/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jena.sparql.expr;

import org.apache.jena.sparql.ARQInternalErrorException;
import org.apache.jena.sparql.engine.binding.Binding;
import org.apache.jena.sparql.expr.nodevalue.XSDFuncOp;
import org.apache.jena.sparql.function.FunctionEnv;
import org.apache.jena.sparql.sse.Tags;

/** IF(expr, expr, expr) */

public class E_If extends ExprFunction3 {
    private static final String functionName = Tags.tagIf;

    private final Expr condition;
    private final Expr thenExpr;
    private final Expr elseExpr;

    public E_If(Expr condition, Expr thenExpr, Expr elseExpr) {
        // Don't let the parent eval the theEpxr or ifExpr.
        super(condition, thenExpr, elseExpr, functionName);
        // Better names,
        this.condition = condition;
        this.thenExpr = thenExpr;
        this.elseExpr = elseExpr;
    }

    @Override
    public Expr copy(Expr arg1, Expr arg2, Expr arg3) {
        return new E_If(arg1, arg2, arg3);
    }

    /** Functional form evaluation */
    @Override
    protected NodeValue evalSpecial(Binding binding, FunctionEnv env) {
        NodeValue nv = condition.eval(binding, env);
        boolean ebv = XSDFuncOp.effectiveBooleanValue(nv);
        if ( ebv )
            return thenExpr.eval(binding, env);
        else
            return elseExpr.eval(binding, env);
    }

    @Override
    public NodeValue eval(NodeValue x, NodeValue y, NodeValue z) {
        throw new ARQInternalErrorException();
    }
}
