*
	 * @param string $menu The HTML output.
	 * @param array  $args An array of arguments. See wp_page_menu()
	 *                     for information on accepted arguments.
	 */
	$menu = apply_filters( 'wp_page_menu', $menu, $args );

	if ( $args['echo'] ) {
		echo $menu;
	} else {
		return $menu;
	}
}

//
// Page helpers.
//

/**
 * Retrieve HTML list content for page list.
 *
 * @uses Walker_Page to create HTML list content.
 * @since 2.1.0
 *
 * @param array $pages
 * @param int   $depth
 * @param int   $current_page
 * @param array $r
 * @return string
 */
function walk_page_tree( $pages, $depth, $current_page, $r ) {
	if ( empty( $r['walker'] ) ) {
		$walker = new Walker_Page;
	} else {
		/**
		 * @var Walker $walker
		 */
		$walker = $r['walker'];
	}

	foreach ( (array) $pages as $page ) {
		if ( $page->post_parent ) {
			$r['pages_with_children'][ $page->post_parent ] = true;
		}
	}

	return $walker->walk( $pages, $depth, $r, $current_page );
}

/**
 * Retrieve HTML dropdown (select) content for page list.
 *
 * @since 2.1.0
 * @since 5.3.0 Formalized the existing `...$args` parameter by adding it
 *              to the function signature.
 *
 * @uses Walker_PageDropdown to create HTML dropdown content.
 * @see Walker_PageDropdown::walk() for parameters and return description.
 *
 * @param mixed ...$args Elements array, maximum hierarchical depth and optional additional arguments.
 * @return string
 */
function walk_page_dropdown_tree( ...$args ) {
	if ( empty( $args[2]['walker'] ) ) { // The user's options are the third parameter.
		$walker = new Walker_PageDropdown;
	} else {
		/**
		 * @var Walker $walker
		 */
		$walker = $args[2]['walker'];
	}

	return $walker->walk( ...$args );
}

//
// Attachments.
//

/**
 * Display an attachment page link using an image or icon.
 *
 * @since 2.0.0
 *
 * @param int|WP_Post $id Optional. Post ID or post object.
 * @param bool        $fullsize     Optional. Whether to use full size. Default false.
 * @param bool        $deprecated   Deprecated. Not used.
 * @param bool        $permalink    Optional. Whether to include permalink. Default false.
 */
function the_attachment_link( $id = 0, $fullsize = false, $deprecated = false, $permalink = false ) {
	if ( ! empty( $deprecated ) ) {
		_deprecated_argument( __FUNCTION__, '2.5.0' );
	}

	if ( $fullsize ) {
		echo wp_get_attachment_link( $id, 'full', $permalink );
	} else {
		echo wp_get_attachment_link( $id, 'thumbnail', $permalink );
	}
}

/**
 * Retrieve an attachment page link using an image or icon, if possible.
 *
 * @since 2.5.0
 * @since 4.4.0 The `$id` parameter can now accept either a post ID or `WP_Post` object.
 *
 * @param int|WP_Post  $id        Optional. Post ID or post object.
 * @param string|int[] $size      Optional. Image size. Accepts any registered image size name, or an array
 *                                of width and height values in pixels (in that order). Default 'thumbnail'.
 * @param bool         $permalink Optional. Whether to add permalink to image. Default false.
 * @param bool         $icon      Optional. Whether the attachment is an icon. Default false.
 * @param string|false $text      Optional. Link text to use. Activated by passing a string, false otherwise.
 *                                Default false.
 * @param array|string $attr      Optional. Array or string of attributes. Default empty.
 * @return string HTML content.
 */
function wp_get_attachment_link( $id = 0, $size = 'thumbnail', $permalink = false, $icon = false, $text = false, $attr = '' ) {
	$_post = get_post( $id );

	if ( empty( $_post ) || ( 'attachment' !== $_post->post_type ) || ! wp_get_attachment_url( $_post->ID ) ) {
		return __( 'Missing Attachment' );
	}

