/*
 * Copyright 2012-2017 Red Hat, Inc.
 *
 * This file is part of Thermostat.
 *
 * Thermostat is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2, or (at your
 * option) any later version.
 *
 * Thermostat is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Thermostat; see the file COPYING.  If not see
 * <http://www.gnu.org/licenses/>.
 *
 * Linking this code with other modules is making a combined work
 * based on this code.  Thus, the terms and conditions of the GNU
 * General Public License cover the whole combination.
 *
 * As a special exception, the copyright holders of this code give
 * you permission to link this code with independent modules to
 * produce an executable, regardless of the license terms of these
 * independent modules, and to copy and distribute the resulting
 * executable under terms of your choice, provided that you also
 * meet, for each linked independent module, the terms and conditions
 * of the license of that module.  An independent module is a module
 * which is not derived from or based on this code.  If you modify
 * this code, you may extend this exception to your version of the
 * library, but you are not obligated to do so.  If you do not wish
 * to do so, delete this exception statement from your version.
 */

package com.redhat.thermostat.gateway.common.core.auth;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import com.redhat.thermostat.gateway.common.core.auth.keycloak.Action;

public abstract class RealmAuthorizer {

    /**
     * A RealmAuthorizer that will deny any request.
     */
    public static final RealmAuthorizer DENY_ALL_AUTHORIZER = new RealmAuthorizer(Collections.<Role>emptySet()) {};

    protected final Set<Role> clientRoles;

    protected RealmAuthorizer(Set<Role> clientRoles) {
        this.clientRoles = clientRoles;
    }

    public boolean readable() {
        return checkActionExists(Action.READ);
    }

    public boolean writable() {
        return checkActionExists(Action.WRITE);
    }

    public boolean updatable() {
        return checkActionExists(Action.UPDATE);
    }

    public boolean deletable() {
        return checkActionExists(Action.DELETE);
    }

    public boolean checkActionExists(String action) {
        for (Role role : clientRoles) {
            if (role.containsAction(action)) {
                return  true;
            }
        }
        return false;
    }

    public Set<String> getReadableRealms() {
        return getRealmsWithAction(Action.READ);
    }

    public Set<String> getWritableRealms() {
        return getRealmsWithAction(Action.WRITE);
    }

    public Set<String> getUpdatableRealms() {
        return getRealmsWithAction(Action.UPDATE);
    }

    public Set<String> getDeletableRealms() {
        return getRealmsWithAction(Action.DELETE);
    }

    public Set<String> getRealmsWithAction(String action) {
        Set<String> realms = new HashSet<>();
        for (Role role : clientRoles) {
            if (role.containsAction(action)) {
                realms.add(role.getRealm());
            }
        }
        return Collections.unmodifiableSet(realms);
    }

}