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

// operator-bitwise.go
package expr

import (
	"git.portale-stac.it/go-pkg/expr/kern"
	"git.portale-stac.it/go-pkg/expr/scan"
)

//-------- Bitwise NOT term

func newBitwiseNotTerm(tk *scan.Token) (inst *scan.Term) {
	return &scan.Term{
		Tk:       *tk,
		Children: make([]*scan.Term, 0, 1),
		Position: scan.PosPrefix,
		Priority: scan.PriBitwiseNot,
		EvalFunc: evalBitwiseNot,
	}
}

func evalBitwiseNot(ctx kern.ExprContext, opTerm *scan.Term) (v any, err error) {
	var value any

	if value, err = opTerm.EvalPrefix(ctx); err != nil {
		return
	}

	if kern.IsInteger(value) {
		i, _ := value.(int64)
		v = ^i
	} else {
		err = opTerm.ErrIncompatiblePrefixPostfixType(value)
	}
	return
}

//-------- Bitwise AND term

func newBitwiseAndTerm(tk *scan.Token) (inst *scan.Term) {
	return &scan.Term{
		Tk:       *tk,
		Children: make([]*scan.Term, 0, 2),
		Position: scan.PosInfix,
		Priority: scan.PriBitwiseAnd,
		EvalFunc: evalBitwiseAnd,
	}
}

func bitwiseAnd(opTerm *scan.Term, leftValue, rightValue any) (v any, err error) {
	var leftInt, rightInt int64
	var lok, rok bool

	leftInt, lok = leftValue.(int64)
	rightInt, rok = rightValue.(int64)

	if lok && rok {
		v = leftInt & rightInt
	} else {
		err = opTerm.ErrIncompatibleTypes(leftValue, rightValue)
	}
	return
}

func evalBitwiseAnd(ctx kern.ExprContext, opTerm *scan.Term) (v any, err error) {
	var leftValue, rightValue any

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

//-------- Bitwise OR term

func newBitwiseOrTerm(tk *scan.Token) (inst *scan.Term) {
	return &scan.Term{
		Tk:       *tk,
		Children: make([]*scan.Term, 0, 2),
		Position: scan.PosInfix,
		Priority: scan.PriBitwiseOr,
		EvalFunc: evalBitwiseOr,
	}
}

func bitwiseOr(opTerm *scan.Term, leftValue, rightValue any) (v any, err error) {
	var leftInt, rightInt int64
	var lok, rok bool

	leftInt, lok = leftValue.(int64)
	rightInt, rok = rightValue.(int64)

	if lok && rok {
		v = leftInt | rightInt
	} else {
		err = opTerm.ErrIncompatibleTypes(leftValue, rightValue)
	}
	return
}

func evalBitwiseOr(ctx kern.ExprContext, opTerm *scan.Term) (v any, err error) {
	var leftValue, rightValue any

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

	v, err = bitwiseOr(opTerm, leftValue, rightValue)
	return
}

//-------- Bitwise XOR term

func newBitwiseXorTerm(tk *scan.Token) (inst *scan.Term) {
	return &scan.Term{
		Tk:       *tk,
		Children: make([]*scan.Term, 0, 2),
		Position: scan.PosInfix,
		Priority: scan.PriBitwiseXor,
		EvalFunc: evalBitwiseXor,
	}
}

func bitwiseXor(opTerm *scan.Term, leftValue, rightValue any) (v any, err error) {
	var leftInt, rightInt int64
	var lok, rok bool

	leftInt, lok = leftValue.(int64)
	rightInt, rok = rightValue.(int64)

	if lok && rok {
		v = leftInt ^ rightInt
	} else {
		err = opTerm.ErrIncompatibleTypes(leftValue, rightValue)
	}
	return
}

func evalBitwiseXor(ctx kern.ExprContext, opTerm *scan.Term) (v any, err error) {
	var leftValue, rightValue any

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

	v, err = bitwiseXor(opTerm, leftValue, rightValue)
	return
}

// init
func init() {
	scan.RegisterTermConstructor(scan.SymTilde, newBitwiseNotTerm)
	scan.RegisterTermConstructor(scan.SymAmpersand, newBitwiseAndTerm)
	scan.RegisterTermConstructor(scan.SymVertBar, newBitwiseOrTerm)
	scan.RegisterTermConstructor(scan.SymCaret, newBitwiseXorTerm)
}