"""Fake (in-memory only) storage writer for testing."""

from plaso.lib import definitions
from plaso.storage import writer
from plaso.storage.fake import fake_store


class FakeStorageWriter(writer.StorageWriter):
    """Fake (in-memory only) storage writer object.

    Attributes:
      task_completion (TaskCompletion): task completion attribute container.
      task_start (TaskStart): task start attribute container.
    """

    def __init__(self, storage_type=definitions.STORAGE_TYPE_SESSION):
        """Initializes a storage writer object.

        Args:
          storage_type (Optional[str]): storage type.
        """
        super().__init__(storage_type=storage_type)
        self._first_written_event_data_index = 0
        self._first_written_event_source_index = 0
        self._written_event_data_index = 0
        self._written_event_source_index = 0
        self.task_completion = None
        self.task_start = None

    def GetFirstWrittenEventData(self):
        """Retrieves the first event data that was written after open.

        Using GetFirstWrittenEventData and GetNextWrittenEventData newly
        added event data can be retrieved in order of addition.

        Returns:
          EventData: event data or None if there are no newly written ones.

        Raises:
          OSError: when the storage writer is closed.
        """
        if not self._store:
            raise OSError("Unable to read from closed storage writer.")

        event_data = self._store.GetAttributeContainerByIndex(
            self._CONTAINER_TYPE_EVENT_DATA, self._first_written_event_data_index
        )
        self._written_event_data_index = self._first_written_event_data_index + 1
        return event_data

    def GetNextWrittenEventData(self):
        """Retrieves the next event data that was written after open.

        Returns:
          EventData: event data or None if there are no newly written ones.

        Raises:
          OSError: when the storage writer is closed.
        """
        if not self._store:
            raise OSError("Unable to read from closed storage writer.")

        event_data = self._store.GetAttributeContainerByIndex(
            self._CONTAINER_TYPE_EVENT_DATA, self._written_event_data_index
        )
        self._written_event_data_index += 1
        return event_data

    def GetFirstWrittenEventSource(self):
        """Retrieves the first event source that was written after open.

        Using GetFirstWrittenEventSource and GetNextWrittenEventSource newly
        added event sources can be retrieved in order of addition.

        Returns:
          EventSource: event source or None if there are no newly written ones.

        Raises:
          OSError: when the storage writer is closed.
        """
        if not self._store:
            raise OSError("Unable to read from closed storage writer.")

        event_source = self._store.GetAttributeContainerByIndex(
            self._CONTAINER_TYPE_EVENT_SOURCE, self._first_written_event_source_index
        )
        self._written_event_source_index = self._first_written_event_source_index + 1
        return event_source

    def GetNextWrittenEventSource(self):
        """Retrieves the next event source that was written after open.

        Returns:
          EventSource: event source or None if there are no newly written ones.

        Raises:
          OSError: when the storage writer is closed.
        """
        if not self._store:
            raise OSError("Unable to read from closed storage writer.")

        event_source = self._store.GetAttributeContainerByIndex(
            self._CONTAINER_TYPE_EVENT_SOURCE, self._written_event_source_index
        )
        self._written_event_source_index += 1
        return event_source

    def Open(self, **unused_kwargs):
        """Opens the storage writer.

        Raises:
          OSError: if the storage writer is already opened.
        """
        if self._store:
            raise OSError("Storage writer already opened.")

        self._store = fake_store.FakeStore()
        self._store.Open()

        self._first_written_event_data_index = 0
        self._first_written_event_source_index = 0
        self._written_event_data_index = 0
        self._written_event_source_index = 0
