package securecookie

import "fmt"

var _ Codec = (*LiteCodec)(nil)

func NewLiteCodec() *LiteCodec {
	s := &LiteCodec{
		sz: GobEncoder{},
	}
	return s
}

// LiteCodec encodes and decodes
type LiteCodec struct {
	err error
	sz  Serializer
}

// Encoding sets the encoding/serialization method for cookies.
//
// Default is encoding/gob.  To encode special structures using encoding/gob,
// they must be registered first using gob.Register().
func (s *LiteCodec) SetSerializer(sz Serializer) *LiteCodec {
	s.sz = sz

	return s
}

// Encode encodes a value.
func (s *LiteCodec) Encode(name string, value interface{}) (string, error) {
	if s.err != nil {
		return "", s.err
	}
	var err error
	var b []byte
	// Serialize.
	if b, err = s.sz.Serialize(value); err != nil {
		return "", cookieError{cause: fmt.Errorf(`%w: %s`, err, name), typ: usageError}
	}
	// Done.
	return string(b), nil
}

// Decode decodes a value. The dst argument must be a pointer.
func (s *LiteCodec) Decode(name, value string, dst interface{}, _ ...int) error {
	if s.err != nil {
		return s.err
	}
	// Deserialize.
	if err := s.sz.Deserialize([]byte(value), dst); err != nil {
		return cookieError{cause: fmt.Errorf(`%w: %s`, err, name), typ: decodeError}
	}
	// Done.
	return nil
}