package cgeo.geocaching.geopoint;

import cgeo.geocaching.ICoordinates;
import cgeo.geocaching.R;
import cgeo.geocaching.geopoint.GeopointFormatter.Format;
import cgeo.geocaching.geopoint.direction.DDD;
import cgeo.geocaching.geopoint.direction.DMM;
import cgeo.geocaching.geopoint.direction.DMS;
import cgeo.geocaching.geopoint.direction.Direction;
import cgeo.geocaching.network.Network;
import cgeo.geocaching.network.Parameters;
import cgeo.geocaching.utils.Log;

import org.apache.commons.lang3.StringUtils;
import org.json.JSONArray;
import org.json.JSONObject;

import android.location.Location;
import android.os.Parcel;
import android.os.Parcelable;

/**
 * Abstraction of geographic point.
 */
public final class Geopoint implements ICoordinates, Parcelable {
    public static final double deg2rad = Math.PI / 180;
    public static final double rad2deg = 180 / Math.PI;
    public static final float erad = 6371.0f;

    private final double latitude;
    private final double longitude;

    private Direction direction;
    private DDD ddd;
    private DMM dmm;
    private DMS dms;

    /**
     * Creates new Geopoint with given latitude and longitude (both degree).
     *
     * @param lat
     *            latitude
     * @param lon
     *            longitude
     */
    public Geopoint(final double lat, final double lon)
    {
        latitude = lat;
        longitude = lon;
    }

    /**
     * Creates new Geopoint with latitude and longitude parsed from string.
     *
     * @param text
     *            string to parse
     * @throws Geopoint.ParseException
     *             if the string cannot be parsed
     * @see GeopointParser#parse(String)
     */
    public Geopoint(final String text) {
        final Geopoint parsed = GeopointParser.parse(text);
        this.latitude = parsed.latitude;
        this.longitude = parsed.longitude;
    }

    /**
     * Creates new Geopoint with latitude and longitude parsed from strings.
     *
     * @param latText
     *            latitude string to parse
     * @param lonText
     *            longitude string to parse
     * @throws Geopoint.ParseException
     *             if any argument string cannot be parsed
     * @see GeopointParser#parse(String, String)
     */
    public Geopoint(final String latText, final String lonText) {
        this(GeopointParser.parseLatitude(latText), GeopointParser.parseLongitude(lonText));
    }

    /**
     * Creates new Geopoint with given Location.
     *
     * @param loc
     *            the Location to clone
     */
    public Geopoint(final Location loc) {
        this(loc.getLatitude(), loc.getLongitude());
    }

    /**
     * Create new Geopoint from Parcel.
     *
     * @param in
     *            a Parcel to read the saved data from
     */
    public Geopoint(final Parcel in) {
        latitude = in.readDouble();
        longitude = in.readDouble();
    }

    /**
     * Get latitude in degree.
     *
     * @return latitude
     */
    public double getLatitude()
    {
        return latitude;
    }

    /**
     * Get latitude in microdegree.
     *
     * @return latitude
     */
    public int getLatitudeE6()
    {
        return (int) Math.round(latitude * 1E6);
    }

    /**
     * Get longitude in degree.
     *
     * @return longitude
     */
    public double getLongitude()
    {
        return longitude;
    }

    /**
     * Get longitude in microdegree.
     *
     * @return longitude
     */
    public int getLongitudeE6()
    {
        return (int) Math.round(longitude * 1E6);
    }

    /**
     * Get distance and bearing from the current point to a target.
     *
     * @param target
     *            The target
     * @return An array of floats: the distance in meters, then the bearing in degrees
     */
    private float[] pathTo(final Geopoint target) {
        float[] results = new float[2];
        android.location.Location.distanceBetween(latitude, longitude, target.latitude, target.longitude, results);
        return results;
    }

    /**
     * Calculates distance to given Geopoint in km.
     *
     * @param point
     *            target
     * @return distance in km
     * @throws GeopointException
     *             if there is an error in distance calculation
     */
    public float distanceTo(final ICoordinates point)
    {
        return pathTo(point.getCoords())[0] / 1000;
    }

    /**
     * Calculates bearing to given Geopoint in degree.
     *
     * @param point
     *            target
     * @return bearing in degree, in the [0,360[ range
     */
    public float bearingTo(final ICoordinates point)
    {
        // Android library returns a bearing in the [-180;180] range
        final float bearing = pathTo(point.getCoords())[1];
        return bearing < 0 ? bearing + 360 : bearing;
    }

