package snapshot

import (
	"os"
	"syscall"
	"time"
)

// getCTime extracts the file creation time (birth time) from os.FileInfo.
//
// On macOS (Darwin), this returns the birth time (Birthtimespec) from the
// underlying syscall.Stat_t. macOS HFS+ and APFS filesystems natively track
// file creation time, making this a true "created at" timestamp.
//
// Falls back to modification time if the underlying Sys() data is not a
// *syscall.Stat_t (e.g. when using in-memory filesystems for testing).
func getCTime(info os.FileInfo) time.Time {
	stat, ok := info.Sys().(*syscall.Stat_t)
	if !ok {
		return info.ModTime()
	}
	return time.Unix(stat.Birthtimespec.Sec, stat.Birthtimespec.Nsec).UTC()
}