/*
 * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.sun.org.apache.xalan.internal.xsltc.compiler;

import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
import com.sun.org.apache.bcel.internal.generic.PUSH;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Util;
import com.sun.org.apache.xml.internal.serializer.ElemDesc;
import com.sun.org.apache.xml.internal.serializer.ToHTMLStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.List;
import java.util.Map;
import java.util.Set;

Author:
Jacek Ambroziak, Santiago Pericas-Geertsen, Morten Jorgensen
@LastModified
: Oct 2017/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 * @author Morten Jorgensen
 * @LastModified: Oct 2017
 */
final class LiteralElement extends Instruction {

    private String _name;
    private LiteralElement _literalElemParent = null;
    private List<SyntaxTreeNode> _attributeElements = null;
    private Map<String, String> _accessedPrefixes = null;

    // True if all attributes of this LRE are unique, i.e. they all have
    // different names. This flag is set to false if some attribute
    // names are not known at compile time.
    private boolean _allAttributesUnique = false;

    
Returns the QName for this literal element
/**
     * Returns the QName for this literal element
     */
    public QName getName() {
        return _qname;
    }

    
Displays the contents of this literal element
/**
     * Displays the contents of this literal element
     */
    public void display(int indent) {
        indent(indent);
        Util.println("LiteralElement name = " + _name);
        displayContents(indent + IndentIncrement);
    }

    
Returns the namespace URI for which a prefix is pointing to
/**
     * Returns the namespace URI for which a prefix is pointing to
     */
    private String accessedNamespace(String prefix) {
        if (_literalElemParent != null) {
            String result = _literalElemParent.accessedNamespace(prefix);
            if (result != null) {
                return result;
            }
        }
        return _accessedPrefixes != null ? _accessedPrefixes.get(prefix) : null;
    }

    
Method used to keep track of what namespaces that are references by
this literal element and its attributes. The output must contain a
definition for each namespace, so we stuff them in a map.
/**
     * Method used to keep track of what namespaces that are references by
     * this literal element and its attributes. The output must contain a
     * definition for each namespace, so we stuff them in a map.
     */
    public void registerNamespace(String prefix, String uri,
                                  SymbolTable stable, boolean declared) {

        // Check if the parent has a declaration for this namespace
        if (_literalElemParent != null) {
            final String parentUri = _literalElemParent.accessedNamespace(prefix);
            if (parentUri != null && parentUri.equals(uri)) {
                return;
            }
        }

        // Check if we have any declared namespaces
        if (_accessedPrefixes == null) {
            // use Hashtable for behavior compatibility
            _accessedPrefixes = new Hashtable<>();
        }
        else {
            if (!declared) {
                // Check if this node has a declaration for this namespace
                final String old = _accessedPrefixes.get(prefix);
                if (old != null) {
                    if (old.equals(uri))
                        return;
                    else
                        prefix = stable.generateNamespacePrefix();
                }
            }
        }

        if (!prefix.equals("xml")) {
            _accessedPrefixes.put(prefix,uri);
        }
    }

    
Translates the prefix of a QName according to the rules set in
the attributes of xsl:stylesheet. Also registers a QName to assure
that the output element contains the necessary namespace declarations.
/**
     * Translates the prefix of a QName according to the rules set in
     * the attributes of xsl:stylesheet. Also registers a QName to assure
     * that the output element contains the necessary namespace declarations.
     */
    private String translateQName(QName qname, SymbolTable stable) {
        // Break up the QName and get prefix:localname strings
        String localname = qname.getLocalPart();
        String prefix = qname.getPrefix();

        // Treat default namespace as "" and not null
        if (prefix == null)
            prefix = Constants.EMPTYSTRING;
        else if (prefix.equals(XMLNS_PREFIX))
            return(XMLNS_PREFIX);

        // Check if we must translate the prefix
        final String alternative = stable.lookupPrefixAlias(prefix);
        if (alternative != null) {
            stable.excludeNamespaces(prefix);
            prefix = alternative;
        }

        // Get the namespace this prefix refers to
        String uri = lookupNamespace(prefix);
        if (uri == null) return(localname);

        // Register the namespace as accessed
        registerNamespace(prefix, uri, stable, false);

