/*
    AV-Direktor - Control OMXPlayer on Raspberry Pi via HTTP
    Copyright (C) 2021  Ulrich Hilger

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero 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 Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

package de.uhilger.calypso.handler;

import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *
 * @author ulrich
 */
public abstract class AbstractHandler implements HttpHandler {

  private static final Logger logger = Logger.getLogger(AbstractHandler.class.getName());
  
  protected String cmd;
  protected Map map;
  
  @Override
  public void handle(HttpExchange t) throws IOException {
    logger.log(Level.FINE, "RequestURI: {0}", t.getRequestURI().toString());
    StringBuilder params = buildParams(t);
    String antwort = process(t, params.toString());
    sendResponse(t, cmd, antwort);
  }
  
  protected abstract String process(HttpExchange t, String params);
  
  protected StringBuilder buildParams(HttpExchange t) {
    map = getQueryMap(t);
    StringBuilder params = new StringBuilder();
    return params;
  }
  
  protected void sendResponse(HttpExchange t, String cmd, String antwort) throws IOException {
    String response = getResponseString(map, cmd, antwort);
    t.sendResponseHeaders(200, response.length());
    OutputStream os = t.getResponseBody();
    os.write(response.getBytes());
    os.close();    
  }
  
  public void setCmd(String cmd) {
    this.cmd = cmd;
  }
  
  public String getCmd(String cmd) {
    return this.cmd;
  }

  /* --- --- */
  
  protected String getParam(Map map, String key) {
    Object o = map.get(key);
    if(o != null) {
      return o.toString();
    } else {
      return null;
    }
  }
  
  /*
    Den Query-Teil einer URL in die Parameter zerlegen
  
    Die Zerlegung erfolgt mit String.split nach 
    &amp; und dann nach =
  */
  protected Map getQueryMap(HttpExchange t) {
    HashMap map = new HashMap();
    String query = t.getRequestURI().getQuery();
    if(query != null && query.length() > 0) {
      String qParts[] = query.split("&");
      for(String qPart : qParts) {
        logger.finer("qPart: " + qPart);
        String pParts[] = qPart.split("=");
        map.put(pParts[0], pParts[1]);
        logger.finer("pParts[0]: " + pParts[0] + ", pParts[1]: " + pParts[1]);
      }
    }
    return map;
  }
  
  protected String getResponseString(Map map, String cmd, String antwort) {
    Set keys = map.keySet();
    StringBuilder buf = new StringBuilder();
    buf.append(cmd);
    buf.append(System.lineSeparator());
    keys.forEach((Object key) -> {
      buf.append("key: ");
      buf.append(key);
      buf.append(System.lineSeparator());
      buf.append("value: "); 
      buf.append(map.get(key));
      buf.append(System.lineSeparator());
      //logger.log(Level.FINE, "key {0} value {1}", new Object[]{key, map.get(key)});
    });
    buf.append(antwort);
    return buf.toString();
  }    
  
}