from __future__ import annotations

import logging
import re
import socket
from datetime import datetime
from threading import Event, Lock, Thread
from typing import Any

import pytz
import telnetlib3

from core.config import SERVER_OWNER_CALLSIGN
from core.utils import decode_telnet_bytes
from data.spot import Spot
from providers.spot.spot_provider import SpotProvider

logger = logging.getLogger(__name__)


class DXCluster(SpotProvider):
    """Spot provider for a DX Cluster. Hostname, port, login_prompt, login_callsign and allow_rbn_spots are provided in config.
    See config-example.yml for examples."""

    _LINE_PATTERN_EXCLUDE_RBN = re.compile(
        r"^DX de ([a-z0-9/]+):\s+([0-9.]+)\s+([a-z0-9/]+)\s+(.*)\s+(\d{4}Z)",
        re.IGNORECASE,
    )
    _LINE_PATTERN_ALLOW_RBN = re.compile(
        r"^DX de ([a-z0-9/]+)-?#?:\s+([0-9.]+)\s+([a-z0-9/]+)\s+(.*)\s+(\d{4}Z)",
        re.IGNORECASE,
    )

    def __init__(self, provider_config: dict[str, Any]) -> None:
        """Constructor requires hostname and port"""

        name = provider_config.get("name", "Cluster")
        super().__init__(name, provider_config)
        self._hostname: str = provider_config["host"]
        self._port: int = provider_config["port"]
        self._login_prompt: str = provider_config.get("login_prompt", "login:")
        self._login_callsign: str = provider_config.get("login_callsign", SERVER_OWNER_CALLSIGN)
        self._allow_rbn_spots: bool = provider_config.get("allow_rbn_spots", False)
        self._spot_line_pattern: re.Pattern[str] = (
            self._LINE_PATTERN_ALLOW_RBN if self._allow_rbn_spots else self._LINE_PATTERN_EXCLUDE_RBN
        )
        self._telnet: telnetlib3.Telnet | None = None
        self._telnet_lock: Lock = Lock()
        self._thread: Thread | None = None
        self._stop_event: Event = Event()

    def start(self) -> None:
        self._thread = Thread(target=self._handle, name=f"DXClusterSpotProvider-{self.name}", daemon=True)
        self._thread.start()

    def stop(self) -> None:
        self._stop_event.set()
        with self._telnet_lock:
            if self._telnet:
                try:
                    self._telnet.sock.shutdown(socket.SHUT_RDWR)
                except (AttributeError, OSError):
                    pass
                self._telnet.close()
        if self._thread:
            self._thread.join(timeout=5)
            if self._thread.is_alive():
                logger.warning(f"DX Cluster {self._hostname} worker thread did not exit on time and will be killed.")

    def _handle(self) -> None:
        while not self._stop_event.is_set():
            connected = False
            while not connected and not self._stop_event.is_set():
                try:
                    self.status = "Connecting"
                    logger.info(f"DX Cluster {self._hostname} connecting...")
                    new_telnet = telnetlib3.Telnet(self._hostname, self._port)
                    with self._telnet_lock:
                        self._telnet = new_telnet
                        if self._stop_event.is_set():
                            # stop() was called while we were connecting, close the connection rather than trying to
                            # read when we know it won't work
                            new_telnet.close()
                            break
                    self._telnet.read_until(self._login_prompt.encode("latin-1"))
                    self._telnet.write(f"{self._login_callsign}\n".encode("latin-1"))
                    connected = True
                    logger.info(f"DX Cluster {self._hostname} connected.")
                except ConnectionRefusedError:
                    self.status = "Error"
                    logger.warning(f"Connection refused to DX cluster {self._hostname}")
                    self._stop_event.wait(timeout=300)
                except Exception:
                    self.status = "Error"
                    logger.exception(f"Exception while connecting to DX Cluster Provider ({self._hostname}).")
                    self._stop_event.wait(timeout=5)

            self.status = "Waiting for Data"
            while connected and not self._stop_event.is_set():
                try:
                    # Check new telnet info against regular expression
                    telnet_output = self._telnet.read_until("\n".encode("latin-1"))
                    match = self._spot_line_pattern.match(decode_telnet_bytes(telnet_output))
                    if match:
                        spot_time = datetime.strptime(match.group(5), "%H%MZ").replace(tzinfo=pytz.UTC)
                        spot_datetime = datetime.combine(
                            datetime.now(pytz.UTC).date(),
                            spot_time.time(),
                            tzinfo=pytz.UTC,
                        )
                        spot = Spot(
                            source=self.name,
                            dx_call=match.group(3),
                            de_call=match.group(1),
                            freq=float(match.group(2)) * 1000,
                            comment=match.group(4).strip(),
                            time=spot_datetime.timestamp(),
                        )

                        # Add to our list
                        self._submit(spot)

                        self.status = "OK"
                        self.last_update_time = datetime.now(pytz.UTC)
                        logger.debug(f"Data received from DX Cluster {self._hostname}.")

                except EOFError:
                    connected = False
                    if not self._stop_event.is_set():
                        self.status = "Restarting"
                        logger.warning(f"Disconnected from DX Cluster {self._hostname}. Reconnecting...")
                        self._stop_event.wait(timeout=5)
                    else:
                        logger.info(f"DX Cluster {self._hostname} shutting down...")
                        self.status = "Shutting down"
                except Exception:
                    connected = False
                    if not self._stop_event.is_set():
                        self.status = "Error"
                        logger.exception(f"Exception in DX Cluster Provider ({self._hostname})")
                        self._stop_event.wait(timeout=5)
                    else:
                        logger.info(f"DX Cluster {self._hostname} shutting down...")
                        self.status = "Shutting down"

            self.status = "Disconnected"