        // Construct the new name for the element (may be unchanged)
        if (prefix != Constants.EMPTYSTRING)
            return(prefix+":"+localname);
        else
            return(localname);
    }

    
Add an attribute to this element
/**
     * Add an attribute to this element
     */
    public void addAttribute(SyntaxTreeNode attribute) {
        if (_attributeElements == null) {
            _attributeElements = new ArrayList<>(2);
        }
        _attributeElements.add(attribute);
    }

    
Set the first attribute of this element
/**
     * Set the first attribute of this element
     */
    public void setFirstAttribute(SyntaxTreeNode attribute) {
        if (_attributeElements == null) {
            _attributeElements = new ArrayList<>(2);
        }
        _attributeElements.add(0, attribute);
    }

    
Type-check the contents of this element. The element itself does not
need any type checking as it leaves nothign on the JVM's stack.
/**
     * Type-check the contents of this element. The element itself does not
     * need any type checking as it leaves nothign on the JVM's stack.
     */
    public Type typeCheck(SymbolTable stable) throws TypeCheckError {
        // Type-check all attributes
        if (_attributeElements != null) {
            for (SyntaxTreeNode node : _attributeElements) {
                node.typeCheck(stable);
            }
        }
        typeCheckContents(stable);
        return Type.Void;
    }

    
This method starts at a given node, traverses all namespace mappings,
and assembles a list of all prefixes that (for the given node) maps
to _ANY_ namespace URI. Used by literal result elements to determine
/**
     * This method starts at a given node, traverses all namespace mappings,
     * and assembles a list of all prefixes that (for the given node) maps
     * to _ANY_ namespace URI. Used by literal result elements to determine
     */
    public Set<Map.Entry<String, String>> getNamespaceScope(SyntaxTreeNode node) {
        Map<String, String> all = new HashMap<>();

        while (node != null) {
            Map<String, String> mapping = node.getPrefixMapping();
            if (mapping != null) {
                mapping.entrySet().stream().forEach((entry) -> {
                    all.putIfAbsent(entry.getKey(), entry.getValue());
                });
            }
            node = node.getParent();
        }
        return all.entrySet();
    }

    
Determines the final QName for the element and its attributes.
Registers all namespaces that are used by the element/attributes
/**
     * Determines the final QName for the element and its attributes.
     * Registers all namespaces that are used by the element/attributes
     */
    public void parseContents(Parser parser) {
        final SymbolTable stable = parser.getSymbolTable();
        stable.setCurrentNode(this);

        // Check if in a literal element context
        SyntaxTreeNode parent = getParent();
        if (parent != null && parent instanceof LiteralElement) {
            _literalElemParent = (LiteralElement) parent;
        }

        _name = translateQName(_qname, stable);

        // Process all attributes and register all namespaces they use
        final int count = _attributes.getLength();
        for (int i = 0; i < count; i++) {
            final QName qname = parser.getQName(_attributes.getQName(i));
            final String uri = qname.getNamespace();
            final String val = _attributes.getValue(i);

            // Handle xsl:use-attribute-sets. Attribute sets are placed first
            // in the vector or attributes to make sure that later local
            // attributes can override an attributes in the set.
            if (qname.equals(parser.getUseAttributeSets())) {
                if (!Util.isValidQNames(val)) {
                    ErrorMsg err = new ErrorMsg(ErrorMsg.INVALID_QNAME_ERR, val, this);
                    parser.reportError(Constants.ERROR, err);
               }
                setFirstAttribute(new UseAttributeSets(val, parser));
            }
            // Handle xsl:extension-element-prefixes
            else if (qname.equals(parser.getExtensionElementPrefixes())) {
                stable.excludeNamespaces(val);
            }
            // Handle xsl:exclude-result-prefixes
            else if (qname.equals(parser.getExcludeResultPrefixes())) {
                stable.excludeNamespaces(val);
            }
            else {
                // Ignore special attributes (e.g. xmlns:prefix and xmlns)
                final String prefix = qname.getPrefix();
                if (prefix != null && prefix.equals(XMLNS_PREFIX) ||
                    prefix == null && qname.getLocalPart().equals(XMLNS_PREFIX) ||
                    uri != null && uri.equals(XSLT_URI))
                {
                    continue;
                }

