// License: GPL. For details, see LICENSE file.
package org.openstreetmap.josm.data.osm;

import java.awt.geom.Rectangle2D;
import java.util.Objects;

import org.openstreetmap.josm.data.Bounds;
import org.openstreetmap.josm.data.IBounds;
import org.openstreetmap.josm.data.coor.ILatLon;
import org.openstreetmap.josm.data.coor.LatLon;
import org.openstreetmap.josm.data.coor.QuadTiling;

/**
 * A BBox represents an area in lat/lon space. It is used for the quad tree.
 *
 * In contrast to a {@link Bounds} object, a BBox can represent an invalid (empty) area.
 */
public class BBox implements IBounds {

    protected double xmin = Double.POSITIVE_INFINITY;
    protected double xmax = Double.NEGATIVE_INFINITY;
    protected double ymin = Double.POSITIVE_INFINITY;
    protected double ymax = Double.NEGATIVE_INFINITY;

    /**
     * Constructs a new (invalid) BBox
     */
    public BBox() {
        // Nothing to do
    }

    /**
     * Constructs a new {@code BBox} defined by a single point.
     *
     * @param x X coordinate
     * @param y Y coordinate
     * @since 6203
     */
    public BBox(final double x, final double y) {
        add(x, y);
    }

    /**
     * Constructs a new {@code BBox} defined by points <code>a</code> and <code>b</code>.
     * Result is minimal BBox containing both points if they are both valid, else undefined
     *
     * @param a first point
     * @param b second point
     */
    public BBox(LatLon a, LatLon b) {
        this(a.lon(), a.lat(), b.lon(), b.lat());
    }

    /**
     * Constructs a new {@code BBox} from another one.
     *
     * @param copy the BBox to copy
     */
    public BBox(BBox copy) {
        this.xmin = copy.xmin;
        this.xmax = copy.xmax;
        this.ymin = copy.ymin;
        this.ymax = copy.ymax;
    }

    /**
     * Creates bbox around the coordinate (x, y).
     * Coordinate defines center of bbox, its edge will be 2*r.
     *
     * @param x X coordinate
     * @param y Y coordinate
     * @param r size
     * @since 13140
     */
    public BBox(double x, double y, double r) {
        this(x - r, y - r, x + r, y + r);
    }

    /**
     * Create minimal BBox so that {@code this.bounds(ax,ay)} and {@code this.bounds(bx,by)} will both return true
     * @param ax left or right X value (-180 .. 180)
     * @param ay top or bottom Y value (-90 .. 90)
     * @param bx left or right X value (-180 .. 180)
     * @param by top or bottom Y value (-90 .. 90)
     */
    public BBox(double ax, double ay, double bx, double by) {
        if (!(Double.isNaN(ax) || Double.isNaN(ay) || Double.isNaN(bx) || Double.isNaN(by))) {
            add(ax, ay);
            add(bx, by);
        }
        // otherwise use default which is an invalid BBox
    }

    /**
     * Create BBox for all nodes of the way with known coordinates.
     * If no node has a known coordinate, an invalid BBox is returned.
     * @param w the way
     */
    public BBox(IWay<?> w) {
        for (INode ll : w.getNodes()) {
            add(ll);
        }
    }

    /**
     * Create BBox for a node. An invalid BBox is returned if the coordinates are not known.
     * @param n the node
     */
    public BBox(INode n) {
        this((ILatLon) n);
    }

    /**
     * Create BBox for a given latlon. An invalid BBox is returned if the coordinates are not known.
     * @param ll The lat lon position
     */
    public BBox(ILatLon ll) {
        add(ll);
    }

    /**
     * Add a point to an existing BBox. Extends this bbox if necessary so that this.bounds(c) will return true
     * if c is a valid LatLon instance.
     * Kept for binary compatibility
     * @param c a LatLon point
     */
    public final void add(LatLon c) {
        add((ILatLon) c);
    }

    /**
     * Add a point to an existing BBox. Extends this bbox if necessary so that this.bounds(c) will return true
     * if c is a valid LatLon instance.
     * If it is invalid or <code>null</code>, this call is ignored.
     * @param c a LatLon point.
     */
    public final void add(ILatLon c) {
        if (c != null) {
            add(c.lon(), c.lat());
        }
    }

    /**
     * Extends this bbox to include the point (x, y)
     * @param x X coordinate
     * @param y Y coordinate
     */
    public final void add(double x, double y) {
        if (!Double.isNaN(x) && !Double.isNaN(y)) {
            set(Math.min(xmin, x), Math.max(xmax, x), Math.min(ymin, y), Math.max(ymax, y));
        }
    }

