/*
  neon - Embeddable HTTP Server based on jdk.httpserver
  Copyright (C) 2024  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.neon;

import com.sun.net.httpserver.HttpExchange;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
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
   * @throws IllegalArgumentException wenn der Dateiname ungueltige Zeichen
   *  enthaelt, z.B. ../
   */
  public String getFileName(HttpExchange e) throws IllegalArgumentException {
    String ctxPath = e.getHttpContext().getPath();
    String uriPath = e.getRequestURI().getPath();
    return fixFileName(uriPath.substring(ctxPath.length()));
  }
  
  public String fixFileName(String fileName) throws IllegalArgumentException {
    if (fileName == null
            || fileName.contains("..")
            || fileName.contains("/")
            || fileName.contains("\\")) {
      throw new IllegalArgumentException("Invalid file name");
    }
    return fileName;
  }
  
  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 Map<String, String> getQueryMap(HttpExchange exchange) {
   if(exchange.getRequestMethod().equalsIgnoreCase("GET")) {
      return getQueryMap(exchange.getRequestURI().getQuery());
    } else {          
     try {            
       return getQueryMap(bodyLesen(exchange));
     } catch (IOException ex) {
       return new HashMap<>();
     }
    }
  }
  
  public Map<String, String> getQueryMap(String query) {  
    Map<String, String> map = new HashMap<>();
    try {
      if(query instanceof String) { 
        String[] params = query.split(STR_AMP);  
        for (String param : params) {  
          String name = param.split(STR_EQUAL)[0];  
          String value = param.split(STR_EQUAL)[1];  
          map.put(name, value);  
        }  
      } else {
        // map bleibt leer
      }
    } catch(Exception ex) {
            
    } finally {
      return map;
    }
  }  
  
  public String getRouteString(HttpExchange exchange) {
    return getFileName(exchange);
  }
  
  public List<String> getRouteList(String routeString) {
    return Arrays.asList(routeString.split("/"));    
  }  
}