// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.searchlib.rankingexpression.rule;

import com.yahoo.searchlib.rankingexpression.evaluation.Value;

import java.util.List;

/**
 * A mathematical operator
 *
 * @author bratseth
 */
public enum ArithmeticOperator {

    OR(0, "||") { public Value evaluate(Value x, Value y) {
        return x.or(y);
    }},
    AND(1, "&&") { public Value evaluate(Value x, Value y) {
        return x.and(y);
    }},
    PLUS(2, "+") { public Value evaluate(Value x, Value y) {
        return x.add(y);
    }},
    MINUS(3, "-") { public Value evaluate(Value x, Value y) {
        return x.subtract(y);
    }},
    MULTIPLY(4, "*") { public Value evaluate(Value x, Value y) {
        return x.multiply(y);
    }},
    DIVIDE(5, "/") { public Value evaluate(Value x, Value y) {
        return x.divide(y);
    }},
    MODULO(6, "%") { public Value evaluate(Value x, Value y) {
        return x.modulo(y);
    }},
    POWER(7, "^") { public Value evaluate(Value x, Value y) {
        return x.power(y);
    }};

    /** A list of all the operators in this in order of decreasing precedence */
    public static final List<ArithmeticOperator> operatorsByPrecedence = List.of(POWER, MODULO, DIVIDE, MULTIPLY, MINUS, PLUS, AND, OR);

    private final int precedence;
    private final String image;

    private ArithmeticOperator(int precedence, String image) {
        this.precedence = precedence;
        this.image = image;
    }

    /** Returns true if this operator has precedence over the given operator */
    public boolean hasPrecedenceOver(ArithmeticOperator op) {
        return precedence > op.precedence;
    }

    public abstract Value evaluate(Value x, Value y);

    @Override
    public String toString() {
        return image;
    }

}