    /**
     * Extends this bbox to include the bbox other. Does nothing if other is not valid.
     * @param other a bbox
     */
    public final void add(BBox other) {
        if (other.isValid()) {
            set(Math.min(xmin, other.xmin), Math.max(xmax, other.xmax), Math.min(ymin, other.ymin), Math.max(ymax, other.ymax));
        }
    }

    protected void set(double xmin, double xmax, double ymin, double ymax) {
        this.xmin = xmin;
        this.xmax = xmax;
        this.ymin = ymin;
        this.ymax = ymax;
    }

    /**
     * Extends this bbox to include the bbox of the primitive extended by extraSpace.
     * @param primitive an OSM primitive
     * @param extraSpace the value to extend the primitives bbox. Unit is in LatLon degrees.
     */
    public void addPrimitive(OsmPrimitive primitive, double extraSpace) {
        this.addPrimitive((IPrimitive) primitive, extraSpace);
    }

    /**
     * Extends this bbox to include the bbox of the primitive extended by extraSpace.
     * @param primitive an primitive
     * @param extraSpace the value to extend the primitives bbox. Unit is in LatLon degrees.
     * @since 17862
     */
    public void addPrimitive(IPrimitive primitive, double extraSpace) {
        IBounds primBbox = primitive.getBBox();
        add(primBbox.getMinLon() - extraSpace, primBbox.getMinLat() - extraSpace);
        add(primBbox.getMaxLon() + extraSpace, primBbox.getMaxLat() + extraSpace);
    }

    /**
     * Extends this bbox to include the bbox of the primitive extended by extraSpace.
     * @param latLon a LatLon
     * @param extraSpace the value to extend the primitives bbox. Unit is in LatLon degrees.
     * @since 15877
     */
    public void addLatLon(LatLon latLon, double extraSpace) {
        Objects.requireNonNull(latLon, "LatLon cannot be null");
        add(latLon);
        add(latLon.getX() - extraSpace, latLon.getY() - extraSpace);
        add(latLon.getX() + extraSpace, latLon.getY() + extraSpace);
    }

    /**
     * Gets the height of the bbox.
     * @return The difference between ymax and ymin. 0 for invalid bboxes.
     */
    public double height() {
        return getHeight();
    }

    @Override
    public double getHeight() {
        if (isValid()) {
            return ymax - ymin;
        } else {
            return 0;
        }
    }

    /**
     * Gets the width of the bbox.
     * @return The difference between xmax and xmin. 0 for invalid bboxes.
     */
    public double width() {
        return getWidth();
    }

    @Override
    public double getWidth() {
        if (isValid()) {
            return xmax - xmin;
        } else {
            return 0;
        }
    }

    /**
     * Gets the area of the bbox.
     * @return the area computed from {@link #width()} and {@link #height()}
     */
    public double area() {
        return width() * height();
    }

    /**
     * Tests, whether the bbox {@code b} lies completely inside this bbox.
     * @param b bounding box
     * @return {@code true} if {@code b} lies completely inside this bbox
     */
    public boolean bounds(BBox b) {
        return contains(b);
    }

    /**
     * Tests, whether the Point {@code c} lies within the bbox.
     * @param c point
     * @return {@code true} if {@code c} lies within the bbox
     */
    public boolean bounds(LatLon c) {
        return contains(c);
    }

    /**
     * Tests, whether two BBoxes intersect as an area.
     * I.e. whether there exists a point that lies in both of them.
     * @param b other bounding box
     * @return {@code true} if this bbox intersects with the other
     */
    public boolean intersects(BBox b) {
        return intersects((IBounds) b);
    }

    /**
     * Returns the top-left point.
     * @return The top-left point
     */
    public LatLon getTopLeft() {
        return new LatLon(ymax, xmin);
    }

    /**
     * Returns the latitude of top-left point.
     * @return The latitude of top-left point
     * @since 6203
     */
    public double getTopLeftLat() {
        return getMaxLat();
    }

    @Override
    public double getMaxLat() {
        return ymax;
    }

    /**
     * Returns the longitude of top-left point.
     * @return The longitude of top-left point
     * @since 6203
     */
    public double getTopLeftLon() {
        return getMinLon();
    }

    @Override
    public double getMinLon() {
        return xmin;
    }

    /**
     * Returns the bottom-right point.
     * @return The bottom-right point
     */
    public LatLon getBottomRight() {
        return new LatLon(ymin, xmax);
    }

    /**
     * Returns the latitude of bottom-right point.
     * @return The latitude of bottom-right point
     * @since 6203
     */
    public double getBottomRightLat() {
        return getMinLat();
    }

    @Override
    public double getMinLat() {
        return ymin;
    }

    /**
     * Returns the longitude of bottom-right point.
     * @return The longitude of bottom-right point
     * @since 6203
     */
    public double getBottomRightLon() {
        return getMaxLon();
    }

