/*
 * Copyright 2016 Google LLC
 *
 * 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 com.example.appengine;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

abstract class AbstractGuestbookServlet extends HttpServlet {

  private final AbstractGuestbook guestbook;

  public AbstractGuestbookServlet(AbstractGuestbook guestbook) {
    this.guestbook = guestbook;
  }

  private void renderGuestbook(HttpServletRequest req, HttpServletResponse resp)
      throws IOException, ServletException {
    resp.setContentType("text/html");
    resp.setCharacterEncoding("UTF-8");
    req.setAttribute("greetings", guestbook.listGreetings());
    req.getRequestDispatcher("/guestbook.jsp").forward(req, resp);
  }

  @Override
  public void doGet(HttpServletRequest req, HttpServletResponse resp)
      throws IOException, ServletException {
    renderGuestbook(req, resp);
  }

  @Override
  public void doPost(HttpServletRequest req, HttpServletResponse resp)
      throws IOException, ServletException {
    String content = req.getParameter("content");
    if (content == null || content.isEmpty()) {
      resp.sendError(HttpServletResponse.SC_BAD_REQUEST, "missing content");
      return;
    }
    guestbook.appendGreeting(content);
    renderGuestbook(req, resp);
  }
}
