/*
 * The contents of this file are subject to the terms of the Common Development and
 * Distribution License (the License). You may not use this file except in compliance with the
 * License.
 *
 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
 * specific language governing permission and limitations under the License.
 *
 * When distributing Covered Software, include this CDDL Header Notice in each file and include
 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
 * Header, with the fields enclosed by brackets [] replaced by your own identifying
 * information: "Portions copyright [year] [name of copyright owner]".
 *
 * Copyright 2015 ForgeRock AS.
 */

package org.forgerock.openam.services.baseurl;

import javax.servlet.http.HttpServletRequest;

import com.sun.identity.shared.debug.Debug;
import org.forgerock.json.resource.http.HttpContext;
import org.forgerock.openam.utils.OpenAMSettings;

/**
 * A {@link BaseURLProvider} that uses the X-Forwarded-* headers to deduce the base URL.
 */
public class XForwardedHeadersBaseURLProvider extends BaseURLProvider {
    private static final String SCHEME_HEADER = "X-Forwarded-Proto";
    private static final String HOST_HEADER = "X-Forwarded-Host";

    private final Debug debug = Debug.getInstance("amBaseURL");

    @Override
    protected String getBaseURL(HttpServletRequest request) {
        return getBaseURL(request.getHeader(SCHEME_HEADER), request.getHeader(HOST_HEADER));
    }

    @Override
    protected String getBaseURL(HttpContext context) {
        return getBaseURL(getHeaderValueFromList(context, SCHEME_HEADER), getHeaderValueFromList(context, HOST_HEADER));
    }

    private String getHeaderValueFromList(HttpContext context, String headerName) {
        if (context.getHeader(headerName).size() >= 1) {
            if (debug.warningEnabled() && context.getHeader(headerName).size() > 1) {
                debug.warning("Http header '{}' contains more that one element: '{}'. We will use the first one = '{}'",
                        headerName, context.getHeader(headerName), context.getHeader(headerName).get(0));
            }
            return context.getHeader(headerName).get(0);
        }
        return "";
    }

    private String getBaseURL(String schemeHeader, String hostHeader) {
        return schemeHeader + "://" + hostHeader;
    }

    @Override
    void init(OpenAMSettings settings, String realm) {
        //no-op
    }
}