"""Manages a running devtools instance"""
from __future__ import annotations

import asyncio
import base64
import json
import pickle
from json import JSONDecodeError
from time import time
from typing import cast

from aiohttp import WSMessage, WSMsgType
from aiohttp.abc import Request
from aiohttp.web_ws import WebSocketResponse
from rich.console import Console
from rich.markup import escape
import msgpack

from textual._log import LogGroup
from textual.devtools.renderables import (
    DevConsoleLog,
    DevConsoleNotice,
    DevConsoleHeader,
)

QUEUEABLE_TYPES = {"client_log", "client_spillover"}


class DevtoolsService:
    """A running instance of devtools has a single DevtoolsService which is
    responsible for tracking connected client applications.
    """

    def __init__(
        self,
        update_frequency: float,
        verbose: bool = False,
        exclude: list[str] | None = None,
    ) -> None:
        """
        Args:
            update_frequency (float): The number of seconds to wait between
                sending updates of the console size to connected clients.
            verbose (bool): Enable verbose logging on client.
            exclude (list[str]): List of log groups to exclude from output.
        """
        self.update_frequency = update_frequency
        self.verbose = verbose
        self.exclude = set(name.upper() for name in exclude) if exclude else set()
        self.console = Console()
        self.shutdown_event = asyncio.Event()
        self.clients: list[ClientHandler] = []

    async def start(self):
        """Starts devtools tasks"""
        self.size_poll_task = asyncio.create_task(self._console_size_poller())
        self.console.print(DevConsoleHeader(verbose=self.verbose))

    @property
    def clients_connected(self) -> bool:
        """Returns True if there are connected clients, False otherwise."""
        return len(self.clients) > 0

    async def _console_size_poller(self) -> None:
        """Poll console dimensions, and add a `server_info` message to the Queue
        any time a change occurs. We only poll if there are clients connected,
        and if we're not shutting down the server.
        """
        current_width = self.console.width
        current_height = self.console.height
        await self._send_server_info_to_all()
        while not self.shutdown_event.is_set():
            width = self.console.width
            height = self.console.height
            dimensions_changed = width != current_width or height != current_height
            if dimensions_changed:
                await self._send_server_info_to_all()
                current_width = width
                current_height = height
            try:
                await asyncio.wait_for(
                    self.shutdown_event.wait(), timeout=self.update_frequency
                )
            except asyncio.TimeoutError:
                pass

    async def _send_server_info_to_all(self) -> None:
        """Add `server_info` message to the queues of every client"""
        for client_handler in self.clients:
            await self.send_server_info(client_handler)

    async def send_server_info(self, client_handler: ClientHandler) -> None:
        """Send information about the server e.g. width and height of Console to
        a connected client.

        Args:
            client_handler (ClientHandler): The client to send information to
        """
        await client_handler.send_message(
            {
                "type": "server_info",
                "payload": {
                    "width": self.console.width,
                    "height": self.console.height,
                    "verbose": self.verbose,
                },
            }
        )

    async def handle(self, request: Request) -> WebSocketResponse:
        """Handles a single client connection"""
        client = ClientHandler(request, service=self)
        self.clients.append(client)
        websocket = await client.run()
        self.clients.remove(client)
        return websocket

    async def shutdown(self) -> None:
        """Stop server async tasks and clean up all client handlers"""

        # Stop polling/writing Console dimensions to clients
        self.shutdown_event.set()
        await self.size_poll_task

        # We're shutting down the server, so inform all connected clients
        for client in self.clients:
            await client.close()
        self.clients.clear()


class ClientHandler:
    """Handles a single client connection to the devtools.
    A single DevtoolsService managers many ClientHandlers. A single ClientHandler
    corresponds to a single running Textual application instance, and is responsible
    for communication with that Textual app.
    """

    def __init__(self, request: Request, service: DevtoolsService) -> None:
        """
        Args:
            request (Request): The aiohttp.Request associated with this client
            service (DevtoolsService): The parent DevtoolsService which is responsible
                for the handling of this client.
        """
        self.request = request
        self.service = service
        self.websocket = WebSocketResponse()

    async def send_message(self, message: dict[str, object]) -> None:
        """Send a message to a client

