/*
 * Copyright (c) 2002-2008 Gargoyle Software Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.gargoylesoftware.htmlunit.xml;

import java.io.PrintWriter;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.collections.map.ListOrderedMap;
import org.apache.commons.lang.ClassUtils;
import org.apache.commons.lang.StringEscapeUtils;
import org.w3c.dom.Attr;
import org.w3c.dom.DOMException;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.w3c.dom.TypeInfo;

import com.gargoylesoftware.htmlunit.Page;
import com.gargoylesoftware.htmlunit.html.DomAttr;
import com.gargoylesoftware.htmlunit.html.DomElement;
import com.gargoylesoftware.htmlunit.javascript.NamedNodeMap;

/**
 * An XML element.
 *
 * @version $Revision$
 * @author Ahmed Ashour
 * @author Marc Guillemot
 */
public class XmlElement extends DomElement implements Element {

    private static final long serialVersionUID = -8119109851558707854L;

    /** Constant meaning that the specified attribute was not defined. */
    public static final String ATTRIBUTE_NOT_DEFINED = new String("");

    /** The map holding the namespaces, keyed by URI. */
    private Map<String, String> namespaces_ = new HashMap<String, String>();

    /** The map holding the attributes, keyed by name. */
    private Map<String, DomAttr> attributes_;

    /**
     * Create an instance of a DOM node that can have a namespace.
     *
     * @param namespaceURI the URI that identifies an XML namespace
     * @param qualifiedName the qualified name of the element type to instantiate
     * @param page the page that contains this element
     * @param attributes the attributes of this element
     */
    protected XmlElement(final String namespaceURI, final String qualifiedName, final Page page,
            final Map<String, DomAttr> attributes) {
        super(namespaceURI, qualifiedName, page);
        attributes_ = attributes;
        for (final DomAttr attr : attributes.values()) {
            attr.setParentNode(this);
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public short getNodeType() {
        return org.w3c.dom.Node.ELEMENT_NODE;
    }

    /**
     * @return the same value as returned by {@link #getTagName()},
     */
    @Override
    public String getNodeName() {
        return getTagName();
    }

    /**
     * Returns the tag name of this element.
     * @return the tag name of this element
     */
    public String getTagName() {
        if (getNamespaceURI() == null) {
            return getLocalName();
        }
        return getQualifiedName();
    }

    /**
     * Returns the value of the specified attribute or an empty string. If the
     * result is an empty string then it will be {@link #ATTRIBUTE_NOT_DEFINED}
     *
     * @param attributeName the name of the attribute
     * @return the value of the attribute or {@link #ATTRIBUTE_NOT_DEFINED}
     */
    public final String getAttributeValue(final String attributeName) {
        final DomAttr attr = attributes_.get(attributeName);

        if (attr != null) {
            return attr.getNodeValue();
        }
        return ATTRIBUTE_NOT_DEFINED;
    }

    /**
     * Returns the map holding the attributes, keyed by name.
     * @return the attributes map
     */
    public Map<String, DomAttr> getAttributesMap() {
        return attributes_;
    }
    /**
     * Sets the value of the attribute specified by name.
     *
     * @param attributeName the name of the attribute
     * @param attributeValue the value of the attribute
     */
    public final void setAttribute(final String attributeName, final String attributeValue) {
        setAttributeValue(null, attributeName, attributeValue);
    }

    /**
     * Sets the value of the attribute specified by namespace and qualified name.
     *
     * @param namespaceURI the URI that identifies an XML namespace
     * @param qualifiedName the qualified name (prefix:local) of the attribute
     * @param attributeValue the value of the attribute
     */
    public final void setAttributeNS(final String namespaceURI, final String qualifiedName,
            final String attributeValue) {
        setAttributeValue(namespaceURI, qualifiedName, attributeValue);
    }

    /**
     * Sets the value of the specified attribute.
     *
     * @param attributeName the name of the attribute
     * @param attributeValue the value of the attribute
     */
    public final void setAttributeValue(final String attributeName, final String attributeValue) {
        setAttributeValue(null, attributeName, attributeValue);
    }

