/*
 *      Book Catalog - Catalog your book collection.
 *      
 *      Copyright (C) 2009 Joshua Walters
 *      URL: http://joshwalters.com
 *      
 *      This file is part of Book Catalog.
 *      
 *      Book Catalog 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.
 *      
 *      Book Catalog 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 Book Catalog.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.joshwalters.bookcatalog.isbnlookup;

import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.List;

import com.google.gdata.client.books.BooksService;
import com.google.gdata.client.books.VolumeQuery;
import com.google.gdata.data.books.VolumeEntry;
import com.google.gdata.data.books.VolumeFeed;
import com.google.gdata.data.dublincore.Creator;
import com.google.gdata.data.dublincore.Subject;
import com.google.gdata.data.dublincore.Title;
import com.google.gdata.util.ServiceException;

/**
 * Performs book lookup with GData.
 * 
 * @author Josh Walters
 */
public class GDataISBNLookup extends ISBNLookup {

	/**
	 * Used for looking up the book.
	 */
	private BooksService service;
	/**
	 * The URL for the Google volumes feed.
	 */
	public final String FEED_URL = "http://books.google.com/books/feeds/volumes";

	/**
	 * Sets up the book service.
	 */
	public GDataISBNLookup() {
		service = new BooksService("BookCatalog-1.0");
	}

	/**
	 * Searches for a book.
	 */
	public void searchBooks(String barcode) throws NoBookFound,
			InvalidSearchTerms {
		// Clear all the book data fields
		emptyDataFields();
		// Purify the barcode, get the price if possible, and return just the
		// ISBN
		ISBN = purifyBarcode(barcode);
		// Perform the query
		VolumeQuery query;
		try {
			query = new VolumeQuery(new URL(FEED_URL));
			query.setFullTextQuery(ISBN);
			// Only return one result
			query.setMaxResults(1);
			VolumeFeed volumeFeed = service.query(query, VolumeFeed.class);
			// Process the result
			processVolumeFeed(volumeFeed);
		} catch (MalformedURLException e) {
			// Print the error to the error stream
			System.err.println(e.getMessage());
		} catch (IOException e) {
			// Print the error to the error stream
			System.err.println(e.getMessage());
		} catch (ServiceException e) {
			// Print the error to the error stream
			System.err.println(e.getMessage());
		}
	}

	/**
	 * Processes the result feed to get the book data.
	 * 
	 * @param volumeFeed
	 * @throws IOException
	 * @throws ServiceException
	 * @throws NoBookFound
	 */
	private void processVolumeFeed(VolumeFeed volumeFeed) throws IOException,
			ServiceException, NoBookFound {
		List<VolumeEntry> volumeEntries = volumeFeed.getEntries();
		if (volumeEntries.size() == 0) {
			throw new NoBookFound();
		}
		// Send the data to be stored in the class
		storeVolumeEntry(volumeEntries.get(0));
	}

	/**
	 * Store the data in the class variables.
	 * 
	 * @param entry
	 * @throws IOException
	 * @throws ServiceException
	 */
	private void storeVolumeEntry(VolumeEntry entry) throws IOException,
			ServiceException {
		// Get the book title(s).
		for (Title t : entry.getTitles()) {
			if (title == null) {
				title = t.getValue();
			} else {
				title += ", " + t.getValue();
			}
		}
		// Get the book creator(s).
		for (Creator c : entry.getCreators()) {
			if (author == null) {
				author = c.getValue();
			} else {
				author += ", " + c.getValue();
			}
		}
		// Get the book date.
		if (entry.getDates().size() > 0) {
			date = entry.getDates().get(0).getValue();
		}
		// Get the book description.
		if (entry.getDescriptions().size() > 0) {
			description = entry.getDescriptions().get(0).getValue();
		}
		// Get the book subject(s).
		for (Subject s : entry.getSubjects()) {
			if (subject == null) {
				subject = s.getValue();
			} else {
				subject += ", " + s.getValue();
			}
		}
		// Get the book publisher.
		if (entry.getPublishers().size() > 0) {
			publisher = entry.getPublishers().get(0).getValue();
		}
	}
}