#!/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):
        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):
        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):
        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)