stays readable on the image.', 'mm-post-grid' ),
				),
				'terms' => array(
					'title'       => __( 'Categories', 'mm-post-grid' ),
					'description' => '',
				),
				'links' => array(
					'title'       => __( 'Links, buttons and pagination', 'mm-post-grid' ),
					'description' => __( 'Pagination and load more sit on your page rather than on a card, so they use the button colours and your theme text colour.', 'mm-post-grid' ),
				),
			),
			'advanced' => array(
				'advanced' => array(
					'title'       => __( 'Advanced', 'mm-post-grid' ),
					'description' => '',
				),
			),
		);
	}

	/**
	 * Returns the field labels and help text in display order.
	 *
	 * @since 0.1
	 * @return array<string, array<string, string>>
	 */
	public static function fields() {
		return array(
			// General, posts.
			'post_type'           => array(
				'tab'     => 'general',
				'section' => 'query',
				'label'   => __( 'Post type', 'mm-post-grid' ),
				'help'    => __( 'Only publicly viewable post types are listed.', 'mm-post-grid' ),
			),
			'posts_per_page'      => array(
				'tab'     => 'general',
				'section' => 'query',
				'label'   => __( 'Posts per grid', 'mm-post-grid' ),
				'help'    => __( 'Between 1 and 48. With pagination on, this is the number per page.', 'mm-post-grid' ),
			),
			'orderby'             => array(
				'tab'     => 'general',
				'section' => 'query',
				'label'   => __( 'Order by', 'mm-post-grid' ),
				'help'    => '',
			),
			'order'               => array(
				'tab'     => 'general',
				'section' => 'query',
				'label'   => __( 'Direction', 'mm-post-grid' ),
				'help'    => '',
			),
			'pagination'          => array(
				'tab'     => 'general',
				'section' => 'query',
				'label'   => __( 'Pagination', 'mm-post-grid' ),
				'help'    => __( 'Load more falls back to a normal next page link when JavaScript is unavailable.', 'mm-post-grid' ),
			),

			// General, layout.
			'columns'             => array(
				'tab'     => 'general',
				'section' => 'layout',
				'label'   => __( 'Columns on desktop', 'mm-post-grid' ),
				'help'    => '',
			),
			'columns_tablet'      => array(
				'tab'     => 'general',
				'section' => 'layout',
				'label'   => __( 'Columns on tablet', 'mm-post-grid' ),
				'help'    => '',
			),
			'columns_mobile'      => array(
				'tab'     => 'general',
				'section' => 'layout',
				'label'   => __( 'Columns on mobile', 'mm-post-grid' ),
				'help'    => '',
			),
			'gap'                 => array(
				'tab'     => 'general',
				'section' => 'layout',
				'label'   => __( 'Gap between cards', 'mm-post-grid' ),
				'help'    => '',
				'unit'    => 'px',
			),
			'image_size'          => array(
				'tab'     => 'general',
				'section' => 'layout',
				'label'   => __( 'Image size', 'mm-post-grid' ),
				'help'    => __( 'Pick the smallest size that still looks sharp at your column width.', 'mm-post-grid' ),
			),
			'image_ratio'         => array(
				'tab'     => 'general',
				'section' => 'layout',
				'label'   => __( 'Image ratio', 'mm-post-grid' ),
				'help'    => __( 'A fixed ratio keeps every card the same height. Original keeps the uploaded proportions.', 'mm-post-grid' ),
			),

