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#  ┃ 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.

    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")
        super().__init__(**kwargs)

    async def run(self) -> web.WebSocketResponse:
        def inner(msg):
            asyncio.get_running_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:
                    self.session.handle_request(msg.data)

        finally:
            self.session.close()
        return self._ws
