#!/usr/bin/python

import os
import subprocess
import time

# Variables globales
selectedDiskPath = ""
selectedMountPoint = ""
mountFlag = False


# Fonction SelectDisk : sélectionne une image disque
def SelectDisk(diskPath):
	global selectedDiskPath
	global mountFlag
	
	if mountFlag == True:
		print("Error : you must umount the current partition before select a new disk")
		return -1
	
	if os.path.isfile(diskPath) == True:
		selectedDiskPath = diskPath
		return 0
	else:
		print("Error : invalid disk path")
		return -2


# Fonction SelectMountPoint : sélectionne un répertoire pour le montage
def SelectMountPoint(dirPath):
	global selectedMountPoint
	global mountFlag
	
	if mountFlag == True:
		print("Error : you must umount the current partition before select a new mount point")
		return -1
	
	if os.path.isdir(dirPath) == True:
		selectedMountPoint = dirPath
		return 0
	else:
		print("Error : invalid dir path")
		return -2


# Fonction MountPart : Monte dans le répertoire sélectionné la partition <partNum> du disque sélectionné
def MountPart(partNum):
	global selectedDiskPath
	global selectedMountPoint
	global mountFlag
	
	if mountFlag == True:
		print("Error : a partition is aready mounted")
		return -1
	
	if partNum >= 0 and partNum < 4:
		uid = str(os.getuid())
		gid = str(os.getgid())
		off = subprocess.check_output(["tools/readpt", selectedDiskPath, str(partNum), "start_LBA"], stderr=None)
		partOffset = str(int(off) * 512)
		mountOptions = "loop,rw,offset={0},users,uid={1},gid={2}".format(partOffset, uid, gid)
		if subprocess.call(["/usr/bin/sudo", "/bin/mount", "-o", mountOptions, selectedDiskPath, selectedMountPoint], stdin=None, stdout=None, stderr=None) == 0:
			time.sleep(1)
			print("Partition ", partNum, " mounted")
			mountFlag = True
			return 0
		else:
			print("Error : unable to mount partition ", partNum)
			return -3
	else:
		return -2


# Fonction UmountPart : Démonte la partition montée
def UmountPart():
	global selectedMountPoint
	global mountFlag
	
	if mountFlag == False:
		print("Error : no partition mounted")
		return -1

	if subprocess.call(["/usr/bin/sudo", "/bin/umount", selectedMountPoint], stdin=None, stdout=None, stderr=None) == 0:
		time.sleep(1)
		print("Umount partition")
		mountFlag = False
		return 0
	else:
		print("Error : unable to umount partition")
		return -2



# Programme principal
print("\n########################################")
print("### NutsOS Disk Management Tool v1.0 ###")
print("########################################\n")
quit = False
while quit != True:
	cmd = input("#> ")
	args = cmd.split(sep=' ')
	if args[0] == "seldisk":
		if len(args) == 2:
			SelectDisk(args[1])
		else:
			print("Command error : seldisk <disk>")
	elif args[0] == "selmnt":
		if len(args) == 2:
			SelectMountPoint(args[1])
		else:
			print("Command error : selmnt <mountpoint>")
	elif args[0] == "mount":
		if len(args) == 2:
			MountPart(int(args[1]))
		else:
			print("Command error : mount <partition>")
	elif args[0] == "umount":
		if len(args) == 1:
			UmountPart()
		else:
			print("Command error : umount")
	elif args[0] == "quit":
		quit = True
		if mountFlag == True:
			UmountPart()
	else:
		print("Command error : unknown command")