/*
 * 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.server.auth.keycloak;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.redhat.thermostat.gateway.common.core.auth.RealmAuthorizer;
import com.redhat.thermostat.gateway.common.core.auth.keycloak.KeycloakRealmAuthorizer.CannotReduceRealmsException;
import com.redhat.thermostat.gateway.common.core.auth.keycloak.KeycloakRealmAuthorizerServletAdapter;

public class KeycloakRequestFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // Do nothing
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        try {
            HttpServletRequest httpServletRequest = (HttpServletRequest) request;
            KeycloakRealmAuthorizerServletAdapter adapter = new KeycloakRealmAuthorizerServletAdapter();
            RealmAuthorizer realmAuthorizer = adapter.createAuthorizer(httpServletRequest);

            httpServletRequest.setAttribute(RealmAuthorizer.class.getName(), realmAuthorizer);

            chain.doFilter(request, response);
        } catch (CannotReduceRealmsException e) {
            HttpServletResponse httpServletResponse = (HttpServletResponse) response;
            httpServletResponse.sendError(HttpServletResponse.SC_BAD_REQUEST, "Invalid realms header");
        }
    }

    @Override
    public void destroy() {
        // Do nothing
    }
}