#  ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
#  ┃ ██████ ██████ ██████       █      █      █      █      █ █▄  ▀███ █       ┃
#  ┃ ▄▄▄▄▄█ █▄▄▄▄▄ ▄▄▄▄▄█  ▀▀▀▀▀█▀▀▀▀▀ █ ▀▀▀▀▀█ ████████▌▐███ ███▄  ▀█ █ ▀▀▀▀▀ ┃
#  ┃ █▀▀▀▀▀ █▀▀▀▀▀ █▀██▀▀ ▄▄▄▄▄ █ ▄▄▄▄▄█ ▄▄▄▄▄█ ████████▌▐███ █████▄   █ ▄▄▄▄▄ ┃
#  ┃ █      ██████ █  ▀█▄       █ ██████      █      ███▌▐███ ███████▄ █       ┃
#  ┣━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┫
#  ┃ Copyright (c) 2017, the Perspective Authors.                              ┃
#  ┃ ╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌ ┃
#  ┃ This file is part of the Perspective library, distributed under the terms ┃
#  ┃ of the [Apache License 2.0](https://www.apache.org/licenses/LICENSE-2.0). ┃
#  ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛

from aiohttp import web, WSMsgType
import perspective
import asyncio


class PerspectiveAIOHTTPHandler(object):
    """`PerspectiveAIOHTTPHandler` is a drop-in implementation of Perspective.

    Use it inside AIOHTTP routing to create a server-side Perspective that is
    ready to receive websocket messages from the front-end `perspective-viewer`.

    The Perspective client and server will automatically keep the Websocket
    alive without timing out.

    # Security

    `PerspectiveAIOHTTPHandler` is a reference integration with no
    authentication, authorization, origin enforcement, or rate limiting,
    and is not safe to expose to untrusted networks — see
    [`SECURITY.md`](https://github.com/perspective-dev/perspective/blob/master/SECURITY.md)
    for the full threat model.

    # Examples

    >>> server = Server()
    >>> async def websocket_handler(request):
    ...    handler = PerspectiveAIOHTTPHandler(perspective_server=server, request=request)
    ...    await handler.run()

    >>> app = web.Application()
    >>> app.router.add_get("/websocket", websocket_handler)
    """

    def __init__(self, **kwargs):
        self.server = kwargs.pop("perspective_server", perspective.GLOBAL_SERVER)
        self._request = kwargs.pop("request")
        self._executor = kwargs.pop("executor", None)
        self._loop = kwargs.pop("loop", asyncio.get_event_loop())
        super().__init__(**kwargs)

    async def run(self) -> web.WebSocketResponse:
        def inner(msg):
            self._loop.create_task(self._ws.send_bytes(msg))

        self.session = self.server.new_session(inner)
        try:
            self._ws = web.WebSocketResponse()
            await self._ws.prepare(self._request)
            async for msg in self._ws:
                if msg.type == WSMsgType.BINARY:
                    if self._executor is not None:
                        self._executor.submit(self.session.handle_request, msg.data)
                    else:
                        self.session.handle_request(msg.data)
        finally:
            self.session.close()
        return self._ws