/*
 * 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.io.OutputStreamWriter;
import java.util.Properties;
import java.util.StringTokenizer;

import javax.xml.transform.OutputKeys;

import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.INVOKEVIRTUAL;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.PUSH;
import org.apache.bcel.generic.PUTFIELD;
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.Util;
import org.apache.xml.serializer.Encodings;
import org.apache.xml.utils.XML11Char;

/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 * @author Morten Jorgensen
 */
final class Output extends TopLevelElement {

    // TODO: use three-value variables for boolean values: true/false/default

    // These attributes are extracted from the xsl:output element. They also
    // appear as fields (with the same type, only public) in the translet
    private String  _version;
    private String  _method;
    private String  _encoding;
    private boolean _omitHeader = false;
    private String  _standalone;
    private String  _doctypePublic;
    private String  _doctypeSystem;
    private String  _cdata;
    private boolean _indent = false;
    private String  _mediaType;
    private String _indentamount;
    
    // Disables this output element (when other element has higher precedence)
    private boolean _disabled = false;

    // Some global constants
    private final static String STRING_SIG = "Ljava/lang/String;";
    private final static String XML_VERSION = "1.0";
    private final static String HTML_VERSION = "4.0";

    /**
     * Displays the contents of this element (for debugging)
     */
    public void display(int indent) {
	indent(indent);
	Util.println("Output " + _method);
    }

    /**
     * Disables this <xsl:output> element in case where there are some other
     * <xsl:output> element (from a different imported/included stylesheet)
     * with higher precedence.
     */
    public void disable() {
	_disabled = true;
    }

    public boolean enabled() {
	return !_disabled;
    }

    public String getCdata() {
	return _cdata;
    }

    public String getOutputMethod() {
    	return _method;
    }
    
    private void transferAttribute(Output previous, String qname) {
        if (!hasAttribute(qname) && previous.hasAttribute(qname)) {
            addAttribute(qname, previous.getAttribute(qname));            
        }        
    }
    
    public void mergeOutput(Output previous) {
        // Transfer attributes from previous xsl:output
        transferAttribute(previous, "version");
        transferAttribute(previous, "method");
        transferAttribute(previous, "encoding");
        transferAttribute(previous, "doctype-system");
        transferAttribute(previous, "doctype-public");      
        transferAttribute(previous, "media-type");
        transferAttribute(previous, "indent");        
        transferAttribute(previous, "omit-xml-declaration");
        transferAttribute(previous, "standalone");
        
        // Merge cdata-section-elements
        if (previous.hasAttribute("cdata-section-elements")) {
            // addAttribute works as a setter if it already exists
            addAttribute("cdata-section-elements",
                previous.getAttribute("cdata-section-elements") + ' ' +
                getAttribute("cdata-section-elements"));
        }

        // Transfer non-standard attributes as well
        String prefix = lookupPrefix("http://xml.apache.org/xalan");
        if (prefix != null) {
            transferAttribute(previous, prefix + ':' + "indent-amount");
        }
        prefix = lookupPrefix("http://xml.apache.org/xslt");
        if (prefix != null) {
            transferAttribute(previous, prefix + ':' + "indent-amount");
        }                
    }

    /**
     * Scans the attribute list for the xsl:output instruction
     */
    public void parseContents(Parser parser) {
	final Properties outputProperties = new Properties();

	// Ask the parser if it wants this <xsl:output> element
	parser.setOutput(this);

	// Do nothing if other <xsl:output> element has higher precedence
	if (_disabled) return;

	String attrib = null;

	// Get the output version
	_version = getAttribute("version");
	if (_version.equals(Constants.EMPTYSTRING)) {
	    _version = null;
	}
	else {
	    outputProperties.setProperty(OutputKeys.VERSION, _version);
	}

	// Get the output method - "xml", "html", "text" or <qname> (but not ncname)
	_method = getAttribute("method");
	if (_method.equals(Constants.EMPTYSTRING)) {
	    _method = null;
	}
	if (_method != null) {
            _method = _method.toLowerCase();
            if ((_method.equals("xml"))||
                (_method.equals("html"))||
                (_method.equals("text"))||
                ((XML11Char.isXML11ValidQName(_method)&&(_method.indexOf(":") > 0)))) {
	       outputProperties.setProperty(OutputKeys.METHOD, _method);
            } else {
                reportError(this, parser, ErrorMsg.INVALID_METHOD_IN_OUTPUT, _method);
            }
	}

