<?php

// (c) Copyright by authors of the Tiki Wiki CMS Groupware Project
//
// All Rights Reserved. See copyright.txt for details and a complete list of authors.
// Licensed under the GNU LESSER GENERAL PUBLIC LICENSE. See license.txt for details.
// $Id$

class Perms_Applier
{
    private $objects = [];
    private $restriction = false;

    public function addObject(Perms_Reflection_Container $object)
    {
        $this->objects[] = $object;
    }

    public function apply(Perms_Reflection_PermissionSet $set)
    {
        foreach ($this->objects as $object) {
            $this->applyOnObject($object, $set);
        }
        $cachelib = TikiLib::lib('cache');
        $cachelib->empty_type_cache('fgals_perms');
    }

    public function restrictPermissions(array $permissions)
    {
        $this->restriction = array_fill_keys($permissions, true);
    }

    private function applyOnObject($object, $set)
    {
        $current = $object->getDirectPermissions();
        $parent = $object->getParentPermissions();

        if ($parent) {
            $comparator = new Perms_Reflection_PermissionComparator($set, $parent);

            if ($comparator->equal() && $this->isPossible($current, $set)) {
                $null = new Perms_Reflection_PermissionSet();

                $this->realApply($object, $current, $null);
                return;
            }
        }

        $this->realApply($object, $current, $set);
    }

    private function isPossible($current, $target)
    {
        if ($this->restriction === false) {
            return true;
        }

        $comparator = new Perms_Reflection_PermissionComparator($current, $target);
        $changes = array_merge($comparator->getAdditions(), $comparator->getRemovals());

        foreach ($changes as $addition) {
            list($group, $permission) = $addition;
            if (! isset($this->restriction[$permission])) {
                return false;
            }
        }

        return true;
    }

    private function realApply($object, $current, $target)
    {
        $comparator = new Perms_Reflection_PermissionComparator($current, $target);

        foreach ($comparator->getAdditions() as $addition) {
            list($group, $permission) = $addition;
            $this->attempt($object, 'add', $group, $permission);
        }

        foreach ($comparator->getRemovals() as $removal) {
            list($group, $permission) = $removal;
            $this->attempt($object, 'remove', $group, $permission);
        }
    }

    private function attempt($object, $method, $group, $permission)
    {
        if ($this->restriction === false || isset($this->restriction[$permission])) {
            call_user_func([ $object, $method ], $group, $permission);
        }
    }
}