package com.mapbox.mapboxsdk.geometry;

import android.os.Parcel;
import android.os.Parcelable;
import android.support.annotation.NonNull;

import com.mapbox.mapboxsdk.exceptions.InvalidLatLngBoundsException;

import java.util.ArrayList;
import java.util.List;

/**
 * A geographical area representing a latitude/longitude aligned rectangle.
 */
public class LatLngBounds implements Parcelable {

    private final double mLatNorth;
    private final double mLatSouth;
    private final double mLonEast;
    private final double mLonWest;

    /**
     * Construct a new LatLngBounds based on its corners, given in NESW
     * order.
     *
     * @param northLatitude Northern Latitude
     * @param eastLongitude Eastern Longitude
     * @param southLatitude Southern Latitude
     * @param westLongitude Western Longitude
     */
    LatLngBounds(final double northLatitude, final double eastLongitude, final double southLatitude, final double westLongitude) {
        this.mLatNorth = northLatitude;
        this.mLonEast = eastLongitude;
        this.mLatSouth = southLatitude;
        this.mLonWest = westLongitude;
    }

    /**
     * Calculates the centerpoint of this LatLngBounds by simple interpolation and returns
     * it as a point. This is a non-geodesic calculation which is not the geographic center.
     *
     * @return LatLng center of this LatLngBounds
     */
    public LatLng getCenter() {
        return new LatLng((this.mLatNorth + this.mLatSouth) / 2,
                (this.mLonEast + this.mLonWest) / 2);
    }

    public double getLatNorth() {
        return this.mLatNorth;
    }

    public double getLatSouth() {
        return this.mLatSouth;
    }

    public double getLonEast() {
        return this.mLonEast;
    }

    public double getLonWest() {
        return this.mLonWest;
    }

    /**
     * Get the area spanned by this LatLngBounds
     *
     * @return LatLngSpan area
     */
    public LatLngSpan getSpan() {
        return new LatLngSpan(getLatitudeSpan(), getLongitudeSpan());
    }

    /**
     * Get the absolute distance, in degrees, between the north and
     * south boundaries of this LatLngBounds
     *
     * @return Span distance
     */
    public double getLatitudeSpan() {
        return Math.abs(this.mLatNorth - this.mLatSouth);
    }

    /**
     * Get the absolute distance, in degrees, between the west and
     * east boundaries of this LatLngBounds
     *
     * @return Span distance
     */
    public double getLongitudeSpan() {
        return Math.abs(this.mLonEast - this.mLonWest);
    }


    /**
     * Validate if LatLngBounds is empty, determined if absolute distance is
     *
     * @return boolean indicating if span is empty
     */
    public boolean isEmptySpan() {
        return getLongitudeSpan() == 0.0 || getLatitudeSpan() == 0.0;
    }

    @Override
    public String toString() {
        return "N:" + this.mLatNorth + "; E:" + this.mLonEast + "; S:" + this.mLatSouth + "; W:" + this.mLonWest;
    }

    /**
     * Constructs a LatLngBounds that contains all of a list of LatLng
     * objects. Empty lists will yield invalid LatLngBounds.
     *
     * @param latLngs List of LatLng objects
     * @return LatLngBounds
     */
    static LatLngBounds fromLatLngs(final List<? extends ILatLng> latLngs) {
        double minLat = 90,
                minLon = 180,
                maxLat = -90,
                maxLon = -180;

        for (final ILatLng gp : latLngs) {
            final double latitude = gp.getLatitude();
            final double longitude = gp.getLongitude();

            minLat = Math.min(minLat, latitude);
            minLon = Math.min(minLon, longitude);
            maxLat = Math.max(maxLat, latitude);
            maxLon = Math.max(maxLon, longitude);
        }

        return new LatLngBounds(maxLat, maxLon, minLat, minLon);
    }

    public LatLng[] toLatLngs() {
        return new LatLng[]{new LatLng(mLatNorth, mLonEast), new LatLng(mLatSouth, mLonWest)};
    }

    /**
     * Determines whether this LatLngBounds matches another one via LatLng.
     *
     * @param o another object
     * @return a boolean indicating whether the LatLngBounds are equal
     */
    @Override
    public boolean equals(final Object o) {
        if (this == o) return true;
        if (o instanceof LatLngBounds) {
            LatLngBounds other = (LatLngBounds) o;
            return mLatNorth == other.getLatNorth()
                    && mLatSouth == other.getLatSouth()
                    && mLonEast == other.getLonEast()
                    && mLonWest == other.getLonWest();
        }
        return false;
    }

