/*
 * 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.
 */
/*
 * $Id$
 */

package org.apache.xalan.xsltc.compiler;

import java.util.Vector;

import org.apache.bcel.generic.ALOAD;
import org.apache.bcel.generic.ASTORE;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.GETFIELD;
import org.apache.bcel.generic.INVOKESTATIC;
import org.apache.bcel.generic.INVOKEVIRTUAL;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.LocalVariableGen;
import org.apache.bcel.generic.PUSH;
import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
import org.apache.xalan.xsltc.compiler.util.ErrorMsg;
import org.apache.xalan.xsltc.compiler.util.MethodGenerator;
import org.apache.xalan.xsltc.compiler.util.Type;
import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
import org.apache.xalan.xsltc.compiler.util.Util;

import org.apache.xml.serializer.ElemDesc;
import org.apache.xml.serializer.SerializationHandler;
import org.apache.xml.utils.XML11Char;

/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 * @author Morten Jorgensen
 * @author Erwin Bolwidt <ejb@klomp.org>
 * @author Gunnlaugur Briem <gthb@dimon.is>
 */
final class XslAttribute extends Instruction {

    private String _prefix;
    private AttributeValue _name; 	// name treated as AVT (7.1.3)
    private AttributeValueTemplate _namespace = null;
    private boolean _ignore = false;
    private boolean _isLiteral = false;  // specified name is not AVT  

    /**
     * Returns the name of the attribute
     */
    public AttributeValue getName() {
	return _name;
    }

    /**
     * Displays the contents of the attribute
     */
    public void display(int indent) {
	indent(indent);
	Util.println("Attribute " + _name);
	displayContents(indent + IndentIncrement);
    }
		
    /**
     * Parses the attribute's contents. Special care taken for namespaces.
     */
    public void parseContents(Parser parser) {
	boolean generated = false;
	final SymbolTable stable = parser.getSymbolTable();

	String name = getAttribute("name");
	String namespace = getAttribute("namespace");
	QName qname = parser.getQName(name, false);
	final String prefix = qname.getPrefix();

        if (((prefix != null) && (prefix.equals(XMLNS_PREFIX)))||(name.equals(XMLNS_PREFIX))) {
	    reportError(this, parser, ErrorMsg.ILLEGAL_ATTR_NAME_ERR, name);
	    return;
	}
  
        _isLiteral = Util.isLiteral(name);
        if (_isLiteral) {
            if (!XML11Char.isXML11ValidQName(name)) {
                reportError(this, parser, ErrorMsg.ILLEGAL_ATTR_NAME_ERR, name);
                return;
            }
        }

	// Ignore attribute if preceeded by some other type of element
	final SyntaxTreeNode parent = getParent();
	final Vector siblings = parent.getContents();
	for (int i = 0; i < parent.elementCount(); i++) {
	    SyntaxTreeNode item = (SyntaxTreeNode)siblings.elementAt(i);
	    if (item == this) break;

	    // These three objects result in one or more attribute output
	    if (item instanceof XslAttribute) continue;
	    if (item instanceof UseAttributeSets) continue;
	    if (item instanceof LiteralAttribute) continue;
	    if (item instanceof Text) continue;

	    // These objects _can_ result in one or more attribute
	    // The output handler will generate an error if not (at runtime)
	    if (item instanceof If) continue;
	    if (item instanceof Choose) continue;
 	    if (item instanceof CopyOf) continue;
 	    if (item instanceof VariableBase) continue;

	    // Report warning but do not ignore attribute
	    reportWarning(this, parser, ErrorMsg.STRAY_ATTRIBUTE_ERR, name);
	}

	// Get namespace from namespace attribute?
	if (namespace != null && namespace != Constants.EMPTYSTRING) {
	    _prefix = lookupPrefix(namespace);
	    _namespace = new AttributeValueTemplate(namespace, parser, this);
	}
	// Get namespace from prefix in name attribute?
	else if (prefix != null && prefix != Constants.EMPTYSTRING) {
	    _prefix = prefix;
	    namespace = lookupNamespace(prefix);
	    if (namespace != null) {
		_namespace = new AttributeValueTemplate(namespace, parser, this);
	    }
	}
	
	// Common handling for namespaces:
	if (_namespace != null) {
	    // Generate prefix if we have none
	    if (_prefix == null || _prefix == Constants.EMPTYSTRING) {
		if (prefix != null) {
		    _prefix = prefix;
		}
		else {
		    _prefix = stable.generateNamespacePrefix();
		    generated = true;
		}
	    }
	    else if (prefix != null && !prefix.equals(_prefix)) {
		_prefix = prefix;
	    }

	    name = _prefix + ":" + qname.getLocalPart();