	$url = wp_get_attachment_url( $_post->ID );

	if ( $permalink ) {
		$url = get_attachment_link( $_post->ID );
	}

	if ( $text ) {
		$link_text = $text;
	} elseif ( $size && 'none' !== $size ) {
		$link_text = wp_get_attachment_image( $_post->ID, $size, $icon, $attr );
	} else {
		$link_text = '';
	}

	if ( '' === trim( $link_text ) ) {
		$link_text = $_post->post_title;
	}

	if ( '' === trim( $link_text ) ) {
		$link_text = esc_html( pathinfo( get_attached_file( $_post->ID ), PATHINFO_FILENAME ) );
	}
	/**
	 * Filters a retrieved attachment page link.
	 *
	 * @since 2.7.0
	 * @since 5.1.0 Added the `$attr` parameter.
	 *
	 * @param string       $link_html The page link HTML output.
	 * @param int          $id        Post ID.
	 * @param string|int[] $size      Requested image size. Can be any registered image size name, or
	 *                                an array of width and height values in pixels (in that order).
	 * @param bool         $permalink Whether to add permalink to image. Default false.
	 * @param bool         $icon      Whether to include an icon.
	 * @param string|false $text      If string, will be link text.
	 * @param array|string $attr      Array or string of attributes.
	 */
	return apply_filters( 'wp_get_attachment_link', "<a href='" . esc_url( $url ) . "'>$link_text</a>", $id, $size, $permalink, $icon, $text, $attr );
}

/**
 * Wrap attachment in paragraph tag before content.
 *
 * @since 2.0.0
 *
 * @param string $content
 * @return string
 */
function prepend_attachment( $content ) {
	$post = get_post();

	if ( empty( $post->post_type ) || 'attachment' !== $post->post_type ) {
		return $content;
	}

	if ( wp_attachment_is( 'video', $post ) ) {
		$meta = wp_get_attachment_metadata( get_the_ID() );
		$atts = array( 'src' => wp_get_attachment_url() );
		if ( ! empty( $meta['width'] ) && ! empty( $meta['height'] ) ) {
			$atts['width']  = (int) $meta['width'];
			$atts['height'] = (int) $meta['height'];
		}
		if ( has_post_thumbnail() ) {
			$atts['poster'] = wp_get_attachment_url( get_post_thumbnail_id() );
		}
		$p = wp_video_shortcode( $atts );
	} elseif ( wp_attachment_is( 'audio', $post ) ) {
		$p = wp_audio_shortcode( array( 'src' => wp_get_attachment_url() ) );
	} else {
		$p = '<p class="attachment">';
		// Show the medium sized image representation of the attachment if available, and link to the raw file.
		$p .= wp_get_attachment_link( 0, 'medium', false );
		$p .= '</p>';
	}

	/**
	 * Filters the attachment markup to be prepended to the post content.
	 *
	 * @since 2.0.0
	 *
	 * @see prepend_attachment()
	 *
	 * @param string $p The attachment HTML output.
	 */
	$p = apply_filters( 'prepend_attachment', $p );

	return "$p\n$content";
}

//
// Misc.
//

/**
 * Retrieve protected post password form content.
 *
 * @since 1.0.0
 *
 * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global $post.
 * @return string HTML content for password form for password protected post.
 */
function get_the_password_form( $post = 0 ) {
	$post   = get_post( $post );
	$label  = 'pwbox-' . ( empty( $post->ID ) ? rand() : $post->ID );
	$output = '<form action="' . esc_url( site_url( 'wp-login.php?action=postpass', 'login_post' ) ) . '" class="post-password-form" method="post">
	<p>' . __( 'This content is password protected. To view it please enter your password below:' ) . '</p>
	<p><label for="' . $label . '">' . __( 'Password:' ) . ' <input name="post_password" id="' . $label . '" type="password" size="20" /></label> <input type="submit" name="Submit" value="' . esc_attr_x( 'Enter', 'post password form' ) . '" /></p></form>
	';

	/**
	 * Filters the HTML output for the protected post password form.
	 *
	 * If modifying the password field, please note that the core database schema
	 * limits the password field to 20 characters regardless of the value of the
	 * size attribute in the form input.
	 *
	 * @since 2.7.0
	 * @since 5.8.0 Added the `$post` parameter.
	 *
	 * @param string  $output The password form HTML output.
	 * @param WP_Post $post   Post object.
	 */
	return apply_filters( 'the_password_form', $output, $post );
}

