/**
 * 
 * APDPlat - Application Product Development Platform
 * Copyright (c) 2013, 杨尚川, [email protected]
 * 
 * This program 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 3 of the License, or
 * (at your option) any later version.
 * 
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 * 
 */

package org.apdplat.qa.api;

import edu.stanford.nlp.util.StringUtils;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apdplat.qa.SharedQuestionAnsweringSystem;
import org.apdplat.qa.model.CandidateAnswer;
import org.apdplat.qa.model.Question;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Json over HTTP 接口
 * @author 杨尚川
 */
@WebServlet(name = "ask", urlPatterns = {"/api/ask"})
public class AskServlet extends HttpServlet {
    private static final Logger LOG = LoggerFactory.getLogger(AskServlet.class);

    /**
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code>
     * methods.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("application/json;charset=UTF-8"); 
        response.setCharacterEncoding("UTF-8"); 
        request.setCharacterEncoding("UTF-8");
        
        String questionStr = request.getParameter("q");
        String n = request.getParameter("n");
        int topN = -1;
        if(n != null && StringUtils.isNumeric(n)){
            topN = Integer.parseInt(n);
        }
        Question question = null;
        List<CandidateAnswer> candidateAnswers = null;
        if (questionStr != null && questionStr.trim().length() > 3) {
            question = SharedQuestionAnsweringSystem.getInstance().answerQuestion(questionStr);
            if (question != null) {
                candidateAnswers = question.getAllCandidateAnswer();
            }
        }
        LOG.info("问题："+questionStr); 
        try (PrintWriter out = response.getWriter()) {
            String json = JsonGenerator.generate(candidateAnswers, topN);
            out.println(json);
            LOG.info("答案："+json);
        }
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}