/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2017, Open Source Geospatial Foundation (OSGeo)
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library 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
 *    Lesser General Public License for more details.
 */
package org.geotools.process.raster;

import java.awt.RenderingHints;
import java.awt.image.RenderedImage;

import javax.media.jai.RenderedOp;
import javax.media.jai.operator.ExtremaDescriptor;

import org.geotools.coverage.grid.GridCoverage2D;
import org.geotools.coverage.processing.CoverageProcessor;
import org.geotools.process.ProcessException;
import org.geotools.process.factory.DescribeParameter;
import org.geotools.process.factory.DescribeProcess;
import org.geotools.process.factory.DescribeResult;
import org.geotools.renderer.i18n.Errors;
import org.geotools.resources.i18n.ErrorKeys;
import org.geotools.resources.image.ImageUtilities;
import org.opengis.parameter.ParameterValueGroup;
import org.opengis.util.ProgressListener;

/**
 * A transparency holes-dashes filling process
 * 
 * @author Daniele Romagnoli - GeoSolutions
 *
 * @source $URL$
 */
@DescribeProcess(title = "TransparencyFill", description = "Fill transparent pixels")
public class TransparencyFillProcess implements RasterProcess {

    private static final CoverageProcessor PROCESSOR = CoverageProcessor.getInstance();

    @DescribeResult(name = "result", description = "The processed coverage")
    public GridCoverage2D execute(
            @DescribeParameter(name = "data", description = "Input coverage") GridCoverage2D coverage,
//            @DescribeParameter(name = "type", description = "Type of filling algorithm", min = 0) FillType type,
            ProgressListener listener) throws ProcessException {

        if (coverage == null) {
            throw new ProcessException(Errors.format(ErrorKeys.NULL_ARGUMENT_$1, "coverage"));
        }

        RenderedImage ri = coverage.getRenderedImage();

        // If no transparency is involved, no need to do the checks
        boolean hasTransparency = ri != null ? ri.getColorModel().hasAlpha() : false;
        if (!hasTransparency) {
            return coverage;
        }
        int numBands = ri.getSampleModel().getNumBands();
        RenderingHints renderingHints = null;

        if (numBands == 4 || numBands == 2) {
            // Looking for statistics on alpha channel
            renderingHints = ImageUtilities.getRenderingHints(ri);
            RenderedOp extremaOp = ExtremaDescriptor.create(ri, null, 1, 1, false, 1,
                    renderingHints);
            double[][] extrema = (double[][]) extremaOp.getProperty("Extrema");
            double[] mins = extrema[0];
            // check if alpha is 255 on every pixel (fully opaque)
            hasTransparency = !(mins[mins.length - 1] == 255); // fully opaque
        }

        if (!hasTransparency) {
            return coverage;
        }

        // Do the transparency fill operation
        final ParameterValueGroup param = PROCESSOR.getOperation("TransparencyFill")
                .getParameters();
        param.parameter("source").setValue(coverage);
//        if (type != null && type instanceof FillType) { 
//            param.parameter("type").setValue(type);
//        }
        return (GridCoverage2D) PROCESSOR.doOperation(param);
    }

}