Registers dashboard widgets.

Handles POST data, sets up filters.

function wp_dashboard_setup() {
	global $wp_registered_widgets, $wp_registered_widget_controls, $wp_dashboard_control_callbacks;

	$screen = get_current_screen();

	/* Register Widgets and Controls */
	$wp_dashboard_control_callbacks = array();

	// Browser version
	$check_browser = wp_check_browser_version();

	if ( $check_browser && $check_browser['upgrade'] ) {
		add_filter( 'postbox_classes_dashboard_dashboard_browser_nag', 'dashboard_browser_nag_class' );

		if ( $check_browser['insecure'] ) {
			wp_add_dashboard_widget( 'dashboard_browser_nag', __( 'You are using an insecure browser!' ), 'wp_dashboard_browser_nag' );
		} else {
			wp_add_dashboard_widget( 'dashboard_browser_nag', __( 'Your browser is out of date!' ), 'wp_dashboard_browser_nag' );
		}
	}

	// PHP Version.
	$check_php = wp_check_php_version();

	if ( $check_php && current_user_can( 'update_php' ) ) {
		// If "not acceptable" the widget will be shown.
		if ( isset( $check_php['is_acceptable'] ) && ! $check_php['is_acceptable'] ) {
			add_filter( 'postbox_classes_dashboard_dashboard_php_nag', 'dashboard_php_nag_class' );

			if ( $check_php['is_lower_than_future_minimum'] ) {
				wp_add_dashboard_widget( 'dashboard_php_nag', __( 'PHP Update Required' ), 'wp_dashboard_php_nag' );
			} else {
				wp_add_dashboard_widget( 'dashboard_php_nag', __( 'PHP Update Recommended' ), 'wp_dashboard_php_nag' );
			}
		}
	}

	// Site Health.
	if ( current_user_can( 'view_site_health_checks' ) && ! is_network_admin() ) {
		if ( ! class_exists( 'WP_Site_Health' ) ) {
			require_once ABSPATH . 'wp-admin/includes/class-wp-site-health.php';
		}

		WP_Site_Health::get_instance();

		wp_enqueue_style( 'site-health' );
		wp_enqueue_script( 'site-health' );

		wp_add_dashboard_widget( 'dashboard_site_health', __( 'Site Health Status' ), 'wp_dashboard_site_health' );
	}

	// Right Now.
	if ( is_blog_admin() && current_user_can( 'edit_posts' ) ) {
		wp_add_dashboard_widget( 'dashboard_right_now', __( 'At a Glance' ), 'wp_dashboard_right_now' );
	}

	if ( is_network_admin() ) {
		wp_add_dashboard_widget( 'network_dashboard_right_now', __( 'Right Now' ), 'wp_network_dashboard_right_now' );
	}

	// Activity Widget.
	if ( is_blog_admin() ) {
		wp_add_dashboard_widget( 'dashboard_activity', __( 'Activity' ), 'wp_dashboard_site_activity' );
	}

	// QuickPress Widget.
	if ( is_blog_admin() && current_user_can( get_post_type_object( 'post' )->cap->create_posts ) ) {
		$quick_draft_title = sprintf( '%1$s %2$s', __( 'Quick Draft' ), __( 'Your Recent Drafts' ) );
		wp_add_dashboard_widget( 'dashboard_quick_press', $quick_draft_title, 'wp_dashboard_quick_press' );
	}

	// WordPress Events and News.
	wp_add_dashboard_widget( 'dashboard_primary', __( 'WordPress Events and News' ), 'wp_dashboard_events_news' );

	if ( is_network_admin() ) {

		/**
		 * Fires after core widgets for the Network Admin dashboard have been registered.
		 *
		 * @since 3.1.0
		 */
		do_action( 'wp_network_dashboard_setup' );

		/**
		 * Filters the list of widgets to load for the Network Admin dashboard.
		 *
		 * @since 3.1.0
		 *
		 * @param string[] $dashboard_widgets An array of dashboard widget IDs.
		 */
		$dashboard_widgets = apply_filters( 'wp_network_dashboard_widgets', array() );
	} elseif ( is_user_admin() ) {

		/**
		 * Fires after core widgets for the User Admin dashboard have been registered.
		 *
		 * @since 3.1.0
		 */
		do_action( 'wp_user_dashboard_setup' );

		/**
		 * Filters the list of widgets to load for the User Admin dashboard.
		 *
		 * @since 3.1.0
		 *
		 * @param string[] $dashboard_widgets An array of dashboard widget IDs.
		 */
		$dashboard_widgets = apply_filters( 'wp_user_dashboard_widgets', array() );
	} else {

		/**
		 * Fires after core widgets for the admin dashboard have been registered.
		 *
		 * @since 2.5.0
		 */
		do_action( 'wp_dashboard_setup' );

		/**
		 * Filters the list of widgets to load for the admin dashboard.
		 *
		 * @since 2.5.0
		 *
		 * @param string[] $dashboard_widgets An array of dashboard widget IDs.
		 */
		$dashboard_widgets = apply_filters( 'wp_dashboard_widgets', array() );
	}

	foreach ( $dashboard_widgets as $widget_id ) {
		$name = empty( $wp_registered_widgets[ $widget_id ]['all_link'] ) ? $wp_registered_widgets[ $widget_id ]['name'] : $wp_registered_widgets[ $widget_id ]['name'] . " " . __( 'View all' ) . '';
		wp_add_dashboard_widget( $widget_id, $name, $wp_registered_widgets[ $widget_id ]['callback'], $wp_registered_widget_controls[ $widget_id ]['callback'] );
	}

	if ( 'POST' === $_SERVER['REQUEST_METHOD'] && isset( $_POST['widget_id'] ) ) {
		check_admin_referer( 'edit-dashboard-widget_' . $_POST['widget_id'], 'dashboard-widget-nonce' );
		ob_start(); // Hack - but the same hack wp-admin/widgets.php uses.
		wp_dashboard_trigger_widget_control( $_POST['widget_id'] );
		ob_end_clean();
		wp_redirect( remove_query_arg( 'edit' ) );
		exit;
	}

	/** This action is documented in wp-admin/includes/meta-boxes.php */
	do_action( 'do_meta_boxes', $screen->id, 'normal', '' );

	/** This action is documented in wp-admin/includes/meta-boxes.php */
	do_action( 'do_meta_boxes', $screen->id, 'side', '' );
}