                // Handle all other literal attributes
                final String name = translateQName(qname, stable);
                LiteralAttribute attr = new LiteralAttribute(name, val, parser, this);
                addAttribute(attr);
                attr.setParent(this);
                attr.parseContents(parser);
            }
        }

        // Register all namespaces that are in scope, except for those that
        // are listed in the xsl:stylesheet element's *-prefixes attributes
        Set<Map.Entry<String, String>> include = getNamespaceScope(this);
        for (Map.Entry<String, String> entry : include) {
            final String prefix = entry.getKey();
            if (!prefix.equals("xml")) {
                final String uri = lookupNamespace(prefix);
                if (uri != null && !stable.isExcludedNamespace(uri)) {
                    registerNamespace(prefix, uri, stable, true);
                }
            }
        }

        parseChildren(parser);

        // Process all attributes and register all namespaces they use
        for (int i = 0; i < count; i++) {
            final QName qname = parser.getQName(_attributes.getQName(i));
            final String val = _attributes.getValue(i);

            // Handle xsl:extension-element-prefixes
            if (qname.equals(parser.getExtensionElementPrefixes())) {
                stable.unExcludeNamespaces(val);
            }
            // Handle xsl:exclude-result-prefixes
            else if (qname.equals(parser.getExcludeResultPrefixes())) {
                stable.unExcludeNamespaces(val);
            }
        }
    }

    protected boolean contextDependent() {
        return dependentContents();
    }

    
Compiles code that emits the literal element to the output handler,
first the start tag, then namespace declaration, then attributes,
then the element contents, and then the element end tag. Since the
value of an attribute may depend on a variable, variables must be
compiled first.
/**
     * Compiles code that emits the literal element to the output handler,
     * first the start tag, then namespace declaration, then attributes,
     * then the element contents, and then the element end tag. Since the
     * value of an attribute may depend on a variable, variables must be
     * compiled first.
     */
    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {

        final ConstantPoolGen cpg = classGen.getConstantPool();
        final InstructionList il = methodGen.getInstructionList();

        // Check whether all attributes are unique.
        _allAttributesUnique = checkAttributesUnique();

        // Compile code to emit element start tag
        il.append(methodGen.loadHandler());

        il.append(new PUSH(cpg, _name));
        il.append(DUP2);                // duplicate these 2 args for endElement
        il.append(methodGen.startElement());

        // The value of an attribute may depend on a (sibling) variable
        int j = 0;
        while (j < elementCount())  {
            final SyntaxTreeNode item = elementAt(j);
            if (item instanceof Variable) {
                item.translate(classGen, methodGen);
            }
            j++;
        }

        // Compile code to emit namespace attributes
        if (_accessedPrefixes != null) {
            for (Map.Entry<String, String> entry : _accessedPrefixes.entrySet()) {
                final String prefix = entry.getKey();
                final String uri = entry.getValue();
                il.append(methodGen.loadHandler());
                il.append(new PUSH(cpg, prefix));
                il.append(new PUSH(cpg, uri));
                il.append(methodGen.namespace());
            }
        }

        // Output all attributes
        if (_attributeElements != null) {
            for (SyntaxTreeNode node : _attributeElements) {
                if (!(node instanceof XslAttribute)) {
                    node.translate(classGen, methodGen);
                }
            }
        }

        // Compile code to emit attributes and child elements
        translateContents(classGen, methodGen);

        // Compile code to emit element end tag
        il.append(methodGen.endElement());
    }

    
Return true if the output method is html.
/**
     * Return true if the output method is html.
     */
    private boolean isHTMLOutput() {
        return getStylesheet().getOutputMethod() == Stylesheet.HTML_OUTPUT;
    }

    
Return the ElemDesc object for an HTML element.
Return null if the output method is not HTML or this is not a
valid HTML element.
/**
     * Return the ElemDesc object for an HTML element.
     * Return null if the output method is not HTML or this is not a
     * valid HTML element.
     */
    public ElemDesc getElemDesc() {
        if (isHTMLOutput()) {
            return ToHTMLStream.getElemDesc(_name);
        }
        else
            return null;
    }

