<?php
/**
 * Capability mapping.
 *
 * @package TurtleReport
 */

namespace TurtleReport\Access;

defined( 'ABSPATH' ) || exit;

/**
 * Maps the plugin's meta capabilities onto WordPress permissions.
 *
 * Use these anywhere access matters:
 *
 *     current_user_can( Capabilities::MANAGE );
 *     current_user_can( Capabilities::VIEW_REPORTS );
 *     current_user_can( Capabilities::VIEW_SITE, $site_id );
 *
 * They are resolved through map_meta_cap, so role-editor plugins and
 * other code can inspect or extend them in the normal way.
 */
final class Capabilities {

	/** Manage connections, sites and access. */
	const MANAGE = 'turtlereport_manage';

	/** Open the Reports screen (true when the user can see at least one site). */
	const VIEW_REPORTS = 'turtlereport_view_reports';

	/** View one site's report. Requires the site ID as an argument. */
	const VIEW_SITE = 'turtlereport_view_site';

	/**
	 * Access rules.
	 *
	 * @var AccessPolicy
	 */
	private $policy;

	/**
	 * Constructor.
	 *
	 * @param AccessPolicy $policy Access rules.
	 */
	public function __construct( AccessPolicy $policy ) {
		$this->policy = $policy;
	}

	/**
	 * Hooks into WordPress.
	 *
	 * @return void
	 */
	public function register() {
		add_filter( 'map_meta_cap', array( $this, 'map' ), 10, 4 );
	}

	/**
	 * The primitive capability that lets a user manage the plugin.
	 *
	 * Defaults to manage_options, which a Multisite Super Admin always has.
	 *
	 * @return string
	 */
	public static function manage_primitive() {
		/**
		 * Filters the capability required to manage TurtleReport.
		 *
		 * Only administrators should hold it: managers can read every site's
		 * report and add Google credentials.
		 *
		 * @param string $capability Default 'manage_options'.
		 */
		return (string) apply_filters( 'turtlereport_manage_capability', 'manage_options' );
	}

	/**
	 * Resolves the plugin's meta capabilities.
	 *
	 * @param string[] $caps    Primitive capabilities WordPress will check.
	 * @param string   $cap     Capability being checked.
	 * @param int      $user_id User ID.
	 * @param array    $args    Extra arguments, e.g. the site ID.
	 * @return string[]
	 */
	public function map( $caps, $cap, $user_id, $args ) {
		switch ( $cap ) {
			case self::MANAGE:
				return array( self::manage_primitive() );

			case self::VIEW_REPORTS:
				return $this->policy->has_any_access( (int) $user_id ) ? array( 'read' ) : array( 'do_not_allow' );

			case self::VIEW_SITE:
				$site_id = isset( $args[0] ) ? (string) $args[0] : '';
				return '' !== $site_id && $this->policy->can_view( (int) $user_id, $site_id ) ? array( 'read' ) : array( 'do_not_allow' );
		}
		return $caps;
	}
}