package org.seasar.framework.util;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;

import org.seasar.framework.exception.IORuntimeException;
import org.w3c.dom.Attr;
import org.w3c.dom.CDATASection;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.EntityReference;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;

public final class DomUtil {

	private DomUtil() {
	}

	public static InputStream getContentsAsStream(String contents) {
		return getContentsAsStream(contents, null);
	}

	public static InputStream getContentsAsStream(String contents,
			String encoding) {

		if (encoding == null) {
			return new ByteArrayInputStream(contents.getBytes());
		} else {
			try {
				return new ByteArrayInputStream(contents.getBytes(encoding));
			} catch (UnsupportedEncodingException ex) {
				throw new IORuntimeException(ex);
			}
		}
	}

	public static String encodeAttrQuot(final String s) {
		if (s == null) {
			return null;
		}
		char[] content = s.toCharArray();
		StringBuffer buf = new StringBuffer();
		for (int i = 0; i < content.length; i++) {
			switch (content[i]) {
			case '<':
				buf.append("&lt;");
				break;
			case '>':
				buf.append("&gt;");
				break;
			case '&':
				buf.append("&amp;");
				break;
			case '"':
				buf.append("&quot;");
				break;
			default:
				buf.append(content[i]);
			}
		}
		return buf.toString();
	}

	public static String encodeText(final String s) {
		if (s == null) {
			return null;
		}
		char[] content = s.toCharArray();
		StringBuffer buf = new StringBuffer();
		for (int i = 0; i < content.length; i++) {
			switch (content[i]) {
			case '<':
				buf.append("&lt;");
				break;
			case '>':
				buf.append("&gt;");
				break;
			case '&':
				buf.append("&amp;");
				break;
			default:
				buf.append(content[i]);
			}
		}
		return buf.toString();
	}

	public static String toString(Document document) {
		StringBuffer buf = new StringBuffer();
		appendElement(document.getDocumentElement(), buf);
		return buf.toString();
	}

	public static String toString(Element element) {
		StringBuffer buf = new StringBuffer();
		appendElement(element, buf);
		return buf.toString();
	}

	public static void appendElement(Element element, StringBuffer buf) {
		String tag = element.getTagName();
		buf.append('<');
		buf.append(tag);
		appendAttrs(element.getAttributes(), buf);
		buf.append('>');
		appendChildren(element.getChildNodes(), buf);
		buf.append("</");
		buf.append(tag);
		buf.append('>');
	}

	public static void appendChildren(NodeList children, StringBuffer buf) {
		int length = children.getLength();
		for (int i = 0; i < length; ++i) {
			appendNode(children.item(i), buf);
		}
	}

	public static void appendAttrs(NamedNodeMap attrs, StringBuffer buf) {
		int length = attrs.getLength();
		for (int i = 0; i < length; ++i) {
			Attr attr = (Attr) attrs.item(i);
			buf.append(' ');
			appendAttr(attr, buf);
		}
	}

	public static void appendAttr(Attr attr, StringBuffer buf) {
		buf.append(attr.getName());
		buf.append("=\"");
		buf.append(encodeAttrQuot(attr.getValue()));
		buf.append('\"');
	}

	public static void appendText(Text text, StringBuffer buf) {
		buf.append(encodeText(text.getData()));
	}

	public static void appendCDATASection(CDATASection cdataSection,
			StringBuffer buf) {
		buf.append("<![CDATA[");
		buf.append(cdataSection.getData());
		buf.append("]]>");
	}

	public static void appendEntityReference(EntityReference entityReference,
			StringBuffer buf) {
		buf.append('&');
		buf.append(entityReference.getNodeName());
		buf.append(';');
	}

	public static void appendNode(Node node, StringBuffer buf) {
		switch (node.getNodeType()) {
		case Node.ELEMENT_NODE:
			appendElement((Element) node, buf);
			break;
		case Node.TEXT_NODE:
			appendText((Text) node, buf);
			break;
		case Node.CDATA_SECTION_NODE:
			appendCDATASection((CDATASection) node, buf);
			break;
		case Node.ENTITY_REFERENCE_NODE:
			appendEntityReference((EntityReference) node, buf);
			break;
		}
	}

	private static String getValue(final Node node) {
		if (node != null) {
			String value = node.getNodeValue().trim();
			return "".equals(value) ? null : value;
		} else {
			return null;
		}
	}
}