        Args:
            message (dict[str, object]): The dict which will be sent
                to the client.
        """
        await self.outgoing_queue.put(message)

    async def _consume_outgoing(self) -> None:
        """Consume messages from the outgoing (server -> client) Queue."""
        while True:
            message_json = await self.outgoing_queue.get()
            if message_json is None:
                self.outgoing_queue.task_done()
                break
            type = message_json["type"]
            if type == "server_info":
                await self.websocket.send_json(message_json)
            self.outgoing_queue.task_done()

    async def _consume_incoming(self) -> None:
        """Consume messages from the incoming (client -> server) Queue, and print
        the corresponding renderables to the console for each message.
        """
        last_message_time: float | None = None
        while True:
            message = await self.incoming_queue.get()
            if message is None:
                self.incoming_queue.task_done()
                break

            type = message["type"]
            if type == "client_log":
                payload = message["payload"]
                if LogGroup(payload.get("group", 0)).name in self.service.exclude:
                    continue
                encoded_segments = payload["segments"]
                segments = pickle.loads(encoded_segments)
                message_time = time()
                if (
                    last_message_time is not None
                    and message_time - last_message_time > 0.5
                ):
                    # Print a rule if it has been longer than half a second since the last message
                    self.service.console.rule()
                self.service.console.print(
                    DevConsoleLog(
                        segments=segments,
                        path=payload["path"],
                        line_number=payload["line_number"],
                        unix_timestamp=payload["timestamp"],
                        group=payload.get("group", 0),
                        verbosity=payload.get("verbosity", 0),
                        severity=payload.get("severity", 0),
                    )
                )
                last_message_time = message_time
            elif type == "client_spillover":
                spillover = int(message["payload"]["spillover"])
                info_renderable = DevConsoleNotice(
                    f"Discarded {spillover} messages", level="warning"
                )
                self.service.console.print(info_renderable)
            self.incoming_queue.task_done()

    async def run(self) -> WebSocketResponse:
        """Prepare the websocket and communication queues, and continuously
        read messages from the queues.

        Returns:
            WebSocketResponse: The WebSocketResponse associated with this client.
        """

        await self.websocket.prepare(self.request)
        self.incoming_queue: asyncio.Queue[dict | None] = asyncio.Queue()
        self.outgoing_queue: asyncio.Queue[dict | None] = asyncio.Queue()
        self.outgoing_messages_task = asyncio.create_task(self._consume_outgoing())
        self.incoming_messages_task = asyncio.create_task(self._consume_incoming())

        if self.request.remote:
            self.service.console.print(
                DevConsoleNotice(f"Client '{escape(self.request.remote)}' connected")
            )
        try:
            await self.service.send_server_info(client_handler=self)
            async for message in self.websocket:
                message = cast(WSMessage, message)

                if message.type in (WSMsgType.TEXT, WSMsgType.BINARY):

                    try:
                        if isinstance(message.data, bytes):
                            message = msgpack.unpackb(message.data)
                        else:
                            message = json.loads(message.data)
                    except JSONDecodeError:
                        self.service.console.print(escape(str(message.data)))
                        continue

                    type = message.get("type")
                    if not type:
                        continue
                    if (
                        type in QUEUEABLE_TYPES
                        and not self.service.shutdown_event.is_set()
                    ):
                        await self.incoming_queue.put(message)
                elif message.type == WSMsgType.ERROR:
                    self.service.console.print(
                        DevConsoleNotice("Websocket error occurred", level="error")
                    )
                    break
        except Exception as error:
            self.service.console.print(DevConsoleNotice(str(error), level="error"))
        finally:
            if self.request.remote:
                self.service.console.print(
                    "\n",
                    DevConsoleNotice(
                        f"Client '{escape(self.request.remote)}' disconnected"
                    ),
                )
            await self.close()

        return self.websocket

    async def close(self) -> None:
        """Stop all incoming/outgoing message processing,
        and shutdown the websocket connection associated with this
        client.
        """

        # Stop any writes to the websocket first
        await self.outgoing_queue.put(None)
        await self.outgoing_messages_task

        # Now we can shut the socket down
        await self.websocket.close()

        # This task is independent of the websocket
        await self.incoming_queue.put(None)
        await self.incoming_messages_task