			// Content, elements.
			'show_image'          => array(
				'tab'     => 'content',
				'section' => 'elements',
				'label'   => __( 'Featured image', 'mm-post-grid' ),
				'help'    => '',
			),
			'image_fallback'      => array(
				'tab'     => 'content',
				'section' => 'elements',
				'label'   => __( 'Image placeholder', 'mm-post-grid' ),
				'help'    => __( 'Shows a plain tinted block when a post has no featured image, so the rows stay even.', 'mm-post-grid' ),
			),
			'show_category'       => array(
				'tab'     => 'content',
				'section' => 'elements',
				'label'   => __( 'Category', 'mm-post-grid' ),
				'help'    => __( 'Uses the category for posts, or the first public taxonomy of the post type.', 'mm-post-grid' ),
			),
			'show_title'          => array(
				'tab'     => 'content',
				'section' => 'elements',
				'label'   => __( 'Title', 'mm-post-grid' ),
				'help'    => '',
			),
			'show_excerpt'        => array(
				'tab'     => 'content',
				'section' => 'elements',
				'label'   => __( 'Excerpt', 'mm-post-grid' ),
				'help'    => '',
			),
			'show_date'           => array(
				'tab'     => 'content',
				'section' => 'elements',
				'label'   => __( 'Date', 'mm-post-grid' ),
				'help'    => '',
			),
			'show_author'         => array(
				'tab'     => 'content',
				'section' => 'elements',
				'label'   => __( 'Author', 'mm-post-grid' ),
				'help'    => '',
			),
			'show_read_more'      => array(
				'tab'     => 'content',
				'section' => 'elements',
				'label'   => __( 'Read more link', 'mm-post-grid' ),
				'help'    => '',
			),

			// Content, text.
			'title_tag'           => array(
				'tab'     => 'content',
				'section' => 'text',
				'label'   => __( 'Title element', 'mm-post-grid' ),
				'help'    => __( 'Match the heading level to the page around the grid. Use h3 under an h2 section title.', 'mm-post-grid' ),
			),
			'excerpt_length'      => array(
				'tab'     => 'content',
				'section' => 'text',
				'label'   => __( 'Excerpt length', 'mm-post-grid' ),
				'help'    => __( 'Number of words. Set 0 to print the excerpt exactly as written.', 'mm-post-grid' ),
				'unit'    => __( 'words', 'mm-post-grid' ),
			),
			'read_more_text'      => array(
				'tab'     => 'content',
				'section' => 'text',
				'label'   => __( 'Read more label', 'mm-post-grid' ),
				'help'    => __( 'Screen readers also hear the post title after the label.', 'mm-post-grid' ),
			),

			// Styling, card.
			'card_layout'         => array(
				'tab'     => 'styling',
				'section' => 'card',
				'label'   => __( 'Card layout', 'mm-post-grid' ),
				'help'    => __( 'Horizontal puts the image beside the text once a card is wider than 460px, so it suits one or two columns. Overlay lays the text over the image.', 'mm-post-grid' ),
			),
			'card_bg'             => array(
				'tab'     => 'styling',
				'section' => 'card',
				'label'   => __( 'Background', 'mm-post-grid' ),
				'help'    => __( 'Leave empty for a transparent card.', 'mm-post-grid' ),
			),
			'card_border_color'   => array(
				'tab'     => 'styling',
				'section' => 'card',
				'label'   => __( 'Border colour', 'mm-post-grid' ),
				'help'    => '',
			),
			'card_border_width'   => array(
				'tab'     => 'styling',
				'section' => 'card',
				'label'   => __( 'Border width', 'mm-post-grid' ),
				'help'    => '',
				'unit'    => 'px',
			),
			'card_radius'         => array(
				'tab'     => 'styling',
				'section' => 'card',
				'label'   => __( 'Corner radius', 'mm-post-grid' ),
				'help'    => '',
				'unit'    => 'px',
			),
			'card_padding'        => array(
				'tab'     => 'styling',
				'section' => 'card',
				'label'   => __( 'Inner spacing', 'mm-post-grid' ),
				'help'    => '',
				'unit'    => 'px',
			),
			'content_gap'         => array(
				'tab'     => 'styling',
				'section' => 'card',
				'label'   => __( 'Space between elements', 'mm-post-grid' ),
				'help'    => '',
				'unit'    => 'px',
			),
			'card_shadow'         => array(
				'tab'     => 'styling',
				'section' => 'card',
				'label'   => __( 'Shadow', 'mm-post-grid' ),
				'help'    => '',
			),
			'hover_effect'        => array(
				'tab'     => 'styling',
				'section' => 'card',
				'label'   => __( 'Hover effect', 'mm-post-grid' ),
				'help'    => __( 'Border colours the card border, so it needs a border width of at least 1px.', 'mm-post-grid' ),
			),
			'card_border_hover'   => array(
				'tab'     => 'styling',
				'section' => 'card',
				'label'   => __( 'Border colour on hover', 'mm-post-grid' ),
				'help'    => __( 'Leave empty to follow the accent colour.', 'mm-post-grid' ),
				'depends' => array( 'hover_effect', array( 'border' ) ),
			),
			'text_align'          => array(
				'tab'     => 'styling',
				'section' => 'card',
				'label'   => __( 'Text alignment', 'mm-post-grid' ),
				'help'    => '',
			),

