// Copyright (C) MongoDB, Inc. 2017-present.

//

// 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

package bson

import (

"errors"

"fmt"

"reflect"

)

// stringCodec is the Codec used for string values.

type stringCodec struct{}

// Assert that stringCodec satisfies the typeDecoder interface, which allows it to be

// used by collection type decoders (e.g. map, slice, etc) to set individual values in a

// collection.

var _ typeDecoder = &stringCodec{}

// EncodeValue is the ValueEncoder for string types.

func (sc *stringCodec) EncodeValue(_ EncodeContext, vw ValueWriter, val reflect.Value) error {

if val.Kind() != reflect.String {

return ValueEncoderError{

Name: "StringEncodeValue",

Kinds: []reflect.Kind{reflect.String},

Received: val,

}

}

return vw.WriteString(val.String())

}

func (sc *stringCodec) decodeType(dc DecodeContext, vr ValueReader, t reflect.Type) (reflect.Value, error) {

if t.Kind() != reflect.String {

return emptyValue, ValueDecoderError{

Name: "StringDecodeValue",

Kinds: []reflect.Kind{reflect.String},

Received: reflect.Zero(t),

}

}

var str string

var err error

switch vr.Type() {

case TypeString:

str, err = vr.ReadString()

if err != nil {

return emptyValue, err

}

case TypeObjectID:

if dc.objectIDAsHexString {

oid, err := vr.ReadObjectID()

if err != nil {

return emptyValue, err

}

str = oid.Hex()

} else {

const msg = "decoding an object ID into a string is not supported by default " +

"(set Decoder.ObjectIDAsHexString to enable decoding as a hexadecimal string)"

return emptyValue, errors.New(msg)

}

case TypeSymbol:

str, err = vr.ReadSymbol()

if err != nil {

return emptyValue, err

}

case TypeBinary:

data, subtype, err := vr.ReadBinary()

if err != nil {

return emptyValue, err

}

if subtype != TypeBinaryGeneric && subtype != TypeBinaryBinaryOld {

return emptyValue, decodeBinaryError{subtype: subtype, typeName: "string"}

}

str = string(data)

case TypeNull:

if err = vr.ReadNull(); err != nil {

return emptyValue, err

}

case TypeUndefined:

if err = vr.ReadUndefined(); err != nil {

return emptyValue, err

}

default:

return emptyValue, fmt.Errorf("cannot decode %v into a string type", vr.Type())

}

return reflect.ValueOf(str), nil

}

// DecodeValue is the ValueDecoder for string types.

func (sc *stringCodec) DecodeValue(dctx DecodeContext, vr ValueReader, val reflect.Value) error {

if !val.CanSet() || val.Kind() != reflect.String {

return ValueDecoderError{Name: "StringDecodeValue", Kinds: []reflect.Kind{reflect.String}, Received: val}

}

elem, err := sc.decodeType(dctx, vr, val.Type())

if err != nil {

return err

}

val.SetString(elem.String())

return nil

}