<?php
/**
 * Build Administration Menu.
 *
 * @package WordPress
 * @subpackage Administration
 */

if ( is_network_admin() ) {

    /**
     * Fires before the administration menu loads in the Network Admin.
     *
     * The hook fires before menus and sub-menus are removed based on user privileges.
     *
     * @since 3.1.0
     * @access private
     */
    do_action( '_network_admin_menu' );
} elseif ( is_user_admin() ) {

    /**
     * Fires before the administration menu loads in the User Admin.
     *
     * The hook fires before menus and sub-menus are removed based on user privileges.
     *
     * @since 3.1.0
     * @access private
     */
    do_action( '_user_admin_menu' );
} else {

    /**
     * Fires before the administration menu loads in the admin.
     *
     * The hook fires before menus and sub-menus are removed based on user privileges.
     *
     * @since 2.2.0
     * @access private
     */
    do_action( '_admin_menu' );
}

/**
 * @global array $menu
 * @global array $submenu
 * @global array $compat
 */
global $menu, $submenu, $compat;

// Create list of page plugin hook names.
foreach ( $menu as $menu_page ) {
    $pos = strpos( $menu_page[2], '?' );

    if ( false !== $pos ) {
        // Handle post_type=post|page|foo pages.
        $hook_name = substr( $menu_page[2], 0, $pos );
        $hook_args = substr( $menu_page[2], $pos + 1 );
        wp_parse_str( $hook_args, $hook_args );

        // Set the hook name to be the post type.
        if ( isset( $hook_args['post_type'] ) ) {
            $hook_name = $hook_args['post_type'];
        } else {
            $hook_name = basename( $hook_name, '.php' );
        }
        unset( $hook_args );
    } else {
        $hook_name = basename( $menu_page[2], '.php' );
    }

    $hook_name = sanitize_title( $hook_name );

    if ( isset( $compat[ $hook_name ] ) ) {
        $hook_name = $compat[ $hook_name ];
    } elseif ( ! $hook_name ) {
        continue;
    }

    $admin_page_hooks[ $menu_page[2] ] = $hook_name;
}
unset( $menu_page, $compat );

$_wp_submenu_nopriv = array();
$_wp_menu_nopriv    = array();
// Loop over submenus and remove pages for which the user does not have privs.
foreach ( $submenu as $parent => $sub ) {
    foreach ( $sub as $index => $data ) {
        if ( ! current_user_can( $data[1] ) ) {
            unset( $submenu[ $parent ][ $index ] );
            $_wp_submenu_nopriv[ $parent ][ $data[2] ] = true;
        }
    }
    unset( $index, $data );

    if ( empty( $submenu[ $parent ] ) ) {
        unset( $submenu[ $parent ] );
    }
}
unset( $sub, $parent );

/*
 * Loop over the top-level menu.
 * Menus for which the original parent is not accessible due to lack of privileges
 * will have the next submenu in line be assigned as the new menu parent.
 */
foreach ( $menu as $id => $data ) {
    if ( empty( $submenu[ $data[2] ] ) ) {
        continue;
    }

    $subs       = $submenu[ $data[2] ];
    $first_sub  = reset( $subs );
    $old_parent = $data[2];
    $new_parent = $first_sub[2];

    /*
     * If the first submenu is not the same as the assigned parent,
     * make the first submenu the new parent.
     */
    if ( $new_parent !== $old_parent ) {
        $_wp_real_parent_file[ $old_parent ] = $new_parent;

        $menu[ $id ][2] = $new_parent;

        foreach ( $submenu[ $old_parent ] as $index => $data ) {
            $submenu[ $new_parent ][ $index ] = $submenu[ $old_parent ][ $index ];
            unset( $submenu[ $old_parent ][ $index ] );
        }
        unset( $submenu[ $old_parent ], $index );

        if ( isset( $_wp_submenu_nopriv[ $old_parent ] ) ) {
            $_wp_submenu_nopriv[ $new_parent ] = $_wp_submenu_nopriv[ $old_parent ];
        }
    }
}
unset( $id, $data, $subs, $first_sub, $old_parent, $new_parent );

if ( is_network_admin() ) {

    /**
     * Fires before the administration menu loads in the Network Admin.
     *
     * @since 3.1.0
     *
     * @param string $context Empty context.
     */
    do_action( 'network_admin_menu', '' );
} elseif ( is_user_admin() ) {

    /**
     * Fires before the administration menu loads in the User Admin.
     *
     * @since 3.1.0
     *
     * @param string $context Empty context.
     */
    do_action( 'user_admin_menu', '' );
} else {

    /**
     * Fires before the administration menu loads in the admin.
     *
     * @since 1.5.0
     *
     * @param string $context Empty context.
     */
    do_action( 'admin_menu', '' );
}

/*
 * Remove menus that have no accessible submenus and require privileges
 * that the user does not have. Run re-parent loop again.
 */
foreach ( $menu as $id => $data ) {
    if ( ! current_user_can( $data[1] ) ) {
        $_wp_menu_nopriv[ $data[2] ] = true;
    }

    /*
     * If there is only one submenu and it is has same destination as the parent,
     * remove the submenu.
     */
    if ( ! empty( $submenu[ $data[2] ] ) && 1 === count( $submenu[ $data[2] ] ) ) {
        $subs      = $submenu[ $data[2] ];
        $first_sub = reset( $subs );

        if ( $data[2] === $first_sub[2] ) {
            unset( $submenu[ $data[2] ] );
        }
    }