			// Styling, image.
			'image_radius'        => array(
				'tab'     => 'styling',
				'section' => 'image',
				'label'   => __( 'Image corner radius', 'mm-post-grid' ),
				'help'    => __( 'Ignored in the overlay layout, where the card corners shape the image.', 'mm-post-grid' ),
				'unit'    => 'px',
			),
			'image_hover'         => array(
				'tab'     => 'styling',
				'section' => 'image',
				'label'   => __( 'Image hover effect', 'mm-post-grid' ),
				'help'    => '',
			),
			'media_width'         => array(
				'tab'     => 'styling',
				'section' => 'image',
				'label'   => __( 'Image width', 'mm-post-grid' ),
				'help'    => __( 'Share of the card width the image takes in the horizontal layout.', 'mm-post-grid' ),
				'unit'    => '%',
				'depends' => array( 'card_layout', array( 'horizontal' ) ),
			),
			'overlay_opacity'     => array(
				'tab'     => 'styling',
				'section' => 'image',
				'label'   => __( 'Overlay strength', 'mm-post-grid' ),
				'help'    => __( 'How dark the gradient behind the text gets. The minimum of 50 keeps light text readable on bright photos.', 'mm-post-grid' ),
				'unit'    => '%',
				'depends' => array( 'card_layout', array( 'overlay' ) ),
			),

			// Styling, typography.
			'title_color'         => array(
				'tab'     => 'styling',
				'section' => 'type',
				'label'   => __( 'Title colour', 'mm-post-grid' ),
				'help'    => '',
			),
			'title_hover_color'   => array(
				'tab'     => 'styling',
				'section' => 'type',
				'label'   => __( 'Title colour on hover', 'mm-post-grid' ),
				'help'    => '',
			),
			'title_size'          => array(
				'tab'     => 'styling',
				'section' => 'type',
				'label'   => __( 'Title size', 'mm-post-grid' ),
				'help'    => '',
				'unit'    => 'px',
			),
			'title_weight'        => array(
				'tab'     => 'styling',
				'section' => 'type',
				'label'   => __( 'Title weight', 'mm-post-grid' ),
				'help'    => '',
			),
			'title_line_height'   => array(
				'tab'     => 'styling',
				'section' => 'type',
				'label'   => __( 'Title line height', 'mm-post-grid' ),
				'help'    => __( 'Relative to the title size: 135 means 1.35 times the size.', 'mm-post-grid' ),
				'unit'    => '%',
			),
			'title_lines'         => array(
				'tab'     => 'styling',
				'section' => 'type',
				'label'   => __( 'Maximum title lines', 'mm-post-grid' ),
				'help'    => __( 'Longer titles end with an ellipsis. 0 always shows the full title.', 'mm-post-grid' ),
			),
			'meta_color'          => array(
				'tab'     => 'styling',
				'section' => 'type',
				'label'   => __( 'Meta colour', 'mm-post-grid' ),
				'help'    => __( 'Used for the date and the author line.', 'mm-post-grid' ),
			),
			'meta_size'           => array(
				'tab'     => 'styling',
				'section' => 'type',
				'label'   => __( 'Meta size', 'mm-post-grid' ),
				'help'    => '',
				'unit'    => 'px',
			),
			'excerpt_color'       => array(
				'tab'     => 'styling',
				'section' => 'type',
				'label'   => __( 'Excerpt colour', 'mm-post-grid' ),
				'help'    => '',
			),
			'excerpt_size'        => array(
				'tab'     => 'styling',
				'section' => 'type',
				'label'   => __( 'Excerpt size', 'mm-post-grid' ),
				'help'    => '',
				'unit'    => 'px',
			),
			'excerpt_line_height' => array(
				'tab'     => 'styling',
				'section' => 'type',
				'label'   => __( 'Excerpt line height', 'mm-post-grid' ),
				'help'    => __( 'Relative to the excerpt size.', 'mm-post-grid' ),
				'unit'    => '%',
			),
			'excerpt_lines'       => array(
				'tab'     => 'styling',
				'section' => 'type',
				'label'   => __( 'Maximum excerpt lines', 'mm-post-grid' ),
				'help'    => __( 'Clamping keeps the cards in a row the same height. 0 always shows the full excerpt.', 'mm-post-grid' ),
			),

