from __future__ import annotations

import logging
import re
import time
from datetime import datetime, UTC

from yuxi.channel.extensions.slack.constants import (
    SLACK_DEDUPE_MAX_SIZE,
    SLACK_DEDUPE_TTL_SECONDS,
    SLACK_MENTION_PATTERN,
    SLACK_MESSAGE_SUBTYPES_SYSTEM,
)
from yuxi.channel.extensions.slack.types import SlackBotIdentity, SlackInboundEvent
from yuxi.channel.message.models import (
    GroupContext,
    MentionSource,
    MessageType,
    PeerInfo,
    UnifiedMessage,
)
from yuxi.channel.routing.models import PeerKind

logger = logging.getLogger(__name__)


class SlackMonitor:
    def __init__(self):
        self._dedupe: dict[str, float] = {}

    def _dedupe_key(self, event: SlackInboundEvent) -> str:
        return f"{event.channel}:{event.ts}"

    def _is_duplicate(self, event: SlackInboundEvent) -> bool:
        key = self._dedupe_key(event)
        now = time.monotonic()

        if key in self._dedupe:
            if now - self._dedupe[key] < SLACK_DEDUPE_TTL_SECONDS:
                return True

        self._dedupe[key] = now

        if len(self._dedupe) > SLACK_DEDUPE_MAX_SIZE:
            expired = [k for k, v in self._dedupe.items() if now - v >= SLACK_DEDUPE_TTL_SECONDS]
            for k in expired:
                del self._dedupe[k]

        return False

    async def convert_event(
        self,
        event: SlackInboundEvent,
        bot_identity: SlackBotIdentity,
        account_id: str,
    ) -> UnifiedMessage | None:
        if self.should_drop_mismatched_event(event, bot_identity):
            return None

        if self.is_system_event(event):
            return None

        if self.is_echo(event, bot_identity):
            return None

        if self._is_duplicate(event):
            logger.debug("Dropping duplicate event: channel=%s ts=%s", event.channel, event.ts)
            return None

        return self._build_unified_message(event, bot_identity, account_id)

    def should_drop_mismatched_event(self, event: SlackInboundEvent, bot_identity: SlackBotIdentity) -> bool:
        if event.api_app_id and bot_identity.api_app_id and event.api_app_id != bot_identity.api_app_id:
            logger.debug(
                "Dropping event: api_app_id mismatch %s != %s",
                event.api_app_id,
                bot_identity.api_app_id,
            )
            return True

        if event.team_id and bot_identity.team_id and event.team_id != bot_identity.team_id:
            logger.debug(
                "Dropping event: team_id mismatch %s != %s",
                event.team_id,
                bot_identity.team_id,
            )
            return True

        return False

    def is_system_event(self, event: SlackInboundEvent) -> bool:
        return event.subtype in SLACK_MESSAGE_SUBTYPES_SYSTEM

    def is_echo(self, event: SlackInboundEvent, bot_identity: SlackBotIdentity) -> bool:
        if not event.bot_id or not bot_identity.bot_id:
            return False
        return event.bot_id == bot_identity.bot_id

    def _build_unified_message(
        self,
        event: SlackInboundEvent,
        bot_identity: SlackBotIdentity,
        account_id: str,
    ) -> UnifiedMessage:
        peer_kind = self._determine_peer_kind(event.channel_type)

        media_urls, media_types = self._extract_media(event)

        message_type = MessageType.TEXT
        if media_urls:
            message_type = self._detect_message_type(media_types)

        display_name = event.user_real_name or event.user_name or event.user

        sender = PeerInfo(
            kind=peer_kind,
            id=event.user,
            display_name=display_name,
            username=event.user_name or event.user,
        )

        text = event.text or ""
        mentioned_user_ids = self._extract_mentioned_user_ids(text)
        cleaned_text = self._strip_slack_mentions(text)

        was_mentioned = len(mentioned_user_ids) > 0
        bot_user_id = bot_identity.bot_user_id
        explicitly_mentioned_bot = bot_user_id and bot_user_id in mentioned_user_ids

        mention_source = MentionSource.NONE
        if explicitly_mentioned_bot:
            mention_source = MentionSource.EXPLICIT_BOT
        elif was_mentioned:
            mention_source = MentionSource.MENTION_PATTERN

        thread_id = None
        if self.is_thread_message(event):
            thread_id = event.thread_ts

        group = GroupContext(
            id=event.channel,
            thread_id=thread_id,
        )

        timestamp = None
        if event.event_ts:
            try:
                timestamp = datetime.fromtimestamp(float(event.event_ts), tz=UTC)
            except (ValueError, TypeError):
                pass

        return UnifiedMessage(
            msg_id=event.ts,
            channel_type="slack",
            account_id=account_id,
            content=cleaned_text,
            sender=sender,
            message_type=message_type,
            media_urls=media_urls,
            media_types=media_types,
            group=group,
            timestamp=timestamp,
            was_mentioned=was_mentioned,
            explicitly_mentioned_bot=explicitly_mentioned_bot,
            mentioned_user_ids=mentioned_user_ids,
            mention_source=mention_source,
            raw_payload=event.raw,
        )

    @staticmethod
    def _determine_peer_kind(channel_type: str) -> PeerKind:
        if channel_type in ("im", "mpim"):
            return PeerKind.DIRECT
        return PeerKind.GROUP

    @staticmethod
    def _extract_media(event: SlackInboundEvent) -> tuple[list[str], list[str]]:
        urls: list[str] = []
        types: list[str] = []

        for f in event.files:
            url = f.get("url_private_download") or f.get("url_private") or f.get("permalink") or ""
            if url:
                urls.append(url)

            mimetype = f.get("mimetype", "") or f.get("filetype", "")
            types.append(mimetype)

        return urls, types

    @staticmethod
    def _detect_message_type(media_types: list[str]) -> MessageType:
        for mt in media_types:
            lower = mt.lower()
            if lower.startswith("image/"):
                return MessageType.IMAGE
            if lower.startswith("audio/") or lower.startswith("voice/"):
                return MessageType.VOICE
        return MessageType.FILE

    @staticmethod
    def _strip_slack_mentions(text: str) -> str:
        return re.sub(SLACK_MENTION_PATTERN, "", text).strip()

    @staticmethod
    def _extract_mentioned_user_ids(text: str) -> list[str]:
        return re.findall(SLACK_MENTION_PATTERN, text)

    @staticmethod
    def is_thread_message(event: SlackInboundEvent) -> bool:
        return bool(event.thread_ts and event.thread_ts != event.ts)