	// Get the output encoding - any value accepted here
	_encoding = getAttribute("encoding");
	if (_encoding.equals(Constants.EMPTYSTRING)) {
	    _encoding = null;
	}
	else {
	    try {
		// Create a write to verify encoding support
                String canonicalEncoding;
                canonicalEncoding = Encodings.convertMime2JavaEncoding(_encoding);
		OutputStreamWriter writer =
		    new OutputStreamWriter(System.out, canonicalEncoding); 
	    }
	    catch (java.io.UnsupportedEncodingException e) {
		ErrorMsg msg = new ErrorMsg(ErrorMsg.UNSUPPORTED_ENCODING,
					    _encoding, this);
		parser.reportError(Constants.WARNING, msg);
	    }
	    outputProperties.setProperty(OutputKeys.ENCODING, _encoding);
	}

	// Should the XML header be omitted - translate to true/false
	attrib = getAttribute("omit-xml-declaration");
	if (!attrib.equals(Constants.EMPTYSTRING)) {
	    if (attrib.equals("yes")) {
		_omitHeader = true;
	    }
	    outputProperties.setProperty(OutputKeys.OMIT_XML_DECLARATION, attrib);
	}

	// Add 'standalone' decaration to output - use text as is
	_standalone = getAttribute("standalone");
	if (_standalone.equals(Constants.EMPTYSTRING)) {
	    _standalone = null;
	}
	else {
	    outputProperties.setProperty(OutputKeys.STANDALONE, _standalone);
	}

	// Get system/public identifiers for output DOCTYPE declaration
	_doctypeSystem = getAttribute("doctype-system");
	if (_doctypeSystem.equals(Constants.EMPTYSTRING)) {
	    _doctypeSystem = null;
	}
	else {
	    outputProperties.setProperty(OutputKeys.DOCTYPE_SYSTEM, _doctypeSystem);
	}


	_doctypePublic = getAttribute("doctype-public");
	if (_doctypePublic.equals(Constants.EMPTYSTRING)) {
	    _doctypePublic = null;
	}
	else {
	    outputProperties.setProperty(OutputKeys.DOCTYPE_PUBLIC, _doctypePublic);
	}

	// Names the elements of whose text contents should be output as CDATA
	_cdata = getAttribute("cdata-section-elements");
	if (_cdata.equals(Constants.EMPTYSTRING)) {
	    _cdata = null;
	}
	else {
	    StringBuffer expandedNames = new StringBuffer();
	    StringTokenizer tokens = new StringTokenizer(_cdata);

	    // Make sure to store names in expanded form
	    while (tokens.hasMoreTokens()) {
            	String qname = tokens.nextToken();
                if (!XML11Char.isXML11ValidQName(qname)) {
                    ErrorMsg err = new ErrorMsg(ErrorMsg.INVALID_QNAME_ERR, qname, this);
                    parser.reportError(Constants.ERROR, err);	
                }	    	
		expandedNames.append(
        	   parser.getQName(qname).toString()).append(' ');
	    }
	    _cdata = expandedNames.toString();
	    outputProperties.setProperty(OutputKeys.CDATA_SECTION_ELEMENTS, 
		_cdata);
	}

	// Get the indent setting - only has effect for xml and html output
	attrib = getAttribute("indent");
	if (!attrib.equals(EMPTYSTRING)) {
	    if (attrib.equals("yes")) {
		_indent = true;
	    }
	    outputProperties.setProperty(OutputKeys.INDENT, attrib);
	}
	else if (_method != null && _method.equals("html")) {
	    _indent = true;
	}
	
        // indent-amount: extension attribute of xsl:output
        _indentamount = getAttribute(
            lookupPrefix("http://xml.apache.org/xalan"), "indent-amount");
        //  Hack for supporting Old Namespace URI.
        if (_indentamount.equals(EMPTYSTRING)){
            _indentamount = getAttribute(
                lookupPrefix("http://xml.apache.org/xslt"), "indent-amount");
        }
        if (!_indentamount.equals(EMPTYSTRING)) {
            outputProperties.setProperty("indent_amount", _indentamount);
        }
        
	// Get the MIME type for the output file
	_mediaType = getAttribute("media-type");
	if (_mediaType.equals(Constants.EMPTYSTRING)) {
	    _mediaType = null;
	}
	else {
	    outputProperties.setProperty(OutputKeys.MEDIA_TYPE, _mediaType);
	}

