package models.formulas.meta;

import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import exceptions.IllegalTypeException;
import lombok.Getter;
import models.algebra.Variable;
import models.formulas.EquationFormula;
import models.formulas.Formula;
import models.terms.EvaluatableTerm;
import models.terms.RDLTerm;
import models.terms.meta.MatchConstraint;
import models.terms.meta.MetaRDLTerm;

@Getter
public class MetaEquationFormula extends MetaFormula {

	private MetaRDLTerm leftSideHand;
	private MetaRDLTerm rightSideHand;
	
	public MetaEquationFormula(MetaRDLTerm left, MetaRDLTerm right) {
		if (! left.isEvaluatableTerm()) {
			throw new IllegalTypeException();
		}
		if (! right.isEvaluatableTerm()) {
			throw new IllegalTypeException();
		}
		
		this.leftSideHand = left;
		this.rightSideHand = right;
	}
	
	@Override
	public Set<MatchConstraint> isMatchedBy(Formula formula, MatchConstraint constraint) {
		Set<MatchConstraint> result = new HashSet<>();
		if (! (formula instanceof EquationFormula)) {
			return result;
		}
		EquationFormula eq = (EquationFormula) formula;
		result = leftSideHand.isMatchedBy(eq.getLeftSideHand(), constraint);
		return rightSideHand.isMatchedBy(eq.getRightSideHand(), result);
	}
	
	@Override
	public EquationFormula substitution(Map<Variable, RDLTerm> binding) {
		return new EquationFormula((EvaluatableTerm) leftSideHand.substitute(binding), (EvaluatableTerm) rightSideHand.substitute(binding));
	}
	
	public String toString() {
		return leftSideHand.toString() + " = " + rightSideHand.toString();
	}
	
	public boolean equals(Object another) {
		if (! (another instanceof MetaEquationFormula)) {
			return false;
		}
		MetaEquationFormula anohterFormula = (MetaEquationFormula) another;
		return leftSideHand.equals(anohterFormula.getLeftSideHand()) && rightSideHand.equals(anohterFormula.getRightSideHand());
	}
	
	public int hashCode() {
		return ("MEF" + toString()).hashCode();
	}

	@Override
	public <T extends RDLTerm> Set<T> getSubTerms(Class<T> clazz) {
		Set<T> result = new HashSet<>();
		result.addAll(leftSideHand.getSubTerms(clazz).values());
		result.addAll(rightSideHand.getSubTerms(clazz).values());
		return result;
	}
	
}