			// Styling, categories.
			'term_style'          => array(
				'tab'     => 'styling',
				'section' => 'terms',
				'label'   => __( 'Category style', 'mm-post-grid' ),
				'help'    => '',
			),
			'term_color'          => array(
				'tab'     => 'styling',
				'section' => 'terms',
				'label'   => __( 'Category colour', 'mm-post-grid' ),
				'help'    => __( 'Leave empty to follow the accent colour.', 'mm-post-grid' ),
			),

			// Styling, links.
			'accent_color'        => array(
				'tab'     => 'styling',
				'section' => 'links',
				'label'   => __( 'Accent colour', 'mm-post-grid' ),
				'help'    => __( 'Used for text links and focus outlines inside the cards.', 'mm-post-grid' ),
			),
			'button_style'        => array(
				'tab'     => 'styling',
				'section' => 'links',
				'label'   => __( 'Read more style', 'mm-post-grid' ),
				'help'    => '',
			),
			'button_size'         => array(
				'tab'     => 'styling',
				'section' => 'links',
				'label'   => __( 'Button size', 'mm-post-grid' ),
				'help'    => '',
				'depends' => array( 'button_style', array( 'button', 'outline' ) ),
			),
			'button_bg'           => array(
				'tab'     => 'styling',
				'section' => 'links',
				'label'   => __( 'Button colour', 'mm-post-grid' ),
				'help'    => __( 'Fills the button, draws the outline style, and colours load more and the current page number.', 'mm-post-grid' ),
			),
			'button_bg_hover'     => array(
				'tab'     => 'styling',
				'section' => 'links',
				'label'   => __( 'Button colour on hover', 'mm-post-grid' ),
				'help'    => '',
			),
			'button_color'        => array(
				'tab'     => 'styling',
				'section' => 'links',
				'label'   => __( 'Button text colour', 'mm-post-grid' ),
				'help'    => __( 'Keep enough contrast against the button colour.', 'mm-post-grid' ),
			),
			'button_radius'       => array(
				'tab'     => 'styling',
				'section' => 'links',
				'label'   => __( 'Button corner radius', 'mm-post-grid' ),
				'help'    => '',
				'unit'    => 'px',
			),
			'pagination_align'    => array(
				'tab'     => 'styling',
				'section' => 'links',
				'label'   => __( 'Pagination alignment', 'mm-post-grid' ),
				'help'    => __( 'Also aligns the load more button.', 'mm-post-grid' ),
			),

			// Advanced.
			'disable_css'         => array(
				'tab'     => 'advanced',
				'section' => 'advanced',
				'label'   => __( 'Skip the plugin stylesheet', 'mm-post-grid' ),
				'help'    => __( 'For developers who style the grid in their own theme. The markup and the class names stay the same.', 'mm-post-grid' ),
			),
			'delete_data'         => array(
				'tab'     => 'advanced',
				'section' => 'advanced',
				'label'   => __( 'Delete settings on uninstall', 'mm-post-grid' ),
				'help'    => __( 'Off by default, so deactivating and reinstalling keeps your setup. Posts are never deleted either way.', 'mm-post-grid' ),
			),
		);
	}

	/**
	 * Registers the option, sections and fields.
	 *
	 * @since 0.1
	 * @return void
	 */
	public function register_settings() {
		register_setting(
			Settings::GROUP,
			Settings::OPTION,
			array(
				'type'              => 'array',
				'sanitize_callback' => array( Settings::class, 'sanitize' ),
				'default'           => Settings::defaults(),
				'show_in_rest'      => false,
			)
		);

		foreach ( self::sections() as $tab => $sections ) {
			foreach ( $sections as $section => $data ) {
				add_settings_section(
					'mmpg_' . $section,
					$data['title'],
					array( $this, 'render_section' ),
					'mmpg_settings_' . $tab
				);
			}
		}

