/* ====================================================================
   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.extractor;

import static org.apache.poi.hssf.model.InternalWorkbook.OLD_WORKBOOK_DIR_ENTRY_NAME;
import static org.apache.poi.hssf.model.InternalWorkbook.WORKBOOK_DIR_ENTRY_NAMES;

import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.apache.poi.POIOLE2TextExtractor;
import org.apache.poi.POITextExtractor;
import org.apache.poi.hssf.OldExcelFormatException;
import org.apache.poi.hssf.extractor.EventBasedExcelExtractor;
import org.apache.poi.hssf.extractor.ExcelExtractor;
import org.apache.poi.poifs.filesystem.DirectoryEntry;
import org.apache.poi.poifs.filesystem.DirectoryNode;
import org.apache.poi.poifs.filesystem.Entry;
import org.apache.poi.poifs.filesystem.NPOIFSFileSystem;
import org.apache.poi.poifs.filesystem.OPOIFSFileSystem;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;
import org.apache.poi.util.POILogFactory;
import org.apache.poi.util.POILogger;

/**
 * Figures out the correct POIOLE2TextExtractor for your supplied
 *  document, and returns it.
 *  
 * <p>Note 1 - will fail for many file formats if the POI Scratchpad jar is
 *  not present on the runtime classpath</p>
 * <p>Note 2 - for text extractor creation across all formats, use
 *  {@link org.apache.poi.extractor.ExtractorFactory} contained within
 *  the OOXML jar.</p>
 * <p>Note 3 - rather than using this, for most cases you would be better
 *  off switching to <a href="http://tika.apache.org">Apache Tika</a> instead!</p>
 */
@SuppressWarnings("WeakerAccess")
public class OLE2ExtractorFactory {
    private static final POILogger LOGGER = POILogFactory.getLogger(OLE2ExtractorFactory.class); 
    
    /** Should this thread prefer event based over usermodel based extractors? */
    private static final ThreadLocal<Boolean> threadPreferEventExtractors = new ThreadLocal<Boolean>() {
        @Override
        protected Boolean initialValue() { return Boolean.FALSE; }
    };

    /** Should all threads prefer event based over usermodel based extractors? */
    private static Boolean allPreferEventExtractors;

    /**
     * Should this thread prefer event based over usermodel based extractors?
     * (usermodel extractors tend to be more accurate, but use more memory)
     * Default is false.
     */
    public static boolean getThreadPrefersEventExtractors() {
        return threadPreferEventExtractors.get();
    }

    /**
     * Should all threads prefer event based over usermodel based extractors?
     * (usermodel extractors tend to be more accurate, but use more memory)
     * Default is to use the thread level setting, which defaults to false.
     */
    public static Boolean getAllThreadsPreferEventExtractors() {
        return allPreferEventExtractors;
    }

    /**
     * Should this thread prefer event based over usermodel based extractors?
     * Will only be used if the All Threads setting is null.
     */
    public static void setThreadPrefersEventExtractors(boolean preferEventExtractors) {
        threadPreferEventExtractors.set(preferEventExtractors);
    }

    /**
     * Should all threads prefer event based over usermodel based extractors?
     * If set, will take preference over the Thread level setting.
     */
    public static void setAllThreadsPreferEventExtractors(Boolean preferEventExtractors) {
        allPreferEventExtractors = preferEventExtractors;
    }

    /**
     * Should this thread use event based extractors is available?
     * Checks the all-threads one first, then thread specific.
     */
    protected static boolean getPreferEventExtractor() {
        if(allPreferEventExtractors != null) {
            return allPreferEventExtractors;
        }
        return threadPreferEventExtractors.get();
    }

    public static POIOLE2TextExtractor createExtractor(POIFSFileSystem fs) throws IOException {
        // Only ever an OLE2 one from the root of the FS
        return (POIOLE2TextExtractor)createExtractor(fs.getRoot());
    }
    public static POIOLE2TextExtractor createExtractor(NPOIFSFileSystem fs) throws IOException {
        // Only ever an OLE2 one from the root of the FS
        return (POIOLE2TextExtractor)createExtractor(fs.getRoot());
    }
    public static POIOLE2TextExtractor createExtractor(OPOIFSFileSystem fs) throws IOException {
        // Only ever an OLE2 one from the root of the FS
        return (POIOLE2TextExtractor)createExtractor(fs.getRoot());
    }

    public static POITextExtractor createExtractor(InputStream input) throws IOException {
        Class<?> cls = getOOXMLClass();
        if (cls != null) {
            // Use Reflection to get us the full OOXML-enabled version
            try {
                Method m = cls.getDeclaredMethod("createExtractor", InputStream.class);
                return (POITextExtractor)m.invoke(null, input);
            } catch (IllegalArgumentException iae) {
                throw iae;
            } catch (Exception e) {
                throw new IllegalArgumentException("Error creating Extractor for InputStream", e);
            }
        } else {
            // Best hope it's OLE2....
            return createExtractor(new NPOIFSFileSystem(input));
        }
    }

