/*
 * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
 *
 * SPDX-License-Identifier: EPL-2.0
 */
package tools.refinery.store.query.literal;

import tools.refinery.store.query.equality.LiteralEqualityHelper;
import tools.refinery.store.query.equality.LiteralHashCodeHelper;
import tools.refinery.store.query.substitution.Substitution;
import tools.refinery.store.query.term.Variable;

import java.util.Set;

public enum BooleanLiteral implements CanNegate<BooleanLiteral> {
	TRUE(true),
	FALSE(false);

	private final boolean value;

	BooleanLiteral(boolean value) {
		this.value = value;
	}

	@Override
	public Set<Variable> getOutputVariables() {
		return Set.of();
	}

	@Override
	public Set<Variable> getInputVariables(Set<? extends Variable> positiveVariablesInClause) {
		return Set.of();
	}

	@Override
	public Set<Variable> getPrivateVariables(Set<? extends Variable> positiveVariablesInClause) {
		return Set.of();
	}

	@Override
	public Literal substitute(Substitution substitution) {
		// No variables to substitute.
		return this;
	}

	@Override
	public BooleanLiteral negate() {
		return fromBoolean(!value);
	}

	@Override
	public boolean equalsWithSubstitution(LiteralEqualityHelper helper, Literal other) {
		return equals(other);
	}

	@Override
	public int hashCodeWithSubstitution(LiteralHashCodeHelper helper) {
		return hashCode();
	}

	@Override
	public String toString() {
		return Boolean.toString(value);
	}

	public static BooleanLiteral fromBoolean(boolean value) {
		return value ? TRUE : FALSE;
	}
}