/* ====================================================================
   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 org.apache.poi.hslf.record;

import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;

import org.apache.poi.util.LittleEndian;

import static org.apache.logging.log4j.util.Unbox.box;

/**
 * A container record that specifies information about the footers on a presentation slide.
 * <p>
 * It contains:
 * <ul>
 * <li> 1. {@link HeadersFootersAtom}
 * <li> 2. {@link CString }, Instance UserDate (0), optional: Stores the user's date.
 *    This is the date that the user wants in the footers, instead of today's date.
 * <li> 3. {@link CString }, Instance Header (1), optional: Stores the Header's contents.
 * <li> 4. {@link CString }, Instance Footer (2), optional: Stores the Footer's contents.
 * </ul>
 */
public final class HeadersFootersContainer extends RecordContainer {

    /**
     * "instance" field in the record header indicating that this HeadersFootersContaine
     *  is applied for slides
     */
    public static final short SlideHeadersFootersContainer = 0x3F;
    /**
      * "instance" field in the record header indicating that this HeadersFootersContaine
     *   is applied for notes and handouts
      */
    public static final short NotesHeadersFootersContainer = 0x4F;

    public static final int USERDATEATOM    = 0;
    public static final int HEADERATOM      = 1;
    public static final int FOOTERATOM      = 2;

    private byte[] _header;
    private HeadersFootersAtom hdAtom;
    private CString csDate, csHeader, csFooter;

    protected HeadersFootersContainer(byte[] source, int start, int len) {
        // Grab the header
        _header = Arrays.copyOfRange(source, start, start+8);

        _children = Record.findChildRecords(source,start+8,len-8);
        findInterestingChildren();
    }

    /**
     * Go through our child records, picking out the ones that are
     *  interesting, and saving those for use by the easy helper
     *  methods.
     */
    private void findInterestingChildren() {
        for (Record child : _children) {
            if (child instanceof HeadersFootersAtom) {
                hdAtom = (HeadersFootersAtom) child;
            } else if (child instanceof CString) {
                CString cs = (CString) child;
                int opts = cs.getOptions() >> 4;
                switch (opts) {
                    case USERDATEATOM:
                        csDate = cs;
                        break;
                    case HEADERATOM:
                        csHeader = cs;
                        break;
                    case FOOTERATOM:
                        csFooter = cs;
                        break;
                    default:
                        LOG.atWarn().log("Unexpected CString.Options in HeadersFootersContainer: {}", box(opts));
                        break;
                }
            } else {
                LOG.atWarn().log("Unexpected record in HeadersFootersContainer: {}", child);
            }
        }
    }

    public HeadersFootersContainer(short options) {
        _header = new byte[8];
        LittleEndian.putShort(_header, 0, options);
        LittleEndian.putShort(_header, 2, (short)getRecordType());

        hdAtom = new HeadersFootersAtom();
        _children = new org.apache.poi.hslf.record.Record[]{
            hdAtom
        };
        csDate = csHeader = csFooter = null;

    }

    /**
     * Return the type, which is <code>{@link RecordTypes#HeadersFooters}</code>
     */
    public long getRecordType() {
        return RecordTypes.HeadersFooters.typeID;
    }

    /**
     * Must be either {@link #SlideHeadersFootersContainer} or {@link #NotesHeadersFootersContainer}
     *
     * @return "instance" field in the record header
     */
    public int getOptions(){
        return LittleEndian.getShort(_header, 0);
    }

    /**
     * Write the contents of the record back, so it can be written to disk
     */
    public void writeOut(OutputStream out) throws IOException {
        writeOut(_header[0],_header[1],getRecordType(),_children,out);
    }

    /**
     * HeadersFootersAtom stores the basic information of the header and footer structure.
     *
     * @return <code>HeadersFootersAtom</code>
     */
    public HeadersFootersAtom getHeadersFootersAtom(){
        return hdAtom;
    }

    /**
     * A {@link CString} record that stores the user's date.
     * <p>This is the date that the user wants in the footers, instead of today's date.</p>
     *
     * @return A {@link CString} record that stores the user's date or <code>null</code>
     */
    public CString getUserDateAtom(){
        return csDate;
    }

    /**
     * A {@link CString} record that stores the Header's contents.
     *
     * @return A {@link CString} record that stores the Header's contents or <code>null</code>
     */
    public CString getHeaderAtom(){
        return csHeader;
    }

    /**
     * A {@link CString} record that stores the Footers's contents.
     *
     * @return A {@link CString} record that stores the Footers's contents or <code>null</code>
     */
    public CString getFooterAtom(){
        return csFooter;
    }

    /**
     * Insert a {@link CString} record that stores the user's date.
     *
     * @return  the created {@link CString} record that stores the user's date.
     */
    public CString addUserDateAtom(){
        if(csDate != null) return csDate;

        csDate = new CString();
        csDate.setOptions(USERDATEATOM << 4);

        addChildAfter(csDate, hdAtom);

        return csDate;
    }

    /**
     * Insert a {@link CString} record that stores the user's date.
     *
     * @return  the created {@link CString} record that stores the user's date.
     */
    public CString addHeaderAtom(){
        if(csHeader != null) return csHeader;

        csHeader = new CString();
        csHeader.setOptions(HEADERATOM << 4);

        org.apache.poi.hslf.record.Record r = hdAtom;
        if(csDate != null) r = hdAtom;
        addChildAfter(csHeader, r);

        return csHeader;
    }

    /**
     * Insert a {@link CString} record that stores the user's date.
     *
     * @return  the created {@link CString} record that stores the user's date.
     */
    public CString addFooterAtom(){
        if(csFooter != null) return csFooter;

        csFooter = new CString();
        csFooter.setOptions(FOOTERATOM << 4);

        org.apache.poi.hslf.record.Record r = hdAtom;
        if(csHeader != null) r = csHeader;
        else if(csDate != null) r = csDate;
        addChildAfter(csFooter, r);

        return csFooter;
    }
}