package dk.itu.mario.level.grammar;

import java.util.ArrayList;
import java.util.List;

public class OrClause implements Clause {
	private double[] chances;
	private List<Clause> subClauses = new ArrayList<Clause>();

	public OrClause(double[] chances, Clause... subClauses) {
		this.chances = chances;
		double chanceTotal = 0.0;
		for (double chance : chances) {
			chanceTotal += chance;
		}
		if (Math.abs(chanceTotal - 1.0) > 0.01) {
			throw new IllegalArgumentException(
					"Total or-clause chances must sum to 1.0.");
		}
		for (Clause clause : subClauses) {
			this.subClauses.add(clause);
		}
	}
	
	@Override
	public boolean isChoice() {
		return true;
	}

	@Override
	public boolean isTerminal() {
		return false;
	}
	@Override
	public Clause makeRandomChoice() {
		double rand = Math.random();
		for (int i = 0; i < chances.length; i++) {
			if (rand < chances[i]) {
				return subClauses.get(i);
			}
			rand -= chances[i];
		}
		return subClauses.get(chances.length - 1);
	}

	@Override
	public int getNumSubClauses() {
		return subClauses.size();
	}
	
	public Clause getSubClause(int index) {
		throw new UnsupportedOperationException();
	}
	
	@Override
	public boolean isVariable() {
		return false;
	}
}