/*
   Licensed to Plutext Pty Ltd under one or more contributor license agreements.  
   
 *  This file is part of docx4j.

    docx4j is licensed 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 org.docx4j.convert.out.common.preprocess;

import javax.xml.transform.TransformerException;

import org.docx4j.TraversalUtil;
import org.docx4j.convert.out.common.ConversionSectionWrapper;
import org.docx4j.model.fields.FldSimpleModel;
import org.docx4j.model.fields.FormattingSwitchHelper;
import org.docx4j.model.structure.HeaderFooterPolicy;
import org.docx4j.openpackaging.parts.WordprocessingML.FooterPart;
import org.docx4j.openpackaging.parts.WordprocessingML.HeaderPart;
import org.docx4j.utils.TraversalUtilVisitor;
import org.docx4j.wml.CTSimpleField;


/** This class collects information about the use of page numbering fields,
 *  and their formatting. <br>
 *  It checks for fields of the type: PAGE, NUMPAGES, SECTIONPAGES
 */
public class PageNumberInformationCollector {

	public static PageNumberInformation process(ConversionSectionWrapper sectionWrapper, boolean dummyPageNumbering) {
	PageNumberInformation ret = new PageNumberInformation(sectionWrapper.getSectPr());
	FieldVisitor fldVisitor = null;
	HeaderFooterPolicy headerFooterPolicy = sectionWrapper.getHeaderFooterPolicy();
		//If it is a dummyPageNumberInformation the data is read from the sectPr,
		//and it is assumed that there are no NUMPAGES and SECTIONPAGES fields
		//the result will allways be a single pass conversion.
		if (!dummyPageNumbering) {
			fldVisitor = new FieldVisitor(ret);
			TraversalUtil.visit(sectionWrapper.getContent(), fldVisitor);
			process(headerFooterPolicy.getFirstHeader(), fldVisitor);
			process(headerFooterPolicy.getFirstFooter(), fldVisitor);
			process(headerFooterPolicy.getDefaultHeader(), fldVisitor);
			process(headerFooterPolicy.getDefaultFooter(), fldVisitor);
			process(headerFooterPolicy.getEvenHeader(), fldVisitor);
			process(headerFooterPolicy.getEvenFooter(), fldVisitor);
		}
		return ret;
	}
	
	protected static void process(FooterPart footer, FieldVisitor fldVisitor) {
		if ((footer != null) && (!footer.getContent().isEmpty())) {
			TraversalUtil.visit(footer.getContent(), fldVisitor);
		}
	}
	
	protected static void process(HeaderPart header, FieldVisitor fldVisitor) {
		if ((header != null) && (!header.getContent().isEmpty())) {
			TraversalUtil.visit(header.getContent(), fldVisitor);
		}
	}

	protected static class FieldVisitor extends TraversalUtilVisitor<CTSimpleField> {
		private static final Object PAGE_FIELD_TYPE = "PAGE";
		private static final Object NUMPAGES_FIELD_TYPE = "NUMPAGES";
		private static final Object SECTIONPAGES_FIELD_TYPE = "SECTIONPAGES";
		
		protected PageNumberInformation results = null;
		protected FldSimpleModel fldSimpleModel = new FldSimpleModel();
		
		public FieldVisitor(PageNumberInformation results) {
			this.results = results;
		}

		@Override
		public void apply(CTSimpleField element) {
		String instr = element.getInstr();
		String fieldType = FormattingSwitchHelper.getFldSimpleName(instr);
			if (PAGE_FIELD_TYPE.equals(fieldType)) {
				results.setPagePresent(true);
				results.setPageFormat(extractFormat(instr));
			}
			else if (NUMPAGES_FIELD_TYPE.equals(fieldType)) {
				results.setNumpagesPresent(true);
				results.setNumpagesFormat(extractFormat(instr));
			}
			else if (SECTIONPAGES_FIELD_TYPE.equals(fieldType)) {
				results.setSectionpagesPresent(true);
				results.setSectionpagesFormat(extractFormat(instr));
			}
		}

		protected String extractFormat(String instr) {
		String ret = null;
			try {
				fldSimpleModel.build(instr);
				return FormattingSwitchHelper.findFirstSwitchValue("\\*", fldSimpleModel.getFldParameters(), true);
			} catch (TransformerException e) {
				ret = null;
			}
			return ret;
		}
		
	}
}