text: """
  """
  from abc import ABCMeta, abstractmethod
  from typing import AsyncGenerator, Callable, Iterable, Optional, Sequence
  
  from prompt_toolkit.document import Document
  from prompt_toolkit.eventloop import generator_to_async_generator
  from prompt_toolkit.filters import FilterOrBool, to_filter
  from prompt_toolkit.formatted_text import AnyFormattedText, StyleAndTextTuples
  
  __all__ = [
      "Completion",
      "Completer",
      "ThreadedCompleter",
      "DummyCompleter",
      "DynamicCompleter",
      "CompleteEvent",
      "ConditionalCompleter",
      "merge_completers",
      "get_common_complete_suffix",
  ]
  
  
  class Completion:
      """
      :param text: The new string that will be inserted into the document.
      :param start_position: Position relative to the cursor_position where the
          new text will start. The text will be inserted between the
          start_position and the original cursor position.
      :param display: (optional string or formatted text) If the completion has
          to be displayed differently in the completion menu.
      :param display_meta: (Optional string or formatted text) Meta information
          about the completion, e.g. the path or source where it's coming from.
          This can also be a callable that returns a string.
      :param style: Style string.
      :param selected_style: Style string, used for a selected completion.
          This can override the `style` parameter.
      """
  
      def __init__(
          self,
          text: str,
          start_position: int = 0,
          display: Optional[AnyFormattedText] = None,
          display_meta: Optional[AnyFormattedText] = None,
          style: str = "",
          selected_style: str = "",
      ) -> None:
  
          from prompt_toolkit.formatted_text import to_formatted_text
  
          self.text = text
          self.start_position = start_position
          self._display_meta = display_meta
  
          if display is None:
              display = text
  
          self.display = to_formatted_text(display)
  
          self.style = style
          self.selected_style = selected_style
  
          assert self.start_position <= 0
  
      def __repr__(self) -> str:
          if isinstance(self.display, str) and self.display == self.text:
              return "%s(text=%r, start_position=%r)" % (
                  self.__class__.__name__,
                  self.text,
                  self.start_position,
              )
          else:
              return "%s(text=%r, start_position=%r, display=%r)" % (
                  self.__class__.__name__,
                  self.text,
                  self.start_position,
                  self.display,
              )
  
      def __eq__(self, other: object) -> bool:
          if not isinstance(other, Completion):
              return False
          return (
              self.text == other.text
              and self.start_position == other.start_position
              and self.display == other.display
              and self._display_meta == other._display_meta
          )
  
      def __hash__(self) -> int:
          return hash((self.text, self.start_position, self.display, self._display_meta))
  
      @property
      def display_text(self) -> str:
          "The 'display' field as plain text."
          from prompt_toolkit.formatted_text import fragment_list_to_text
  
          return fragment_list_to_text(self.display)
  
      @property
      def display_meta(self) -> StyleAndTextTuples:
          "Return meta-text. (This is lazy when using a callable)."
          from prompt_toolkit.formatted_text import to_formatted_text
  
          return to_formatted_text(self._display_meta or "")
  
      @property
      def display_meta_text(self) -> str:
          "The 'meta' field as plain text."
          from prompt_toolkit.formatted_text import fragment_list_to_text
  
          return fragment_list_to_text(self.display_meta)
  
      def new_completion_from_position(self, position: int) -> "Completion":
          """
          (Only for internal use!)
          Get a new completion by splitting this one. Used by `Application` when
          it needs to have a list of new completions after inserting the common
          prefix.
          """
          assert position - self.start_position >= 0
  
          return Completion(
              text=self.text[position - self.start_position :],
              display=self.display,
              display_meta=self._display_meta,
          )
  
  
  class CompleteEvent:
      """
      Event that called the completer.
  
      :param text_inserted: When True, it means that completions are requested
          because of a text insert. (`Buffer.complete_while_typing`.)
      :param completion_requested: When True, it means that the user explicitly
          pressed the `Tab` key in order to view the completions.
  
      These two flags can be used for instance to implement a completer that
      shows some completions when ``Tab`` has been pressed, but not
      automatically when the user presses a space. (Because of
      `complete_while_typing`.)
      """
  
      def __init__(
          self, text_inserted: bool = False, completion_requested: bool = False
      ) -> None:
          assert not (text_inserted and completion_requested)
  
          #: Automatic completion while typing.
          self.text_inserted = text_inserted
  
          #: Used explicitly requested completion by pressing 'tab'.
          self.completion_requested = completion_requested
  
      def __repr__(self) -> str:
          return "%s(text_inserted=%r, completion_requested=%r)" % (
              self.__class__.__name__,
              self.text_inserted,
              self.completion_requested,
          )
  
  
  class Completer(metaclass=ABCMeta):
      """
      Base class for completer implementations.
      """
  
      @abstractmethod
      def get_completions(
          self, document: Document, complete_event: CompleteEvent
      ) -> Iterable[Completion]:
          """
          This should be a generator that yields :class:`.Completion` instances.
  
          If the generation of completions is something expensive (that takes a
          lot of time), consider wrapping this `Completer` class in a
          `ThreadedCompleter`. In that case, the completer algorithm runs in a
          background thread and completions will be displayed as soon as they
          arrive.
  
          :param document: :class:`~prompt_toolkit.document.Document` instance.
          :param complete_event: :class:`.CompleteEvent` instance.
          """
          while False:
              yield
  
      async def get_completions_async(
          self, document: Document, complete_event: CompleteEvent
      ) -> AsyncGenerator[Completion, None]:
          """
          Asynchronous generator for completions. (Probably, you won't have to
          override this.)
  