		$schema = Settings::schema();

		foreach ( self::fields() as $key => $ui ) {
			if ( ! isset( $schema[ $key ] ) ) {
				continue;
			}

			add_settings_field(
				'mmpg_' . $key,
				$ui['label'],
				array( $this, 'render_field' ),
				'mmpg_settings_' . $ui['tab'],
				'mmpg_' . $ui['section'],
				array(
					'label_for' => 'mmpg-' . $key,
					'key'       => $key,
					'field'     => $schema[ $key ],
					'ui'        => $ui,
					'class'     => self::row_class( $ui ),
				)
			);
		}
	}

	/**
	 * Prints the description of a section.
	 *
	 * @since 0.1
	 *
	 * @param array<string, mixed> $section Section data from the Settings API.
	 * @return void
	 */
	public function render_section( $section ) {
		$id = isset( $section['id'] ) ? (string) $section['id'] : '';

		foreach ( self::sections() as $sections ) {
			foreach ( $sections as $slug => $data ) {
				if ( 'mmpg_' . $slug === $id && '' !== $data['description'] ) {
					echo '<p class="mmpg-section-desc">' . esc_html( $data['description'] ) . '</p>';

					return;
				}
			}
		}
	}

	/**
	 * Prints one field.
	 *
	 * @since 0.1
	 *
	 * @param array<string, mixed> $args Field arguments from the Settings API.
	 * @return void
	 */
	public function render_field( $args ) {
		$key     = (string) $args['key'];
		$field   = (array) $args['field'];
		$ui      = (array) $args['ui'];
		$type    = isset( $field['type'] ) ? $field['type'] : 'text';
		$value   = Settings::get( $key );
		$id      = 'mmpg-' . $key;
		$name    = Settings::OPTION . '[' . $key . ']';
		$help    = isset( $ui['help'] ) ? (string) $ui['help'] : '';
		$desc_id = '' !== $help ? $id . '-desc' : '';

		switch ( $type ) {
			case 'bool':
				// The hidden input makes sure an unchecked box is still submitted.
				?>
				<input type="hidden" name="<?php echo esc_attr( $name ); ?>" value="0" />
				<input
					type="checkbox"
					class="mmpg-switch"
					role="switch"
					id="<?php echo esc_attr( $id ); ?>"
					name="<?php echo esc_attr( $name ); ?>"
					value="1"
					<?php checked( 1, (int) $value ); ?>
					<?php echo '' !== $desc_id ? 'aria-describedby="' . esc_attr( $desc_id ) . '"' : ''; ?>
				/>
				<?php
				break;

			case 'int':
				?>
				<span class="mmpg-input-group">
				<input
					type="number"
					class="small-text"
					id="<?php echo esc_attr( $id ); ?>"
					name="<?php echo esc_attr( $name ); ?>"
					value="<?php echo esc_attr( (string) $value ); ?>"
					min="<?php echo esc_attr( (string) ( isset( $field['min'] ) ? $field['min'] : 0 ) ); ?>"
					max="<?php echo esc_attr( (string) ( isset( $field['max'] ) ? $field['max'] : 999 ) ); ?>"
					step="1"
					<?php echo '' !== $desc_id ? 'aria-describedby="' . esc_attr( $desc_id ) . '"' : ''; ?>
				/>
				<?php if ( ! empty( $ui['unit'] ) ) : ?>
					<span class="mmpg-unit"><?php echo esc_html( $ui['unit'] ); ?></span>
				<?php endif; ?>
				</span>
				<?php
				break;

			case 'color':
				?>
				<input
					type="text"
					class="mmpg-color-field"
					id="<?php echo esc_attr( $id ); ?>"
					name="<?php echo esc_attr( $name ); ?>"
					value="<?php echo esc_attr( (string) $value ); ?>"
					data-default-color="<?php echo esc_attr( (string) ( isset( $field['default'] ) ? $field['default'] : '' ) ); ?>"
					<?php echo '' !== $desc_id ? 'aria-describedby="' . esc_attr( $desc_id ) . '"' : ''; ?>
				/>
				<?php
				break;

