/*
 * [Formula.java]
 *
 * Summary: Display chemical formula, usually of a gas.
 *
 * Copyright: (c) 2005-2017 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:
 *  1.0 2009-09-14 original version
 *  1.1 2010-11-12 rename from Gas to Chemical to Formula, handle double digits
 */
package com.mindprod.htmlmacros.macro;

import com.mindprod.common18.ST;
import com.mindprod.fastcat.FastCat;

import java.util.regex.Pattern;

import static java.lang.System.*;

/**
 * Display chemical formula, usually of a gas.
 * <p/>
 * The main purpose of this is to keep formulas on one line, and accurate.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.1 2010-11-12 rename from Gas to Chemical to Formula, handle double digits
 * @since 2009-09-14
 */
@SuppressWarnings( { "UnusedDeclaration" } )
public final class Formula extends Macro
    {
    /**
     * how to use the macro
     */
    private static final String USAGE = "\nFormula macro needs formula e.g. CO2";

    private static final Pattern crack = Pattern.compile( " " );

    /**
     * guts of Age macro expansion
     *
     * @param formula formula of the gas to expandNoRef
     *
     * @return HTML expansion of the formula
     */
    private String expand( String formula )
        {
        String[] components = crack.split( formula );
        for ( String component : components )
            {
            if ( ST.isLegal( component, "0123456789" ) )
                {
                continue;
                }
            else
                {
                switch ( component )
                    {
                    case "&rArr;":
                    case "&rarr;":
                    case "+":
                    case "-":
                    case "C12H22O11": // sucrose
                    case "C12": // carbon 12
                    case "C13": // carbon 13
                    case "C14": // carbon 14
                    case "CH3CH2OH": // ethanol
                    case "C3H7OH": // isopropanol
                    case "C6H12O6": // glucose/fructos
                    case "C8H18": // octane
                    case "CH4": // methane
                    case "ClO2": // chlorine dioxide
                    case "CO2": // carbon dioxide
                    case "D2":  // deuterium
                    case "D2O": // heavy water
                    case "H+":  // hydrogen ion
                    case "H2":  // hydrogen
                    case "H2O": // water
                    case "H2O2": // hydrogen peroxide
                    case "H2S":  // hydrogen sulphide
                    case "HCN":  // hydrogen cyanide
                    case "N2":   // nitrogen
                    case "N2O":  // nitrous oxide
                    case "NF3":  // nitrogen  fluoride
                    case "NH4":  // ammonia
                    case "NaCl": // salt
                    case "NaOH": // sodium hydroxide
                    case "O2":   // oxygen
                    case "O3":   // ozone
                    case "OH-":  // hydroxyl ion
                    case "SF6":  // sulphur  fluoride
                        break;
                    default:
                        err.println( "Warning: Formula macro: unusual gas/chemical formula : " + formula + " at " + component + "\n" );
                        break;
                    }
                }
            }
        final FastCat sb = new FastCat( formula.length() * 3 );
        boolean inMolecule = false;
        formula = formula.replace( "&rArr;", "\u21d2" );
        formula = formula.replace( "&rarr;", "\u2192" );
        sb.append( "<span class=\"formula\">" );
        for ( int i = 0; i < formula.length(); i++ )
            {
            // we do NOT use  <sub></sub>
            final char c = formula.charAt( i );
            if ( c == '+' )
                {
                if ( inMolecule )
                    {
                    sb.append( "&#x207a;" );  // superscript +
                    }
                else
                    {
                    sb.append( '+' );
                    }
                }
            else if ( c == '-' )
                {
                if ( inMolecule )
                    {
                    sb.append( "&#x207b;" );// superscript -
                    }
                else
                    {
                    sb.append( '-' );
                    }
                }
            else if ( '0' <= c && c <= '9' )
                {
                if ( inMolecule )
                    {
                    sb.append( "&#x208" );
                    sb.append( c );        // subscript digit
                    sb.append( ';' );
                    }
                else
                    {
                    sb.append( c );
                    }
                }
            else if ( c == ' ' )
                {
                inMolecule = false;
                sb.append( c );
                }
            else if ( c == '\u21d2' )
                {
                inMolecule = false;
                sb.append( "&rArr;" );
                }
            else if ( c == '\u2192' )
                {
                inMolecule = false;
                sb.append( "&rarr;" );
                }
            else
                {
                inMolecule = true;
                sb.append( c );
                }
            }
        sb.append( "</span>" );
        return sb.toString();
        }

    /**
     * Generate Formula formula
     *
     * @param parms   formula without spaces or superscripts
     * @param quiet   true if want output suppressed.
     * @param verbose @return expanded macro text
     */
    public String expandMacro( String[] parms, final boolean quiet, final boolean verbose )
        {
        if ( !quiet )
            {
            out.print( "C" );
            }
        if ( parms.length != 1 )
            {
            throw new IllegalArgumentException( USAGE );
            }
        return expand( parms[ 0 ] );
        }
    }