//go:build linux

package metrics

import (
	"strings"
	"syscall"
)

func ReadDiskUsage(path string) (DiskUsage, error) {
	p := strings.TrimSpace(path)
	if p == "" {
		p = "/"
	}
	var st syscall.Statfs_t
	if err := syscall.Statfs(p, &st); err != nil {
		return DiskUsage{Path: p}, err
	}
	total := st.Blocks * uint64(st.Bsize)
	free := st.Bavail * uint64(st.Bsize)
	used := total - free
	usedPct := 0.0
	if total > 0 {
		usedPct = float64(used) / float64(total) * 100
	}
	return DiskUsage{
		Path:       p,
		TotalBytes: total,
		FreeBytes:  free,
		UsedBytes:  used,
		UsedPct:    usedPct,
	}, nil
}