/**
	 * Returns the image entries for a given term.
	 *
	 * @since 4.0.0
	 *
	 * @param  \WP_Term $term The term object.
	 * @return array          The image entries.
	 */
	public function term( $term ) {
		if ( aioseo()->sitemap->helpers->excludeImages() ) {
			return [];
		}

		$id = get_term_meta( $term->term_id, 'thumbnail_id', true );
		if ( ! $id ) {
			return [];
		}

		return $this->buildEntries( [ $id ] );
	}

	/**
	 * Builds the image entries.
	 *
	 * @since 4.0.0
	 *
	 * @param  array $images The images, consisting of attachment IDs or external URLs.
	 * @return array         The image entries.
	 */
	private function buildEntries( $images ) {
		$entries = [];
		foreach ( $images as $image ) {
			$idOrUrl  = $this->getImageIdOrUrl( $image );
			$imageUrl = is_numeric( $idOrUrl ) ? wp_get_attachment_url( $idOrUrl ) : $idOrUrl;
			$imageUrl = aioseo()->sitemap->helpers->formatUrl( $imageUrl );
			if ( ! $imageUrl || ! preg_match( $this->getImageExtensionRegexPattern(), $imageUrl ) ) {
				continue;
			}

			$entries[ $idOrUrl ] = [ 'image:loc' => $imageUrl ];
		}

		return array_values( $entries );
	}

	/**
	 * Returns the ID of the image if it's hosted on the site. Otherwise it returns the external URL.
	 *
	 * @since 4.1.3
	 *
	 * @param  int|string $image The attachment ID or URL.
	 * @return int|string        The attachment ID or URL.
	 */
	private function getImageIdOrUrl( $image ) {
		if ( is_numeric( $image ) ) {
			return $image;
		}

		$attachmentId = false;
		if ( aioseo()->helpers->isValidAttachment( $image ) ) {
			$attachmentId = aioseo()->helpers->attachmentUrlToPostId( $image );
		}

		return $attachmentId ? $attachmentId : $image;
	}

	/**
	 * Extracts all image URls and IDs from the post.
	 *
	 * @since 4.0.0
	 *
	 * @return array The image URLs and IDs.
	 */
	private function extract() {
		$images = [];

		if ( has_post_thumbnail( $this->post ) ) {
			$images[] = get_the_post_thumbnail_url( $this->post );
		}

		// Get the galleries here before doShortcodes() runs below to prevent buggy behaviour.
		// WordPress is supposed to only return the attached images but returns a different result if the shortcode has no valid attributes, so we need to grab them manually.
		$images = array_merge( $images, $this->getPostGalleryImages() );

		// Now, get the remaining images from image tags in the post content.
		$parsedPostContent = do_blocks( $this->post->post_content );
		$parsedPostContent = aioseo()->helpers->doShortcodes( $parsedPostContent, true, $this->post->ID );
		$parsedPostContent = preg_replace( '/\s\s+/u', ' ', trim( $parsedPostContent ) ); // Trim both internal and external whitespace.

		// Get the images from any third-party plugins/themes that are active.
		$thirdParty = new ThirdParty( $this->post, $parsedPostContent );
		$images     = array_merge( $images, $thirdParty->extract() );

		preg_match_all( '#<img[^>]+src="([^">]+)"#', $parsedPostContent, $matches );
		foreach ( $matches[1] as $url ) {
			$images[] = aioseo()->helpers->makeUrlAbsolute( $url );
		}

		return array_unique( $images );
	}

	/**
	 * Returns all images from WP Core post galleries.
	 *
	 * @since 4.2.2
	 *
	 * @return array[string] The image URLs.
	 */
	private function getPostGalleryImages() {
		$images    = [];
		$galleries = get_post_galleries( $this->post, false );
		foreach ( $galleries as $gallery ) {
			foreach ( $gallery['src'] as $imageUrl ) {
				$images[] = $imageUrl;
			}
		}

		// Now, get rid of them so that we don't process the shortcodes again.
		$regex                    = get_shortcode_regex( [ 'gallery' ] );
		$this->post->post_content = preg_replace( "/$regex/i", '', $this->post->post_content );

		return $images;
	}

	/**
	 * Removes image dimensions from the slug.
	 *
	 * @since 4.0.0
	 *
	 * @param  array $urls         The image URLs.
	 * @return array $preparedUrls The formatted image URLs.
	 */
	private function removeImageDimensions( $urls ) {
		$preparedUrls = [];
		foreach ( $urls as $url ) {
			$preparedUrls[] = aioseo()->helpers->removeImageDimensions( $url );
		}

		return array_unique( array_filter( $preparedUrls ) );
	}

	/**
	 * Stores the image data for a given post in our DB table.
	 *
	 * @since 4.0.5
	 *
	 * @param  int   $postId The post ID.
	 * @param  array $images The images.
	 * @return void
	 */
	private function updatePost( $postId, $images = [] ) {
		$post                    = \AIOSEO\Plugin\Common\Models\Post::getPost( $postId );
		$meta                    = $post->exists() ? [] : aioseo()->migration->meta->getMigratedPostMeta( $postId );
		$meta['post_id']         = $postId;
		$meta['images']          = ! empty( $images ) ? $images : null;
		$meta['image_scan_date'] = gmdate( 'Y-m-d H:i:s' );

		$post->set( $meta );
		$post->save();
	}

	/**
	 * Returns the image extension regex pattern.
	 *
	 * @since 4.2.2
	 *
	 * @return string
	 */
	public function getImageExtensionRegexPattern() {
		static $pattern;
		if ( null !== $pattern ) {
			return $pattern;
		}

		$pattern = '/http.*\.(' . implode( '|', $this->supportedExtensions ) . ')$/i';

		return $pattern;
	}
}