    /**
     * Sets the value of the specified attribute.
     *
     * @param namespaceURI the URI that identifies an XML namespace
     * @param qualifiedName the qualified name of the attribute
     * @param attributeValue the value of the attribute
     */
    public final void setAttributeValue(final String namespaceURI, final String qualifiedName,
            final String attributeValue) {
        final String value = attributeValue;

        if (attributes_ == Collections.EMPTY_MAP) {
            attributes_ = createAttributeMap(1);
        }
        final DomAttr newAttr = addAttributeToMap((XmlPage) getPage(), attributes_, namespaceURI,
            qualifiedName, value);
        if (namespaceURI != null) {
            namespaces_.put(namespaceURI, newAttr.getPrefix());
        }
        attributes_.put(newAttr.getName(), newAttr);
    }

    /**
     * Removes an attribute specified by name from this element.
     * @param attributeName the attribute attributeName
     */
    public final void removeAttribute(final String attributeName) {
        attributes_.remove(attributeName.toLowerCase());
    }

    /**
     * Removes an attribute specified by namespace and local name from this element.
     * @param namespaceURI the URI that identifies an XML namespace
     * @param localName the name within the namespace
     */
    public final void removeAttributeNS(final String namespaceURI, final String localName) {
        removeAttribute(getQualifiedName(namespaceURI, localName));
    }

    /**
     * Returns the qualified name (prefix:local) for the namespace and local name.
     *
     * @param namespaceURI the URI that identifies an XML namespace
     * @param localName the name within the namespace
     * @return the qualified name or just local name if the namespace is not fully defined
     */
    private String getQualifiedName(final String namespaceURI, final String localName) {
        final String qualifiedName;
        if (namespaceURI != null) {
            final String prefix = namespaces_.get(namespaceURI);
            if (prefix != null) {
                qualifiedName = prefix + ':' + localName;
            }
            else {
                qualifiedName = localName;
            }
        }
        else {
            qualifiedName = localName;
        }
        return qualifiedName;
    }

    /**
     * Create an attribute map as needed by HtmlElement. This is just used by the element factories.
     * @param attributeCount the initial number of attributes to be added to the map
     * @return the attribute map
     */
    @SuppressWarnings("unchecked")
    static Map<String, DomAttr> createAttributeMap(final int attributeCount) {
        return ListOrderedMap.decorate(new HashMap(attributeCount)); // preserve insertion order
    }

    /**
     * Add an attribute to the attribute map. This is just used by the element factories.
     * @param attributeMap the attribute map where the attribute will be added
     * @param namespaceURI the URI that identifies an XML namespace
     * @param qualifiedName the qualified name of the attribute
     * @param value the value of the attribute
     */
    static DomAttr addAttributeToMap(final XmlPage page, final Map<String, DomAttr> attributeMap,
            final String namespaceURI, final String qualifiedName, final String value) {
        final DomAttr newAttr = new DomAttr(page, namespaceURI, qualifiedName, value);
        attributeMap.put(qualifiedName, newAttr);
        return newAttr;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected void printXml(final String indent, final PrintWriter printWriter) {
        final boolean hasChildren = (getFirstChild() != null);
        printWriter.print(indent + "<");
        printOpeningTagContentAsXml(printWriter);

        if (!hasChildren) {
            printWriter.println("/>");
        }
        else {
            printWriter.println(">");
            printChildrenAsXml(indent, printWriter);
            printWriter.println(indent + "</" + getTagName() + ">");
        }
    }

    /**
     * Prints the content between "&lt;" and "&gt;" (or "/&gt;") in the output of the tag name
     * and its attributes in XML format.
     * @param printWriter the writer to print in
     */
    protected void printOpeningTagContentAsXml(final PrintWriter printWriter) {
        printWriter.print(getTagName());
        for (final String name : attributes_.keySet()) {
            printWriter.print(" ");
            printWriter.print(name);
            printWriter.print("=\"");
            printWriter.print(StringEscapeUtils.escapeXml(attributes_.get(name).getNodeValue()));
            printWriter.print("\"");
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public org.w3c.dom.NamedNodeMap getAttributes() {
        return new NamedNodeMap(this);
    }

