from __future__ import annotations

import re
import time
import uuid
from typing import Any

from yuxi.channels.models import (
    ChannelIdentity,
    ChannelMessage,
    ChannelType,
    ChatType,
    EventType,
    MentionsInfo,
    MessageType,
)


def _parse_irc_time_tag(time_tag: str) -> int:
    """解析 IRCv3 server-time 标签为毫秒时间戳"""
    import datetime

    try:
        ts_str = time_tag.replace("Z", "+00:00")
        dt = datetime.datetime.fromisoformat(ts_str)
        return int(dt.timestamp() * 1000)
    except (ValueError, TypeError):
        return int(time.time() * 1000)


def normalize_inbound(
    raw: dict[str, Any],
    channel_id: str,
    channel_type: ChannelType,
    nick: str,
) -> ChannelMessage | None:
    sender_nick = raw.get("sender_nick", "unknown")
    target = raw.get("target", "")
    text = raw.get("text", "")

    if not text or not text.strip():
        return None

    is_channel = target.startswith("#") or target.startswith("&")

    chat_id = target if is_channel else f"dm_{sender_nick}"
    chat_type = ChatType.GROUP if is_channel else ChatType.DIRECT

    mentioned_user_ids: list[str] = []
    is_bot_mentioned = _check_bot_mention(text, nick)
    if is_channel:
        for word in text.split():
            if word.startswith("@"):
                mentioned_user_ids.append(word[1:])

    server_time = raw.get("time")
    ts = _parse_irc_time_tag(server_time) if server_time else int(time.time() * 1000)

    return ChannelMessage(
        identity=ChannelIdentity(
            channel_id=channel_id,
            channel_type=channel_type,
            channel_user_id=sender_nick,
            channel_chat_id=chat_id,
            channel_message_id=f"{sender_nick}:{ts}:{uuid.uuid4().hex[:8]}",
        ),
        event_type=EventType.MESSAGE_RECEIVED,
        message_type=MessageType.TEXT,
        chat_type=chat_type,
        content=text,
        mentions=MentionsInfo(
            mentioned_user_ids=mentioned_user_ids,
            is_bot_mentioned=is_bot_mentioned,
        ),
        metadata={
            "irc_target": target,
            "is_channel": is_channel,
            "account": raw.get("account"),
        },
    )


def resolve_chat_id(target: str, sender_nick: str) -> str:
    from .session import resolve_chat_id as _resolve

    return _resolve(target, sender_nick)


def _check_bot_mention(text: str, nick: str) -> bool:
    """Check if bot nick is mentioned with word boundary awareness."""
    pattern = rf"\b{re.escape(nick)}\b[:,]?"
    return bool(re.search(pattern, text))