          Asynchronous generator of :class:`.Completion` objects.
          """
          for item in self.get_completions(document, complete_event):
              yield item
  
  
  class ThreadedCompleter(Completer):
      """
      Wrapper that runs the `get_completions` generator in a thread.
  
      (Use this to prevent the user interface from becoming unresponsive if the
      generation of completions takes too much time.)
  
      The completions will be displayed as soon as they are produced. The user
      can already select a completion, even if not all completions are displayed.
      """
  
      def __init__(self, completer: Completer) -> None:
          self.completer = completer
  
      def get_completions(
          self, document: Document, complete_event: CompleteEvent
      ) -> Iterable[Completion]:
          return self.completer.get_completions(document, complete_event)
  
      async def get_completions_async(
          self, document: Document, complete_event: CompleteEvent
      ) -> AsyncGenerator[Completion, None]:
          """
          Asynchronous generator of completions.
          """
          async for completion in generator_to_async_generator(
              lambda: self.completer.get_completions(document, complete_event)
          ):
              yield completion
  
      def __repr__(self) -> str:
          return "ThreadedCompleter(%r)" % (self.completer,)
  
  
  class DummyCompleter(Completer):
      """
      A completer that doesn't return any completion.
      """
  
      def get_completions(
          self, document: Document, complete_event: CompleteEvent
      ) -> Iterable[Completion]:
          return []
  
      def __repr__(self) -> str:
          return "DummyCompleter()"
  
  
  class DynamicCompleter(Completer):
      """
      Completer class that can dynamically returns any Completer.
  
      :param get_completer: Callable that returns a :class:`.Completer` instance.
      """
  
      def __init__(self, get_completer: Callable[[], Optional[Completer]]) -> None:
          self.get_completer = get_completer
  
      def get_completions(
          self, document: Document, complete_event: CompleteEvent
      ) -> Iterable[Completion]:
          completer = self.get_completer() or DummyCompleter()
          return completer.get_completions(document, complete_event)
  
      async def get_completions_async(
          self, document: Document, complete_event: CompleteEvent
      ) -> AsyncGenerator[Completion, None]:
          completer = self.get_completer() or DummyCompleter()
  
          async for completion in completer.get_completions_async(
              document, complete_event
          ):
              yield completion
  
      def __repr__(self) -> str:
          return "DynamicCompleter(%r -> %r)" % (self.get_completer, self.get_completer())
  
  
  class ConditionalCompleter(Completer):
      """
      Wrapper around any other completer that will enable/disable the completions
      depending on whether the received condition is satisfied.
  
      :param completer: :class:`.Completer` instance.
      :param filter: :class:`.Filter` instance.
      """
  
      def __init__(self, completer: Completer, filter: FilterOrBool) -> None:
          self.completer = completer
          self.filter = to_filter(filter)
  
      def __repr__(self) -> str:
          return "ConditionalCompleter(%r, filter=%r)" % (self.completer, self.filter)
  
      def get_completions(
          self, document: Document, complete_event: CompleteEvent
      ) -> Iterable[Completion]:
          # Get all completions in a blocking way.
          if self.filter():
              for c in self.completer.get_completions(document, complete_event):
                  yield c
  
      async def get_completions_async(
          self, document: Document, complete_event: CompleteEvent
      ) -> AsyncGenerator[Completion, None]:
  
          # Get all completions in a non-blocking way.
          if self.filter():
              async for item in self.completer.get_completions_async(
                  document, complete_event
              ):
                  yield item
  
  
  class _MergedCompleter(Completer):
      """
      Combine several completers into one.
      """
  
      def __init__(self, completers: Sequence[Completer]) -> None:
          self.completers = completers
  
      def get_completions(
          self, document: Document, complete_event: CompleteEvent
      ) -> Iterable[Completion]:
          # Get all completions from the other completers in a blocking way.
          for completer in self.completers:
              for c in completer.get_completions(document, complete_event):
                  yield c
  
      async def get_completions_async(
          self, document: Document, complete_event: CompleteEvent
      ) -> AsyncGenerator[Completion, None]:
  
          # Get all completions from the other completers in a non-blocking way.
          for completer in self.completers:
              async for item in completer.get_completions_async(document, complete_event):
                  yield item
  
  
  def merge_completers(
      completers: Sequence[Completer], deduplicate: bool = False
  ) -> Completer:
      """
      Combine several completers into one.
  
      :param deduplicate: If `True`, wrap the result in a `DeduplicateCompleter`
          so that completions that would result in the same text will be
          deduplicated.
      """
      if deduplicate:
          from .deduplicate import DeduplicateCompleter
  
          return DeduplicateCompleter(_MergedCompleter(completers))
  
      return _MergedCompleter(completers)
  
  
  def get_common_complete_suffix(
      document: Document, completions: Sequence[Completion]
  ) -> str:
      """
      Return the common prefix for all completions.
      """
      # Take only completions that don't change the text before the cursor.
      def doesnt_change_before_cursor(completion: Completion) -> bool:
          end = completion.text[: -completion.start_position]
          return document.text_before_cursor.endswith(end)
  
      completions2 = [c for c in completions if doesnt_change_before_cursor(c)]
  
      # When there is at least one completion that changes the text before the
      # cursor, don't return any common part.
      if len(completions2) != len(completions):
          return ""
  
      # Return the common prefix.
      def get_suffix(completion: Completion) -> str:
          return completion.text[-completion.start_position :]
  
      return _commonprefix([get_suffix(c) for c in completions2])
  
  
  def _commonprefix(strings: Iterable[str]) -> str:
      # Similar to os.path.commonprefix
      if not strings:
          return ""
  
      else:
          s1 = min(strings)
          s2 = max(strings)
  
          for i, c in enumerate(s1):
              if c != s2[i]:
                  return s1[:i]
  
          return s1
  