			case 'choice':
			case 'post_type':
			case 'image_size':
				$choices = self::choices( $key, $type, $field );
				?>
				<select
					id="<?php echo esc_attr( $id ); ?>"
					name="<?php echo esc_attr( $name ); ?>"
					<?php echo '' !== $desc_id ? 'aria-describedby="' . esc_attr( $desc_id ) . '"' : ''; ?>
				>
					<?php foreach ( $choices as $choice_value => $choice_label ) : ?>
						<option value="<?php echo esc_attr( (string) $choice_value ); ?>" <?php selected( (string) $value, (string) $choice_value ); ?>>
							<?php echo esc_html( $choice_label ); ?>
						</option>
					<?php endforeach; ?>
				</select>
				<?php
				break;

			default:
				?>
				<input
					type="text"
					class="regular-text"
					id="<?php echo esc_attr( $id ); ?>"
					name="<?php echo esc_attr( $name ); ?>"
					value="<?php echo esc_attr( (string) $value ); ?>"
					<?php echo '' !== $desc_id ? 'aria-describedby="' . esc_attr( $desc_id ) . '"' : ''; ?>
				/>
				<?php
				break;
		}

		if ( '' !== $help ) {
			printf(
				'<p class="description" id="%1$s">%2$s</p>',
				esc_attr( $desc_id ),
				esc_html( $help )
			);
		}
	}

	/**
	 * Returns the table row class of a field.
	 *
	 * A field that only matters for some values of another field gets a class
	 * such as mmpg-when-card_layout--horizontal. The admin script hides the row
	 * while it does not apply; without JavaScript every row stays visible and
	 * every value is still saved.
	 *
	 * @since 0.1
	 *
	 * @param array<string, mixed> $ui Field UI definition.
	 * @return string
	 */
	private static function row_class( array $ui ) {
		$classes = array( 'mmpg-row' );

		if ( isset( $ui['depends'][0], $ui['depends'][1] ) && is_array( $ui['depends'][1] ) ) {
			$values    = array_map( 'sanitize_html_class', $ui['depends'][1] );
			$classes[] = 'mmpg-when-' . sanitize_html_class( $ui['depends'][0] ) . '--' . implode( '--', $values );
		}

		return implode( ' ', $classes );
	}

	/**
	 * Returns the options of a select field.
	 *
	 * @since 0.1
	 *
	 * @param string               $key   Setting key.
	 * @param string               $type  Schema type.
	 * @param array<string, mixed> $field Schema entry.
	 * @return array<string, string>
	 */
	private static function choices( $key, $type, array $field ) {
		if ( 'post_type' === $type ) {
			$choices    = array();
			$post_types = get_post_types( array( 'public' => true ), 'objects' );

			foreach ( $post_types as $post_type ) {
				if ( ! is_post_type_viewable( $post_type ) ) {
					continue;
				}

				$choices[ $post_type->name ] = $post_type->labels->singular_name . ' (' . $post_type->name . ')';
			}

			return $choices;
		}

		if ( 'image_size' === $type ) {
			$choices  = array();
			$subsizes = wp_get_registered_image_subsizes();

			foreach ( Settings::image_sizes() as $size ) {
				if ( isset( $subsizes[ $size ]['width'], $subsizes[ $size ]['height'] ) ) {
					$choices[ $size ] = sprintf(
						/* translators: 1: Image size name, 2: Width in pixels, 3: Height in pixels. */
						_x( '%1$s (%2$d × %3$d)', 'image size option', 'mm-post-grid' ),
						$size,
						(int) $subsizes[ $size ]['width'],
						(int) $subsizes[ $size ]['height']
					);
				} else {
					$choices[ $size ] = $size;
				}
			}

			return $choices;
		}

		$labels  = self::choice_labels();
		$choices = array();

		foreach ( (array) ( isset( $field['choices'] ) ? $field['choices'] : array() ) as $choice ) {
			$choices[ $choice ] = isset( $labels[ $key ][ $choice ] ) ? $labels[ $key ][ $choice ] : (string) $choice;
		}