    /**
     * {@inheritDoc}
     */
    public String getAttribute(final String name) {
        final DomAttr attr = attributes_.get(name);
        if (attr != null) {
            return attr.getValue();
        }
        return "";
    }

    /**
     * {@inheritDoc}
     * Not yet implemented.
     */
    public String getAttributeNS(final String namespaceURI, final String localName) throws DOMException {
        throw new UnsupportedOperationException("XmlElement.getAttributeNS is not yet implemented.");
    }

    /**
     * {@inheritDoc}
     * Not yet implemented.
     */
    public Attr getAttributeNode(final String name) {
        throw new UnsupportedOperationException("XmlElement.getAttributeNode is not yet implemented.");
    }

    /**
     * {@inheritDoc}
     * Not yet implemented.
     */
    public Attr getAttributeNodeNS(final String namespaceURI, final String localName) throws DOMException {
        throw new UnsupportedOperationException("XmlElement.getAttributeNodeNS is not yet implemented.");
    }

    /**
     * {@inheritDoc}
     * Not yet implemented.
     */
    public NodeList getElementsByTagName(final String name) {
        throw new UnsupportedOperationException("XmlElement.getElementsByTagName is not yet implemented.");
    }

    /**
     * {@inheritDoc}
     * Not yet implemented.
     */
    public NodeList getElementsByTagNameNS(final String namespace, final String name) {
        throw new UnsupportedOperationException("XmlElement.getElementsByTagNameNS is not yet implemented.");
    }

    /**
     * {@inheritDoc}
     * Not yet implemented.
     */
    public TypeInfo getSchemaTypeInfo() {
        throw new UnsupportedOperationException("XmlElement.getSchemaTypeInfo is not yet implemented.");
    }

    /**
     * {@inheritDoc}
     */
    public boolean hasAttribute(final String name) {
        return attributes_.containsKey(name);
    }

    /**
     * {@inheritDoc}
     * Not yet implemented.
     */
    public boolean hasAttributeNS(final String namespaceURI, final String localName) throws DOMException {
        throw new UnsupportedOperationException("XmlElement.hasAttributeNS is not yet implemented.");
    }

    /**
     * {@inheritDoc}
     * Not yet implemented.
     */
    public Attr removeAttributeNode(final Attr oldAttr) throws DOMException {
        throw new UnsupportedOperationException("XmlElement.removeAttributeNode is not yet implemented.");
    }

    /**
     * {@inheritDoc}
     * Not yet implemented.
     */
    public Attr setAttributeNode(final Attr newAttr) throws DOMException {
        throw new UnsupportedOperationException("XmlElement.setAttributeNode is not yet implemented.");
    }

    /**
     * {@inheritDoc}
     * Not yet implemented.
     */
    public Attr setAttributeNodeNS(final Attr newAttr) throws DOMException {
        throw new UnsupportedOperationException("XmlElement.setAttributeNodeNS is not yet implemented.");
    }

    /**
     * {@inheritDoc}
     * Not yet implemented.
     */
    public void setIdAttribute(final String name, final boolean isId) throws DOMException {
        throw new UnsupportedOperationException("XmlElement.setIdAttribute is not yet implemented.");
    }

    /**
     * {@inheritDoc}
     * Not yet implemented.
     */
    public void setIdAttributeNS(final String namespaceURI, final String localName, final boolean isId)
        throws DOMException {
        throw new UnsupportedOperationException("XmlElement.setIdAttributeNS is not yet implemented.");
    }

    /**
     * {@inheritDoc}
     * Not yet implemented.
     */
    public void setIdAttributeNode(final Attr idAttr, final boolean isId) throws DOMException {
        throw new UnsupportedOperationException("XmlElement.setIdAttributeNode is not yet implemented.");
    }

    /**
     * Just for debug purposes.
     * {@inheritDoc}
     */
    @Override
    public String toString() {
        return ClassUtils.getShortClassName(getClass())
            + "[<" + getTagName() + " ...>]";
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean hasAttributes() {
        return !attributes_.isEmpty();
    }
}