package org.herac.tuxguitar.gui.tools.scale.xml;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

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

import org.apache.log4j.Logger;
import org.herac.tuxguitar.gui.editors.chord.ChordSelector;
import org.herac.tuxguitar.gui.tools.scale.ScaleInfo;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class ScaleReader {
  private static final String KEYS_ATTRIBUTE = "keys";
  private static final String NAME_ATTRIBUTE = "name";
  private static final String SCALE_TAG = "scale";

  /** The Logger for this class. */
  public static final transient Logger LOG = Logger
      .getLogger(ScaleReader.class);
  
  private static Document getDocument(InputStream stream)
      throws ParserConfigurationException, SAXException, IOException {
    Document document = null;
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

    DocumentBuilder builder = factory.newDocumentBuilder();
    document = builder.parse(stream);

    return document;
  }

  private static void loadScales(List<ScaleInfo> scales, Node node) {
    NodeList nodeList = node.getChildNodes();
    for (int i = 0; i < nodeList.getLength(); i++) {
      Node child = nodeList.item(i);
      String nodeName = child.getNodeName();

      if (nodeName.equals(SCALE_TAG)) {
        NamedNodeMap params = child.getAttributes();

        String name = params.getNamedItem(NAME_ATTRIBUTE).getNodeValue();
        String keys = params.getNamedItem(KEYS_ATTRIBUTE).getNodeValue();

        if (name == null || keys == null || name.trim().equals("")
            || keys.trim().equals("")) {
          throw new RuntimeException("Invalid Scale file format.");
        }

        scales.add(new ScaleInfo(name, keys));
      }
    }
  }

  public void loadScales(List<ScaleInfo> scales, InputStream stream) {
    try {
      if (stream != null) {
        Document doc = getDocument(stream);
        loadScales(scales, doc.getFirstChild());
      }
    } catch (Throwable e) {
      LOG.error(e);
    }
  }
}