    private static Class<?> getOOXMLClass() {
        try {
            return OLE2ExtractorFactory.class.getClassLoader().loadClass(
                    "org.apache.poi.extractor.ExtractorFactory"
            );
        } catch (ClassNotFoundException e) {
            LOGGER.log(POILogger.WARN, "POI OOXML jar missing");
            return null;
        }
    }
    private static Class<?> getScratchpadClass() {
        try {
            return OLE2ExtractorFactory.class.getClassLoader().loadClass(
                    "org.apache.poi.extractor.OLE2ScratchpadExtractorFactory"
            );
        } catch (ClassNotFoundException e) {
            LOGGER.log(POILogger.ERROR, "POI Scratchpad jar missing");
            throw new IllegalStateException("POI Scratchpad jar missing, required for ExtractorFactory");
        }
    }
    
    /**
     * Create the Extractor, if possible. Generally needs the Scratchpad jar.
     * Note that this won't check for embedded OOXML resources either, use
     *  {@link org.apache.poi.extractor.ExtractorFactory} for that.
     */
    public static POITextExtractor createExtractor(DirectoryNode poifsDir)
            throws IOException
    {
        // Look for certain entries in the stream, to figure it
        // out from
        for (String workbookName : WORKBOOK_DIR_ENTRY_NAMES) {
            if (poifsDir.hasEntry(workbookName)) {
                if (getPreferEventExtractor()) {
                    return new EventBasedExcelExtractor(poifsDir);
                }
                return new ExcelExtractor(poifsDir);
            }
        }
        if (poifsDir.hasEntry(OLD_WORKBOOK_DIR_ENTRY_NAME)) {
            throw new OldExcelFormatException("Old Excel Spreadsheet format (1-95) "
                    + "found. Please call OldExcelExtractor directly for basic text extraction");
        }
        
        // Ask Scratchpad, or fail trying
        Class<?> cls = getScratchpadClass();
        try {
            Method m = cls.getDeclaredMethod("createExtractor", DirectoryNode.class);
            POITextExtractor ext = (POITextExtractor)m.invoke(null, poifsDir);
            if (ext != null) return ext;
        } catch (IllegalArgumentException iae) {
            throw iae;
        } catch (Exception e) {
            throw new IllegalArgumentException("Error creating Scratchpad Extractor", e);
        }

        throw new IllegalArgumentException("No supported documents found in the OLE2 stream");
    }

    /**
     * Returns an array of text extractors, one for each of
     *  the embedded documents in the file (if there are any).
     * If there are no embedded documents, you'll get back an
     *  empty array. Otherwise, you'll get one open
     *  {@link POITextExtractor} for each embedded file.
     */
    public static POITextExtractor[] getEmbededDocsTextExtractors(POIOLE2TextExtractor ext)
            throws IOException
    {
        // All the embedded directories we spotted
        List<Entry> dirs = new ArrayList<Entry>();
        // For anything else not directly held in as a POIFS directory
        List<InputStream> nonPOIFS = new ArrayList<InputStream>();

        // Find all the embedded directories
        DirectoryEntry root = ext.getRoot();
        if(root == null) {
            throw new IllegalStateException("The extractor didn't know which POIFS it came from!");
        }

        if(ext instanceof ExcelExtractor) {
            // These are in MBD... under the root
            Iterator<Entry> it = root.getEntries();
            while(it.hasNext()) {
                Entry entry = it.next();
                if(entry.getName().startsWith("MBD")) {
                    dirs.add(entry);
                }
            }
        } else {
            // Ask Scratchpad, or fail trying
            Class<?> cls = getScratchpadClass();
            try {
                Method m = cls.getDeclaredMethod(
                        "identifyEmbeddedResources", POIOLE2TextExtractor.class, List.class, List.class);
                m.invoke(null, ext, dirs, nonPOIFS);
            } catch (Exception e) {
                throw new IllegalArgumentException("Error checking for Scratchpad embedded resources", e);
            }
        }

        // Create the extractors
        if(dirs.size() == 0 && nonPOIFS.size() == 0){
            return new POITextExtractor[0];
        }

        ArrayList<POITextExtractor> e = new ArrayList<POITextExtractor>();
        for (Entry dir : dirs) {
            e.add(createExtractor(
                    (DirectoryNode) dir
            ));
        }
        for (InputStream nonPOIF : nonPOIFS) {
            try {
                e.add(createExtractor(nonPOIF));
            } catch (IllegalArgumentException ie) {
                // Ignore, just means it didn't contain
                //  a format we support as yet
                LOGGER.log(POILogger.WARN, ie);
            } catch (Exception xe) {
                // Ignore, invalid format
                LOGGER.log(POILogger.WARN, xe);
            }
        }
        return e.toArray(new POITextExtractor[e.size()]);
    }
}