// License: GPL. See LICENSE file for details.

package org.openstreetmap.josm.gui;

import static org.openstreetmap.josm.tools.I18n.marktr;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.geom.Rectangle2D;

import javax.swing.JComponent;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.actions.HelpAction.Helpful;
import org.openstreetmap.josm.data.coor.LatLon;
import org.openstreetmap.josm.data.projection.Projection;

public class MapScaler extends JComponent implements Helpful {

    private final NavigatableComponent mv;
    public MapScaler(NavigatableComponent mv, Projection proj) {
        this.mv = mv;
        setSize(100,30);
        setOpaque(false);
    }

    @Override public void paint(Graphics g) {
        LatLon ll1 = mv.getLatLon(0,0);
        LatLon ll2 = mv.getLatLon(100,0);
        double dist = ll1.greatCircleDistance(ll2);
        String text = dist > 1000 ? (Math.round(dist/100)/10.0)+" km" : Math.round(dist*10)/10+" m";
        Rectangle2D bound = g.getFontMetrics().getStringBounds(text, g);
        g.setColor(Main.pref.getColor(marktr("scale"), Color.white));
        g.drawLine(0, 5, 99, 5);
        g.drawLine(0, 0, 0, 10);
        g.drawLine(99, 0, 99, 10);
        g.drawLine(49, 0, 49, 10);
        g.drawLine(24, 3, 24, 7);
        g.drawLine(74, 3, 74, 7);
        g.drawString(text, (int)(50-bound.getWidth()/2), 23);
    }

    public String helpTopic() {
        return "MapView/Scaler";
    }
}