d20-charsheet/src/main/lombok/org/leumasjaffe/charsheet/model/features/DDPropertyChooser.java

package org.leumasjaffe.charsheet.model.features;

import java.util.Collections;
import java.util.List;

import org.leumasjaffe.charsheet.model.DDCharacterClass;

import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.JsonTypeInfo.Id;

import lombok.AccessLevel;
import lombok.RequiredArgsConstructor;
import lombok.experimental.FieldDefaults;
import lombok.experimental.NonFinal;

@JsonTypeInfo(use=Id.MINIMAL_CLASS)
public interface DDPropertyChooser {
	default int getTimes() { return 1; }
	String getHeader();
	default List<String> getChoices() { return Collections.emptyList(); }
	public DDProperty get(int selectedIndex);
	default boolean applySideEffects(DDCharacterClass to, int selectedIndex) {
		to.addFeature(get(selectedIndex));
		return true;
	}
	default void undoSideEffects(DDCharacterClass to, int selectedIndex) {
		to.removeFeature(get(selectedIndex));
	}
	
	@RequiredArgsConstructor
	@FieldDefaults(level=AccessLevel.PRIVATE, makeFinal=true)
	public static class State {
		DDCharacterClass ddCharacter;
		DDPropertyChooser chooser;
		@NonFinal boolean hasApplied = false;
		@NonFinal int previousIndex = -1;
		
		public void apply(int selectedIndex) {
			if (hasApplied) { chooser.undoSideEffects(ddCharacter, previousIndex); }
			hasApplied = chooser.applySideEffects(ddCharacter, previousIndex = selectedIndex);
		}		
	}
}