package discovery

import "strings"

// NormaliseImage strips the tag and digest from an image reference,
// returning the bare repository name.
//
// Tricky case: "localhost:5000/foo:v1" — the first colon is a port,
// not a tag. We disambiguate by splitting on "/" first and only
// treating colons in the last segment as tag separators.
func NormaliseImage(ref string) string {
	if at := strings.Index(ref, "@"); at >= 0 {
		ref = ref[:at]
	}
	slash := strings.LastIndex(ref, "/")
	if slash < 0 {
		if colon := strings.Index(ref, ":"); colon >= 0 {
			return ref[:colon]
		}
		return ref
	}
	prefix, last := ref[:slash], ref[slash+1:]
	if colon := strings.Index(last, ":"); colon >= 0 {
		last = last[:colon]
	}
	return prefix + "/" + last
}

// ImagesMatch reports whether two image references resolve to the same
// repository, ignoring tag and digest. Case-sensitive per spec section 5.2.
func ImagesMatch(a, b string) bool {
	return NormaliseImage(a) == NormaliseImage(b)
}