package au.gov.amsa.geo.distance;
   
   import static au.gov.amsa.geo.distance.DistanceTravelledCalculator.calculateTrafficDensity;
   import static au.gov.amsa.geo.distance.Renderer.saveAsPng;
   import static com.google.common.base.Optional.of;
   
   import java.io.File;
   import java.util.List;
   import java.util.concurrent.atomic.AtomicInteger;
  
  import org.apache.log4j.Logger;
  import org.joda.time.DateTime;
  
  import rx.Observable;
  import rx.Observer;
  import rx.functions.Action1;
  import rx.functions.Func1;
  import au.gov.amsa.geo.Util;
  import au.gov.amsa.geo.distance.DistanceTravelledCalculator.CalculationResult;
  import au.gov.amsa.geo.model.Options;
  
  public class DistanceTravelledMovieMaker {
  
  	private static Logger log = Logger
  			.getLogger(DistanceTravelledMovieMaker.class);
  
  	/**
  	 * Saves a sequence of image files of Vessel Traffic Density plots to the
  	 * <code>imageDirectory</code> with filenames map1.png, map2.png, etc.
  	 * 
  	 * @param options
  	 * @param files
  	 * @param times
  	 * @param imageDirectory
  	 */
  	private static void saveImagesWithTimeRange(final Options options,
  			final Observable<File> files, Observable<Long> times,
  			final String imageDirectory) {
  
  		times.buffer(2, 1).doOnNext(new Action1<List<Long>>() {
  			AtomicInteger i = new AtomicInteger();
  
  			@Override
  			public void call(List<Long> pair) {
  				if (pair.size() < 2)
  					return;
  				Long startTime = pair.get(0);
  				Long finishTime = pair.get(1);
  				saveImageWithTimeRange(options, files, startTime, finishTime,
  						imageDirectory + "/map" + i.incrementAndGet() + ".png");
  			}
  		}).subscribe(reportErrors());
  
  	}
  
  	private static Observer<Object> reportErrors() {
  		return new Observer<Object>() {
  
  			@Override
  			public void onCompleted() {
  				log.info("completed");
  			}
  
  			@Override
  			public void onError(Throwable e) {
  				log.error(e.getMessage(), e);
  				throw new RuntimeException(e);
  			}
  
  			@Override
  			public void onNext(Object t) {
  				// do nothing
  			}
  
  		};
  	}
  
  	private static void saveImageWithTimeRange(Options options,
  			final Observable<File> files, long startTime, long finishTime,
  			String filename) {
  		Options op = options.buildFrom()
  		// set start time
  				.startTime(of(startTime))
  				// set finish time
  				.finishTime(of(finishTime))
  				// build
  				.build();
  		CalculationResult result = calculateTrafficDensity(op, files);
  		saveAsPng(Renderer.createImage(op, 2, 1600, result), new File(filename));
  	}
  
  	private static Options createOptions(double cellSizeDegrees) {
  		return Options.builder()
  		// set origin latitude
  				.originLat(0)
  				// set origin longitudue
  				.originLon(0)
  				// square cell size in degrees
  				.cellSizeDegrees(cellSizeDegrees)
 				// set bounds
 				// sabine bounds:
 				// .bounds(new Bounds(-10, 110, -45, 158))
 				// .bounds(new Bounds(15, 90, -20, 125))
 				// build options
 				.build();
 	}
 
 	public static void main(String[] args) {
 
 		double cellSizeDegrees = 0.2;
 		Options options = createOptions(cellSizeDegrees);
 
 		String directory = System.getProperty("user.home")
 				+ "/Downloads/positions-365-days";
 
 		final Observable<File> files = Util.getFiles(directory, "craft-");
 
 		Observable<Long> times = Observable.range(1, 13).map(
 				new Func1<Integer, Long>() {
 
 					@Override
 					public Long call(Integer n) {
 						return DateTime.parse("2013-06-01").plusMonths(n - 1)
 								.getMillis();
 					}
 				});
 		saveImagesWithTimeRange(options, files, times, "target");
 
 	}
 
 }