/**
 * 
 */
package ddoa.project.luminis.dashboard.paginas.calendar;

import java.io.IOException;
import java.util.LinkedList;
import java.util.List;
import java.util.TimeZone;

import org.joda.time.DateMidnight;

import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.auth.oauth2.CredentialStore;
import com.google.api.client.auth.oauth2.MemoryCredentialStore;
import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.client.util.DateTime;
import com.google.api.services.calendar.Calendar;
import com.google.api.services.calendar.model.Event;

import ddoa.project.luminis.dashboard.config.exceptions.CalendarException;

/**
 * File description<br/>
 * <br/>
 * Project LuminisDashboardWebapp<br/>
 * ddoa.project.luminis.dashboard.paginas.calendar.CalendarAPI.java<br/>
 * Created on May 29, 2014 2:26:26 PM
 * 
 * @author Brord van Wierst
 */
public class CalendarAPI {
	/** Global instance of the HTTP transport. */
	private static final HttpTransport HTTP_TRANSPORT = new NetHttpTransport();

	/** Global instance of the JSON factory. */
	private static final JsonFactory JSON_FACTORY = new JacksonFactory();

	/** Global instance of the credential storage */
	private static final CredentialStore credentialStore = new MemoryCredentialStore();

	String emailId;
	String clientId;
	String clientSecret;

	/**
	 * 
	 * @param emailId
	 * @param clientId
	 * @param clientSecret
	 */
	public CalendarAPI(String emailId, String clientId, String clientSecret) {
		this.emailId = emailId;
		this.clientId = clientId;
		this.clientSecret = clientSecret;
	}

	public Credential getCredential() {
		try {
			Credential credential = new GoogleCredential.Builder()
					.setTransport(HTTP_TRANSPORT)
					.setClientSecrets(clientId, clientSecret)
					.setJsonFactory(JSON_FACTORY).build();
			credentialStore.store(emailId, credential);
			if (credential != null && credentialStore.load(emailId, credential)) {
				return credential;
			} else {
				return null;
			}
		} catch (IOException e) {
			throw new CalendarException("Could not load credential", e);
		}
	}

	public List<Event> getEvents() throws CalendarException {
		Credential credential = getCredential();
		if (credential != null) {
			Calendar cal = new Calendar.Builder(
					HTTP_TRANSPORT, 
					JSON_FACTORY,
					credential)
			.setApplicationName("Luminis").build();

			try {
				List<Event> googleEvents = cal
						.events()
						.list(emailId)
						.setSingleEvents(true)
						.setOrderBy("startTime")
						.setTimeMin(
								new DateTime(new DateMidnight().toDate(),
										TimeZone.getDefault()))
						.setTimeMax(
								new DateTime(new DateMidnight().toDateTime()
										.plusDays(1).minusMillis(1).toDate(),
										TimeZone.getDefault())).execute()
						.getItems();

				// Google returns null when there are not results
				if (googleEvents != null) {
					return googleEvents;
				} else {
					return new LinkedList<Event>();
				}
			} catch (IOException ioe) {
				throw new CalendarException(
						"An error occurred when retrieving events", ioe);
			}
		} else {
			return null;
		}
	}
}