// This Source Code is in the Public Domain per: http://unlicense.org
package org.litesoft.core.formatters;

public class FractionalPartFormatHelper implements NumericFormatPartHelper {
    String mFormat;

    public FractionalPartFormatHelper( String pFormat ) {
        mFormat = pFormat;
    }

    public void process( StringBuilder pSB, NFparsedparts pParts ) {
        String zParsedFractionalPart = pParts.getFractionalDigits();

//        if( pParts.isDecimalFound() )
//        {
        pSB.append( "." );
//        }
//        else
//        {
        // todo: should throw formatting exception?
//        }

        switch ( mFormat.length() ) {
            case 1: // 0 or #
                if ( mFormat.equals( "0" ) ) {
                    if ( zParsedFractionalPart.length() > 1 ) {
                        throw new IllegalArgumentException( "Fractional part " + zParsedFractionalPart + " is too large to be formatted" );
                    } else if ( zParsedFractionalPart.length() == 0 ) {
                        pSB.append( "0" );
                        pSB.append( pParts.getAfterAnyDigits() );
                    } else {
                        pSB.append( zParsedFractionalPart );
                        pSB.append( pParts.getAfterAnyDigits() );
                    }
                } else if ( mFormat.equals( "#" ) ) {
                    pSB.append( zParsedFractionalPart );
                    pSB.append( pParts.getAfterAnyDigits() );
                } else {
                    throw new IllegalArgumentException( "Illegal Fractional Part Format String" );
                }
                break;
            case 2: // 0# or 00
                if ( mFormat.equals( "0#" ) ) {
                    if ( zParsedFractionalPart.length() >= 1 ) {
                        pSB.append( zParsedFractionalPart );
                        pSB.append( pParts.getAfterAnyDigits() );
                    } else {
                        pSB.append( "0" );
                        pSB.append( pParts.getAfterAnyDigits() );
                    }
                } else if ( mFormat.equals( "00" ) ) {
                    if ( zParsedFractionalPart.length() == 1 ) {
                        pSB.append( zParsedFractionalPart );
                        pSB.append( "0" );
                    } else if ( zParsedFractionalPart.length() == 2 ) {
                        pSB.append( zParsedFractionalPart );
                    } else {
                        pSB.append( roundTwoDecimalPlaces( zParsedFractionalPart ) );
                    }
                } else {
                    throw new IllegalArgumentException( "Illegal Fractional Part Format String" );
                }
                break;
//            case 3: // 00# or 000
//                if ( mFormat.equals( "00#" ) )
//                {
////                    pSB.append( incertCommas( zParsedFractionalPart ) );
//                }
//                else
//                {
//                    throw new IllegalArgumentException( "Illegal Fractional Part Format String" );
//                }
//                break;
            default:
                break;
        }
    }

    private String roundTwoDecimalPlaces( String pToRound ) {
        // 12.435   would be rounded up   to 12.44. The number to be rounded (3) is rounded to the nearest even digit (4).
        // 12.445   would be rounded down to 12.44. The number to be rounded (4) is not rounded up because it is an even digit.
        // 12.44501 would be rounded up   to 12.45. The number to be rounded (4) is followed by a five and by additional nonzero digits.

        char[] zDecimalChars = pToRound.toCharArray();

        int second = Integer.parseInt( "" + zDecimalChars[1] );
        int third = Integer.parseInt( "" + zDecimalChars[2] );

        if ( pToRound.length() == 3 ) {
            if ( (second % 2) != 0 ) // is odd
            {
                if ( third >= 5 ) {
                    second++;
                }
            } else {
                if ( third > 5 ) {
                    second++;
                }
            }
        }

        if ( pToRound.length() > 3 ) {
            int rest = Integer.parseInt( pToRound.substring( 2 ) );

            if ( (third == 5) && (rest > 0) ) {
                second++;
            }

            if ( third > 5 ) {
                second++;
            }
        }

        StringBuilder sb = new StringBuilder();
        sb.append( zDecimalChars[0] );
        sb.append( second );

        return sb.toString();
    }
}