// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
// All rights reserved.

// operator-shift.go
package expr

//-------- shift term

func newRightShiftTerm(tk *Token) (inst *term) {
	return &term{
		tk:       *tk,
		children: make([]*term, 0, 2),
		position: posInfix,
		priority: priBinShift,
		evalFunc: evalRightShift,
	}
}

func evalRightShift(ctx ExprContext, opTerm *term) (v any, err error) {
	var leftValue, rightValue any

	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
		return
	}

	if IsInteger(leftValue) && IsInteger(rightValue) {
		leftInt := leftValue.(int64)
		rightInt := rightValue.(int64)
		v = leftInt >> rightInt
	} else {
		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
	}
	return
}

func newLeftShiftTerm(tk *Token) (inst *term) {
	return &term{
		tk:       *tk,
		children: make([]*term, 0, 2),
		position: posInfix,
		priority: priBinShift,
		evalFunc: evalLeftShift,
	}
}

func evalLeftShift(ctx ExprContext, opTerm *term) (v any, err error) {
	var leftValue, rightValue any

	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
		return
	}

	if IsInteger(leftValue) && IsInteger(rightValue) {
		leftInt := leftValue.(int64)
		rightInt := rightValue.(int64)
		v = leftInt << rightInt
	} else {
		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
	}
	return
}

// func evalAssignAppend(ctx ExprContext, self *term) (v any, err error) {
// 	var leftValue, rightValue any

// 	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
// 		return
// 	}

// 	if IsList(leftValue) {
// 		list, _ := leftValue.(*ListType)
// 		newList := append(*list, rightValue)
// 		v = &newList
// 		if
// 	} else {
// 		err = self.errIncompatibleTypes(leftValue, rightValue)
// 	}
// 	return
// }

// init
func init() {
	registerTermConstructor(SymDoubleGreater, newRightShiftTerm)
	registerTermConstructor(SymDoubleLess, newLeftShiftTerm)
}