#!/usr/bin/python

import routefs
from routes import Mapper

from syslog import *
from time import time

import os
import errno

from invirt.config import structs as config
from invirt import database

realpath = "/home/machines/"

class ConsoleFS(routefs.RouteFS):
	"""
	ConsoleFS creates a series of subdirectories each mirroring the same real
	directory, except for a single file - the .k5login - which is dynamically
	generated for each subdirectory
	"""
	
	def __init__(self, *args, **kw):
		"""Initialize the filesystem and set it to allow_other access besides
		the user who mounts the filesystem (i.e. root)
		"""
		super(ConsoleFS, self).__init__(*args, **kw)
		self.lasttime = 0
		self.machines = []
		self.fuse_args.add("allow_other", True)
		
		openlog('invirt-consolefs ', LOG_PID, LOG_DAEMON)
		
		syslog(LOG_DEBUG, 'Init complete.')
	
	def make_map(self):
		m = Mapper()
		m.connect('', controller='getMachines')
		m.connect(':machine', controller='getMirror')
		m.connect(':machine/.k5login', controller='getK5login')
		m.connect(':machine/*(path)', controller='getMirror')
		return m
	
	def recache(self):
		"""Refresh the local cache of VMs if the cache is more than 15 minutes old
		"""
		if time() - self.lasttime > 5:
			self.lasttime = time()
			database.clear_cache()
			self.machines = dict((machine.name, machine) for machine in database.session.query(database.Machine).all())

	def getMachines(self, **kw):
		"""Get the list of VMs in the database"""
		self.recache()
		return self.machines.keys()
	
	def getMirror(self, machine, path='', **kw):
		"""Translate the path into its realpath equivalent, and return that
		"""
		real = realpath + path
		if os.path.isdir(real):
			# The list is converted to a set so that we can handle the case 
			# where there is already a .k5login in the realpath gracefully	  
			return routefs.Directory(set(os.listdir(real) + ['.k5login']))
		elif os.path.islink(real):
			return routefs.Symlink(os.readlink(real))
		elif os.path.isfile(real):
			return open(real).read()
		else:
			return -errno.EINVAL
	
 	def getK5login(self, machine, **kw):
		"""Build the ACL for a machine and turn it into a .k5login file
		"""
		self.recache()
		machine = self.machines[machine]
		users = [acl.user for acl in machine.acl]
		return "\n".join(map(self.userToPrinc, users) + [''])
	
	def mirrorPath(self, path):
		"""Translate a virtual path to its real path counterpart"""
		return realpath + "/".join(getParts(path)[1:])
	
	def userToPrinc(self, user):
		"""Convert Kerberos v4-style names to v5-style and append a default
		realm if none is specified
		"""
		if '@' in user:
			(princ, realm) = user.split('@')
		else:
			princ = user
			realm = config.authn[0].realm
		
		return princ.replace('.', '/') + '@' + realm

if __name__ == '__main__':
	database.connect()
	routefs.main(ConsoleFS)
