/*-
 * ============LICENSE_START=======================================================
 * ONAP
 * ================================================================================
 * Copyright (C) 2018 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * 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.
 * ============LICENSE_END=========================================================
 */

package org.onap.policy.common.endpoints.http.server;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public abstract class AuthorizationFilter implements Filter {

    private static Logger logger = LoggerFactory.getLogger(AuthorizationFilter.class);

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
        throws IOException, ServletException {

        if (!(servletRequest instanceof HttpServletRequest)) {
            throw new ServletException("Not an HttpServletRequest instance");
        }

        if (!(servletResponse instanceof HttpServletResponse)) {
            throw new ServletException("Not an HttpServletResponse instance");
        }

        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        String role = getRole(request);
        boolean authorized = request.isUserInRole(role);

        logger.info("user {} in role {} is {}authorized to {}",
            request.getUserPrincipal(), role, ((authorized) ? "" : "NOT "), request.getMethod());

        if (!authorized) {
            response.setStatus(HttpServletResponse.SC_FORBIDDEN);
        } else {
            filterChain.doFilter(servletRequest, servletResponse);
        }
    }

    protected abstract String getRole(HttpServletRequest request);
}