/*
 * Copyright 2005-2008 Les Hazlewood
 *
 * 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.jsecurity.authz;

import org.jsecurity.authz.permission.PermissionResolver;
import org.jsecurity.authz.permission.PermissionResolverAware;
import org.jsecurity.realm.Realm;
import org.jsecurity.util.Initializable;

import java.util.Collection;
import java.util.List;

/**
 * A <tt>ModularRealmAuthorizer</tt> is an <tt>Authorizer</tt> implementation that consults one or more configured
 * {@link Realm Realm}s during an authorization operation.
 *
 * @author Les Hazlewood
 * @since 0.2
 */
public class ModularRealmAuthorizer implements Authorizer, Initializable, PermissionResolverAware {

    protected Collection<Realm> realms = null;
    protected PermissionResolver permissionResolver = null;

    public ModularRealmAuthorizer() {
    }

    public ModularRealmAuthorizer(List<Realm> realms) {
        setRealms(realms);
        init();
    }

    public Collection<Realm> getRealms() {
        return this.realms;
    }

    public void setRealms(Collection<Realm> realms) {
        this.realms = realms;
    }

    public PermissionResolver getPermissionResolver() {
        return permissionResolver;
    }

    public void setPermissionResolver(PermissionResolver permissionResolver) {
        this.permissionResolver = permissionResolver;
    }

    public void init() {
        Collection<Realm> realms = getRealms();
        if (realms == null || realms.isEmpty()) {
            String msg = "One or more realms must be configured.";
            throw new IllegalStateException(msg);
        }
        PermissionResolver resolver = getPermissionResolver();
        if (resolver != null) {
            for (Realm realm : realms) {
                if (realm instanceof PermissionResolverAware) {
                    ((PermissionResolverAware) realm).setPermissionResolver(resolver);
                }
            }
        }
    }


    public boolean isPermitted(Object subjectIdentifier, String permission) {
        for (Realm realm : getRealms()) {
            if (realm.isPermitted(subjectIdentifier, permission)) {
                return true;
            }
        }
        return false;
    }

    public boolean isPermitted(Object subjectIdentifier, Permission permission) {
        for (Realm realm : getRealms()) {
            if (realm.isPermitted(subjectIdentifier, permission)) {
                return true;
            }
        }
        return false;
    }

    public boolean[] isPermitted(Object subjectIdentifier, String... permissions) {
        if (permissions != null && permissions.length > 0) {
            boolean[] isPermitted = new boolean[permissions.length];
            for (int i = 0; i < permissions.length; i++) {
                isPermitted[i] = isPermitted(subjectIdentifier, permissions[i]);
            }
            return isPermitted;
        }
        return new boolean[0];
    }

    public boolean[] isPermitted(Object subjectIdentifier, List<Permission> permissions) {
        if (permissions != null && !permissions.isEmpty()) {
            boolean[] isPermitted = new boolean[permissions.size()];
            int i = 0;
            for (Permission p : permissions) {
                isPermitted[i++] = isPermitted(subjectIdentifier, p);
            }
            return isPermitted;
        }

        return new boolean[0];
    }

    public boolean isPermittedAll(Object subjectIdentifier, String... permissions) {
        if (permissions != null && permissions.length > 0) {
            for (String perm : permissions) {
                if (!isPermitted(subjectIdentifier, perm)) {
                    return false;
                }
            }
        }
        return true;
    }

    public boolean isPermittedAll(Object subjectIdentifier, Collection<Permission> permissions) {
        if (permissions != null && !permissions.isEmpty()) {
            for (Permission permission : permissions) {
                if (!isPermitted(subjectIdentifier, permission)) {
                    return false;
                }
            }
        }
        return true;
    }

    public void checkPermission(Object subjectIdentifier, String permission) throws AuthorizationException {
        if (!isPermitted(subjectIdentifier, permission)) {
            throw new UnauthorizedException("Subject does not have permission [" + permission + "]");
        }
    }

    public void checkPermission(Object subjectIdentifier, Permission permission) throws AuthorizationException {
        if (!isPermitted(subjectIdentifier, permission)) {
            throw new UnauthorizedException("Subject does not have permission [" + permission + "]");
        }
    }

    public void checkPermissions(Object subjectIdentifier, String... permissions) throws AuthorizationException {
        if (permissions != null && permissions.length > 0) {
            for (String perm : permissions) {
                checkPermission(subjectIdentifier, perm);
            }
        }
    }

    public void checkPermissions(Object subjectIdentifier, Collection<Permission> permissions) throws AuthorizationException {
        if (permissions != null) {
            for (Permission permission : permissions) {
                checkPermission(subjectIdentifier, permission);
            }
        }
    }

    public boolean hasRole(Object subjectIdentifier, String roleIdentifier) {
        for (Realm realm : getRealms()) {
            if (realm.hasRole(subjectIdentifier, roleIdentifier)) {
                return true;
            }
        }
        return false;
    }

    public boolean[] hasRoles(Object subjectIdentifier, List<String> roleIdentifiers) {
        if (roleIdentifiers != null && !roleIdentifiers.isEmpty()) {
            boolean[] isPermitted = new boolean[roleIdentifiers.size()];
            int i = 0;
            for (String roleId : roleIdentifiers) {
                isPermitted[i++] = hasRole(subjectIdentifier, roleId);
            }
            return isPermitted;
        }

        return new boolean[0];
    }


    public boolean hasAllRoles(Object subjectIdentifier, Collection<String> roleIdentifiers) {
        for (String roleIdentifier : roleIdentifiers) {
            if (!hasRole(subjectIdentifier, roleIdentifier)) {
                return false;
            }
        }
        return true;
    }

    public void checkRole(Object subjectIdentifier, String role) throws AuthorizationException {
        if (!hasRole(subjectIdentifier, role)) {
            throw new UnauthorizedException("Subject does not have role [" + role + "]");
        }
    }

    public void checkRoles(Object subjectIdentifier, Collection<String> roles) throws AuthorizationException {
        if (roles != null) {
            for (String role : roles) {
                checkRole(subjectIdentifier, role);
            }
        }
    }

}