<?php
/**
 * Bulk alt text editor.
 *
 * Missing alt text is the single most common accessibility failure on the web,
 * and WordPress makes fixing it slow: the Media Library forces one modal per
 * image. This screen lists everything that is missing a description with the
 * picture next to an input, so a few hundred images become a ten-minute job.
 *
 * @package AccessVane
 */

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

/**
 * Renders and powers the alt text screen.
 */
class AccessVane_Alt_Text {

	const PER_PAGE = 30;

	/**
	 * Hook registration.
	 *
	 * @return void
	 */
	public function register() {
		// Rendering is wired up by AccessVane_Admin's submenu entry; the screen
		// saves through the REST route so nothing here needs a form handler.
		add_action( 'admin_enqueue_scripts', array( $this, 'assets' ) );
	}

	/**
	 * Load the inline-save script on this screen only.
	 *
	 * @param string $hook Current admin page hook.
	 * @return void
	 */
	public function assets( $hook ) {
		if ( false === strpos( (string) $hook, 'accessvane-alt-text' ) ) {
			return;
		}

		wp_enqueue_script(
			'accessvane-alt-text',
			ACCESSVANE_URL . 'assets/js/alt-text.js',
			array(),
			ACCESSVANE_VERSION,
			true
		);

		wp_localize_script(
			'accessvane-alt-text',
			'accessVaneAltText',
			array(
				'restUrl' => esc_url_raw( rest_url( AccessVane_REST::NAMESPACE_V1 . '/alt-text' ) ),
				'nonce'   => wp_create_nonce( 'wp_rest' ),
				'strings' => array(
					'saved'  => __( 'Saved', 'accessvane' ),
					'failed' => __( 'Could not save', 'accessvane' ),
				),
			)
		);
	}

	/**
	 * Count images with no alt text.
	 *
	 * @return int
	 */
	private function missing_count() {
		$query = new WP_Query( $this->query_args( 1, 1 ) );

		return (int) $query->found_posts;
	}

	/**
	 * Query arguments for attachments missing alt text.
	 *
	 * Uses a NOT EXISTS / empty-string pair because WordPress writes an empty
	 * string for images that were saved with the field left blank, and no row
	 * at all for images that were never touched.
	 *
	 * @param int $page     Page number.
	 * @param int $per_page Results per page.
	 * @return array
	 */
	private function query_args( $page, $per_page ) {
		return array(
			'post_type'      => 'attachment',
			'post_status'    => 'inherit',
			'post_mime_type' => array( 'image/jpeg', 'image/png', 'image/gif', 'image/webp', 'image/avif' ),
			'posts_per_page' => $per_page,
			'paged'          => $page,
			'orderby'        => 'date',
			'order'          => 'DESC',
			// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query -- the whole purpose of this screen is to find images by a missing meta value.
			'meta_query'     => array(
				'relation' => 'OR',
				array(
					'key'     => '_wp_attachment_image_alt',
					'compare' => 'NOT EXISTS',
				),
				array(
					'key'     => '_wp_attachment_image_alt',
					'value'   => '',
					'compare' => '=',
				),
			),
		);
	}

	/**
	 * A suggested description, offered but never saved automatically.
	 *
	 * Caption first, then title — and never the file name, which describes
	 * nothing. Returning an empty string means "we have nothing useful", which
	 * is a more honest answer than inventing something.
	 *
	 * @param WP_Post $attachment Attachment.
	 * @return string
	 */
	private function suggestion( $attachment ) {
		$caption = trim( (string) $attachment->post_excerpt );

		if ( '' !== $caption ) {
			return $caption;
		}

		$title = trim( (string) $attachment->post_title );

		if ( '' === $title ) {
			return '';
		}

		if ( preg_match( '/\.(jpe?g|png|gif|webp|avif|svg)$/i', $title ) ) {
			return '';
		}

		if ( preg_match( '/^(img|dsc|dscn|pxl|photo|image|screenshot|screen[ _-]?shot|untitled)[ _-]?\d*/i', $title ) ) {
			return '';
		}

		if ( preg_match( '/^\d{6,}$/', $title ) ) {
			return '';
		}

		return $title;
	}

	/**
	 * Render the screen.
	 *
	 * @return void
	 */
	public function render_page() {
		if ( ! current_user_can( 'upload_files' ) ) {
			wp_die( esc_html__( 'You are not allowed to edit media.', 'accessvane' ), 403 );
		}

		$paged = isset( $_GET['paged'] ) ? max( 1, absint( $_GET['paged'] ) ) : 1; // phpcs:ignore WordPress.Security.NonceVerification.Recommended -- read-only pagination.
		$query = new WP_Query( $this->query_args( $paged, self::PER_PAGE ) );
		$total = (int) $query->found_posts;

		echo '<div class="wrap accessvane-wrap">';
		echo '<h1 class="accessvane-title">' . esc_html__( 'Image alt text', 'accessvane' ) . '</h1>';
		echo '<p class="accessvane-intro">' . esc_html__( 'Every image that carries meaning needs a short description of what it shows. Type it and it saves as you go — there is no Save button to remember.', 'accessvane' ) . '</p>';

