import logging
from typing import List

from diskcache import Cache
from nio import AsyncClient, MatrixRoom

from matrix_alertbot.alertmanager import AlertmanagerClient
from matrix_alertbot.chat_functions import send_text_to_room
from matrix_alertbot.config import Config
from matrix_alertbot.errors import AlertmanagerError
from matrix_alertbot.matcher import AlertMatcher, AlertRegexMatcher

logger = logging.getLogger(__name__)


class Command:
    def __init__(
        self,
        client: AsyncClient,
        cache: Cache,
        alertmanager: AlertmanagerClient,
        config: Config,
        command: str,
        room: MatrixRoom,
        sender: str,
        event_id: str,
    ):
        """A command made by a user.

        Args:
            client: The client to communicate to matrix with.

            cache: Bot cache.

            config: Bot configuration parameters.

            command: The command and arguments.

            room: The room the command was sent in.

            event: The event describing the command.
        """
        self.client = client
        self.cache = cache
        self.alertmanager = alertmanager
        self.config = config
        self.command = command
        self.room = room
        self.sender = sender
        self.event_id = event_id
        self.args = self.command.split()[1:]

    async def process(self) -> None:
        """Process the command"""
        if self.command.startswith("ack"):
            await self._ack()
        elif self.command.startswith("unack") or self.command.startswith("nack"):
            await self._unack()
        elif self.command.startswith("help"):
            await self._show_help()
        else:
            await self._unknown_command()

    async def _ack(self) -> None:
        """Acknowledge an alert and silence it for a certain duration in Alertmanager"""
        matchers: List[AlertMatcher] = []
        durations = []
        for arg in self.args:
            if "=~" in arg:
                label, regex = arg.split("=~")
                regex_matcher = AlertRegexMatcher(label, regex)
                matchers.append(regex_matcher)
            elif "=" in arg:
                label, value = arg.split("=")
                matcher = AlertMatcher(label, value)
                matchers.append(matcher)
            else:
                durations.append(arg)

        if len(durations) > 0:
            duration = " ".join(durations)
        else:
            duration = "1d"

        logger.debug(
            f"Receiving a command to create a silence for a duration of {duration}"
        )

        logger.debug(f"Read alert fingerprints for event {self.event_id} from cache")

        if self.event_id not in self.cache:
            logger.error(f"Cannot find fingerprints for event {self.event_id} in cache")
            return

        alert_fingerprints = self.cache[self.event_id]
        logger.debug(f"Found {len(alert_fingerprints)} in cache")

        count_created_silences = 0
        for alert_fingerprint in alert_fingerprints:
            logger.debug(
                f"Create silence for alert with fingerprint {alert_fingerprint} for a duration of {duration}"
            )
            try:
                await self.alertmanager.create_silence(
                    alert_fingerprint,
                    duration,
                    self.room.user_name(self.sender),
                    matchers,
                )
                count_created_silences += 1
            except AlertmanagerError as e:
                logger.exception(f"Unable to create silence: {e}", exc_info=e)

        await send_text_to_room(
            self.client,
            self.room.room_id,
            f"Created {count_created_silences} silences with a duration of {duration}.",
        )

    async def _unack(self) -> None:
        """Delete an alert's acknowledgement of an alert and remove corresponding silence in Alertmanager"""
        matchers: List[AlertMatcher] = []
        for arg in self.args:
            if "=~" in arg:
                label, regex = arg.split("=~")
                regex_matcher = AlertRegexMatcher(label, regex)
                matchers.append(regex_matcher)
            elif "=" in arg:
                label, value = arg.split("=")
                matcher = AlertMatcher(label, value)
                matchers.append(matcher)

        logger.debug("Receiving a command to delete a silence")
        logger.debug(f"Read alert fingerprints for event {self.event_id} from cache")

        if self.event_id not in self.cache:
            logger.error(f"Cannot find fingerprints for event {self.event_id} in cache")
            return

        alert_fingerprints = self.cache[self.event_id]
        logger.debug(f"Found {len(alert_fingerprints)} in cache")

        count_removed_silences = 0
        for alert_fingerprint in alert_fingerprints:
            logger.debug(
                f"Delete silence for alert with fingerprint {alert_fingerprint}"
            )
            try:
                removed_silences = await self.alertmanager.delete_silences(
                    alert_fingerprint, matchers
                )
                count_removed_silences += len(removed_silences)
            except AlertmanagerError as e:
                logger.exception(f"Unable to delete silence: {e}", exc_info=e)

        await send_text_to_room(
            self.client,
            self.room.room_id,
            f"Removed {count_removed_silences} silences.",
        )

    async def _show_help(self) -> None:
        """Show the help text"""
        logger.debug(f"Displaying help to room {self.room.display_name}")
        if not self.args:
            text = (
                "Hello, I am a bot made with matrix-nio! Use `help commands` to view "
                "available commands."
            )
            await send_text_to_room(self.client, self.room.room_id, text)
            return

        topic = self.args[0]
        if topic == "rules":
            text = "These are the rules!"
        elif topic == "commands":
            text = "Available commands: ..."
        else:
            text = "Unknown help topic!"
        await send_text_to_room(self.client, self.room.room_id, text)

    async def _unknown_command(self) -> None:
        logger.debug(
            f"Sending unknown command response to room {self.room.display_name}"
        )
        await send_text_to_room(
            self.client,
            self.room.room_id,
            f"Unknown command '{self.command}'. Try the 'help' command for more information.",
        )