package main

import (
	"fmt"
	"os/exec"
	"strings"
)

func getDiskUsage(path string) (uint64, error) {
	cmd := exec.Command("df", "-B1", path)
	output, err := cmd.CombinedOutput()
	if err != nil {
		return 0, err
	}

	lines := strings.Split(string(output), "\n")
	if len(lines) < 2 {
		return 0, fmt.Errorf("unexpected output from df command")
	}

	fields := strings.Fields(lines[1])
	if len(fields) < 3 {
		return 0, fmt.Errorf("unexpected output format from df command")
	}

	used := fields[2]
	usedBytes, err := parseSize(used)
	if err != nil {
		return 0, err
	}

	return usedBytes, nil
}

func parseSize(sizeStr string) (uint64, error) {
	var size uint64
	unit := sizeStr[len(sizeStr)-1]
	value := sizeStr[:len(sizeStr)-1]

	_, err := fmt.Sscan(value, &size)
	if err != nil {
		return 0, err
	}

	switch unit {
	case 'B':
		return size, nil
	case 'K':
		return size * 1024, nil
	case 'M':
		return size * 1024 * 1024, nil
	case 'G':
		return size * 1024 * 1024 * 1024, nil
	default:
		return 0, fmt.Errorf("unknown unit: %c", unit)
	}
}

func main() {
	path := "/dev/vdb" // 替换为您要查询的硬盘路径，如 "/dev/sda"

	used, err := getDiskUsage(path)
	if err != nil {
		fmt.Println("Error:", err)
		return
	}

	fmt.Printf("Used Disk Space: %d bytes\n", used)
}