/**
 * Determines whether currently in a page template.
 *
 * This template tag allows you to determine if you are in a page template.
 * You can optionally provide a template filename or array of template filenames
 * and then the check will be specific to that template.
 *
 * For more information on this and similar theme functions, check out
 * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 * Conditional Tags} article in the Theme Developer Handbook.
 *
 * @since 2.5.0
 * @since 4.2.0 The `$template` parameter was changed to also accept an array of page templates.
 * @since 4.7.0 Now works with any post type, not just pages.
 *
 * @param string|string[] $template The specific template filename or array of templates to match.
 * @return bool True on success, false on failure.
 */
function is_page_template( $template = '' ) {
	if ( ! is_singular() ) {
		return false;
	}

	$page_template = get_page_template_slug( get_queried_object_id() );

	if ( empty( $template ) ) {
		return (bool) $page_template;
	}

	if ( $template == $page_template ) {
		return true;
	}

	if ( is_array( $template ) ) {
		if ( ( in_array( 'default', $template, true ) && ! $page_template )
			|| in_array( $page_template, $template, true )
		) {
			return true;
		}
	}

	return ( 'default' === $template && ! $page_template );
}

/**
 * Get the specific template filename for a given post.
 *
 * @since 3.4.0
 * @since 4.7.0 Now works with any post type, not just pages.
 *
 * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global $post.
 * @return string|false Page template filename. Returns an empty string when the default page template
 *                      is in use. Returns false if the post does not exist.
 */
function get_page_template_slug( $post = null ) {
	$post = get_post( $post );

	if ( ! $post ) {
		return false;
	}

	$template = get_post_meta( $post->ID, '_wp_page_template', true );

	if ( ! $template || 'default' === $template ) {
		return '';
	}

	return $template;
}

/**
 * Retrieve formatted date timestamp of a revision (linked to that revisions's page).
 *
 * @since 2.6.0
 *
 * @param int|object $revision Revision ID or revision object.
 * @param bool       $link     Optional. Whether to link to revision's page. Default true.
 * @return string|false i18n formatted datetimestamp or localized 'Current Revision'.
 */
function wp_post_revision_title( $revision, $link = true ) {
	$revision = get_post( $revision );
	if ( ! $revision ) {
		return $revision;
	}

	if ( ! in_array( $revision->post_type, array( 'post', 'page', 'revision' ), true ) ) {
		return false;
	}

	/* translators: Revision date format, see https://www.php.net/manual/datetime.format.php */
	$datef = _x( 'F j, Y @ H:i:s', 'revision date format' );
	/* translators: %s: Revision date. */
	$autosavef = __( '%s [Autosave]' );
	/* translators: %s: Revision date. */
	$currentf = __( '%s [Current Revision]' );

	$date      = date_i18n( $datef, strtotime( $revision->post_modified ) );
	$edit_link = get_edit_post_link( $revision->ID );
	if ( $link && current_user_can( 'edit_post', $revision->ID ) && $edit_link ) {
		$date = "<a href='$edit_link'>$date</a>";
	}

	if ( ! wp_is_post_revision( $revision ) ) {
		$date = sprintf( $currentf, $date );
	} elseif ( wp_is_post_autosave( $revision ) ) {
		$date = sprintf( $autosavef, $date );
	}

	return $date;
}

/**
 * Retrieve formatted date timestamp of a revision (linked to that revisions's page).
 *
 * @since 3.6.0
 *
 * @param int|object $revision Revision ID or revision object.
 * @param bool       $link     Optional. Whether to link to revision's page. Default true.
 * @return string|false gravatar, user, i18n formatted datetimestamp or localized 'Current Revision'.
 */
function wp_post_revision_title_expanded( $revision, $link = true ) {
	$revision = get_post( $revision );
	if ( ! $revision ) {
		return $revision;
	}

	if ( ! in_array( $revision->post_type, array( 'post', 'page', 'revision' ), true ) ) {
		return false;
	}

	$author = get_the_author_meta( 'display_name', $revision->post_author );
	/* translators: Revision date format, see https://www.php.net/manual/datetime.format.php */
	$datef = _x( 'F j, Y @ H:i:s', 'revision date format' );

