# This file is Copyright 2020 Volatility Foundation and licensed under the Volatility Software License 1.0
# which is available at https://www.volatilityfoundation.org/license/vsl-v1.0

import hashlib
import json
import logging
import os
import struct
from typing import List

from volatility3.framework import renderers, interfaces, constants, exceptions
from volatility3.framework.configuration import requirements
from volatility3.plugins.windows.registry import hivelist

vollog = logging.getLogger(__name__)


def createservicesid(svc) -> str:
    """ Calculate the Service SID """
    uni = ''.join([c + '\x00' for c in svc])
    sha = hashlib.sha1(uni.upper().encode("utf-8")).digest()  # pylint: disable-msg=E1101
    dec = list()
    for i in range(5):
        ## The use of struct here is OK. It doesn't make much sense
        ## to leverage obj.Object inside this loop.
        dec.append(struct.unpack('<I', sha[i * 4:i * 4 + 4])[0])
    return 'S-1-5-80-' + '-'.join([str(n) for n in dec])


class GetServiceSIDs(interfaces.plugins.PluginInterface):
    """Lists process token sids."""

    _version = (1, 0, 0)
    _required_framework_version = (2, 0, 0)

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        # Find the sids json path (or raise error if its not in the plugin directory).
        for plugin_dir in constants.PLUGINS_PATH:
            sids_json_file_name = os.path.join(plugin_dir, os.path.join("windows", "sids_and_privileges.json"))
            if os.path.exists(sids_json_file_name):
                break
        else:
            vollog.log(constants.LOGLEVEL_VVV, 'sids_and_privileges.json file is missing plugin error')
            raise RuntimeError("The sids_and_privileges.json file missed from you plugin directory")

        # Get service sids dictionary (we need only the service sids).
        with open(sids_json_file_name, 'r') as file_handle:
            self.servicesids = json.load(file_handle)['service sids']

    @classmethod
    def get_requirements(cls) -> List[interfaces.configuration.RequirementInterface]:
        # Since we're calling the plugin, make sure we have the plugin's requirements
        return [
            requirements.ModuleRequirement(name = 'kernel', description = 'Windows kernel',
                                                     architectures = ["Intel32", "Intel64"]),
            requirements.PluginRequirement(name = 'hivelist', plugin = hivelist.HiveList, version = (1, 0, 0))
        ]

    def _generator(self):

        kernel = self.context.modules[self.config['kernel']]
        # Get the system hive
        for hive in hivelist.HiveList.list_hives(context = self.context,
                                                 base_config_path = self.config_path,
                                                 layer_name = kernel.layer_name,
                                                 symbol_table = kernel.symbol_table_name,
                                                 filter_string = 'machine\\system',
                                                 hive_offsets = None):
            # Get ControlSet\Services.
            try:
                services = hive.get_key(r"CurrentControlSet\Services")
            except (KeyError, exceptions.InvalidAddressException):
                try:
                    services = hive.get_key(r"ControlSet001\Services")
                except (KeyError, exceptions.InvalidAddressException):
                    continue

            if services:
                for s in services.get_subkeys():
                    if s.get_name() not in self.servicesids.values():
                        sid = createservicesid(s.get_name())
                        yield (0, (sid, s.get_name()))

    def run(self):
        return renderers.TreeGrid([("SID", str), ("Service", str)], self._generator())
