package cgeo.geocaching.maps;

import cgeo.geocaching.Settings;
import cgeo.geocaching.geopoint.Geopoint;
import cgeo.geocaching.geopoint.IConversion;
import cgeo.geocaching.maps.interfaces.GeneralOverlay;
import cgeo.geocaching.maps.interfaces.GeoPointImpl;
import cgeo.geocaching.maps.interfaces.MapProjectionImpl;
import cgeo.geocaching.maps.interfaces.MapViewImpl;
import cgeo.geocaching.maps.interfaces.OverlayImpl;

import android.app.Activity;
import android.graphics.BlurMaskFilter;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Point;
import android.graphics.Typeface;
import android.util.DisplayMetrics;

public class ScaleOverlay implements GeneralOverlay {

    private static final double SCALE_WIDTH_FACTOR = 1.0 / 2.5;

    private Paint scale = null;
    private Paint scaleShadow = null;
    private BlurMaskFilter blur = null;
    private float pixelDensity = 0;
    private double pixels = 0d;
    private int bottom = 0;
    private double distance = 0d;
    private double distanceRound = 0d;
    private String units = null;
    private OverlayImpl ovlImpl = null;

    public ScaleOverlay(Activity activity, OverlayImpl overlayImpl) {
        this.ovlImpl = overlayImpl;

        DisplayMetrics metrics = new DisplayMetrics();
        activity.getWindowManager().getDefaultDisplay().getMetrics(metrics);
        pixelDensity = metrics.density;
    }

    @Override
    public void drawOverlayBitmap(Canvas canvas, Point drawPosition,
            MapProjectionImpl projection, byte drawZoomLevel) {
        drawInternal(canvas, getOverlayImpl().getMapViewImpl());
    }

    @Override
    public void draw(Canvas canvas, MapViewImpl mapView, boolean shadow) {
        drawInternal(canvas, mapView);
    }

    private void drawInternal(Canvas canvas, MapViewImpl mapView) {

        final double span = mapView.getLongitudeSpan() / 1e6;
        final GeoPointImpl center = mapView.getMapViewCenter();

        pixels = mapView.getWidth() * SCALE_WIDTH_FACTOR; // pixels related to following latitude span
        bottom = mapView.getHeight() - 14; // pixels from bottom side of screen

        final Geopoint leftCoords = new Geopoint(center.getLatitudeE6() / 1e6, center.getLongitudeE6() / 1e6 - span / 2);
        final Geopoint rightCoords = new Geopoint(center.getLatitudeE6() / 1e6, center.getLongitudeE6() / 1e6 + span / 2);

        distance = leftCoords.distanceTo(rightCoords) * SCALE_WIDTH_FACTOR;
        distanceRound = 0d;

        //FIXME: merge with getHumanDistance()
        if (Settings.isUseMetricUnits()) {
            if (distance > 100) { // 100+ km > 1xx km
                distanceRound = Math.floor(distance / 100) * 100;
                units = "km";
            } else if (distance > 10) { // 10 - 100 km > 1x km
                distanceRound = Math.floor(distance / 10) * 10;
                units = "km";
            } else if (distance > 1) { // 1 - 10 km > 1.x km
                distanceRound = Math.floor(distance);
                units = "km";
            } else if (distance > 0.1) { // 100 m - 1 km > 1xx m
                distance *= 1000;
                distanceRound = Math.floor(distance / 100) * 100;
                units = "m";
            } else { // 1 - 100 m > 1x m
                distance *= 1000;
                distanceRound = Math.round(distance / 10) * 10;
                units = "m";
            }
        } else {
            distance /= IConversion.miles2km;

            if (distance > 100) { // 100+ mi > 1xx mi
                distanceRound = Math.floor(distance / 100) * 100;
                units = "mi";
            } else if (distance > 10) { // 10 - 100 mi > 1x mi
                distanceRound = Math.floor(distance / 10) * 10;
                units = "mi";
            } else if (distance > 1) { // 1 - 10 mi > 1.x mi
                distanceRound = Math.floor(distance);
                units = "mi";
            } else if (distance > 0.1) { // 0.1 mi - 1.0 mi > 1xx ft
                distance *= 5280;
                distanceRound = Math.floor(distance / 100) * 100;
                units = "ft";
            } else { // 1 - 100 ft > 1x ft
                distance *= 5280;
                distanceRound = Math.round(distance / 10) * 10;
                units = "ft";
            }
        }

        pixels = Math.round((pixels / distance) * distanceRound);

        if (blur == null) {
            blur = new BlurMaskFilter(3, BlurMaskFilter.Blur.NORMAL);
        }

        if (scaleShadow == null) {
            scaleShadow = new Paint();
            scaleShadow.setAntiAlias(true);
            scaleShadow.setStrokeWidth(4 * pixelDensity);
            scaleShadow.setMaskFilter(blur);
            scaleShadow.setTextSize(14 * pixelDensity);
            scaleShadow.setTypeface(Typeface.DEFAULT_BOLD);
        }

        if (scale == null) {
            scale = new Paint();
            scale.setAntiAlias(true);
            scale.setStrokeWidth(2 * pixelDensity);
            scale.setTextSize(14 * pixelDensity);
            scale.setTypeface(Typeface.DEFAULT_BOLD);
        }

        if (mapView.needsInvertedColors()) {
            scaleShadow.setColor(0xFF000000);
            scale.setColor(0xFFFFFFFF);
        } else {
            scaleShadow.setColor(0xFFFFFFFF);
            scale.setColor(0xFF000000);
        }

        canvas.drawLine(10, bottom, 10, (bottom - (8 * pixelDensity)), scaleShadow);
        canvas.drawLine((int) (pixels + 10), bottom, (int) (pixels + 10), (bottom - (8 * pixelDensity)), scaleShadow);
        canvas.drawLine(8, bottom, (int) (pixels + 12), bottom, scaleShadow);
        canvas.drawText(String.format("%.0f", distanceRound) + " " + units, (float) (pixels - (10 * pixelDensity)), (bottom - (10 * pixelDensity)), scaleShadow);

        canvas.drawLine(11, bottom, 11, (bottom - (6 * pixelDensity)), scale);
        canvas.drawLine((int) (pixels + 9), bottom, (int) (pixels + 9), (bottom - (6 * pixelDensity)), scale);
        canvas.drawLine(10, bottom, (int) (pixels + 10), bottom, scale);
        canvas.drawText(String.format("%.0f", distanceRound) + " " + units, (float) (pixels - (10 * pixelDensity)), (bottom - (10 * pixelDensity)), scale);
    }

    @Override
    public OverlayImpl getOverlayImpl() {
        return ovlImpl;
    }
}