	    /*
	     * TODO: The namespace URI must be passed to the parent 
	     * element but we don't yet know what the actual URI is 
	     * (as we only know it as an attribute value template). 
	     */
	    if ((parent instanceof LiteralElement) && (!generated)) {
		((LiteralElement)parent).registerNamespace(_prefix,
							   namespace,
							   stable, false);
	    }
	}

	if (parent instanceof LiteralElement) {
	    ((LiteralElement)parent).addAttribute(this);
	}

	_name = AttributeValue.create(this, name, parser);
	parseChildren(parser);
    }
	
    public Type typeCheck(SymbolTable stable) throws TypeCheckError {
	if (!_ignore) {
	    _name.typeCheck(stable);
	    if (_namespace != null) {
		_namespace.typeCheck(stable);
	    }
	    typeCheckContents(stable);
	}
	return Type.Void;
    }

    /**
     *
     */
    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
	final ConstantPoolGen cpg = classGen.getConstantPool();
	final InstructionList il = methodGen.getInstructionList();

	if (_ignore) return;
	_ignore = true;    

	// Compile code that emits any needed namespace declaration
	if (_namespace != null) {
	    // public void attribute(final String name, final String value)
	    il.append(methodGen.loadHandler());
	    il.append(new PUSH(cpg,_prefix));
	    _namespace.translate(classGen,methodGen);
	    il.append(methodGen.namespace());
	}
    
        if (!_isLiteral) {
            // if the qname is an AVT, then the qname has to be checked at runtime if it is a valid qname
            LocalVariableGen nameValue =
                    methodGen.addLocalVariable2("nameValue",
                                                Util.getJCRefType(STRING_SIG),
                                                null);
                    
            // store the name into a variable first so _name.translate only needs to be called once  
            _name.translate(classGen, methodGen);
            nameValue.setStart(il.append(new ASTORE(nameValue.getIndex())));
            il.append(new ALOAD(nameValue.getIndex()));
            
            // call checkQName if the name is an AVT
            final int check = cpg.addMethodref(BASIS_LIBRARY_CLASS, "checkAttribQName",
                            "("
                            +STRING_SIG
                            +")V");                 
            il.append(new INVOKESTATIC(check));
            
            // Save the current handler base on the stack
            il.append(methodGen.loadHandler());
            il.append(DUP);     // first arg to "attributes" call            
            
            // load name value again    
            nameValue.setEnd(il.append(new ALOAD(nameValue.getIndex())));            
        } else {    
            // Save the current handler base on the stack
            il.append(methodGen.loadHandler());
            il.append(DUP);     // first arg to "attributes" call
            
            // Push attribute name
            _name.translate(classGen, methodGen);// 2nd arg
    
        }

	// Push attribute value - shortcut for literal strings
	if ((elementCount() == 1) && (elementAt(0) instanceof Text)) {
	    il.append(new PUSH(cpg, ((Text)elementAt(0)).getText()));
	}
	else {
	    il.append(classGen.loadTranslet());
	    il.append(new GETFIELD(cpg.addFieldref(TRANSLET_CLASS,
						   "stringValueHandler",
						   STRING_VALUE_HANDLER_SIG)));
	    il.append(DUP);
	    il.append(methodGen.storeHandler());
	    // translate contents with substituted handler
	    translateContents(classGen, methodGen);
	    // get String out of the handler
	    il.append(new INVOKEVIRTUAL(cpg.addMethodref(STRING_VALUE_HANDLER,
							 "getValue",
							 "()" + STRING_SIG)));
	}

	SyntaxTreeNode parent = getParent();
	if (parent instanceof LiteralElement
	    && ((LiteralElement)parent).allAttributesUnique()) {
            int flags = 0;
	    ElemDesc elemDesc = ((LiteralElement)parent).getElemDesc();
	    
	    // Set the HTML flags
	    if (elemDesc != null && _name instanceof SimpleAttributeValue) {
	    	String attrName = ((SimpleAttributeValue)_name).toString();
	    	if (elemDesc.isAttrFlagSet(attrName, ElemDesc.ATTREMPTY)) {
	    	    flags = flags | SerializationHandler.HTML_ATTREMPTY;
	    	}
	    	else if (elemDesc.isAttrFlagSet(attrName, ElemDesc.ATTRURL)) {
	    	    flags = flags | SerializationHandler.HTML_ATTRURL;
	    	}
	    }
	    il.append(new PUSH(cpg, flags));
	    il.append(methodGen.uniqueAttribute());    
	}
	else {
	    // call "attribute"
	    il.append(methodGen.attribute());
	}
            
	// Restore old handler base from stack
	il.append(methodGen.storeHandler());
    

        
    }

}