    /**
     * Determines whether this LatLngBounds contains a point and the point
     * does not touch its boundary.
     *
     * @param latLng the point which may be contained
     * @return true, if the point is contained within the box.
     */
    public boolean contains(final ILatLng latLng) {
        final double latitude = latLng.getLatitude();
        final double longitude = latLng.getLongitude();
        return ((latitude < this.mLatNorth)
                && (latitude > this.mLatSouth))
                && ((longitude < this.mLonEast)
                && (longitude > this.mLonWest));
    }

    /**
     * Returns a new LatLngBounds that stretches to contain both this and another LatLngBounds.
     *
     * @param bounds LatLngBounds to add
     * @return LatLngBounds
     */
    public LatLngBounds union(LatLngBounds bounds) {
        return union(bounds.getLatNorth(), bounds.getLonEast(), bounds.getLatSouth(), bounds.getLonWest());
    }

    /**
     * Returns a new LatLngBounds that stretches to include another LatLngBounds,
     * given by corner points.
     *
     * @param lonNorth Northern Longitude
     * @param latEast  Eastern Latitude
     * @param lonSouth Southern Longitude
     * @param latWest  Western Longitude
     * @return BoundingBox
     */
    public LatLngBounds union(final double lonNorth, final double latEast, final double lonSouth, final double latWest) {
        return new LatLngBounds((this.mLatNorth < lonNorth) ? lonNorth : this.mLatNorth,
                (this.mLonEast < latEast) ? latEast : this.mLonEast,
                (this.mLatSouth > lonSouth) ? lonSouth : this.mLatSouth,
                (this.mLonWest > latWest) ? latWest : this.mLonWest);
    }

    /**
     * Returns a new LatLngBounds that is the intersection of this with another box
     *
     * @param box LatLngBounds to intersect with
     * @return LatLngBounds
     */
    public LatLngBounds intersect(LatLngBounds box) {
        double minLatWest = Math.max(getLonWest(), box.getLonWest());
        double maxLatEast = Math.min(getLonEast(), box.getLonEast());
        if (maxLatEast > minLatWest) {
            double minLonSouth = Math.max(getLatSouth(), box.getLatSouth());
            double maxLonNorth = Math.min(getLatNorth(), box.getLatNorth());
            if (maxLonNorth > minLonSouth) {
                return new LatLngBounds(maxLonNorth, maxLatEast, minLonSouth, minLatWest);
            }
        }
        return null;
    }

    /**
     * Returns a new LatLngBounds that is the intersection of this with another LatLngBounds
     *
     * @param northLatitude Northern Longitude
     * @param eastLongitude Eastern Latitude
     * @param southLatitude Southern Longitude
     * @param westLongitude Western Latitude
     * @return LatLngBounds
     */
    public LatLngBounds intersect(double northLatitude, double eastLongitude, double southLatitude, double westLongitude) {
        return intersect(new LatLngBounds(northLatitude, eastLongitude, southLatitude, westLongitude));
    }

    public static final Parcelable.Creator<LatLngBounds> CREATOR =
            new Parcelable.Creator<LatLngBounds>() {
                @Override
                public LatLngBounds createFromParcel(final Parcel in) {
                    return readFromParcel(in);
                }

                @Override
                public LatLngBounds[] newArray(final int size) {
                    return new LatLngBounds[size];
                }
            };

    @Override
    public int hashCode() {
        return (int) ((mLatNorth + 90)
                + ((mLatSouth + 90) * 1000)
                + ((mLonEast + 180) * 1000000)
                + ((mLonEast + 180) * 1000000000));
    }

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(final Parcel out, final int arg1) {
        out.writeDouble(this.mLatNorth);
        out.writeDouble(this.mLonEast);
        out.writeDouble(this.mLatSouth);
        out.writeDouble(this.mLonWest);
    }

    private static LatLngBounds readFromParcel(final Parcel in) {
        final double lonNorth = in.readDouble();
        final double latEast = in.readDouble();
        final double lonSouth = in.readDouble();
        final double latWest = in.readDouble();
        return new LatLngBounds(lonNorth, latEast, lonSouth, latWest);
    }

    /**
     * Builder for composing LatLngBounds objects.
     */
    public static final class Builder {

        private List<LatLng> mLatLngList;

        public Builder() {
            mLatLngList = new ArrayList<>();
        }

        public LatLngBounds build() {
            if (mLatLngList.size() < 2) {
                throw new InvalidLatLngBoundsException(mLatLngList.size());
            }
            return LatLngBounds.fromLatLngs(mLatLngList);
        }

        public Builder include(@NonNull LatLng latLng) {
            mLatLngList.add(latLng);
            return this;
        }
    }
}