/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.wicket.authroles.authorization.strategies.role.metadata;

import java.util.HashMap;
import java.util.Map;

import org.apache.wicket.Component;
import org.apache.wicket.authroles.authorization.strategies.role.Roles;
import org.apache.wicket.request.component.IRequestableComponent;
import org.apache.wicket.util.io.IClusterable;


/**
 * An internal data structure that maps a given component class to a set of role strings.
 * Permissions can be granted to instantiate a given component class via authorize(Class, Roles
 * roles) and denied via unauthorize(Class, Roles roles). All authorization can be removed for a
 * given class with authorizeAll(Class).
 * 
 * @author Eelco Hillenius
 * @author Jonathan Locke
 */
public class InstantiationPermissions implements IClusterable
{
        private static final long serialVersionUID = 1L;

        /** Holds roles objects for component classes */
        private final Map<Class<? extends Component>, Roles> rolesForComponentClass = new HashMap<>();

        /**
         * Gives the given role permission to instantiate the given class.
         * 
         * @param <T>
         * @param componentClass
         *            The component class
         * @param rolesToAdd
         *            The roles to add
         */
        public final <T extends Component> void authorize(final Class<T> componentClass,
                final Roles rolesToAdd)
        {
                if (componentClass == null)
                {
                        throw new IllegalArgumentException("Argument componentClass cannot be null");
                }

                if (rolesToAdd == null)
                {
                        throw new IllegalArgumentException("Argument rolesToadd cannot be null");
                }

                Roles roles = rolesForComponentClass.get(componentClass);
                if (roles == null)
                {
                        roles = new Roles();
                        rolesForComponentClass.put(componentClass, roles);
                }
                roles.addAll(rolesToAdd);
        }

        /**
         * Gives all roles permission to instantiate the given class. Note that this is only relevant if
         * a role was previously authorized for that class. If no roles where previously authorized the
         * effect of the unauthorize call is that no roles at all will be authorized for that class.
         * 
         * @param <T>
         * @param componentClass
         *            The component class
         */
        public final <T extends Component> void authorizeAll(final Class<T> componentClass)
        {
                if (componentClass == null)
                {
                        throw new IllegalArgumentException("Argument componentClass cannot be null");
                }

                rolesForComponentClass.remove(componentClass);
        }

        /**
         * Gets the roles that have a binding with the given component class.
         * 
         * @param <T>
         * 
         * @param componentClass
         *            the component class
         * @return the roles that have a binding with the given component class, or null if no entries
         *         are found
         */
        public <T extends IRequestableComponent> Roles authorizedRoles(final Class<T> componentClass)
        {
                if (componentClass == null)
                {
                        throw new IllegalArgumentException("Argument componentClass cannot be null");
                }

                return rolesForComponentClass.get(componentClass);
        }

        /**
         * Removes permission for the given role to instantiate the given class.
         * 
         * @param <T>
         * 
         * @param componentClass
         *            The class
         * @param rolesToRemove
         *            The role to deny
         */
        public final <T extends Component> void unauthorize(final Class<T> componentClass,
                final Roles rolesToRemove)
        {
                if (componentClass == null)
                {
                        throw new IllegalArgumentException("Argument componentClass cannot be null");
                }

                if (rolesToRemove == null)
                {
                        throw new IllegalArgumentException("Argument rolesToRemove cannot be null");
                }

                Roles roles = rolesForComponentClass.get(componentClass);
                if (roles != null)
                {
                        roles.removeAll(rolesToRemove);
                }
                else
                {
                        roles = new Roles();
                        rolesForComponentClass.put(componentClass, roles);
                }

                // If we removed the last authorized role, we authorize the empty role
                // so that removing authorization can't suddenly open something up to
                // everyone.
                if (roles.size() == 0)
                {
                        roles.add(MetaDataRoleAuthorizationStrategy.NO_ROLE);
                }
        }

        /**
         * @return gets map with roles objects for a component classes
         */
        protected final Map<Class<? extends Component>, Roles> getRolesForComponentClass()
        {
                return rolesForComponentClass;
        }
}