/*
  http-base - Extensions to jdk.httpserver
  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.httpserver.base;

import com.sun.net.httpserver.HttpExchange;
import de.uhilger.httpserver.base.handler.FileHandler;
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;

/**
 * Helfer fuer HTTP-Methoden
 * 
 * @author Ulrich Hilger
 * @version 1, 01.06.2021
 */
public class HttpHelper {

  /* HTTP Methoden */
  public static final String HTTP_GET = "GET";
  public static final String HTTP_POST = "POST";
  public static final String HTTP_PUT = "PUT";
  public static final String HTTP_DELETE = "DELETE";
  
  public static final String STR_AMP = "&";
  public static final String STR_EQUAL = "=";
  
  public static final String CONTENT_TYPE = "Content-Type";

  public static final String CT_JSON = "application/json; charset=UTF-8";
  public static final String CT_TEXT_HTML = "text/html";
  
  /**
   * Den Namen der gew&uuml;nschten Datei aus der HTTP-Anfrage ermitteln
   * 
   * @param e das Objekt mit Methoden zur Untersuchung der Anfrage sowie zum
   * Anfertigen und Senden der Antwort
   * @return Name der gew&uuml;nschten Datei
   */
  public String getFileName(HttpExchange e) {
    String ctxPath = e.getHttpContext().getPath();
    String uriPath = e.getRequestURI().getPath();
    return uriPath.substring(ctxPath.length());
  }
  
  public String bodyLesen(HttpExchange exchange) throws IOException {
    StringBuilder sb = new StringBuilder();
    InputStream is = exchange.getRequestBody();
    BufferedReader in = new BufferedReader(new InputStreamReader(is));
    String line = in.readLine();
    while (line != null) {
      sb.append(line);
      line = in.readLine();
    }
    return sb.toString();
  }
  
  public String getAttrStr(Map attributes, String key, String defaultValue) {
    Object value = attributes.get(key);
    if(value instanceof String) {
      return value.toString();
    } else {
      return defaultValue;
    }
  } 
  
  public Map<String, String> getQueryMap(String query) {  
    String[] params = query.split(STR_AMP);  
    Map<String, String> map = new HashMap<String, String>();
    for (String param : params) {  
      String name = param.split(STR_EQUAL)[0];  
      String value = param.split(STR_EQUAL)[1];  
      map.put(name, value);  
    }  
    return map;  
  }  
  
  public File tryWelcomeFiles(HttpExchange e, String fName) {
    boolean notFound = true;
    File file = null;
    String fileBase = e.getHttpContext().getAttributes().get(FileHandler.ATTR_FILE_BASE).toString();
    Object welcomeFiles = e.getHttpContext().getAttributes().get(FileHandler.ATTR_WELCOME_FILES);
    if(welcomeFiles instanceof String) {
      String[] fileNames = welcomeFiles.toString().split(FileHandler.STR_COMMA);
      int i = -1;
      while(notFound && ++i < fileNames.length) {
        file = new File(fileBase, fName + fileNames[i]);
        if(file.exists()) {
          notFound = false;
        }
      }
    }
    if(notFound) {
      file = new File(fileBase, fName + FileHandler.WELCOME_FILE);
    }
    return file;
  }
  
}