SearchTextTask.java

/*
 * Copyright (C) 2013 Alex Kuiper
 *
 * This file is part of PageTurner
 *
 * PageTurner is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * PageTurner is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with PageTurner.  If not, see <http://www.gnu.org/licenses/>.*
 */

package net.nightwhistler.pageturner.epub;

import android.text.SpannableStringBuilder;
import android.text.Spanned;
import jedi.option.Option;
import net.nightwhistler.htmlspanner.HtmlSpanner;
import net.nightwhistler.htmlspanner.SpanStack;
import net.nightwhistler.htmlspanner.TagNodeHandler;
import net.nightwhistler.htmlspanner.handlers.TableHandler;
import net.nightwhistler.pageturner.dto.SearchResult;
import net.nightwhistler.pageturner.scheduling.QueueableAsyncTask;
import nl.siegmann.epublib.domain.Book;
import nl.siegmann.epublib.domain.Resource;
import org.htmlcleaner.TagNode;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import static jedi.functional.FunctionalPrimitives.isEmpty;
import static jedi.option.Options.none;
import static jedi.option.Options.option;

public class SearchTextTask extends QueueableAsyncTask<String, SearchResult, List<SearchResult>> {
	
	private Book book;
	
	private HtmlSpanner spanner;
	
	public SearchTextTask(Book book) {
		this.book = book;
		
		this.spanner = new HtmlSpanner();
		
		DummyHandler dummy = new DummyHandler();
		
        spanner.registerHandler("img", dummy );
        spanner.registerHandler("image", dummy );
        
        spanner.registerHandler("table", new TableHandler() );
	}


	@Override
	public Option<List<SearchResult>> doInBackground(String... params) {

		String searchTerm = params[0];
		Pattern pattern = Pattern.compile(Pattern.quote((searchTerm)),Pattern.CASE_INSENSITIVE);

		List<SearchResult> result = new ArrayList<>();

		try {

			PageTurnerSpine spine = new PageTurnerSpine(book);

			for ( int index=0; index < spine.size(); index++ ) {

				spine.navigateByIndex(index);

				publishProgress( new SearchResult(null, null, index, 0, 0) );

                Option<Resource> currentResource = spine.getCurrentResource();

                if ( ! isEmpty(currentResource) ) {

                    Spanned spanned = spanner.fromHtml( currentResource.unsafeGet().getReader());
                    Matcher matcher = pattern.matcher(spanned);

                    while (matcher.find()) {
                        int from = Math.max(0, matcher.start() - 20);
                        int to = Math.min(spanned.length() - 1, matcher.end() + 20);

                        if (isCancelled()) {
                            return none();
                        }

                        String text = "…" + spanned.subSequence(from, to).toString().trim() + "…";
                        SearchResult res = new SearchResult(searchTerm, text, index, matcher.start(), matcher.end());

                        this.publishProgress(res);
                        result.add(res);
                    }
                } else {
                    return none();
                }

			}
		} catch (IOException io) {
			return none();
		}

		return option(result);
	}
	
	private static class DummyHandler extends TagNodeHandler {
		@Override
		public void handleTagNode(TagNode node, SpannableStringBuilder builder,
				int start, int end, SpanStack stack) {

			 builder.append("\uFFFC");
		}
	}
}