/*
 * 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.http;

import java.io.IOException;
import java.io.Writer;
import java.security.AccessControlException;
import javax.json.Json;
import javax.json.JsonObjectBuilder;
import javax.json.JsonStructure;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public abstract class BaseServlet extends HttpServlet {
    
    public static final String USER_ID = "userId";
    
    @Override
    protected final void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String command = req.getPathInfo();
        try {
            if (command == null || !handle(command, req, resp)) {
                resp.sendError(HttpServletResponse.SC_BAD_REQUEST);
            }
        } catch (Exception error) {
            sendResponse(resp.getWriter(), error);
        }
    }
    
    protected abstract boolean handle(String command, HttpServletRequest req, HttpServletResponse resp) throws Exception;
    
    public long getUserId(HttpSession session) {
        Long userId = (Long) session.getAttribute(USER_ID);
        if (userId == null) {
            throw new AccessControlException("User is not logged in");
        }
        return userId;
    }
    
    public void sendResponse(Writer writer) throws IOException {
        JsonObjectBuilder result = Json.createObjectBuilder();
        result.add("success", true);
        writer.write(result.build().toString());
    }
    
    public void sendResponse(Writer writer, JsonStructure json) throws IOException {
        JsonObjectBuilder result = Json.createObjectBuilder();
        result.add("success", true);
        result.add("data", json);
        writer.write(result.build().toString());
    }
    
    public void sendResponse(Writer writer, Exception error) throws IOException {
        JsonObjectBuilder result = Json.createObjectBuilder();
        result.add("success", false);
        result.add("error", error.getMessage());
        writer.write(result.build().toString());
    }
    
}