# -*- coding: utf-8 -*-
# $Id: fix_stale_refs.py $

"""
This module must be used interactively!
Use with caution as it will delete some values from the regisry!

It tries to locate client references to products that no longer exist.
"""

__copyright__ = \
"""
Copyright (C) 2012-2019 Oracle Corporation

This file is part of VirtualBox Open Source Edition (OSE), as
available from http://www.virtualbox.org. This file is free software;
you can redistribute it and/or modify it under the terms of the GNU
General Public License (GPL) as published by the Free Software
Foundation, in version 2 as it comes in the "COPYING" file of the
VirtualBox OSE distribution. VirtualBox OSE is distributed in the
hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.

The contents of this file may alternatively be used under the terms
of the Common Development and Distribution License Version 1.0
(CDDL) only, as it comes in the "COPYING.CDDL" file of the
VirtualBox OSE distribution, in which case the provisions of the
CDDL are applicable instead of those of the GPL.

You may elect to license modified versions of this file under the
terms and conditions of either the GPL or the CDDL or both.
"""
__version__ = "$Revision: 127855 $"


from _winreg import HKEY_LOCAL_MACHINE, KEY_ALL_ACCESS
from _winreg import OpenKey, CloseKey, EnumKey, QueryInfoKey, EnumValue, DeleteValue, QueryValueEx
from distutils.util import strtobool

def reverse_bytes(hex_string):
    """
    This function reverses the order of bytes in the provided string.
    Each byte is represented by two characters which are reversed as well.
    """
    #print 'reverse_bytes(' + hex_string + ')'
    chars = len(hex_string)
    if chars > 2:
        return reverse_bytes(hex_string[chars/2:]) + reverse_bytes(hex_string[:chars/2])
    else:
        return hex_string[1] + hex_string[0]

def transpose_guid(guid):
    """
    Windows Installer uses different way to present GUID string. This function converts GUID
    from installer's presentation to more conventional form.
    """
    return '{' + reverse_bytes(guid[0:8]) + '-' + reverse_bytes(guid[8:12]) + \
        '-' + reverse_bytes(guid[12:16]) + \
        '-' + reverse_bytes(guid[16:18]) + reverse_bytes(guid[18:20]) + \
        '-' + ''.join([reverse_bytes(guid[i:i+2]) for i in range(20, 32, 2)]) + '}'

PRODUCTS_KEY   = r'SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-5-18\Products'
COMPONENTS_KEY = r'SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-5-18\Components'

def get_installed_products():
    """
    Enumerate all installed products.
    """
    products = {}
    hkey_products = OpenKey(HKEY_LOCAL_MACHINE, PRODUCTS_KEY, 0, KEY_ALL_ACCESS)

    try:
        product_index = 0
        while True:
            product_guid = EnumKey(hkey_products, product_index)
            hkey_product_properties = OpenKey(hkey_products, product_guid + r'\InstallProperties', 0, KEY_ALL_ACCESS)
            try:
                value = QueryValueEx(hkey_product_properties, 'DisplayName')[0]
            except WindowsError, exception:
                if exception.winerror != 2:
                    raise
                value = '<unknown>'
            CloseKey(hkey_product_properties)
            products[product_guid] = value
            product_index += 1
    except WindowsError, exceptione:
        if exceptione.winerror != 259:
            print exceptione.strerror + '.', 'error', exceptione.winerror
    CloseKey(hkey_products)

    print 'Installed products:'
    for product_key in sorted(products.keys()):
        print transpose_guid(product_key), '=', products[product_key]

    print
    return products

def get_missing_products(hkey_components):
    """
    Detect references to missing products.
    """
    products = get_installed_products()

    missing_products = {}

    for component_index in xrange(0, QueryInfoKey(hkey_components)[0]):
        component_guid = EnumKey(hkey_components, component_index)
        hkey_component = OpenKey(hkey_components, component_guid, 0, KEY_ALL_ACCESS)
        clients = []
        for value_index in xrange(0, QueryInfoKey(hkey_component)[1]):
            client_guid, client_path = EnumValue(hkey_component, value_index)[:2]
            clients.append((client_guid, client_path))
            if not client_guid in products:
                if client_guid in missing_products:
                    missing_products[client_guid].append((component_guid, client_path))
                else:
                    missing_products[client_guid] = [(component_guid, client_path)]
        CloseKey(hkey_component)
    return missing_products

def main():
    """
    Enumerate all installed products, go through all components and check if client refences
    point to valid products. Remove references to non-existing products if the user allowed it.
    """
    hkey_components = OpenKey(HKEY_LOCAL_MACHINE, COMPONENTS_KEY, 0, KEY_ALL_ACCESS)

    missing_products = get_missing_products(hkey_components)

    print 'Missing products refer the following components:'
    for product_guid in sorted(missing_products.keys()):
        if product_guid[1:] == '0'*31:
            continue
        print 'Product', transpose_guid(product_guid) + ':'
        for component_guid, component_file in missing_products[product_guid]:
            print ' ' + transpose_guid(component_guid), '=', component_file

        print 'Remove all references to product', transpose_guid(product_guid) + '? [y/n]'
        if strtobool(raw_input().lower()):
            for component_guid, component_file in missing_products[product_guid]:
                hkey_component = OpenKey(hkey_components, component_guid, 0, KEY_ALL_ACCESS)
                print 'Removing reference in ' + transpose_guid(component_guid), '=', component_file
                DeleteValue(hkey_component, product_guid)
                CloseKey(hkey_component)
        else:
            print 'Cancelled removal of product', transpose_guid(product_guid)

    CloseKey(hkey_components)

if __name__ == "__main__":
    main()