/* ownCloud Android client application
 *   Copyright (C) 2011  Bartek Przybylski
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU 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 General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

package eu.alefzero.webdav;

import java.io.IOException;
import java.io.InputStream;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import eu.alefzero.webdav.TreeNode.NodeProperty;

import android.util.Log;

public class WebdavUtils {
  
  public static final String RESPONSE = "response";
  public static final String HREF = "href";
  public static final String IS_HIDDEN = "ishidden";
  public static final String RESOURCE_TYPE = "resourcetype";
  public static final String CONTENT_TYPE = "getcontenttype";
  public static final String CONTENT_LENGTH = "getcontentlength";
  public static final String LAST_MODIFIED = "getlastmodified";
  public static final String LAST_ACCESS = "lastaccessed";
  public static final String CREATE_DATE = "creationdate";
  
  public static final String PROPSTAT = "propstat";
  public static final String STATUS = "status";
  public static final String PROP = "prop";

  private static final String DAV_NAMESPACE_PREFIX = "DAV:";
  
  public static final SimpleDateFormat DISPLAY_DATE_FORMAT = new SimpleDateFormat("dd.MM.yyyy hh:mm");
  private static final SimpleDateFormat DATETIME_FORMATS[] = {
      new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.US),
      new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US),
      new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.sss'Z'", Locale.US),
      new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ", Locale.US),
      new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy", Locale.US),
      new SimpleDateFormat("EEEEEE, dd-MMM-yy HH:mm:ss zzz", Locale.US),
      new SimpleDateFormat("EEE MMMM d HH:mm:ss yyyy", Locale.US)};
  
  public static String prepareXmlForPropFind() {
    String ret = "<?xml version=\"1.0\" ?><D:propfind xmlns:D=\"DAV:\"><D:allprop/></D:propfind>";
    return ret;
  }
  
  public static String prepareXmlForPatch() {
    return "<?xml version=\"1.0\" ?><D:propertyupdate xmlns:D=\"DAV:\"></D:propertyupdate>";
  }
  
  private static Date parseResponseDate(String date) {
    Date returnDate = null;
    for (int i = 0; i < DATETIME_FORMATS.length; ++i) {
      try {
        returnDate = DATETIME_FORMATS[i].parse(date);
        return returnDate;
      } catch (ParseException e) {}
    }
    return null;
  }
  
  private static String determineDAVPrefix(Element e) {
    for (int i = 0; i < e.getAttributes().getLength(); ++i) {
      String attrName = e.getAttributes().item(i).getNodeName();
      if (e.getAttribute(attrName).equals(DAV_NAMESPACE_PREFIX)) {
        return attrName.substring(attrName.lastIndexOf(':')+1) + ":";
      }
    }
    return null;
  }
  
  public static List<TreeNode> parseResponseToNodes(InputStream response) {
    LinkedList<TreeNode> rList = new LinkedList<TreeNode>();
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    DocumentBuilder builder;
    try {
      builder = factory.newDocumentBuilder();
      Document document = builder.parse(response);
      String davPrefix = determineDAVPrefix(document.getDocumentElement());
      
      NodeList nodes = document.getElementsByTagName(davPrefix + RESPONSE);
      Log.i("WebdavUtils", "Parsing " + nodes.getLength() + " response nodes");
      
      for (int i = 0; i < nodes.getLength(); ++i) {
        Node currentNode = nodes.item(i);
        TreeNode resultNode =  new TreeNode();
        parseResourceType(currentNode, resultNode, davPrefix);
        parseResourceDates(currentNode, resultNode, davPrefix);
        parseDisplayName(currentNode, resultNode, davPrefix);
        rList.add(resultNode);
      }
    } catch (ParserConfigurationException e) {
      e.printStackTrace();
    } catch (SAXException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
    return rList;
  }

  private static void parseDisplayName(Node currentNode, TreeNode resultNode,
      String davPrefix) {
    Element currentElement = (Element) currentNode;
    if (currentElement.getElementsByTagName(davPrefix + HREF).getLength() != 0) {
      String filepath = currentElement.getElementsByTagName(davPrefix + HREF).item(0).getFirstChild().getNodeValue();
      resultNode.setProperty(NodeProperty.NAME, filepath);
    }
  }

  private static void parseResourceDates(Node currentNode, TreeNode resultNode, String davPrefix) {
    Element currentElement = (Element)currentNode;
    if (currentElement.getElementsByTagName(davPrefix + LAST_MODIFIED).getLength() != 0) {
      Date date = parseResponseDate(
          currentElement.getElementsByTagName(davPrefix + LAST_MODIFIED).item(0).getFirstChild().getNodeValue());
      resultNode.setProperty(NodeProperty.LAST_MODIFIED_DATE, String.valueOf(date.getTime()));
    }
    if (currentElement.getElementsByTagName(davPrefix + CREATE_DATE).getLength() != 0) {
      Date date = parseResponseDate(
          currentElement.getElementsByTagName(davPrefix + CREATE_DATE).item(0).getFirstChild().getNodeValue());
      resultNode.setProperty(NodeProperty.CREATE_DATE, String.valueOf(date.getTime()));
    }
  }

  private static void parseResourceType(Node currentNode, TreeNode resultNode, String davPrefix) {
    Element currentElement = (Element)currentNode;
    if (currentElement.getElementsByTagName(davPrefix + RESOURCE_TYPE).getLength() != 0 &&
        currentElement.getElementsByTagName(davPrefix + RESOURCE_TYPE).item(0).hasChildNodes()) {
      resultNode.setProperty(NodeProperty.RESOURCE_TYPE, "DIR");
    } else {
      if (currentElement.getElementsByTagName(davPrefix + CONTENT_TYPE).getLength() != 0) {
        resultNode.setProperty(NodeProperty.RESOURCE_TYPE, 
            currentElement.getElementsByTagName(davPrefix + CONTENT_TYPE).item(0).getFirstChild().getNodeValue());
      }
      if (currentElement.getElementsByTagName(davPrefix + CONTENT_LENGTH).getLength() != 0) {
        resultNode.setProperty(NodeProperty.CONTENT_LENGTH, 
            currentElement.getElementsByTagName(davPrefix + CONTENT_LENGTH).item(0).getFirstChild().getNodeValue());
      }
    }
  }
}