// Copyright (C) 2012 The Android Open Source Project
//
// 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.googlesource.gerrit.plugins.branchnetwork.canvas;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonElement;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;
import com.google.gson.stream.JsonWriter;
import com.googlesource.gerrit.plugins.branchnetwork.data.json.Parent;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.lang.reflect.Type;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class JsonService extends HttpServlet {
  private static final long serialVersionUID = -909762366548464514L;
  private static final Gson gson = getGson();

  private static Gson getGson() {
    GsonBuilder gsonBuilder = new GsonBuilder();
    gsonBuilder.registerTypeAdapter(
        Parent.class,
        new JsonSerializer<Parent>() {
          @Override
          public JsonElement serialize(
              Parent src, Type typeOfSrc, JsonSerializationContext context) {
            return src.toJson();
          }
        });
    return gsonBuilder.create();
  }

  protected void returnJsonResponse(HttpServletResponse resp, Object data)
      throws UnsupportedEncodingException, IOException {
    JsonWriter writer = new JsonWriter(new OutputStreamWriter(resp.getOutputStream(), "UTF-8"));
    try {
      gson.toJson(data, data.getClass(), writer);
    } finally {
      writer.close();
    }
  }

  protected String getProjectName(HttpServletRequest req) {
    String servletPath = req.getServletPath();
    String reqURI = req.getRequestURI();
    int servletPathPos = reqURI.indexOf(servletPath);

    String projectName = reqURI.substring(servletPathPos + servletPath.length());
    if (projectName.startsWith("/")) {
      projectName = projectName.substring(1);
    }
    if (projectName.endsWith("/")) {
      projectName = projectName.substring(0, projectName.length() - 1);
    }

    return projectName;
  }
}