# -*- coding: utf-8 -*-
"""
    proxy.py
    ~~~~~~~~
    ⚡⚡⚡ Fast, Lightweight, Pluggable, TLS interception capable proxy server focused on
    Network monitoring, controls & Application development, testing, debugging.

    :copyright: (c) 2013-present by Abhinav Singh and contributors.
    :license: BSD, see LICENSE for more details.
"""
import socket

from abc import ABC, abstractmethod
from uuid import UUID
from typing import Tuple, List, Union, Optional

from .parser import HttpParser

from ..common.flags import Flags
from ..common.types import Readables, Writables
from ..core.event import EventQueue
from ..core.connection import TcpClientConnection


class HttpProtocolHandlerPlugin(ABC):
    """Base HttpProtocolHandler Plugin class.

    NOTE: This is an internal plugin and in most cases only useful for core contributors.
    If you are looking for proxy server plugins see `<proxy.HttpProxyBasePlugin>`.

    Implements various lifecycle events for an accepted client connection.
    Following events are of interest:

    1. Client Connection Accepted
       A new plugin instance is created per accepted client connection.
       Add your logic within __init__ constructor for any per connection setup.
    2. Client Request Chunk Received
       on_client_data is called for every chunk of data sent by the client.
    3. Client Request Complete
       on_request_complete is called once client request has completed.
    4. Server Response Chunk Received
       on_response_chunk is called for every chunk received from the server.
    5. Client Connection Closed
       Add your logic within `on_client_connection_close` for any per connection teardown.
    """

    def __init__(
            self,
            uid: UUID,
            flags: Flags,
            client: TcpClientConnection,
            request: HttpParser,
            event_queue: EventQueue):
        self.uid: UUID = uid
        self.flags: Flags = flags
        self.client: TcpClientConnection = client
        self.request: HttpParser = request
        self.event_queue = event_queue
        super().__init__()

    def name(self) -> str:
        """A unique name for your plugin.

        Defaults to name of the class. This helps plugin developers to directly
        access a specific plugin by its name."""
        return self.__class__.__name__

    @abstractmethod
    def get_descriptors(
            self) -> Tuple[List[socket.socket], List[socket.socket]]:
        return [], []  # pragma: no cover

    @abstractmethod
    def write_to_descriptors(self, w: Writables) -> bool:
        return False  # pragma: no cover

    @abstractmethod
    def read_from_descriptors(self, r: Readables) -> bool:
        return False  # pragma: no cover

    @abstractmethod
    def on_client_data(self, raw: memoryview) -> Optional[memoryview]:
        return raw  # pragma: no cover

    @abstractmethod
    def on_request_complete(self) -> Union[socket.socket, bool]:
        """Called right after client request parser has reached COMPLETE state."""
        return False  # pragma: no cover

    @abstractmethod
    def on_response_chunk(self, chunk: List[memoryview]) -> List[memoryview]:
        """Handle data chunks as received from the server.

        Return optionally modified chunk to return back to client."""
        return chunk  # pragma: no cover

    @abstractmethod
    def on_client_connection_close(self) -> None:
        pass  # pragma: no cover