    /**
     * Calculates geopoint from given bearing and distance.
     *
     * @param bearing
     *            bearing in degree
     * @param distance
     *            distance in km
     * @return the projected geopoint
     */
    public Geopoint project(final double bearing, final double distance)
    {
        final double rlat1 = latitude * deg2rad;
        final double rlon1 = longitude * deg2rad;
        final double rbearing = bearing * deg2rad;
        final double rdistance = distance / erad;

        final double rlat = Math.asin(Math.sin(rlat1) * Math.cos(rdistance) + Math.cos(rlat1) * Math.sin(rdistance) * Math.cos(rbearing));
        final double rlon = rlon1 + Math.atan2(Math.sin(rbearing) * Math.sin(rdistance) * Math.cos(rlat1), Math.cos(rdistance) - Math.sin(rlat1) * Math.sin(rlat));

        return new Geopoint(rlat * rad2deg, rlon * rad2deg);
    }

    @Override
    public boolean equals(final Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null || !(obj instanceof Geopoint)) {
            return false;
        }
        final Geopoint gp = (Geopoint) obj;
        return getLatitudeE6() == gp.getLatitudeE6() && getLongitudeE6() == gp.getLongitudeE6();
    }

    @Override
    public int hashCode() {
        return getLatitudeE6() ^ getLongitudeE6();
    }

    /**
     * Checks if given Geopoint is similar to this Geopoint with tolerance.
     *
     * @param gp
     *            Geopoint to check
     * @param tolerance
     *            tolerance in km
     * @return true if similar, false otherwise
     */
    public boolean isEqualTo(Geopoint gp, double tolerance)
    {
        return null != gp && distanceTo(gp) <= tolerance;
    }

    /**
     * Returns formatted coordinates.
     *
     * @param format
     *            the desired format
     * @see GeopointFormatter
     * @return formatted coordinates
     */
    public String format(GeopointFormatter.Format format)
    {
        return GeopointFormatter.format(format, this);
    }

    /**
     * Returns formatted coordinates with default format.
     * Default format is decimalminutes, e.g. N 52° 36.123 E 010° 03.456
     *
     * @return formatted coordinates
     */
    @Override
    public String toString()
    {
        return format(GeopointFormatter.Format.LAT_LON_DECMINUTE);
    }

    /**
     * Converts this geopoint to value type Direction.
     *
     * @return Direction
     */
    public Direction asDirection() {
        if (direction == null) { // because geopoint is immutable we can "cache" the result
            direction = new Direction(latitude, longitude);
        }
        return direction;
    }

    /**
     * Converts this geopoint to value type DDD.
     *
     * @return
     */
    public DDD asDDD() {
        if (ddd == null) {
            ddd = new DDD(latitude, longitude);
        }
        return ddd;
    }

    /**
     * Converts this geopoint to value type DMM.
     *
     * @return
     */
    public DMM asDMM() {
        if (dmm == null) {
            dmm = new DMM(latitude, longitude);
        }
        return dmm;
    }

    /**
     * Converts this geopoint to value type DMS.
     *
     * @return
     */
    public DMS asDMS() {
        if (dms == null) {
            dms = new DMS(latitude, longitude);
        }
        return dms;
    }

    abstract public static class GeopointException
            extends RuntimeException
    {
        private static final long serialVersionUID = 1L;

        public GeopointException(String msg)
        {
            super(msg);
        }
    }

    public static class ParseException
            extends GeopointException
    {
        private static final long serialVersionUID = 1L;
        public final int resource;

        public ParseException(final String msg, final GeopointParser.LatLon faulty)
        {
            super(msg);
            resource = faulty == GeopointParser.LatLon.LAT ? R.string.err_parse_lat : R.string.err_parse_lon;
        }
    }

    public Double getElevation() {
        try {
            final String uri = "http://maps.googleapis.com/maps/api/elevation/json";
            final Parameters params = new Parameters(
                    "sensor", "false",
                    "locations", format(Format.LAT_LON_DECDEGREE_COMMA));
            final JSONObject response = Network.requestJSON(uri, params);

            if (response == null) {
                return null;
            }

            if (!StringUtils.equalsIgnoreCase(response.getString("status"), "OK")) {
                return null;
            }

            if (response.has("results")) {
                JSONArray results = response.getJSONArray("results");
                JSONObject result = results.getJSONObject(0);
                return result.getDouble("elevation");
            }
        } catch (Exception e) {
            Log.w("cgBase.getElevation: " + e.toString());
        }

        return null;
    }

    @Override
    public Geopoint getCoords() {
        return this;
    }

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

    @Override
    public void writeToParcel(final Parcel dest, final int flags) {
        dest.writeDouble(latitude);
        dest.writeDouble(longitude);
    }

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

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

}