/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.kernel.impl.index.schema.config;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import org.neo4j.configuration.Config;
import org.neo4j.gis.spatial.index.Envelope;
import org.neo4j.values.storable.CoordinateReferenceSystem;

class EnvelopeSettings {
    private static final double DEFAULT_MIN_EXTENT = -1_000_000;
    private static final double DEFAULT_MAX_EXTENT = 1_000_000;
    private static final double DEFAULT_MIN_LATITUDE = -90;
    private static final double DEFAULT_MAX_LATITUDE = 90;
    private static final double DEFAULT_MIN_LONGITUDE = -180;
    private static final double DEFAULT_MAX_LONGITUDE = 180;

    private final CoordinateReferenceSystem crs;
    private Double[] min;
    private Double[] max;

    EnvelopeSettings(CoordinateReferenceSystem crs) {
        this.crs = crs;
        this.min = new Double[crs.getDimension()];
        this.max = new Double[crs.getDimension()];
        Arrays.fill(this.min, Double.NaN);
        Arrays.fill(this.max, Double.NaN);
    }

    static Map<CoordinateReferenceSystem, EnvelopeSettings> envelopeSettingsFromConfig(Config config) {
        Map<CoordinateReferenceSystem, EnvelopeSettings> env = new HashMap<>();
        config.getGroups(CrsConfig.class).forEach((id, crsConfig) -> {
            EnvelopeSettings envelopeSettings = new EnvelopeSettings(crsConfig.crs);
            envelopeSettings.min = config.get(crsConfig.min).toArray(Double[]::new);
            envelopeSettings.max = config.get(crsConfig.max).toArray(Double[]::new);
            env.put(crsConfig.crs, envelopeSettings);
        });

        return env;
    }

    Envelope asEnvelope() {
        int dimension = crs.getDimension();
        assert dimension >= 2;
        double[] min = new double[dimension];
        double[] max = new double[dimension];
        int cartesianStartIndex = 0;
        if (crs.isGeographic()) {
            // Geographic CRS default to extent of the earth in degrees
            min[0] = minOrDefault(0, DEFAULT_MIN_LONGITUDE);
            max[0] = maxOrDefault(0, DEFAULT_MAX_LONGITUDE);
            min[1] = minOrDefault(1, DEFAULT_MIN_LATITUDE);
            max[1] = maxOrDefault(1, DEFAULT_MAX_LATITUDE);
            cartesianStartIndex = 2; // if geographic index has higher than 2D, then other dimensions are cartesian
        }
        for (int i = cartesianStartIndex; i < dimension; i++) {
            min[i] = minOrDefault(i, DEFAULT_MIN_EXTENT);
            max[i] = maxOrDefault(i, DEFAULT_MAX_EXTENT);
        }
        return new Envelope(min, max);
    }

    CoordinateReferenceSystem getCrs() {
        return crs;
    }

    private double minOrDefault(int i, double defVal) {
        return valOrDefault(min[i], defVal);
    }

    private double maxOrDefault(int i, double defVal) {
        return valOrDefault(max[i], defVal);
    }

    private static double valOrDefault(double val, double def) {
        return Double.isNaN(val) ? def : val;
    }
}