		?>
		<div class="accessvane-note">
			<strong><?php esc_html_e( 'How to write a good description', 'accessvane' ); ?></strong>
			<p>
				<?php
				esc_html_e(
					'Say what the image shows, not that it is an image — a screen reader already announces that. "Two people shaking hands outside a shop" is useful. "Image of business" is not. If a picture is purely decorative and carries no information, leave the box empty and tick Decorative; that is the correct answer and tells assistive software to skip it.',
					'accessvane'
				);
				?>
			</p>
		</div>
		<?php

		if ( 0 === $total ) {
			echo '<div class="accessvane-empty"><h2>' . esc_html__( 'Every image has a description', 'accessvane' ) . '</h2>';
			echo '<p>' . esc_html__( 'Nothing in your media library is missing alt text. Worth re-checking after your next batch of uploads.', 'accessvane' ) . '</p></div></div>';

			return;
		}

		printf(
			'<p class="accessvane-meta">%s</p>',
			esc_html(
				sprintf(
					/* translators: %d: number of images. */
					_n( '%d image still needs a description.', '%d images still need a description.', $total, 'accessvane' ),
					$total
				)
			)
		);

		echo '<table class="widefat striped accessvane-table">';
		echo '<thead><tr>';
		echo '<th style="width:110px">' . esc_html__( 'Image', 'accessvane' ) . '</th>';
		echo '<th>' . esc_html__( 'Description (alt text)', 'accessvane' ) . '</th>';
		echo '<th style="width:130px">' . esc_html__( 'Decorative', 'accessvane' ) . '</th>';
		echo '</tr></thead><tbody>';

		foreach ( $query->posts as $attachment ) {
			$thumb      = wp_get_attachment_image_url( $attachment->ID, 'thumbnail' );
			$suggestion = $this->suggestion( $attachment );
			$edit_link  = get_edit_post_link( $attachment->ID );

			echo '<tr class="accessvane-alt-row" data-id="' . esc_attr( $attachment->ID ) . '">';

			echo '<td>';
			if ( $thumb ) {
				printf(
					'<img src="%1$s" alt="%2$s" loading="lazy" width="90">',
					esc_url( $thumb ),
					/* translators: %s: image file name. */
					esc_attr( sprintf( __( 'Preview of %s', 'accessvane' ), $attachment->post_title ) )
				);
			}
			echo '</td>';

			echo '<td>';
			printf(
				'<label class="screen-reader-text" for="accessvane-alt-%1$d">%2$s</label>',
				esc_attr( $attachment->ID ),
				esc_html__( 'Alt text for this image', 'accessvane' )
			);
			printf(
				'<input type="text" class="accessvane-alt-input" id="accessvane-alt-%1$d" value="" placeholder="%2$s">',
				esc_attr( $attachment->ID ),
				esc_attr__( 'Describe what this image shows', 'accessvane' )
			);
			echo '<span class="accessvane-alt-status" role="status" aria-live="polite"></span>';

			if ( '' !== $suggestion ) {
				printf(
					'<p class="accessvane-dim"><button type="button" class="button-link accessvane-alt-suggest" data-suggestion="%1$s">%2$s</button> %3$s</p>',
					esc_attr( $suggestion ),
					esc_html__( 'Use the caption', 'accessvane' ),
					esc_html( '"' . $suggestion . '"' )
				);
			}

			if ( $edit_link ) {
				printf(
					'<p class="accessvane-dim"><a href="%1$s">%2$s</a></p>',
					esc_url( $edit_link ),
					esc_html__( 'Open in Media Library', 'accessvane' )
				);
			}
			echo '</td>';

			echo '<td>';
			printf(
				'<label><input type="checkbox" class="accessvane-alt-decorative"> %s</label>',
				esc_html__( 'Skip it', 'accessvane' )
			);
			echo '</td>';

			echo '</tr>';
		}

		echo '</tbody></table>';

		$pages = (int) ceil( $total / self::PER_PAGE );

		if ( $pages > 1 ) {
			echo '<div class="tablenav"><div class="tablenav-pages">';
			echo wp_kses_post(
				paginate_links(
					array(
						'base'      => add_query_arg( 'paged', '%#%' ),
						'format'    => '',
						'current'   => $paged,
						'total'     => $pages,
						'prev_text' => __( '&laquo; Previous', 'accessvane' ),
						'next_text' => __( 'Next &raquo;', 'accessvane' ),
					)
				)
			);
			echo '</div></div>';
		}

		echo '</div>';

		wp_reset_postdata();
	}
}