"""Common utility functions"""

import asyncio
import json
import socket
import time
import traceback
from fastapi import Depends, HTTPException, Request
from loguru import logger
from common.logger import xlogger
from pydantic import BaseModel
from typing import Optional
from uuid import uuid4

from common.tabby_config import config


class TabbyRequestErrorMessage(BaseModel):
    """Common request error type."""

    message: str
    trace: Optional[str] = None


class TabbyRequestError(BaseModel):
    """Common request error type."""

    error: TabbyRequestErrorMessage


def get_generator_error(message: str, exc_info: bool = True):
    """Get a generator error."""

    generator_error = handle_request_error(message, exc_info)

    return generator_error.model_dump_json()


def handle_request_error(message: str, exc_info: bool = True):
    """Log a request error to the console."""

    trace = traceback.format_exc()
    send_trace = config.network.send_tracebacks

    error_message = TabbyRequestErrorMessage(message=message, trace=trace if send_trace else None)

    request_error = TabbyRequestError(error=error_message)

    # Log the error and provided message to the console
    if trace and exc_info:
        xlogger.error("Error", {"trace": trace, "message": message}, details=trace)

    logger.error(f"Sent to request: {message}")

    return request_error


def handle_request_disconnect(message: str):
    """Wrapper for handling for request disconnection."""

    xlogger.error(message)


class DisconnectHandler:
    def __init__(
        self,
        request: Request,
        description: str,
    ):
        self.request = request
        self.abort_event = asyncio.Event()
        self.last_poll = time.time() - 10
        self.disconnected = False
        self.cleanup_tasks = {}
        self.description = description

    async def poll(self):
        """
        Poll the request status a maximum of 20 times per second. Once request is disconnected
        runs scheduled cleanup tasks and raises asyncio.CancelledError. Caller is responsible for
        forwarding the error back to the endpoint function. The endpoint fn should call poll() at
        least once before returning a non-canceled response
        """

        now = time.time()
        if now < self.last_poll + 0.05:
            return
        self.last_poll = now

        # Check if request has disconnected
        if await self.request.is_disconnected():
            # Set abort signal
            if self.abort_event is not None:
                self.abort_event.set()

            # Trigger any cleanup tasks
            await self.cleanup()

            # Log and raise
            if not self.disconnected:
                xlogger.error(f"Request disconnected: {self.description}")
                self.disconnected = True

            raise asyncio.CancelledError(f"Request disconnected: {self.description}")

    async def add_cleanup_task(self, key, func, args):
        # Intentionally strict
        assert key not in self.cleanup_tasks
        self.cleanup_tasks[key] = (func, args)

    async def finish(self, key):
        # Intentionally strict
        del self.cleanup_tasks[key]

    # Safe to call redundantly, each cleanup task must be called exactly once
    async def cleanup(self):
        for func, args in self.cleanup_tasks.values():
            await func(*args)
        self.cleanup_tasks = {}


async def request_disconnect_loop(request: Request):
    """Polls for a starlette request disconnect."""

    while not await request.is_disconnected():
        await asyncio.sleep(0.5)


async def run_with_request_disconnect(
    request: Request, call_task: asyncio.Task, disconnect_message: str
):
    """Utility function to cancel if a request is disconnected."""

    _, unfinished = await asyncio.wait(
        [
            call_task,
            asyncio.create_task(request_disconnect_loop(request)),
        ],
        return_when=asyncio.FIRST_COMPLETED,
    )
    for task in unfinished:
        task.cancel()

    try:
        return call_task.result()
    except (asyncio.CancelledError, asyncio.InvalidStateError) as ex:
        handle_request_disconnect(disconnect_message)
        raise HTTPException(422, disconnect_message) from ex


def is_port_in_use(port: int) -> bool:
    """
    Checks if a port is in use

    From https://stackoverflow.com/questions/2470971/fast-way-to-test-if-a-port-is-in-use-using-python
    """

    test_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    test_socket.settimeout(1)
    with test_socket:
        return test_socket.connect_ex(("localhost", port)) == 0


async def add_request_id(request: Request):
    """FastAPI depends to add a UUID to a request's state."""

    request.state.id = uuid4().hex
    return request


async def log_request(request: Request):
    """FastAPI depends to log a request to the user."""

    log_message = [f"Information for {request.method} request {request.state.id}:"]

    log_message.append(f"URL: {request.url}")
    log_message.append(f"Headers: {dict(request.headers)}")

    if request.method != "GET":
        body_bytes = await request.body()
        if body_bytes:
            body = json.loads(body_bytes.decode("utf-8"))

            log_message.append(f"Body: {dict(body)}")

    xlogger.info("Request", dict(request), details="\n".join(log_message))


def get_global_depends():
    """Returns global dependencies for a FastAPI app."""

    depends = [Depends(add_request_id)]

    if config.logging.log_requests:
        depends.append(Depends(log_request))

    return depends