<?php
/**
 * Central switch: who is currently seeing the reduced client view?
 *
 * @package QuietAdmin
 */

namespace QuietAdmin;

defined( 'ABSPATH' ) || exit;

/**
 * Class ClientMode.
 *
 * The client view applies to:
 *  - users with the `quietadmin_client` role (always), and
 *  - users with `qa_manage_settings` in Ghost Mode (preview, can be toggled at any time).
 *
 * All other modules query only this class - so Ghost Mode behaves
 * exactly like a real client login.
 *
 * @since 0.1.0
 */
class ClientMode {

	/**
	 * User meta key for Ghost Mode.
	 *
	 * @since 0.1.0
	 * @var string
	 */
	const GHOST_META = 'quietadmin_ghost_mode';

	/**
	 * Computed state per request.
	 *
	 * @since 0.1.0
	 * @var bool|null
	 */
	protected static $state = null;

	/**
	 * Is the reduced client view active for the current user?
	 *
	 * @since 0.1.0
	 *
	 * @return bool
	 */
	public static function is_active() {
		if ( null !== self::$state ) {
			return self::$state;
		}

		$state = false;

		if ( ! is_user_logged_in() ) {
			self::$state = false;
			return false;
		}

		if ( self::is_impersonating() ) {
			// During an impersonation, the target user's view always applies.
			$state = Roles::is_client();
		} elseif ( Roles::is_client() ) {
			$state = true;
		} elseif ( self::is_ghost_mode() && current_user_can( 'qa_manage_settings' ) ) {
			$state = true;
		}

		/**
		 * Turns the client view on or off.
		 *
		 * @since 0.1.0
		 *
		 * @param bool $state True if the reduced view should apply.
		 */
		self::$state = (bool) apply_filters( 'quietadmin_is_client_mode', $state );

		return self::$state;
	}

	/**
	 * Resets the cache (e.g. after a mode switch within the same request).
	 *
	 * @since 0.1.0
	 *
	 * @return void
	 */
	public static function flush() {
		self::$state = null;
	}

	/**
	 * Has the current user enabled Ghost Mode?
	 *
	 * @since 0.1.0
	 *
	 * @param int|null $user_id User ID, defaults to the current user.
	 * @return bool
	 */
	public static function is_ghost_mode( $user_id = null ) {
		$user_id = self::resolve_user_id( $user_id );

		if ( ! $user_id ) {
			return false;
		}

		return (bool) get_user_meta( $user_id, self::GHOST_META, true );
	}

	/**
	 * Toggles Ghost Mode.
	 *
	 * @since 0.1.0
	 *
	 * @param int|null $user_id User ID, defaults to the current user.
	 * @return bool New state.
	 */
	public static function toggle_ghost_mode( $user_id = null ) {
		$user_id = self::resolve_user_id( $user_id );

		if ( ! $user_id ) {
			return false;
		}

		$active = self::is_ghost_mode( $user_id );

		if ( $active ) {
			delete_user_meta( $user_id, self::GHOST_META );
		} else {
			update_user_meta( $user_id, self::GHOST_META, 1 );
		}

		self::flush();

		return ! $active;
	}

	/**
	 * Is an impersonation currently running (support login by an add-on)?
	 *
	 * The plugin itself does not start any impersonation. Extensions report
	 * it via the `quietadmin_impersonation_origin_id` filter.
	 *
	 * @since 0.1.0
	 *
	 * @return bool
	 */
	public static function is_impersonating() {
		return 0 < self::impersonation_origin_id();
	}

	/**
	 * ID of the admin whose session is currently being impersonated.
	 *
	 * @since 0.1.0
	 *
	 * @return int 0 if no impersonation is running.
	 */
	public static function impersonation_origin_id() {
		if ( ! is_user_logged_in() ) {
			return 0;
		}

		/**
		 * ID of the original admin account if an add-on is currently working on behalf of a client.
		 *
		 * @since 0.9.0
		 *
		 * @param int $origin_id Default 0 (no impersonation).
		 */
		return absint( apply_filters( 'quietadmin_impersonation_origin_id', 0 ) );
	}

	/**
	 * Returns the admin account on whose behalf work is currently being done.
	 *
	 * @since 0.1.0
	 *
	 * @return \WP_User|null
	 */
	public static function impersonation_origin() {
		$origin_id = self::impersonation_origin_id();

		if ( ! $origin_id ) {
			return null;
		}

		$user = get_userdata( $origin_id );

		return $user instanceof \WP_User ? $user : null;
	}

	/**
	 * Checks whether the current user may see the agency view.
	 *
	 * @since 0.1.0
	 *
	 * @return bool
	 */
	public static function is_agency() {
		return is_user_logged_in() && current_user_can( 'qa_manage_settings' );
	}

	/**
	 * Resolve the user ID.
	 *
	 * @since 0.1.0
	 *
	 * @param int|null $user_id User ID or null.
	 * @return int
	 */
	private static function resolve_user_id( $user_id ) {
		if ( null === $user_id ) {
			$user = wp_get_current_user();
			return $user instanceof \WP_User ? (int) $user->ID : 0;
		}

		return absint( $user_id );
	}
}