package ie.dcu.apps.ist.actions;

import ie.dcu.segment.*;
import ie.dcu.swt.SwtUtils;
import ie.dcu.util.FileUtils;

import java.io.*;
import java.util.logging.Level;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.FileDialog;

public class ExportTransparentPNGAction extends AppAction {
	
private static final String DEFAULT_SUFFIX = ".png";
	
	private FileDialog dialog;
	private String directory;

	public ExportTransparentPNGAction(ActionManager m) {
		super(m);
	}
	
	@Override 
	public void run() { 
		if (window.hasContext()) {
			File file = getFile();
			if (file != null) {
				directory = file.getParent();
				export(file);
			}
		}		
	}


	private void export(File file) {
		ImageData im = createSemiTransparentImage();
		try {
			SwtUtils.saveImage(im, file);
		} catch (IOException e) {
			handleError(file, e);
		}
	}
	
	
	private ImageData createSemiTransparentImage() {
		SegmentationContext ctx = window.getContext();
		ImageData image = ctx.getImageData();
		SegmentationMask mask = ctx.getMask();
		ImageData result = new ImageData(image.width, image.height, 32, image.palette);
		
		int[] pixels = new int[image.width];
		byte[] alphas = new byte[image.width];
		
		for (int y = 0; y < image.height; y++) {
			image.getPixels(0, y, image.width, pixels, 0);
			
			int offset = y * mask.cols;
			for (int i = 0; i < mask.cols; i++) {
				if (mask.values[i+offset] == SegmentationMask.BACKGROUND) {
					alphas[i] = (byte) 0x00;
				} else {
					alphas[i] = (byte) 0xff;
				}
			}
			
			result.setPixels(0, y, image.width, pixels, 0);
			result.setAlphas(0, y, image.width, alphas, 0);
		}
		
		return result;
	}

	
	private void handleError(File file, IOException e) {
		// Log
		log(Level.WARNING, "Error exporting view as image", e);
		
		// Show error dialog
		error("Error exporting view as image %s: %s", 
				file.getName(), e.getLocalizedMessage()
		);
		
		// Set status message
		status(Error, "Error exporting view as image %s", file.getName());
	}

	
	private File getFile() {
		createExportDialog();
		
		String path = dialog.open();
		if (path != null) {
			return checkFile(path);
		}
		
		return null;
	}
	
	
	private File checkFile(String path) {
		File file = new File(path);

		if (SwtUtils.getImageFormat(file) != -1) {
			return file;
		} 
		
		// Unknown file extension, so assume jpg
		return new File(FileUtils.replaceExtension(path, DEFAULT_SUFFIX));
	}

	
	private void createExportDialog() {
		if (dialog == null) {
			dialog = new FileDialog(window.getShell(), SWT.SAVE | SWT.SHEET);
			dialog.setText("Export Transparent PNG");
			dialog.setFilterExtensions(new String[]{"*.png"});
			dialog.setFilterNames(new String[]{"PNG Images"});
		}
		
		dialog.setFileName(getFileName());
		
		String dir = getDirectory();
		if (dir != null) {
			// Unfortunately this is buggy on SWT/GTK and
			// the filter path isin't always set :'-(
			dialog.setFilterPath(dir);
		}
	}
	
	private String getFileName() {
		File file = window.getContext().getFile();
		return FileUtils.replaceExtension(file.getName(), DEFAULT_SUFFIX);
	}
	
	
	private String getDirectory() {
		if (directory == null) {
			File folder = window.getContext().getFolder();
			directory = (folder != null) ? 
					directory = folder.getAbsolutePath() : null;
		}
		
		return directory;
	}
	
}