	$gravatar = get_avatar( $revision->post_author, 24 );

	$date      = date_i18n( $datef, strtotime( $revision->post_modified ) );
	$edit_link = get_edit_post_link( $revision->ID );
	if ( $link && current_user_can( 'edit_post', $revision->ID ) && $edit_link ) {
		$date = "<a href='$edit_link'>$date</a>";
	}

	$revision_date_author = sprintf(
		/* translators: Post revision title. 1: Author avatar, 2: Author name, 3: Time ago, 4: Date. */
		__( '%1$s %2$s, %3$s ago (%4$s)' ),
		$gravatar,
		$author,
		human_time_diff( strtotime( $revision->post_modified_gmt ) ),
		$date
	);

	/* translators: %s: Revision date with author avatar. */
	$autosavef = __( '%s [Autosave]' );
	/* translators: %s: Revision date with author avatar. */
	$currentf = __( '%s [Current Revision]' );

	if ( ! wp_is_post_revision( $revision ) ) {
		$revision_date_author = sprintf( $currentf, $revision_date_author );
	} elseif ( wp_is_post_autosave( $revision ) ) {
		$revision_date_author = sprintf( $autosavef, $revision_date_author );
	}

	/**
	 * Filters the formatted author and date for a revision.
	 *
	 * @since 4.4.0
	 *
	 * @param string  $revision_date_author The formatted string.
	 * @param WP_Post $revision             The revision object.
	 * @param bool    $link                 Whether to link to the revisions page, as passed into
	 *                                      wp_post_revision_title_expanded().
	 */
	return apply_filters( 'wp_post_revision_title_expanded', $revision_date_author, $revision, $link );
}

/**
 * Display a list of a post's revisions.
 *
 * Can output either a UL with edit links or a TABLE with diff interface, and
 * restore action links.
 *
 * @since 2.6.0
 *
 * @param int|WP_Post $post_id Optional. Post ID or WP_Post object. Default is global $post.
 * @param string      $type    'all' (default), 'revision' or 'autosave'
 */
function wp_list_post_revisions( $post_id = 0, $type = 'all' ) {
	$post = get_post( $post_id );
	if ( ! $post ) {
		return;
	}

	// $args array with (parent, format, right, left, type) deprecated since 3.6.
	if ( is_array( $type ) ) {
		$type = ! empty( $type['type'] ) ? $type['type'] : $type;
		_deprecated_argument( __FUNCTION__, '3.6.0' );
	}

	$revisions = wp_get_post_revisions( $post->ID );
	if ( ! $revisions ) {
		return;
	}

	$rows = '';
	foreach ( $revisions as $revision ) {
		if ( ! current_user_can( 'read_post', $revision->ID ) ) {
			continue;
		}

		$is_autosave = wp_is_post_autosave( $revision );
		if ( ( 'revision' === $type && $is_autosave ) || ( 'autosave' === $type && ! $is_autosave ) ) {
			continue;
		}

		$rows .= "\t<li>" . wp_post_revision_title_expanded( $revision ) . "</li>\n";
	}

	echo "<div class='hide-if-js'><p>" . __( 'JavaScript must be enabled to use this feature.' ) . "</p></div>\n";

	echo "<ul class='post-revisions hide-if-no-js'>\n";
	echo $rows;
	echo '</ul>';
}

/**
 * Retrieves the parent post object for the given post.
 *
 * @since 5.7.0
 *
 * @param int|WP_Post|null $post Optional. Post ID or WP_Post object. Default is global $post.
 * @return WP_Post|null Parent post object, or null if there isn't one.
 */
function get_post_parent( $post = null ) {
	$wp_post = get_post( $post );
	return ! empty( $wp_post->post_parent ) ? get_post( $wp_post->post_parent ) : null;
}

/**
 * Returns whether the given post has a parent post.
 *
 * @since 5.7.0
 *
 * @param int|WP_Post|null $post Optional. Post ID or WP_Post object. Default is global $post.
 * @return bool Whether the post has a parent post.
 */
function has_post_parent( $post = null ) {
	return (bool) get_post_parent( $post );
}