d20-charsheet/src/org/leumasjaffe/charsheet/model/inventory/Money.java

package org.leumasjaffe.charsheet.model.inventory;

import lombok.AccessLevel;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.experimental.FieldDefaults;

@AllArgsConstructor
@Data
@FieldDefaults(level=AccessLevel.PRIVATE)
public class Money implements Comparable<Money> {
	int pp, gp, sp, cp;
	
	Money sum( final Money other ) {
		return new Money(pp + other.pp, gp + other.gp, sp + other.sp, cp + other.cp);
	}
	
	Money subtract( final Money other ) {
		final Money tmp = new Money(pp + other.pp, gp + other.gp, sp + other.sp, cp + other.cp);
		tmp.rebalance( );
		return tmp;
	}
	
	private void rebalance( ) {
		if ( pp < 0 ) { gp += 10 * pp; pp = 0; }
		if ( gp < 0 ) { sp += 10 * gp; gp = 0; }
		if ( sp < 0 ) { cp += 10 * sp; sp = 0; }
		if ( cp < 0 ) { int tmp = (int) Math.ceil( cp / 10.0 ); sp -= tmp; cp += 10 * tmp; }
		if ( sp < 0 ) { int tmp = (int) Math.ceil( sp / 10.0 ); gp -= tmp; sp += 10 * tmp; }
		if ( gp < 0 ) { int tmp = (int) Math.ceil( gp / 10.0 ); pp -= tmp; gp += 10 * tmp; }
	}
	
	public String toString() {
		final StringBuilder str = new StringBuilder();
		if ( pp > 0 ) { str.append(pp).append("pp "); }
		if ( gp > 0 ) { str.append(gp).append("gp "); }
		if ( sp > 0 ) { str.append(sp).append("sp "); }
		if ( cp > 0 ) { str.append(cp).append("cp "); }
		return str.toString();
	}

	@Override
	public int compareTo(Money o) {
		return Integer.compare(asCopper(), o.asCopper());
	}
	
	public static Money fromCopper(int cp) {
		final int pp = cp / 1000; cp -= pp * 1000;
		final int gp = cp / 100; cp -= gp * 100;
		final int sp = cp / 10; cp -= sp * 10;
		return new Money(pp, gp, sp, cp);
	}

	public int asCopper() {
		return cp + sp * 10 + gp * 100 + pp * 1000;
	}
}