/*
 * [Mask.java]
 *
 * Summary: Create shrouded email images from the command line or in your own programs.
 *
 * Copyright: (c) 2009-2017 Roedy Green, Canadian Mind Products, http://mindprod.com
 *
 * Licence: This software may be copied and used freely for any purpose but military.
 *          http://mindprod.com/contact/nonmil.html
 *
 * Requires: JDK 1.8+
 *
 * Created with: JetBrains IntelliJ IDEA IDE http://www.jetbrains.com/idea/
 *
 * Version History:
 *  1.8 2009-04-04 Mask, command line version of Masker.
 */
package com.mindprod.masker;

import com.mindprod.common18.FontFactory;

import javax.imageio.ImageIO;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.GraphicsEnvironment;
import java.awt.RenderingHints;
import java.awt.font.FontRenderContext;
import java.awt.font.LineMetrics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Arrays;
import java.util.HashSet;

import static java.lang.System.*;

/**
 * Create shrouded email images from the command line or in your own programs.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.8 2009-04-04 Mask, command line version of Masker.
 * @since 2009-04-04
 */
public class Mask
    {
    /**
     * Best fonts to use. Takes the first one that is supported on the given system. For official names
     * see http://mindprod.com/fontshower.html
     */
    private static final String[] pngFonts = new String[] {
            "Tiresias PCfont Z",
            "Tiresias PCfont",
            "TiresiasScreenfont",
            "Verdana",
            "Lucida Console",
            "Lucida Sans" };// if none of these supported, will use Dialog.

    /*8 foreground colour for the generated image */
    private static final Color FOREGROUND = new Color( 0x777777 )/* grey */;

    /**
     * font we use to render the email text, initialised later in static init block.
     */
    private static final Font font;
    //

    /**
     * HashSet of names of all supported font families
     */
    private static final HashSet<String> allFontFamilies;

    static
        {
        String[] names = ( GraphicsEnvironment.getLocalGraphicsEnvironment() )
                .getAvailableFontFamilyNames();
        // convert to lower case for case-insensitive lookup
        for ( int i = 0, n = names.length; i < n; i++ )
            {
            names[ i ] = names[ i ].toLowerCase();
            }
        allFontFamilies = new HashSet<>( Arrays.asList( names ) );
        font = bestFont( pngFonts, Font.PLAIN, 18 );
        }

    /**
     * Get the most preferred supported font from a list
     *
     * @param preferredfontNames list of font names, best one first.
     * @param fontStyle          e.g. Font.PLAIN
     * @param fontSize           size of font in points.
     *
     * @return best font that is supported, or a Dialog font if none are.
     * @noinspection SameParameterValue
     */
    private static Font bestFont( String[] preferredfontNames,
                                  int fontStyle,
                                  int fontSize )
        {
        // find first font in that is supported
        for ( String preferredfontName : preferredfontNames )
            {
            if ( allFontFamilies.contains( preferredfontName
                    .toLowerCase() ) )
                {
                return FontFactory.build( preferredfontName, fontStyle, fontSize );
                }
            } // end for
        return FontFactory.build( "Dialog", fontStyle, fontSize );
        }

    /**
     * create a png image of a given email address without user intervention.
     * Use this method to create png email images in your own program.
     *
     * @param pngFile file where to store the image, must have extensions .png. The file may or may not currently exist.
     * @param email   email address e.g. "john@yahoo.com"
     *
     * @throws IOException if cannot write the file.
     */
    @SuppressWarnings( { "WeakerAccess" } )
    public static void createMask( File pngFile, String email ) throws IOException
        {
        email = email.trim();
        // FontMetrics getAscent getHeight, getDescent only approximate, have a
        // lot of white space.
        // We want more accurate LineMetrics.
        // We need a Graphics object in order to do line metrics.
        // This seems like over kill but here we go:
        // create a BufferedImage
        final BufferedImage dummybi = new BufferedImage( 200
                /* dummy */,
                200
                /* dummy */,
                BufferedImage.TYPE_4BYTE_ABGR_PRE );
        final Graphics2D dummyg2d = dummybi.createGraphics();
        dummyg2d.setFont( font );
        final FontMetrics fm = dummyg2d.getFontMetrics();
        final int width = fm.stringWidth( email );
        final FontRenderContext fr = dummyg2d.getFontRenderContext();
        final LineMetrics lm = font.getLineMetrics( email, fr );
        final int ascent = ( int ) ( lm.getAscent() + .5 );
        final int height = ( int ) ( lm.getDescent() + lm.getAscent() + .5 );
        // paint onto a BufferedImage
        final BufferedImage bufferedImage = new BufferedImage( width, height, BufferedImage.TYPE_4BYTE_ABGR_PRE );
        final Graphics2D g2d = bufferedImage.createGraphics();
        // redraw using our paintComponent
        g2d.addRenderingHints( new RenderingHints( RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON ) );
        g2d.setFont( font );
        g2d.setColor( FOREGROUND );
        // background is transparent by default.
        // x,y is bottom left corner of tex
        g2d.drawString( email, 0, ascent );   // y increases going down.
        // write out the BufferedImage as a PNG
        ImageIO.write( bufferedImage, "png" /* format desired */, pngFile );
        }

    /**
     * Create an png email image.
     *
     * @param args email address space name of file with .png extension
     *
     * @throws IOException if cannot write the image file.
     */
    public static void main( String[] args ) throws IOException
        {
        if ( args.length != 2 )
            {
            err.println( "Mask usage is mask.jar john@yahoo.com C:\\temp\\john.png" );
            System.exit( 1 );
            }
        createMask( new File( args[ 1 ] ), args[ 0 ] );
        out.println( "Done" );
        }
    }