////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2013 Saxonica Limited.
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is "Incompatible With Secondary Licenses", as defined by the Mozilla Public License, v. 2.0.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

package net.sf.saxon.pattern;

import net.sf.saxon.om.NamePool;
import net.sf.saxon.om.NodeInfo;
import net.sf.saxon.om.NodeName;
import net.sf.saxon.om.StructuredQName;
import net.sf.saxon.tree.tiny.TinyTree;
import net.sf.saxon.type.ItemType;
import net.sf.saxon.type.TypeHierarchy;

/**
  * NodeTest is an interface that enables a test of whether a node has a particular
  * name and type. A NamespaceTest matches the node type and the namespace URI.
  *
  * @author Michael H. Kay
  */

public final class NamespaceTest extends NodeTest implements QNameTest {

	private NamePool namePool;
	private int nodeKind;
	private short uriCode;
    private String uri;

	public NamespaceTest(NamePool pool, int nodeKind, String uri) {
	    namePool = pool;
		this.nodeKind = nodeKind;
        this.uri = uri;
		this.uriCode = pool.allocateCodeForURI(uri);
	}

    /**
     * Get the node kind matched by this test
     * @return the matching node kind
     */

    public int getNodeKind() {
        return nodeKind;
    }

    /**
     * Test whether this node test is satisfied by a given node. This method is only
     * fully supported for a subset of NodeTests, because it doesn't provide all the information
     * needed to evaluate all node tests. In particular (a) it can't be used to evaluate a node
     * test of the form element(N,T) or schema-element(E) where it is necessary to know whether the
     * node is nilled, and (b) it can't be used to evaluate a node test of the form
     * document-node(element(X)). This in practice means that it is used (a) to evaluate the
     * simple node tests found in the XPath 1.0 subset used in XML Schema, and (b) to evaluate
     * node tests where the node kind is known to be an attribute.
     *
     * @param nodeKind   The kind of node to be matched
     * @param name       identifies the expanded name of the node to be matched.
     *                   The value should be null for a node with no name.
     * @param annotation The actual content type of the node
     */
    @Override
    public boolean matches(int nodeKind, /*@Nullable*/ NodeName name, int annotation) {
        return name != null && name.isInNamespace(uri);
    }

    /**
     * Test whether this node test is satisfied by a given node on a TinyTree. The node
     * must be a document, element, text, comment, or processing instruction node.
     * This method is provided
     * so that when navigating a TinyTree a node can be rejected without
     * actually instantiating a NodeInfo object.
     *
     * @param tree   the TinyTree containing the node
     * @param nodeNr the number of the node within the TinyTree
     */

    public boolean matches(TinyTree tree, int nodeNr) {
        int nameCode = tree.getNameCode(nodeNr);
        return nameCode != -1 &&
                tree.getNodeKind(nodeNr) == nodeKind &&
                uriCode == namePool.getURICode(nameCode);
    }

    /**
     * Test whether this node test is satisfied by a given node. This alternative
     * method is used in the case of nodes where calculating the fingerprint is expensive,
     * for example DOM or JDOM nodes.
     * @param node the node to be matched
     */

    public boolean matches(NodeInfo node) {
        return node.getNodeKind()==nodeKind && node.getURI().equals(uri);
    }

    /**
     * Test whether this NamespaceTest matches a given QName
     * @param qname the QName to be matched
     * @return true if the name matches, false if not
     */

    public boolean matches(StructuredQName qname) {
        return qname.getURI().equals(uri);
    }

    /**
    * Determine the default priority of this node test when used on its own as a Pattern
    */

    public final double getDefaultPriority() {
    	return -0.25;
    }

    /**
    * Determine the types of nodes to which this pattern applies. Used for optimisation.
    * For patterns that match nodes of several types, return Type.NODE
    * @return the type of node matched by this pattern. e.g. Type.ELEMENT or Type.TEXT
    */

    public int getPrimitiveType() {
        return nodeKind;
    }

    /**
     * Get the type from which this item type is derived by restriction. This
     * is the supertype in the XPath type heirarchy, as distinct from the Schema
     * base type: this means that the supertype of xs:boolean is xs:anyAtomicType,
     * whose supertype is item() (rather than xs:anySimpleType).
     * <p>
     * In fact the concept of "supertype" is not really well-defined, because the types
     * form a lattice rather than a hierarchy. The only real requirement on this function
     * is that it returns a type that strictly subsumes this type, ideally as narrowly
     * as possible.
     * @return the supertype, or null if this type is item()
     * @param th the type hierarchy cache
     */

    public ItemType getSuperType(TypeHierarchy th) {
        return NodeKindTest.makeNodeKindTest(nodeKind);
    }

    /**
     * Get a mask indicating which kinds of nodes this NodeTest can match. This is a combination
     * of bits: 1<<Type.ELEMENT for element nodes, 1<<Type.TEXT for text nodes, and so on.
     */

    public int getNodeKindMask() {
        return 1<<nodeKind;
    }

    /**
     * Get the namespace URI matched by this NamespaceTest
     * @return  the namespace URI matched by this NamespaceTest
     */

    public String getNamespaceURI() {
        return uri;
    }

    public String toString() {
        return '{' + uri + "}:*";
    }

    /**
     * Returns a hash code value for the object.
     */

    public int hashCode() {
        return uriCode << 5 + nodeKind;
    }

    /**
     * Indicates whether some other object is "equal to" this one.
     */
    public boolean equals(Object other) {
        return other instanceof NamespaceTest &&
                ((NamespaceTest)other).namePool == namePool &&
                ((NamespaceTest)other).nodeKind == nodeKind &&
                ((NamespaceTest)other).uriCode == uriCode;
    }

}