/*
 * Copyright 2015 Anton Tananaev (anton.tananaev@gmail.com)
 *
 * 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.traccar.api;

import org.traccar.Context;
import org.traccar.api.resource.SessionResource;
import org.traccar.model.User;

import java.lang.reflect.Method;
import java.nio.charset.Charset;
import java.sql.SQLException;
import javax.annotation.security.PermitAll;
import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.container.ContainerRequestContext;
import javax.ws.rs.container.ContainerRequestFilter;
import javax.ws.rs.container.ResourceInfo;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.SecurityContext;
import javax.xml.bind.DatatypeConverter;

public class SecurityRequestFilter implements ContainerRequestFilter {

    public static final String AUTHORIZATION_HEADER = "Authorization";
    public static final String WWW_AUTHENTICATE = "WWW-Authenticate";
    public static final String BASIC_REALM = "Basic realm=\"api\"";

    public static String[] decodeBasicAuth(String auth) {
        auth = auth.replaceFirst("[B|b]asic ", "");
        byte[] decodedBytes = DatatypeConverter.parseBase64Binary(auth);
        if (decodedBytes != null && decodedBytes.length > 0) {
            return new String(decodedBytes, Charset.defaultCharset()).split(":", 2);
        }
        return null;
    }

    @javax.ws.rs.core.Context
    private HttpServletRequest req;

    @javax.ws.rs.core.Context
    private ResourceInfo resourceInfo;

    @Override
    public void filter(ContainerRequestContext requestContext) {
        Method method = resourceInfo.getResourceMethod();
        if (method.isAnnotationPresent(PermitAll.class)) {
            return;
        }

        SecurityContext securityContext = null;

        String authHeader = requestContext.getHeaderString(AUTHORIZATION_HEADER);
        if (authHeader != null) {

            try {
                String[] auth = decodeBasicAuth(authHeader);
                User user = Context.getDataManager().login(auth[0], auth[1]);
                if (user != null) {
                    securityContext = new UserSecurityContext(new UserPrincipal(user.getId()));
                }
            } catch (SQLException e) {
                throw new WebApplicationException(e);
            }

        } else if (req.getSession() != null) {

            Long userId = (Long) req.getSession().getAttribute(SessionResource.USER_ID_KEY);
            if (userId != null) {
                securityContext = new UserSecurityContext(new UserPrincipal(userId));
            }

        }

        if (securityContext != null) {
            requestContext.setSecurityContext(securityContext);
        } else {
            throw new WebApplicationException(
                    Response.status(Response.Status.UNAUTHORIZED).header(WWW_AUTHENTICATE, BASIC_REALM).build());
        }
    }

}