package models.terms.meta;

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

import lombok.Getter;
import models.algebra.Constant;
import models.algebra.Expression;
import models.algebra.Symbol;
import models.algebra.Variable;
import models.terms.RDLTerm;
import models.terms.Resource;
import models.terms.ResourceConstant;

@Getter
public class MetaResource extends MetaVariable {
	
	public MetaResource(Variable variableName, OrderConstraint constraint, Expression order) {
		super(new Symbol("", 0), MetaRDLTerm.TermType.META_RESOURCE_VARIABLE, variableName, constraint, order);
	}
	
	public MetaResource(Variable variableName) {
		super(new Symbol("", 0), MetaRDLTerm.TermType.META_RESOURCE_VARIABLE, variableName, OrderConstraint.ANY, new Constant("0"));
	}
	
	public MetaResource(Variable variableName, Expression order) {
		super(new Symbol("", 0), MetaRDLTerm.TermType.META_RESOURCE_VARIABLE, variableName, OrderConstraint.EQ, order);
	}
	
	@Override
	public Set<MatchConstraint> isMatchedBy(RDLTerm another, MatchConstraint constraint) {
		Set<MatchConstraint> result = new HashSet<>();
		Map<Variable, RDLTerm> binding = constraint.getBinding();
		Map<Variable, OrderVariableConstraint> orderConstraint = constraint.getOrderConstraint();
		if ((! (another instanceof Resource)) && (! (another instanceof ResourceConstant))) {
			return result;
		}
		
		if (! orderConstraintCheck(another, orderConstraint)) {
			return result;
		}
		
		if (! islinearRightNormalizedMatchedBy(another)) {
			return result;
		}
		
		if (! binding.containsKey(this.variableName)) {
			binding.put(this.variableName, another);
			result.add(new MatchConstraint(binding, orderConstraint));
		}
		else if (binding.get(this.variableName).equals(another)) {
			result.add(new MatchConstraint(binding, orderConstraint));
		}
		return result;
	}
}