// Copyright 2018 The CUE Authors
//
// Licensed 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 adt

import "cuelang.org/go/cue/token"

// Op indicates the operation at the top of an expression tree of the expression
// use to evaluate a value.
type Op int

//go:generate go run golang.org/x/tools/cmd/stringer -type=Op -linecomment

// Values of Op.
const (
	NoOp Op = iota

	AndOp // &
	OrOp  // |

	SelectorOp // .
	IndexOp    // []
	SliceOp    // [:]
	CallOp     // ()

	BoolAndOp // &&
	BoolOrOp  // ||

	EqualOp        // ==
	NotOp          // !
	NotEqualOp     // !=
	LessThanOp     // <
	LessEqualOp    // <=
	GreaterThanOp  // >
	GreaterEqualOp // >=

	MatchOp    // =~
	NotMatchOp // !~

	AddOp           // +
	SubtractOp      // -
	MultiplyOp      // *
	FloatQuotientOp // /
	IntQuotientOp   // quo
	IntRemainderOp  // rem
	IntDivideOp     // div
	IntModuloOp     // mod

	InterpolationOp // \()
)

// OpFromToken converts a token.Token to an Op.
func OpFromToken(t token.Token) Op {
	return tokenMap[t]
}

// Token returns the token.Token corresponding to the Op.
func (op Op) Token() token.Token {
	return opMap[op]
}

var tokenMap = map[token.Token]Op{
	token.OR:  OrOp,  // |
	token.AND: AndOp, // &

	token.ADD: AddOp,           // +
	token.SUB: SubtractOp,      // -
	token.MUL: MultiplyOp,      // *
	token.QUO: FloatQuotientOp, // /

	token.IDIV: IntDivideOp,    // div
	token.IMOD: IntModuloOp,    // mod
	token.IQUO: IntQuotientOp,  // quo
	token.IREM: IntRemainderOp, // rem

	token.LAND: BoolAndOp, // &&
	token.LOR:  BoolOrOp,  // ||

	token.EQL: EqualOp,       // ==
	token.LSS: LessThanOp,    // <
	token.GTR: GreaterThanOp, // >
	token.NOT: NotOp,         // !

	token.NEQ:  NotEqualOp,     // !=
	token.LEQ:  LessEqualOp,    // <=
	token.GEQ:  GreaterEqualOp, // >=
	token.MAT:  MatchOp,        // =~
	token.NMAT: NotMatchOp,     // !~
}

var opMap = map[Op]token.Token{}

func init() {
	for t, o := range tokenMap {
		opMap[o] = t
	}
}
