d20-charsheet/src/main/lombok/org/leumasjaffe/charsheet/view/level/ExperienceDialog.java

package org.leumasjaffe.charsheet.view.level;

import java.util.Arrays;

import javax.swing.JOptionPane;

import org.leumasjaffe.charsheet.model.DDCharacter;
import org.leumasjaffe.charsheet.model.observable.IntValue;
import org.leumasjaffe.observer.ObserverDispatch;

import lombok.experimental.UtilityClass;

@UtilityClass
public class ExperienceDialog {
	private int[] EXPERIENCE_CACHE;
	static {
		final int levelsToCalc = 20;
		EXPERIENCE_CACHE = new int[levelsToCalc];
		for (int i = 0; i < levelsToCalc; ++i) {
			EXPERIENCE_CACHE[i] = experienceForLevel(i+1);
		}
	}

	public void gainExperience(DDCharacter model) {
		final String input = JOptionPane.showInputDialog("How much experience");
		if (input == null || input.isEmpty()) return;
		final int exp = Integer.parseInt(input);
		if (exp <= 0) return;
		final IntValue mdlExp = model.getExperience();
		mdlExp.value(mdlExp.value()+exp);
		ObserverDispatch.notifySubscribers(mdlExp, null);
	}
	
	public static int computeLevelsNeeded(DDCharacter chara, int bonusLevels) {
		final int exp = chara.getExperience().value();
		final int currentLevel = chara.getLevel();
		final int expectedLevel = Math.abs(Arrays.binarySearch(EXPERIENCE_CACHE, exp) + 1);
		return bonusLevels + expectedLevel - currentLevel;
	}

	public int experienceForLevel(int level) {
		return 500 * level * (level - 1);
	}
}