    // If submenu is empty...
    if ( empty( $submenu[ $data[2] ] ) ) {
        // And user doesn't have privs, remove menu.
        if ( isset( $_wp_menu_nopriv[ $data[2] ] ) ) {
            unset( $menu[ $id ] );
        }
    }
}
unset( $id, $data, $subs, $first_sub );

/**
 * Adds a CSS class to a string.
 *
 * @since 2.7.0
 *
 * @param string $class_to_add The CSS class to add.
 * @param string $classes      The string to add the CSS class to.
 * @return string The string with the CSS class added.
 */
function add_cssclass( $class_to_add, $classes ) {
    if ( empty( $classes ) ) {
        return $class_to_add;
    }

    return $classes . ' ' . $class_to_add;
}

/**
 * Adds CSS classes for top-level administration menu items.
 *
 * The list of added classes includes `.menu-top-first` and `.menu-top-last`.
 *
 * @since 2.7.0
 *
 * @param array $menu The array of administration menu items.
 * @return array The array of administration menu items with the CSS classes added.
 */
function add_menu_classes( $menu ) {
    $first_item  = false;
    $last_order  = false;
    $items_count = count( $menu );

    $i = 0;

    foreach ( $menu as $order => $top ) {
        ++$i;

        if ( 0 === $order ) { // Dashboard is always shown/single.
            $menu[0][4] = add_cssclass( 'menu-top-first', $top[4] );
            $last_order = 0;
            continue;
        }

        if ( str_starts_with( $top[2], 'separator' ) && false !== $last_order ) { // If separator.
            $first_item = true;
            $classes    = $menu[ $last_order ][4];

            $menu[ $last_order ][4] = add_cssclass( 'menu-top-last', $classes );
            continue;
        }

        if ( $first_item ) {
            $first_item = false;
            $classes    = $menu[ $order ][4];

            $menu[ $order ][4] = add_cssclass( 'menu-top-first', $classes );
        }

        if ( $i === $items_count ) { // Last item.
            $classes = $menu[ $order ][4];

            $menu[ $order ][4] = add_cssclass( 'menu-top-last', $classes );
        }

        $last_order = $order;
    }

    /**
     * Filters administration menu array with classes added for top-level items.
     *
     * @since 2.7.0
     *
     * @param array $menu Associative array of administration menu items.
     */
    return apply_filters( 'add_menu_classes', $menu );
}

uksort( $menu, 'strnatcasecmp' ); // Make it all pretty.

/**
 * Filters whether to enable custom ordering of the administration menu.
 *
 * See the {@see 'menu_order'} filter for reordering menu items.
 *
 * @since 2.8.0
 *
 * @param bool $custom Whether custom ordering is enabled. Default false.
 */
if ( apply_filters( 'custom_menu_order', false ) ) {
    $menu_order = array();

    foreach ( $menu as $menu_item ) {
        $menu_order[] = $menu_item[2];
    }
    unset( $menu_item );

    $default_menu_order = $menu_order;

    /**
     * Filters the order of administration menu items.
     *
     * A truthy value must first be passed to the {@see 'custom_menu_order'} filter
     * for this filter to work. Use the following to enable custom menu ordering:
     *
     *     add_filter( 'custom_menu_order', '__return_true' );
     *
     * @since 2.8.0
     *
     * @param array $menu_order An ordered array of menu items.
     */
    $menu_order = apply_filters( 'menu_order', $menu_order );
    $menu_order = array_flip( $menu_order );

    $default_menu_order = array_flip( $default_menu_order );

    /**
     * @global array $menu_order
     * @global array $default_menu_order
     *
     * @param array $a
     * @param array $b
     * @return int
     */
    function sort_menu( $a, $b ) {
        global $menu_order, $default_menu_order;

        $a = $a[2];
        $b = $b[2];

        if ( isset( $menu_order[ $a ] ) && ! isset( $menu_order[ $b ] ) ) {
            return -1;
        } elseif ( ! isset( $menu_order[ $a ] ) && isset( $menu_order[ $b ] ) ) {
            return 1;
        } elseif ( isset( $menu_order[ $a ] ) && isset( $menu_order[ $b ] ) ) {
            return $menu_order[ $a ] <=> $menu_order[ $b ];
        } else {
            return $default_menu_order[ $a ] <=> $default_menu_order[ $b ];
        }
    }

    usort( $menu, 'sort_menu' );
    unset( $menu_order, $default_menu_order );
}

// Prevent adjacent separators.
$prev_menu_was_separator = false;
foreach ( $menu as $id => $data ) {
    if ( false === stristr( $data[4], 'wp-menu-separator' ) ) {

        // This item is not a separator, so falsey the toggler and do nothing.
        $prev_menu_was_separator = false;
    } else {

        // The previous item was a separator, so unset this one.
        if ( true === $prev_menu_was_separator ) {
            unset( $menu[ $id ] );
        }

        // This item is a separator, so truthy the toggler and move on.
        $prev_menu_was_separator = true;
    }
}
unset( $id, $data, $prev_menu_was_separator );

// Remove the last menu item if it is a separator.
$last_menu_key = array_keys( $menu );
$last_menu_key = array_pop( $last_menu_key );
if ( ! empty( $menu ) && 'wp-menu-separator' === $menu[ $last_menu_key ][4] ) {
    unset( $menu[ $last_menu_key ] );
}
unset( $last_menu_key );

if ( ! user_can_access_admin_page() ) {

    /**
     * Fires when access to an admin page is denied.
     *
     * @since 2.5.0
     */
    do_action( 'admin_page_access_denied' );

    wp_die( __( 'Sorry, you are not allowed to access this page.' ), 403 );
}

$menu = add_menu_classes( $menu );