		return $choices;
	}

	/**
	 * Returns the human readable labels of the choice fields.
	 *
	 * @since 0.1
	 * @return array<string, array<string, string>>
	 */
	private static function choice_labels() {
		return array(
			'orderby'          => array(
				'date'          => __( 'Publish date', 'mm-post-grid' ),
				'modified'      => __( 'Last modified', 'mm-post-grid' ),
				'title'         => __( 'Title', 'mm-post-grid' ),
				'menu_order'    => __( 'Menu order', 'mm-post-grid' ),
				'comment_count' => __( 'Comment count', 'mm-post-grid' ),
				'rand'          => __( 'Random', 'mm-post-grid' ),
				'ID'            => __( 'Post ID', 'mm-post-grid' ),
			),
			'order'            => array(
				'DESC' => __( 'Descending', 'mm-post-grid' ),
				'ASC'  => __( 'Ascending', 'mm-post-grid' ),
			),
			'pagination'       => array(
				'none'      => __( 'None', 'mm-post-grid' ),
				'numbers'   => __( 'Page numbers', 'mm-post-grid' ),
				'prev_next' => __( 'Previous and next', 'mm-post-grid' ),
				'load_more' => __( 'Load more', 'mm-post-grid' ),
			),
			'image_ratio'      => array(
				'16-9'  => __( 'Wide, 16:9', 'mm-post-grid' ),
				'16-10' => __( 'Wide, 16:10', 'mm-post-grid' ),
				'3-2'   => __( 'Classic, 3:2', 'mm-post-grid' ),
				'4-3'   => __( 'Standard, 4:3', 'mm-post-grid' ),
				'1-1'   => __( 'Square', 'mm-post-grid' ),
				'3-4'   => __( 'Portrait, 3:4', 'mm-post-grid' ),
				'auto'  => __( 'Original proportions', 'mm-post-grid' ),
			),
			'card_shadow'      => array(
				'none'   => __( 'None', 'mm-post-grid' ),
				'soft'   => __( 'Soft', 'mm-post-grid' ),
				'medium' => __( 'Medium', 'mm-post-grid' ),
				'strong' => __( 'Strong', 'mm-post-grid' ),
			),
			'title_tag'        => array(
				'h2'  => 'h2',
				'h3'  => 'h3',
				'h4'  => 'h4',
				'h5'  => 'h5',
				'h6'  => 'h6',
				'p'   => __( 'Paragraph', 'mm-post-grid' ),
				'div' => __( 'Plain block', 'mm-post-grid' ),
			),
			'button_style'     => array(
				'link'    => __( 'Text link', 'mm-post-grid' ),
				'button'  => __( 'Button', 'mm-post-grid' ),
				'outline' => __( 'Outline button', 'mm-post-grid' ),
			),
			'button_size'      => array(
				'small'  => __( 'Small', 'mm-post-grid' ),
				'medium' => __( 'Medium', 'mm-post-grid' ),
				'large'  => __( 'Large', 'mm-post-grid' ),
			),
			'card_layout'      => array(
				'stacked'    => __( 'Image above the text', 'mm-post-grid' ),
				'horizontal' => __( 'Image beside the text', 'mm-post-grid' ),
				'overlay'    => __( 'Text over the image', 'mm-post-grid' ),
			),
			'hover_effect'     => array(
				'lift'   => __( 'Lift with shadow', 'mm-post-grid' ),
				'shadow' => __( 'Shadow only', 'mm-post-grid' ),
				'border' => __( 'Border colour', 'mm-post-grid' ),
				'none'   => __( 'None', 'mm-post-grid' ),
			),
			'text_align'       => array(
				'left'   => __( 'Left', 'mm-post-grid' ),
				'center' => __( 'Centred', 'mm-post-grid' ),
			),
			'image_hover'      => array(
				'zoom'      => __( 'Zoom', 'mm-post-grid' ),
				'none'      => __( 'None', 'mm-post-grid' ),
				'grayscale' => __( 'Greyscale until hover', 'mm-post-grid' ),
			),
			'title_weight'     => array(
				'400' => __( 'Regular', 'mm-post-grid' ),
				'500' => __( 'Medium', 'mm-post-grid' ),
				'600' => __( 'Semibold', 'mm-post-grid' ),
				'700' => __( 'Bold', 'mm-post-grid' ),
				'800' => __( 'Extra bold', 'mm-post-grid' ),
			),
			'term_style'       => array(
				'text'  => __( 'Text', 'mm-post-grid' ),
				'badge' => __( 'Badge', 'mm-post-grid' ),
			),
			'pagination_align' => array(
				'left'   => __( 'Left', 'mm-post-grid' ),
				'center' => __( 'Centre', 'mm-post-grid' ),
				'right'  => __( 'Right', 'mm-post-grid' ),
			),
		);
	}
}