/*
 * Copyright 2016 Red Hat, Inc. and/or its affiliates
 * and other contributors as indicated by the @author tags.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.keycloak.models.utils;

import org.keycloak.models.GroupModel;
import org.keycloak.models.RoleModel;

import java.util.ArrayDeque;
import java.util.Deque;
import java.util.HashSet;
import java.util.Set;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;

/**
 * @author <a href="mailto:sthorger@redhat.com">Stian Thorgersen</a>
 */
public class RoleUtils {

    /**
     *
     * @param groups
     * @param targetGroup
     * @return true if targetGroup is in groups (directly or indirectly via parent child relationship)
     */
    public static boolean isMember(Set<GroupModel> groups, GroupModel targetGroup) {
        if (groups.contains(targetGroup)) return true;

        for (GroupModel mapping : groups) {
            GroupModel child = mapping;
            while(child.getParent() != null) {
                if (child.getParent().equals(targetGroup)) return true;
                child = child.getParent();
            }
        }
        return false;
    }

    /**
     * @param roles
     * @param targetRole
     * @return true if targetRole is in roles (directly or indirectly via composite role)
     */
    public static boolean hasRole(Set<RoleModel> roles, RoleModel targetRole) {
        if (roles.contains(targetRole)) return true;

        for (RoleModel mapping : roles) {
            if (mapping.hasRole(targetRole)) return true;
        }
        return false;
    }

    /**
     * Checks whether the {@code targetRole} is contained in the given group or its parents
     * (if requested)
     * @param group Group to check role for
     * @param targetRole
     * @param checkParentGroup When {@code true}, also parent group is recursively checked for role
     * @return true if targetRole is in roles (directly or indirectly via composite role)
     */
    public static boolean hasRoleFromGroup(GroupModel group, RoleModel targetRole, boolean checkParentGroup) {
        if (group.hasRole(targetRole))
            return true;

        if (checkParentGroup) {
            GroupModel parent = group.getParent();
            return parent != null && hasRoleFromGroup(parent, targetRole, true);
        }

        return false;
    }

    /**
     * Checks whether the {@code targetRole} is contained in any of the {@code groups} or their parents
     * (if requested)
     * @param groups
     * @param targetRole
     * @param checkParentGroup When {@code true}, also parent group is recursively checked for role
     * @return true if targetRole is in roles (directly or indirectly via composite role)
     */
    public static boolean hasRoleFromGroup(Iterable<GroupModel> groups, RoleModel targetRole, boolean checkParentGroup) {
        if (groups == null) {
            return false;
        }

        return StreamSupport.stream(groups.spliterator(), false)
                .anyMatch(group -> hasRoleFromGroup(group, targetRole, checkParentGroup));
    }

    /**
     * Recursively expands composite roles into their composite.
     * @param role
     * @return Stream of containing all of the composite roles and their components.
     */
    public static Stream<RoleModel> expandCompositeRolesStream(RoleModel role) {
        Stream.Builder<RoleModel> sb = Stream.builder();
        Set<RoleModel> roles = new HashSet<>();

        Deque<RoleModel> stack = new ArrayDeque<>();
        stack.add(role);

        while (! stack.isEmpty()) {
            RoleModel current = stack.pop();
            sb.add(current);

            if (current.isComposite()) {
                current.getComposites().stream()
                  .filter(r -> ! roles.contains(r))
                  .forEach(r -> {
                    roles.add(r);
                    stack.add(r);
                  });
            }
        }

        return sb.build();
    }

}