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package com.oracle.truffle.js.nodes.binary;

import java.util.Objects;
import java.util.Set;

import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.instrumentation.InstrumentableNode;
import com.oracle.truffle.api.instrumentation.Tag;
import com.oracle.truffle.api.nodes.NodeInfo;
import com.oracle.truffle.js.nodes.JavaScriptNode;
import com.oracle.truffle.js.nodes.Truncatable;
import com.oracle.truffle.js.nodes.access.JSConstantNode;
import com.oracle.truffle.js.nodes.access.JSConstantNode.JSConstantIntegerNode;
import com.oracle.truffle.js.nodes.cast.JSToInt32Node;
import com.oracle.truffle.js.nodes.cast.JSToNumericNode;
import com.oracle.truffle.js.nodes.instrumentation.JSTags.BinaryOperationTag;
import com.oracle.truffle.js.nodes.unary.JSUnaryNode;
import com.oracle.truffle.js.runtime.BigInt;
import com.oracle.truffle.js.runtime.Errors;
import com.oracle.truffle.js.runtime.SafeInteger;

11.7.2 The Signed Right Shift Operator ( >> ), special-cased for the step to be a constant
integer value.
/**
 * 11.7.2 The Signed Right Shift Operator ( >> ), special-cased for the step to be a constant
 * integer value.
 */
@NodeInfo(shortName = ">>")
public abstract class JSRightShiftConstantNode extends JSUnaryNode {

    protected final int shiftValue;

    protected JSRightShiftConstantNode(JavaScriptNode operand, int shiftValue) {
        super(operand);
        this.shiftValue = shiftValue;
    }

    public static JavaScriptNode create(JavaScriptNode left, JavaScriptNode right) {
        assert right instanceof JSConstantIntegerNode;
        int shiftValue = ((JSConstantIntegerNode) right).executeInt(null);
        if (left instanceof JSConstantIntegerNode) {
            int leftValue = ((JSConstantIntegerNode) left).executeInt(null);
            return JSConstantNode.createInt(leftValue >> shiftValue);
        }
        Truncatable.truncate(left);
        return JSRightShiftConstantNodeGen.create(left, shiftValue);
    }

    @Override
    public boolean hasTag(Class<? extends Tag> tag) {
        if (tag == BinaryOperationTag.class) {
            return true;
        } else {
            return super.hasTag(tag);
        }
    }

    @Override
    public InstrumentableNode materializeInstrumentableNodes(Set<Class<? extends Tag>> materializedTags) {
        if (materializedTags.contains(BinaryOperationTag.class)) {
            // need to call the generated factory directly to avoid constant optimizations
            JSConstantNode constantNode = JSConstantNode.createInt(shiftValue);
            JavaScriptNode node = JSRightShiftNodeGen.create(cloneUninitialized(getOperand(), materializedTags), constantNode);
            transferSourceSectionAddExpressionTag(this, constantNode);
            transferSourceSectionAndTags(this, node);
            return node;
        } else {
            return this;
        }
    }

    public abstract int executeInt(Object a);

    @Specialization
    protected int doInteger(int a) {
        return a >> shiftValue;
    }

    @Specialization
    protected int doSafeInteger(SafeInteger a) {
        return a.intValue() >> shiftValue;
    }

    @Specialization
    protected int doDouble(double a,
                    @Cached("create()") JSToInt32Node leftInt32Node) {
        return leftInt32Node.executeInt(a) >> shiftValue;
    }

    @Specialization
    protected void doBigInt(@SuppressWarnings("unused") BigInt a) {
        throw Errors.createTypeErrorCannotMixBigIntWithOtherTypes(this);
    }

    @Specialization(replaces = {"doInteger", "doSafeInteger", "doDouble", "doBigInt"})
    protected int doGeneric(Object a,
                    @Cached("create()") JSToNumericNode leftToNumeric,
                    @Cached("makeCopy()") JSRightShiftConstantNode innerShiftNode) {
        Object leftOperand = leftToNumeric.execute(a);
        return innerShiftNode.executeInt(leftOperand);
    }

    @Override
    public boolean isResultAlwaysOfType(Class<?> clazz) {
        return clazz == int.class;
    }

    protected JSRightShiftConstantNode makeCopy() {
        return (JSRightShiftConstantNode) copyUninitialized(null);
    }

    @Override
    protected JavaScriptNode copyUninitialized(Set<Class<? extends Tag>> materializedTags) {
        return JSRightShiftConstantNodeGen.create(cloneUninitialized(getOperand(), materializedTags), shiftValue);
    }

    @Override
    public String expressionToString() {
        if (getOperand() != null) {
            return "(" + Objects.toString(getOperand().expressionToString(), INTERMEDIATE_VALUE) + " >> " + shiftValue + ")";
        }
        return null;
    }
}