package org.simantics.maps.elevation.server;

import java.awt.image.DataBuffer;
import java.nio.file.Path;

import org.geotools.coverage.grid.GridCoverage2D;
import org.geotools.gce.geotiff.GeoTiffReader;
import org.geotools.geometry.Envelope2D;
import org.geotools.referencing.CRS;
import org.opengis.geometry.DirectPosition;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
import org.opengis.referencing.operation.MathTransform;
import org.simantics.maps.elevation.server.prefs.MapsElevationServerPreferences;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class TiffInterface {

    private static final Logger LOGGER = LoggerFactory.getLogger(TiffInterface.class);

    private final Path tifPath;
    private GridCoverage2D coverage;

    private boolean init = false;

    public TiffInterface(Path tifPath) {
        this.tifPath = tifPath;
        loadMetadata();
    }

    private void loadMetadata() {
        GeoTiffReader reader = null;
        try {
            reader = new GeoTiffReader(this.tifPath.toFile());
            this.coverage = reader.read(null);
            this.init = true;
        } catch (Exception e) {
            LOGGER.error("Could not load {}", tifPath, e);
        } finally {
            if (reader != null) {
                reader.dispose();
            }
        }
    }

    public boolean contains(DirectPosition pos) {
        ensureInit();
        Envelope2D e = coverage.getEnvelope2D();
        try {
            MathTransform transform = CRS.findMathTransform(pos.getCoordinateReferenceSystem(), getCRS(), false);
            DirectPosition target = transform.transform(pos, null);
            boolean contains = e.contains(target);
            return contains;
        } catch (Exception ex) {
            ex.printStackTrace();
            return false;
        }
    }
    
    public Number lookup(DirectPosition pos) {
        ensureInit();
        Object r = coverage.evaluate(pos);
        final int dataType = coverage.getRenderedImage().getSampleModel().getDataType();
        int pipeDepthUnderGround = MapsElevationServerPreferences.pipeDepthUnderGround();
        switch (dataType) {
            case DataBuffer.TYPE_BYTE: {
                // TODO: if the result is byte how does one subtract the pipeDepth form the value?
                // Might not be even relevant with this use case 
                return new Byte(((byte[]) r)[0]);
            }
            case DataBuffer.TYPE_SHORT:  // Fall through
            case DataBuffer.TYPE_USHORT: // Fall through
            case DataBuffer.TYPE_INT: {
                int val = ((int[]) r)[0] - pipeDepthUnderGround;
                return new Integer(val);
            }
            case DataBuffer.TYPE_FLOAT: {
                float val = ((float[]) r)[0] - pipeDepthUnderGround;
                return new Float(val);
            }
            case DataBuffer.TYPE_DOUBLE: {
                double val = ((double[]) r)[0] - pipeDepthUnderGround;
                return new Double(val);
            }
            default: return null;
        }
    }

    private void ensureInit() {
        if (!init) {
            throw new IllegalStateException("Interface is not initialized for " + this.tifPath);
        }
    }

    public void close() {
        coverage.dispose(true);
    }

    public Envelope2D getCornerCoords() {
        return coverage.getEnvelope2D();
    }

    public CoordinateReferenceSystem getCRS() {
        return coverage.getCoordinateReferenceSystem();
    }
}