#!/usr/bin/python
#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2011  Marek Marczykowski <marmarek@mimuw.edu.pl>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
#
#

import subprocess
import re
import os
import sys
import fnmatch
from optparse import OptionParser
from qubes.qubes import QubesVmCollection,QubesException
from qubes.qubes import qrexec_client_path

# fields required to be present (and verified) in retrieved desktop file
required_fields = [ "Name", "Exec" ]

# regexps for sanitization of retrieved values
std_re = re.compile(r"^[/a-zA-Z0-9.,&() -]*$")
fields_regexp = {
    "Name": std_re,
    "GenericName": std_re,
    "Comment": std_re,
    "Categories": re.compile(r"^[a-zA-Z0-9/.; -]*$"),
    "Exec": re.compile(r"^[a-zA-Z0-9%>/:.= -]*$"),
}

def get_appmenus(xid):
    p = subprocess.Popen ([qrexec_client_path, '-d', str(xid),
            'user:grep -H = /usr/share/applications/*.desktop'], stdout=subprocess.PIPE)
    untrusted_appmenulist = p.communicate()[0].split('\n')
    if p.returncode != 0:
        raise QubesException("Error getting application list")
    

    row_no = 0
    appmenus = {}
    line_rx = re.compile(r"([a-zA-Z0-9-.]+.desktop):([a-zA-Z0-9-]+(?:\[[a-zA-Z@_]+\])?)=(.*)")
    ignore_rx = re.compile(r".*([a-zA-Z0-9-.]+.desktop):(#.*|\s+)$")
    for untrusted_line in untrusted_appmenulist:
        # Ignore blank lines and comments
        if len(untrusted_line) == 0 or ignore_rx.match(untrusted_line):
            continue 
        # use search instead of match to skip file path
        untrusted_m = line_rx.search(untrusted_line)
        if untrusted_m:
            untrusted_key = untrusted_m.group(2)
            untrusted_value = untrusted_m.group(3)
            if fields_regexp.has_key(untrusted_key):
                if fields_regexp[untrusted_key].match(untrusted_value):
                    # now values are sanitized
                    key = untrusted_key
                    value = untrusted_value
                    filename = untrusted_m.group(1)

                    if not appmenus.has_key(filename):
                        appmenus[filename] = {}

                    appmenus[filename][key]=value
                else:
                    print "Warning: ignoring key %s: %s" % (untrusted_key, untrusted_value)
            # else: ignore this key
        else:
            print "Warning: ignoring line: %s" % (untrusted_line);

    return appmenus


def create_template(path, values):

    # check if all required fields are present
    for key in required_fields:
        if not values.has_key(key):
            print "Warning: not creating/updating '%s' because of missing '%s' key" % (path, key)
            return

    desktop_file = open(path, "w")
    desktop_file.write("[Desktop Entry]\n")
    desktop_file.write("Version=1.0\n")
    desktop_file.write("Type=Application\n")
    desktop_file.write("Terminal=false\n")
    desktop_file.write("X-Qubes-VmName=%VMNAME%\n")
    desktop_file.write("Icon=%VMDIR%/icon.png\n")
    for key in ["Name", "GenericName" ]:
        if values.has_key(key):
            desktop_file.write("{0}=%VMNAME%: {1}\n".format(key, values[key]))
    
    for key in [ "Comment", "Categories" ]:
        if values.has_key(key):
            desktop_file.write("{0}={1}\n".format(key, values[key]))

    desktop_file.write("Exec=qvm-run -q --tray -a %VMNAME% '{0}'\n".format(values['Exec']))
    desktop_file.close()


def main():


    usage = "usage: %prog [options] <vm-name>\n"\
            "Updates desktop file templates for given StandaloneVM or TemplateVM"

    parser = OptionParser (usage)
    parser.add_option ("-v", "--verbose", action="store_true", dest="verbose", default=False)

    (options, args) = parser.parse_args ()
    if (len (args) != 1):
        parser.error ("You must specify at least the VM name!")

    vmname=args[0]

    qvm_collection = QubesVmCollection()
    qvm_collection.lock_db_for_reading()
    qvm_collection.load()
    qvm_collection.unlock_db()

    vm = qvm_collection.get_vm_by_name(vmname)

    if vm is None:
        print "ERROR: A VM with the name '{0}' does not exist in the system.".format(vmname)
        exit(1)

    if not vm.is_updateable():
        print "ERROR: To sync appmenus for non-updateable VM, do it on template instead"
        exit(1)

    if not vm.is_running():
        print "ERROR: Appmenus can be retrieved only from running VM - start it first"
        exit(1)

    # Get appmenus from VM
    xid = vm.get_xid()
    assert xid > 0

    new_appmenus = get_appmenus(xid)

    if len(new_appmenus) == 0:
        print "ERROR: No appmenus received, terminating"
        exit(1)

    assert os.path.exists(vm.appmenus_templates_dir)

    # Create new/update existing templates
    if options.verbose:
        print "--> Got {0} appmenus, storing to disk".format(str(len(new_appmenus)))
    for appmenu_file in new_appmenus.keys():
        if options.verbose:
            if os.path.exists(appmenus_templates_dir + '/' + appmenu_file):
                print "---> Updating {0}".format(appmenu_file)
            else:
                print "---> Creating {0}".format(appmenu_file)
        create_template(appmenus_templates_dir + '/' + appmenu_file, new_appmenus[appmenu_file])

    # Delete appmenus of remove applications
    if options.verbose:
        print "--> Cleaning old files"
    for appmenu_file in os.listdir(appmenus_templates_dir):
        if not fnmatch.fnmatch(appmenu_file, '*.desktop'):
            continue

        if not new_appmenus.has_key(appmenu_file):
            if options.verbose:
                print "---> Removing {0}".format(appmenu_file)
            os.unlink(appmenus_templates_dir + '/' + appmenu_file)

main()