	// Implied properties
	if (_method != null) {
	    if (_method.equals("html")) {
		if (_version == null) {
		    _version = HTML_VERSION;
		}
		if (_mediaType == null) {
		    _mediaType = "text/html";
		}
	    }
	    else if (_method.equals("text")) {
		if (_mediaType == null) {
		    _mediaType = "text/plain";
		}
	    }
	}

	// Set output properties in current stylesheet
	parser.getCurrentStylesheet().setOutputProperties(outputProperties);
    }

    /**
     * Compile code that passes the information in this <xsl:output> element
     * to the appropriate fields in the translet
     */
    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {

	// Do nothing if other <xsl:output> element has higher precedence
	if (_disabled) return;

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

	int field = 0;
        il.append(classGen.loadTranslet());

	// Only update _version field if set and different from default
	if ((_version != null) && (!_version.equals(XML_VERSION))) {
	    field = cpg.addFieldref(TRANSLET_CLASS, "_version", STRING_SIG);
	    il.append(DUP);
	    il.append(new PUSH(cpg, _version));
	    il.append(new PUTFIELD(field));
	}

	// Only update _method field if "method" attribute used
	if (_method != null) {
	    field = cpg.addFieldref(TRANSLET_CLASS, "_method", STRING_SIG);
	    il.append(DUP);
	    il.append(new PUSH(cpg, _method));
	    il.append(new PUTFIELD(field));
	}

	// Only update if _encoding field is "encoding" attribute used
	if (_encoding != null) {
	    field = cpg.addFieldref(TRANSLET_CLASS, "_encoding", STRING_SIG);
	    il.append(DUP);
	    il.append(new PUSH(cpg, _encoding));
	    il.append(new PUTFIELD(field));
	}

	// Only update if "omit-xml-declaration" used and set to 'yes'
	if (_omitHeader) {
	    field = cpg.addFieldref(TRANSLET_CLASS, "_omitHeader", "Z");
	    il.append(DUP);
	    il.append(new PUSH(cpg, _omitHeader));
	    il.append(new PUTFIELD(field));
	}

	// Add 'standalone' decaration to output - use text as is
	if (_standalone != null) {
	    field = cpg.addFieldref(TRANSLET_CLASS, "_standalone", STRING_SIG);
	    il.append(DUP);
	    il.append(new PUSH(cpg, _standalone));
	    il.append(new PUTFIELD(field));
	}

	// Set system/public doctype only if both are set
	field = cpg.addFieldref(TRANSLET_CLASS,"_doctypeSystem",STRING_SIG);
	il.append(DUP);
	il.append(new PUSH(cpg, _doctypeSystem));
	il.append(new PUTFIELD(field));
	field = cpg.addFieldref(TRANSLET_CLASS,"_doctypePublic",STRING_SIG);
	il.append(DUP);
	il.append(new PUSH(cpg, _doctypePublic));
	il.append(new PUTFIELD(field));
	
	// Add 'medye-type' decaration to output - if used
	if (_mediaType != null) {
	    field = cpg.addFieldref(TRANSLET_CLASS, "_mediaType", STRING_SIG);
	    il.append(DUP);
	    il.append(new PUSH(cpg, _mediaType));
	    il.append(new PUTFIELD(field));
	}

	// Compile code to set output indentation on/off
	if (_indent) {
	    field = cpg.addFieldref(TRANSLET_CLASS, "_indent", "Z");
	    il.append(DUP);
	    il.append(new PUSH(cpg, _indent));
	    il.append(new PUTFIELD(field));
	}

        //Compile code to set indent amount.
        if(_indentamount != null && !_indentamount.equals(EMPTYSTRING)){
            field = cpg.addFieldref(TRANSLET_CLASS, "_indentamount", "I");
	    il.append(DUP);
	    il.append(new PUSH(cpg, Integer.parseInt(_indentamount)));
	    il.append(new PUTFIELD(field));
        }
        
	// Forward to the translet any elements that should be output as CDATA
	if (_cdata != null) {
	    int index = cpg.addMethodref(TRANSLET_CLASS,
					 "addCdataElement",
					 "(Ljava/lang/String;)V");

	    StringTokenizer tokens = new StringTokenizer(_cdata);
	    while (tokens.hasMoreTokens()) {
		il.append(DUP);
		il.append(new PUSH(cpg, tokens.nextToken()));
		il.append(new INVOKEVIRTUAL(index));
	    }
	}
	il.append(POP); // Cleanup - pop last translet reference off stack
    }

}
