# This file is Copyright 2019 Volatility Foundation and licensed under the Volatility Software License 1.0
# which is available at https://www.volatilityfoundation.org/license/vsl-v1.0
#

import abc
import datetime
import enum
import io
import json
import logging
import traceback
from typing import Generator, Iterable, List, Optional, Tuple, Type

from volatility import framework
from volatility.framework import renderers, automagic, interfaces, plugins, exceptions
from volatility.framework.configuration import requirements

vollog = logging.getLogger(__name__)


class TimeLinerType(enum.IntEnum):
    CREATED = 1
    MODIFIED = 2
    ACCESSED = 3
    CHANGED = 4


class TimeLinerInterface(metaclass = abc.ABCMeta):
    """Interface defining methods that timeliner will use to generate a body
    file."""

    @abc.abstractmethod
    def generate_timeline(self) -> Generator[Tuple[str, TimeLinerType, datetime.datetime], None, None]:
        """Method generates Tuples of (description, timestamp_type, timestamp)

        These need not be generated in any particular order, sorting
        will be done later
        """


class Timeliner(interfaces.plugins.PluginInterface):
    """Runs all relevant plugins that provide time related information and
    orders the results by time."""

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.timeline = {}
        self.usable_plugins = None
        self.automagics = None

    @classmethod
    def get_usable_plugins(cls, selected_list: List[str] = None) -> List[Type]:
        # Initialize for the run
        plugin_list = list(framework.class_subclasses(TimeLinerInterface))

        # Get the filter from the configuration
        def passthrough(name: str, selected: List[str]) -> bool:
            return True

        filter_func = passthrough
        if selected_list:

            def filter_plugins(name: str, selected: List[str]) -> bool:
                return any([s in name for s in selected])

            filter_func = filter_plugins
        else:
            selected_list = []

        return [plugin_class for plugin_class in plugin_list if filter_func(plugin_class.__name__, selected_list)]

    @classmethod
    def get_requirements(cls) -> List[interfaces.configuration.RequirementInterface]:
        return [
            requirements.StringRequirement(name = 'plugins',
                                           description = "Comma separated list of plugins to run",
                                           optional = True,
                                           default = None),
            requirements.BooleanRequirement(
                name = 'record-config',
                description = "Whether to record the state of all the plugins once complete",
                optional = True,
                default = False)
        ]

    def _generator(self, runable_plugins: List[TimeLinerInterface]) -> Optional[Iterable[Tuple[int, Tuple]]]:
        """Takes a timeline, sorts it and output the data from each relevant
        row from each plugin."""
        # Generate the results for each plugin
        for plugin in runable_plugins:
            plugin_name = plugin.__class__.__name__
            self._progress_callback((runable_plugins.index(plugin) * 100) // len(runable_plugins),
                                    "Running plugin {}...".format(plugin_name))
            try:
                vollog.log(logging.INFO, "Running {}".format(plugin_name))
                for (item, timestamp_type, timestamp) in plugin.generate_timeline():
                    times = self.timeline.get((plugin_name, item), {})
                    if times.get(timestamp_type, None) is not None:
                        vollog.debug("Multiple timestamps for the same plugin/file combination found: {} {}".format(
                            plugin_name, item))
                    times[timestamp_type] = timestamp
                    self.timeline[(plugin_name, item)] = times
            except Exception:
                # FIXME: traceback shouldn't be printed directly, but logged instead
                traceback.print_exc()
                vollog.log(logging.INFO, "Exception occurred running plugin: {}".format(plugin_name))

        for (plugin_name, item) in self.timeline:
            times = self.timeline[(plugin_name, item)]
            data = (0, [
                plugin_name, item,
                times.get(TimeLinerType.CREATED, renderers.NotApplicableValue()),
                times.get(TimeLinerType.MODIFIED, renderers.NotApplicableValue()),
                times.get(TimeLinerType.ACCESSED, renderers.NotApplicableValue()),
                times.get(TimeLinerType.CHANGED, renderers.NotApplicableValue())
            ])
            yield data

    def run(self):
        """Isolate each plugin and run it."""

        # Use all the plugins if there's no filter
        self.usable_plugins = self.usable_plugins or self.get_usable_plugins()
        self.automagics = self.automagics or automagic.available(self._context)
        runable_plugins = []

        # Identify plugins that we can run which output datetimes
        for plugin_class in self.usable_plugins:
            try:
                automagics = automagic.choose_automagic(self.automagics, plugin_class)

                plugin = plugins.construct_plugin(self.context, automagics, plugin_class, self.config_path,
                                                  self._progress_callback, self._file_consumer)

                if isinstance(plugin, TimeLinerInterface):
                    runable_plugins.append(plugin)
            except exceptions.UnsatisfiedException as excp:
                # Remove the failed plugin from the list and continue
                vollog.debug("Unable to satisfy {}: {}".format(plugin_class.__name__, excp.unsatisfied))
                continue

        if self.config.get('record-config', False):
            total_config = {}
            for plugin in runable_plugins:
                old_dict = dict(plugin.build_configuration())
                for entry in old_dict:
                    total_config[interfaces.configuration.path_join(plugin.__class__.__name__, entry)] = old_dict[entry]

            filedata = interfaces.plugins.FileInterface("config.json")
            with io.TextIOWrapper(filedata.data, write_through = True) as fp:
                json.dump(total_config, fp, sort_keys = True, indent = 2)
                self.produce_file(filedata)

        return renderers.TreeGrid(columns = [("Plugin", str), ("Description", str), ("Created Date", datetime.datetime),
                                             ("Modified Date", datetime.datetime), ("Accessed Date", datetime.datetime),
                                             ("Changed Date", datetime.datetime)],
                                  generator = self._generator(runable_plugins))

    def build_configuration(self):
        """Builds the configuration to save for the plugin such that it can be
        reconstructed."""
        vollog.warning("Unable to record configuration data for the timeliner plugin")
        return []