package utils

import (
	"bufio"
	"fmt"
	"os"
	"syscall"
)

// mount_device checks if the device is already mounted at MOUNT_POINT,
// and if not, attempts to mount it as vfat or ext4.
// Returns 0 on success, -1 on error.
func MountDevice() int {
	var DEVICE = os.Getenv("DEVICE")
	var MOUNT_POINT = os.Getenv("MOUNT_POINT")
	if EnsureDir(MOUNT_POINT) < 0 {
		return -1
	}

	// Check if already mounted
	f, err := os.Open("/proc/mounts")
	if err == nil {
		defer f.Close()
		scanner := bufio.NewScanner(f)
		for scanner.Scan() {
			line := scanner.Text()
			// Simple substring check (equivalent to strstr)
			if contains(line, MOUNT_POINT) {
				return 0
			}
		}
		// Ignore scanner errors for simplicity
	}

	// Try mounting as vfat, then ext4
	if err := syscall.Mount(DEVICE, MOUNT_POINT, "vfat", 0, ""); err != nil {
		if err2 := syscall.Mount(DEVICE, MOUNT_POINT, "ext4", 0, ""); err2 != nil {
			// Both failed – print error (like perror) and return -1
			fmt.Fprintf(os.Stderr, "mount: %v (vfat) / %v (ext4)\n", err, err2)
			return -1
		}
	}
	return 0
}

func contains(s, substr string) bool {
	// Simple substring check, equivalent to strstr(s, substr) != NULL
	// You may also use strings.Contains if imported.
	for i := 0; i+len(substr) <= len(s); i++ {
		if s[i:i+len(substr)] == substr {
			return true
		}
	}
	return false
}