////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2018 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.NodeInfo;
import net.sf.saxon.om.NodeName;
import net.sf.saxon.tree.tiny.NodeVectorTree;
import net.sf.saxon.type.ItemType;
import net.sf.saxon.type.SchemaType;
import net.sf.saxon.type.Type;
import net.sf.saxon.type.UType;
import java.util.function.IntPredicate;

/**
 * An AnyChildNodePattern is the pattern node(), which matches any node except a root node,
 * an attribute node, or a namespace node: in other words, any node that is potentially the child of another
 * node. But it matches the node whether or not it actually has a parent.
 */

public final class AnyChildNodeTest extends NodeTest {

    private final static AnyChildNodeTest THE_INSTANCE = new AnyChildNodeTest();

    /**
     * Get the singular instance of this class
     *
     * @return the singular instance
     */

    public static AnyChildNodeTest getInstance() {
        return THE_INSTANCE;
    }

    private AnyChildNodeTest() {
    }

    /**
     * Get the corresponding {@link net.sf.saxon.type.UType}. A UType is a union of primitive item
     * types.
     *
     * @return the smallest UType that subsumes this item type
     */
    public UType getUType() {
        return UType.CHILD_NODE_KINDS;
    }

    /**
     * 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, NodeName name, SchemaType annotation) {
        return  nodeKind == Type.ELEMENT ||
                nodeKind == Type.TEXT ||
                nodeKind == Type.COMMENT ||
                nodeKind == Type.PROCESSING_INSTRUCTION;
    }

    public IntPredicate getMatcher(final NodeVectorTree tree) {
        final byte[] nodeKindArray = tree.getNodeKindArray();
        return nodeNr -> {
            int nodeKind = nodeKindArray[nodeNr] & 0x0f;
            return nodeKind == Type.ELEMENT ||
                    nodeKind == Type.TEXT ||
                    nodeKind == Type.WHITESPACE_TEXT ||
                    nodeKind == Type.COMMENT ||
                    nodeKind == Type.PROCESSING_INSTRUCTION;
        };
    }

    /**
     * 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 matchesNode(NodeInfo node) {
        int nodeKind = node.getNodeKind();
        return  nodeKind == Type.ELEMENT ||
                nodeKind == Type.TEXT ||
                nodeKind == Type.COMMENT ||
                nodeKind == Type.PROCESSING_INSTRUCTION;
    }


    /**
     * Determine the default priority to use if this pattern appears as a match pattern
     * for a template with no explicit priority attribute.
     */

    public double getDefaultPriority() {
        return -0.5;
    }

    /*@NotNull*/
    public String toString() {
        return "( element() | text() | comment() | processing-instruction() )";
    }


    /**
     * Generate Javascript code to test whether an item conforms to this item type
     *
     * @return a Javascript instruction or sequence of instructions, which can be used as the body
     * of a Javascript function, and which returns a boolean indication whether the value of the
     * variable "item" is an instance of this item type.
     * @param knownToBe An item type that the supplied item is known to conform to; the generated code
     *                  can assume that the item is an instance of this type.
     * @param targetVersion The version of Saxon-JS for which code is being generated. Currently either 1 or 2.

     */
    @Override
    public String generateJavaScriptItemTypeTest(ItemType knownToBe, int targetVersion) {
        return "return SaxonJS.U.isNode(item) && (item.nodeType===1 || item.nodeType===3 || item.nodeType===7 || item.nodeType===8);";
    }


}

