package simhash

// TODO: channel scanner

// Return features one-at-a-time to be considered by SimHash.
// This matches (partially) the scanner interface for bufio.Scanner, so those scanner can be reused here.
type FeatureScanner interface {
	Scan() bool
	Bytes() []byte
	Err() error
}

type SliceScanner struct {
	tokens [][]byte
	i      int
}

// NewSliceScanner creates a scanner that returns the byte slices in tokens
func NewSliceScanner(tokens [][]byte) FeatureScanner {
	return &SliceScanner{tokens: tokens}
}

func (s *SliceScanner) Err() error {
	return nil
}

func (s *SliceScanner) Scan() bool {

	if s.i >= len(s.tokens) {
		return false
	}
	s.i++
	return true
}

func (s *SliceScanner) Bytes() []byte {
	return s.tokens[s.i-1]
}