    
Return true if all attributes of this LRE have unique names.
/**
     * Return true if all attributes of this LRE have unique names.
     */
    public boolean allAttributesUnique() {
        return _allAttributesUnique;
    }

    
Check whether all attributes are unique.
/**
     * Check whether all attributes are unique.
     */
    private boolean checkAttributesUnique() {
         boolean hasHiddenXslAttribute = canProduceAttributeNodes(this, true);
         if (hasHiddenXslAttribute)
             return false;

         if (_attributeElements != null) {
             int numAttrs = _attributeElements.size();
             Map<String, SyntaxTreeNode> attrsTable = null;
             for (int i = 0; i < numAttrs; i++) {
                 SyntaxTreeNode node = _attributeElements.get(i);

                 if (node instanceof UseAttributeSets) {
                     return false;
                 }
                 else if (node instanceof XslAttribute) {
                     if (attrsTable == null) {
                        attrsTable = new HashMap<>();
                         for (int k = 0; k < i; k++) {
                             SyntaxTreeNode n = _attributeElements.get(k);
                             if (n instanceof LiteralAttribute) {
                                 LiteralAttribute literalAttr = (LiteralAttribute)n;
                                 attrsTable.put(literalAttr.getName(), literalAttr);
                             }
                         }
                     }

                     XslAttribute xslAttr = (XslAttribute)node;
                     AttributeValue attrName = xslAttr.getName();
                     if (attrName instanceof AttributeValueTemplate) {
                         return false;
                     }
                     else if (attrName instanceof SimpleAttributeValue) {
                         SimpleAttributeValue simpleAttr = (SimpleAttributeValue)attrName;
                         String name = simpleAttr.toString();
                         if (name != null && attrsTable.get(name) != null)
                             return false;
                         else if (name != null) {
                             attrsTable.put(name, xslAttr);
                         }
                     }
                 }
             }
         }
         return true;
    }

    
Return true if the instructions under the given SyntaxTreeNode can produce attribute nodes
to an element. Only return false when we are sure that no attribute node is produced.
Return true if we are not sure. If the flag ignoreXslAttribute is true, the direct
 children of the current node are not included in the check.
/**
     * Return true if the instructions under the given SyntaxTreeNode can produce attribute nodes
     * to an element. Only return false when we are sure that no attribute node is produced.
     * Return true if we are not sure. If the flag ignoreXslAttribute is true, the direct
     * <xsl:attribute> children of the current node are not included in the check.
     */
    private boolean canProduceAttributeNodes(SyntaxTreeNode node, boolean ignoreXslAttribute) {
        List<SyntaxTreeNode> contents = node.getContents();
        for (SyntaxTreeNode child : contents) {
            if (child instanceof Text) {
                Text text = (Text)child;
                if (text.isIgnore())
                    continue;
                else
                    return false;
            }
            // Cannot add an attribute to an element after children have been added to it.
            // We can safely return false when the instruction can produce an output node.
            else if (child instanceof LiteralElement
                || child instanceof ValueOf
                || child instanceof XslElement
                || child instanceof Comment
                || child instanceof Number
                || child instanceof ProcessingInstruction)
                return false;
            else if (child instanceof XslAttribute) {
                if (ignoreXslAttribute)
                    continue;
                else
                    return true;
            }
            // In general, there is no way to check whether <xsl:call-template> or
            // <xsl:apply-templates> can produce attribute nodes. <xsl:copy> and
            // <xsl:copy-of> can also copy attribute nodes to an element. Return
            // true in those cases to be safe.
            else if (child instanceof CallTemplate
                || child instanceof ApplyTemplates
                || child instanceof Copy
                || child instanceof CopyOf)
                return true;
            else if ((child instanceof If
                       || child instanceof ForEach)
                     && canProduceAttributeNodes(child, false)) {
                return true;
            }
            else if (child instanceof Choose) {
                List<SyntaxTreeNode> chooseContents = child.getContents();
                for (SyntaxTreeNode chooseChild : chooseContents) {
                    if (chooseChild instanceof When || chooseChild instanceof Otherwise) {
                        if (canProduceAttributeNodes(chooseChild, false))
                            return true;
                    }
                }
            }
        }
        return false;
    }

}