package org.simantics.scl.compiler.elaboration.java;

import org.simantics.scl.compiler.constants.BooleanConstant;
import org.simantics.scl.compiler.elaboration.expressions.ELiteral;
import org.simantics.scl.compiler.elaboration.expressions.EVariable;
import org.simantics.scl.compiler.elaboration.expressions.Variable;
import org.simantics.scl.compiler.elaboration.query.compilation.QueryCompilationContext;
import org.simantics.scl.compiler.elaboration.relations.AbstractRelation;
import org.simantics.scl.compiler.types.TVar;
import org.simantics.scl.compiler.types.Type;
import org.simantics.scl.compiler.types.Types;

public class CheckRelation extends AbstractRelation {
    public static final CheckRelation INSTANCE = new CheckRelation();
    
    private CheckRelation() {}
    
    @Override
    public TVar[] getTypeVariables() {
        return TVar.EMPTY_ARRAY;
    }
    
    private static final Type[] PARAMETER_TYPES = new Type[] {Types.BOOLEAN};

    @Override
    public Type[] getParameterTypes() {
        return PARAMETER_TYPES;
    }
    
    @Override
    public int getPhase() {
        return 0;
    }

    @Override
    public double getSelectivity(int boundVariables) {
        switch(boundVariables) {
        case F: return 1.0;
        case B: return 0.1;
        default: throw new IllegalArgumentException();
        }
    }
    
    @Override
    public int getRequiredVariablesMask() {
        return F;
    }

    @Override
    public void generate(long location,
            QueryCompilationContext context,
            Type[] typeParameters, Variable[] parameters, int boundVariables) {
        switch(boundVariables) {
        case F:
            context.let(parameters[0], new ELiteral(new BooleanConstant(true)));
            break;
        case B:
            context.condition(new EVariable(parameters[0]));
            break;
        default: throw new IllegalArgumentException();
        }
    }

    @Override
    public String toString() {
        return "Check";
    }
    
}