/*
 * [HTMLEntity.java]
 *
 * Summary: Describes one String literal token for display.
 *
 * Copyright: (c) 2004-2017 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:
 *  2.0 2009-04-19 tidy comments, more accurate colour names
 */
package com.mindprod.jtokens.html;

import com.mindprod.jtokens.Token;

import java.awt.Color;
import java.awt.Font;
import java.util.regex.Pattern;

import static com.mindprod.jtokens.TokenColourScheme.HTML_FOREGROUND_FOR_ALPHA_ENTITY;
import static com.mindprod.jtokens.TokenColourScheme.HTML_FOREGROUND_FOR_DECIMAL_ENTITY;
import static com.mindprod.jtokens.TokenColourScheme.HTML_FOREGROUND_FOR_UNKNOWN_ENTITY;
import static com.mindprod.jtokens.TokenColourScheme.HTML_FOREGROUND_HTML_HEX_ENTITY;
import static com.mindprod.jtokens.TokenFonts.EMPHASIS_FONT_SIZE_IN_POINTS;
import static com.mindprod.jtokens.TokenFonts.MONO_FONTS;

/**
 * Describes one String literal token for display.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 2.0 2009-04-19 tidy comments, more accurate colour names
 * @since 2004-04-24
 */
public final class HTMLEntity extends Token
    {
    /**
     * version number for the class
     */
    static final long serialVersionUID = 1L;

    /**
     * css classes to use for various categories of entity.
     */
    private static final String[] ENTITY_CSS_CLASSES = { "unknownentity", "entity", "hexentity", "decimalentity" };

    /**
     * Colours to use for various categories of entity.
     */
    private static final Color[] FOREGROUNDS_FOR_ENTITIES = {
            HTML_FOREGROUND_FOR_UNKNOWN_ENTITY,
            HTML_FOREGROUND_FOR_ALPHA_ENTITY,
            HTML_FOREGROUND_HTML_HEX_ENTITY,
            HTML_FOREGROUND_FOR_DECIMAL_ENTITY };

    /**
     * fonts to use for various categories of entity.
     */
    private static final Font[] FONTS_FOR_ENTITIES = {
            bestFont( MONO_FONTS, Font.BOLD, EMPHASIS_FONT_SIZE_IN_POINTS ),
            bestFont( MONO_FONTS, Font.PLAIN, EMPHASIS_FONT_SIZE_IN_POINTS ),
            bestFont( MONO_FONTS, Font.PLAIN, EMPHASIS_FONT_SIZE_IN_POINTS ),
            bestFont( MONO_FONTS, Font.PLAIN, EMPHASIS_FONT_SIZE_IN_POINTS ) };

    /**
     * regex to look for decimal entities  #999
     */
    private static final Pattern DECIMAL_ENTITY_PATTERN = Pattern.compile( "#\\d+" );

    /**
     * regex to look for hex entities  #xffff
     */
    private static final Pattern HEX_ENTITY_PATTERN = Pattern.compile( "#x\\p{XDigit}+" );

    /**
     * Is this entity an official known one?
     */
    private final boolean known;

    /**
     * Constructor
     *
     * @param entity literal text without the enclosing "
     * @param known  true if this is an official known entity
     */
    public HTMLEntity( String entity, boolean known )
        {
        // save without lead & trail ;
        super( entity );
        this.known = known;
        }

    /**
     * categorise this entity
     * 0 unknown, 1 known alpha, 2 hex, 3 decimal
     *
     * @return 0..3 category
     */
    private int getCategory()
        {
        if ( known )
            {
            return 1;
            }
        else if ( text.startsWith( "#x" ) && HEX_ENTITY_PATTERN.matcher( text ).matches() )
            {
            return 2;
            }
        else if ( text.startsWith( "#" ) && DECIMAL_ENTITY_PATTERN.matcher( text ).matches() )
            {
            return 3;
            }
        else
            {
            return 0;
            }
        }

    /**
     * font to render this token.
     *
     * @return Font, in the correct size.
     */
    public Font getFont()
        {
        return FONTS_FOR_ENTITIES[ getCategory() ];
        }

    /**
     * foreground colour to render this token.
     *
     * @return Color object.
     */
    public Color getForeground()
        {
        return FOREGROUNDS_FOR_ENTITIES[ getCategory() ];
        }

    /**
     * get the text surrounded by CSS html     * @return decorated HTML in a <span sandwich
     */
    public String getHTML()
        {
        return "<span class=\""
               + ENTITY_CSS_CLASSES[ getCategory() ]
               + "\">&amp;"
               + text
               + ";</span>";
        }

    /**
     * gets the raw text to render this token
     *
     * @return The plain String representation of the text
     */
    public String getText()
        {
        return '&' + text + ';';
        }

    /**
     * Can this token be collapsed with following space or with a following identical token?
     *
     * @return true if can be collapsed simply by combining text
     */
    public boolean isCollapsible()
        {
        // autoinsert of &..; would be confused. Also don't want to mix known
        // and unknown in same token..
        return false;
        }

    /**
     * Is this token useless? In other words would rendering it have no visible effect? NL and Space are not considered
     * useless, unless they have 0 counts. Usually a token is useless because it has and empty or null text string.
     *
     * @return true if this token can be thrown away as useless
     */
    public boolean isUseless()
        {
        return false;
        }
    }