    @Override
    public double getMaxLon() {
        return xmax;
    }

    /**
     * Gets the center of this BBox.
     * @return The center.
     */
    @Override
    public LatLon getCenter() {
        return new LatLon(ymin + (ymax-ymin)/2.0, xmin + (xmax-xmin)/2.0);
    }

    byte getIndex(final int level) {

        byte idx1 = QuadTiling.index(ymin, xmin, level);

        final byte idx2 = QuadTiling.index(ymin, xmax, level);
        if (idx1 == -1) idx1 = idx2;
        else if (idx1 != idx2) return -1;

        final byte idx3 = QuadTiling.index(ymax, xmin, level);
        if (idx1 == -1) idx1 = idx3;
        else if (idx1 != idx3) return -1;

        final byte idx4 = QuadTiling.index(ymax, xmax, level);
        if (idx1 == -1) idx1 = idx4;
        else if (idx1 != idx4) return -1;

        return idx1;
    }

    /**
     * Converts the bounds to a rectangle
     * @return The rectangle in east/north space.
     */
    public Rectangle2D toRectangle() {
        return new Rectangle2D.Double(xmin, ymin, xmax - xmin, ymax - ymin);
    }

    @Override
    public final int hashCode() {
        return Objects.hash(xmin, xmax, ymin, ymax);
    }

    @Override
    public final boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof BBox)) return false;
        BBox b = (BBox) o;
        return Double.compare(b.xmax, xmax) == 0 && Double.compare(b.ymax, ymax) == 0
            && Double.compare(b.xmin, xmin) == 0 && Double.compare(b.ymin, ymin) == 0;
    }

    /**
     * Check if bboxes are functionally equal
     * @param other The other bbox to compare with
     * @param maxDifference The maximum difference (in degrees) between the bboxes. May be null.
     * @return true if they are functionally equivalent
     * @since 15486
     */
    public boolean bboxIsFunctionallyEqual(BBox other, Double maxDifference) {
        return bboxesAreFunctionallyEqual(this, other, maxDifference);
    }

    /**
     * Check if bboxes are functionally equal
     * @param bbox1 A bbox to compare with another bbox
     * @param bbox2 The other bbox to compare with
     * @param maxDifference The maximum difference (in degrees) between the bboxes. May be null.
     * @return true if they are functionally equivalent
     * @since 15483
     */
    public static boolean bboxesAreFunctionallyEqual(BBox bbox1, BBox bbox2, Double maxDifference) {
        if (maxDifference == null) {
            maxDifference = LatLon.MAX_SERVER_PRECISION;
        }
        return (bbox1 != null && bbox2 != null)
                && (Math.abs(bbox1.getBottomRightLat() - bbox2.getBottomRightLat()) <= maxDifference
                        && Math.abs(bbox1.getBottomRightLon() - bbox2.getBottomRightLon()) <= maxDifference
                        && Math.abs(bbox1.getTopLeftLat() - bbox2.getTopLeftLat()) <= maxDifference
                        && Math.abs(bbox1.getTopLeftLon() - bbox2.getTopLeftLon()) <= maxDifference);
    }

    /**
     * Determines if the bbox covers a part of the planet surface.
     * @return true if the bbox covers a part of the planet surface.
     * Height and width must be non-negative, but may (both) be 0.
     * @since 11269
     */
    @Override
    public boolean isValid() {
        return xmin <= xmax && ymin <= ymax;
    }

    /**
     * Determines if the bbox is valid and covers a part of the planet surface.
     * @return true if the bbox is valid and covers a part of the planet surface
     * @since 11269
     */
    public boolean isInWorld() {
        return xmin >= -180.0 && xmax <= 180.0 && ymin >= -90.0 && ymax <= 90.0 && isValid();
    }

    @Override
    public String toString() {
        return "[ x: " + xmin + " -> " + xmax + ", y: " + ymin + " -> " + ymax + " ]";
    }

    /**
     * Creates a CSV string for this bbox
     * @param separator The separator to use
     * @return A string
     */
    public String toStringCSV(String separator) {
        return String.join(separator,
                LatLon.cDdFormatter.format(xmin),
                LatLon.cDdFormatter.format(ymin),
                LatLon.cDdFormatter.format(xmax),
                LatLon.cDdFormatter.format(ymax));
    }

    /**
     * Returns an immutable version of this bbox, i.e., modifying calls throw an {@link UnsupportedOperationException}.
     * @return an immutable version of this bbox
     * @since 17862 (interface)
     */
    public BBox toImmutable() {
        return new Immutable(this);
    }

    private static class Immutable extends BBox {

        Immutable(BBox copy) {
            super(copy);
        }

        @Override
        protected void set(double xmin, double xmax, double ymin, double ymax) {
            throw new UnsupportedOperationException();
        }

        @Override
        public BBox toImmutable() {
            return this;
        }
    }
}