#!/usr/bin/env python

import re
import CryptoBoxPreferences, CryptoBoxLogger, CryptoBoxContainer

class CryptoBox:
	'''Get and set the properties of a CryptoBox'''

	def __init__(self):
		'''reset all variables to default settings'''
		self.cbxPrefs = CryptoBoxPreferences.Preferences()
		self.debug = CryptoBoxLogger.CryptoBoxLogger(
			self.cbxPrefs["debuglevel"],
			self.cbxPrefs["debugfacility"], 
			self.cbxPrefs["logfile"] )
		self.alloweddevices = self.csv2list(self.cbxPrefs["allowed_devices"])
		self.containers = []
		for device in self.allAvailablePartitions():
			if self.deviceIsReallyAllowed(device):
				self.containers.append(CryptoBoxContainer.CryptoBoxContainer(device))

	############################
	### internal methods
	def csv2list(self, csvstring):
		'''transform a csv preferences string into a list'''
		commalist = csvstring.split(",") # split the csv by ","
		list = []
		for element in commalist:
			list.append(element.strip()) # remove whitespaces
		return list

	def deviceIsReallyAllowed(self, device):
		'''return "true" if the given device is white-listed for being used as cryptobox container'''
		for a in self.alloweddevices:
			if re.search('^' + a, device):
				#print "%s allowed for cbx" % a
				return True

	def allAvailablePartitions(self):
		'''retrieve a list of all available containers'''
		ret_list = []
		try:
			fpart = open("/proc/partitions", "r")
			try:
				line = fpart.readline()
				while line:
					p_details = line.split()
					if (len(p_details) == 4):
						(p_major, p_minor, p_size, p_device) = p_details
						if  re.search('^[0-9]*$', p_major) and re.search('^[0-9]*$', p_minor):
							p_parent = re.sub('[1-9]?[0-9]$', '', p_device)
							if p_parent == p_device:
								if [e for e in ret_list if re.search('^' + p_parent + '[1-9]?[0-9]$', e)]:
									"major partition - its children are already in the list"
									pass
								else:
									"major partition - but there are no children for now"
									ret_list.append(p_device)
							else:
								"minor partition - remove parent if necessary"
								if p_parent in ret_list: ret_list.remove(p_parent)
								ret_list.append(p_device)
					line = fpart.readline()
			finally:
				fpart.close()
			return ["/dev/" + e for e in ret_list]
		except IOError:
			self.debugMessage(
				"Could not read /proc/partitions",
				CryptoBoxLogger.DebugLevels["warn"])
			return []

	##################################
	### public methods
	def debugMessage(self, level, text):
		'''print a debug message to the previously choosen debugging facility'''
		self.debug.printMessage(level,text)

	def getContainerList(self):
		'''return a list of all containers of this cryptobox'''
		try:
			return self.containers[:]
		except AttributeError:
			return None

	def getConfigValue(self, key):
		'''return a tuple of key+value from the configfile'''
		return (key, self.cbxPrefs[key])

	def setConfigValue(self, key, value):
		'''save the strings key+value in configfile'''
		self.cbxPrefs[key]=value