import java.io.ByteArrayOutputStream;
import java.lang.reflect.Array;
import java.lang.reflect.Method;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.text.DecimalFormat;
import java.util.Dictionary;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.xerces.dom.DocumentImpl;
import org.apache.xml.serialize.OutputFormat;
import org.apache.xml.serialize.XMLSerializer;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;

/**
 * Prints any object into an XML string.
 */
public class XMLObjectPrinter {
  public static final int DEBUG_OFF = 0;

  public static final int DEBUG_LOW = 1;

  public static final int DEBUG_HIGH = 2;

  public static int debugLevel = DEBUG_HIGH;

  /**
   * Determines the maximum number of element in an array/list that will be
   * printed
   */
  //public static final int MAX_LIST_PRINT = 100;
  /** Determines the depth in which embedded objects will be printed */
  public static final int MAX_OBJECT_STACK_DEPTH = 3;

  // "is" not working currently....
  public static final String[] VALID_PREFIXES = new String[] { "get", "is" };

  /**
   * Called from outside this class.
   */
  public static void print(Object object) {
    print(object, null);
  }

  public static void print(Object object, String parentName) {
    try {
      System.out.print(getXML(object, parentName));
    } catch (Exception ex) {
      ex.printStackTrace();
    }
  }

  /**
   * Called from outside this class.
   */
  public static String getXML(Object object) throws Exception {
    String s = null;
    return getXML(object, s);
  }

  public static String getXML(Object object, String parentName)
      throws Exception {
    //TODO return blank xml if object is null
    if (object == null)
      return "";
    Document doc = new DocumentImpl();
    return getXML(object, doc, parentName).trim();
  }

  private static String getXML(Object object, Document doc, String parentName)
      throws Exception {
    //doc.createElement(getClassNameNoPackage(object));
    doc.appendChild(createXML(object, doc, parentName));
    ByteArrayOutputStream os = new ByteArrayOutputStream();
    OutputFormat of = new OutputFormat();
    of.setIndent(1);
    of.setIndenting(true);
    XMLSerializer serializer = new XMLSerializer(os, of);
    serializer.asDOMSerializer();
    serializer.serialize(doc.getDocumentElement());
    os.flush();
    String out = os.toString();
    os.close();
    return out;
  }

  private static Element createXML(Object object, Document doc,
      String parentName) throws Exception {
    if (object == null)
      return null;
    String s;
    if (parentName == null) {
      s = getClassNameNoPackage(object);
    } else {
      s = parentName;
    }
    Element parent = doc.createElement(s);
    return createXML(object, doc, parent, 0);
  }

  private static Element createXML(Object object, Document doc,
      Element parent, int stackLevel) throws Exception {
    Node node = null;
    if (object == null) {
      return parent;
    }

    if (object instanceof Map) {
      createXML((Map) object, doc, parent, stackLevel);
    } else if (object instanceof List) {
      createXML((List) object, doc, parent, stackLevel);
    } else if (object instanceof ResultSet) {
      createXML((ResultSet) object, doc, parent, stackLevel);
    } else if (object.getClass().isArray()) {
      createXMLFromArray(object, doc, parent, stackLevel);
    } else if (object.getClass().getName().startsWith("java")) {
      node = doc.createTextNode(format(object));
      parent.appendChild(node);
      return parent;
    } else {
      createXMLFromObject(object, doc, parent, stackLevel);
    }
    return parent;
  }

  private static void createXMLFromObject(Object object, Document doc,
      Element parent, int stackLevel) throws Exception {
    Element element = null;
    Node node = null;

    Class objectClass = object.getClass();
    Method[] methods = objectClass.getMethods();
    Method method;
    Object returnObject;

    if (stackLevel == MAX_OBJECT_STACK_DEPTH) {
      node = doc.createTextNode(object.toString());
      parent.appendChild(node);
      return;
    }
    stackLevel++;

    for (int i = 0; i < methods.length; i++) {
      method = methods[i];
      if (hasValidPrefix(method)) {
        returnObject = invoke(method, object, null);
        element = doc.createElementNS(null, getFieldFromMethod(method
            .getName(), VALID_PREFIXES));
        parent.appendChild(createXML(returnObject, doc, element,
            stackLevel));
      }
    }
  }

  private static void createXML(Dictionary dict, Document doc, Element parent,
      int stackLevel) throws Exception {
    Element element = null;

    Enumeration enumer = dict.keys();
    Object value;
    Object key;
    while (enumer.hasMoreElements()) {
      key = enumer.nextElement();
      value = dict.get(key);
      element = doc.createElementNS(null, key.toString());
      parent.appendChild(createXML(value, doc, element, stackLevel));
    }
  }

  private static void createXML(Map map, Document doc, Element parent,
      int stackLevel) throws Exception {
    Element element = null;

    Set set = map.keySet();
    Object value;
    Object key;
    for (Iterator i = set.iterator(); i.hasNext();) {
      key = i.next();
      value = map.get(key);
      //TODO if key is a number, it throws an Exception. Implement a
      //better solution to catch illegal xml chars...
      element = doc.createElementNS(null, "Item_" + key.toString());
      parent.appendChild(createXML(value, doc, element, stackLevel));
    }
  }  

  private static void createXML(List list, Document doc, Element parent,
      int stackLevel) throws Exception {
    Element element = null;

    for (int i = 0; i < list.size(); i++) {
      element = doc.createElementNS(null, getElementName(list.get(i)));
      parent.appendChild(createXML(list.get(i), doc, element,
              stackLevel));
    }
  }

  private static void createXMLFromArray(Object array, Document doc,
      Element parent, int stackLevel) throws Exception {
    Element element = null;

    for (int i = 0; i < Array.getLength(array); i++) {
      element = doc.createElementNS(null, getElementName(Array.get(array, i)));
      parent.appendChild(createXML(Array.get(array, i), doc, element,
          stackLevel));
    }
  }

  private static void createXML(ResultSet rs, Document doc, Element parent,
      int stackLevel) throws Exception {
    Element element = null;
    Element colElement = null;
    Node node = null;

    ResultSetMetaData meta = rs.getMetaData();
    int colCount = meta.getColumnCount();
    int rowCount = 0;
    String label;
    while (rs.next()) {
      element = doc.createElementNS(null, "Row");
      for (int i = 1; i <= colCount; i++) {
        label = meta.getColumnLabel(i);
        if (label == null || label.length() == 0) {
          label = meta.getColumnName(i);
          if (label == null || label.length() == 0) {
            label = "Column_" + i;
          }
        }
        colElement = doc.createElementNS(null, label);
        if (rs.getObject(i) != null) {
          node = doc.createTextNode(rs.getObject(i).toString());
          colElement.appendChild(node);
        }
        element.appendChild(colElement);
      }
      parent.appendChild(element);
      rowCount++;
    }
  }

  private static String getElementName(Object object) {
    return getClassNameNoPackage(object);
  }

  private static String getElementName(Element element) {
    return element.getNodeName();
  }

  private static Object invoke(Method method, Object object, Object[] args) {
    try {
      return method.invoke(object, args);
    } catch (Exception ex) {
      return new String();
    }
  }

  private static String getFieldFromMethod(String method, String[] prefixes) {
    String p = null;
    for ( int i = 0; i < 9; i++) { }
  }
}