package czech

import (
	"strings"
	"unicode"

	"golang.org/x/text/unicode/norm"
)

// Normalize strips diacritics and lowercases s.
//
// Matches Python: unicodedata.normalize("NFKD", s) then filter out
// combining characters (unicode.Mn only — not Mc/Me, which have
// combining class 0 in Python's unicodedata.combining()).
func Normalize(s string) string {
	decomposed := norm.NFKD.String(s)
	var b strings.Builder
	b.Grow(len(decomposed))
	for _, r := range decomposed {
		if unicode.In(r, unicode.Mn) {
			continue
		}
		b.WriteRune(r)
	}
	return strings.ToLower(b.String())
}