import logging
import re
import threading
from typing import Generator, Optional
from src.config import Config
from src.email_client import fetch_unseen_emails, mark_as_seen, Email
from src.ai_client import summarize_email
from src.tg_bot import send_summary, send_thinking, edit_message, format_summary

logger = logging.getLogger(__name__)

_MD_SPECIAL = re.compile(r"([_*\[\]()~`>#+\-=|{}.!\\])")

def _escape_md(text: str) -> str:
    return _MD_SPECIAL.sub(r"\\\1", text)


def _mail_label(mail: Email) -> str:
    sender_short = mail.sender.split("<")[0].strip() if "<" in mail.sender else mail.sender.split("@")[0]
    subject_short = mail.subject[:30] + ("…" if len(mail.subject) > 30 else "")
    return f"{_escape_md(sender_short)} · {_escape_md(subject_short)}"


def poll_accounts(cfg: Config, skip_uids: set[bytes] | None = None) -> Generator[tuple[int, Email], None, None]:
    for idx, acct in enumerate(cfg.email_accounts):
        try:
            logger.info(f"检查邮箱: {acct.username}")
            emails = fetch_unseen_emails(acct, skip_uids=skip_uids)
            if emails:
                logger.info(f"  发现 {len(emails)} 封新邮件")
            for mail in emails:
                yield idx, mail
        except Exception as e:
            logger.error(f"轮询 {acct.username} 失败: {e}", exc_info=True)


def ai_process(cfg: Config, acct_idx: int, mail: Email, tg_msg_id: int = 0) -> Optional[dict]:
    logger.info(f"  正在摘要: {mail.subject}")
    label = _mail_label(mail)
    # 阶段1：显示等待处理
    if tg_msg_id:
        edit_message(cfg.telegram, cfg.telegram.chat_id, tg_msg_id, f"⏳ *等待处理…*\n{label}")
    else:
        tg_msg_id = send_thinking(cfg.telegram, cfg.telegram.chat_id, f"⏳ *等待处理…*\n{label}")

    # 阶段2：AI 处理，更新为思考中
    edit_message(cfg.telegram, cfg.telegram.chat_id, tg_msg_id, f"🤖 *AI思考中…*\n{label}")
    summary = summarize_email(cfg.ai, mail.recipient, mail.subject, mail.sender, mail.body, mail.account_email)
    summary["recipient"] = mail.recipient
    if "@" not in summary.get("sender", ""):
        summary["sender"] = mail.sender
    text = format_summary(summary, mail.account_email)
    # 阶段3：编辑为最终结果
    return {
        "text": text,
        "data": summary,
        "original_body": mail.body,
        "original_sender": mail.sender,
        "original_recipient": mail.recipient,
        "original_reply_to": mail.reply_to,
        "acct_idx": acct_idx,
        "account_email": mail.account_email,
        "uid": mail.uid,
        "folder": mail.folder,
        "thinking_msg_id": tg_msg_id if tg_msg_id else 0,
    }


def tg_send_and_mark(cfg: Config, info: dict):
    acct = cfg.email_accounts[info["acct_idx"]]
    thinking_msg_id = info.get("thinking_msg_id")
    if thinking_msg_id:
        # 编辑思考中消息为实际摘要
        from src.tg_bot import _summary_keyboard
        from src.database import save_email_context
        can_reply = info["data"].get("can_reply", True)
        is_promotion = info["data"].get("category") == "promotion"
        links = info["data"].get("links", [])
        edit_message(cfg.telegram, cfg.telegram.chat_id, thinking_msg_id,
                     info["text"], _summary_keyboard(can_reply, is_promotion, links))
        # 保存上下文用于回调
        save_email_context(thinking_msg_id, {
            "summary_text": info["text"],
            "summary_data": info["data"],
            "original_body": info["original_body"],
            "plain_text": info["data"].get("plain_text", ""),
            "original_sender": info.get("original_sender", ""),
            "original_recipient": info.get("original_recipient", ""),
            "original_reply_to": info.get("original_reply_to", ""),
            "account_email": info.get("account_email", ""),
            "account_idx": info["acct_idx"],
            "sender": info["data"].get("sender", ""),
            "subject": info["data"].get("subject", ""),
            "can_reply": can_reply,
        })
    else:
        # 兜底：没有思考中消息就正常发送
        send_summary(cfg.telegram, cfg.telegram.chat_id,
                     info["text"], info["data"],
                     info["original_body"], info["acct_idx"],
                     original_sender=info.get("original_sender", ""),
                     original_recipient=info.get("original_recipient", ""),
                     original_reply_to=info.get("original_reply_to", ""),
                     account_email=info.get("account_email", ""))
    # 标记已读放到后台线程，不阻塞 TG 发送
    def _bg_mark():
        try:
            mark_as_seen(acct, [(info["uid"], info.get("folder", "INBOX"))])
        except Exception:
            pass
    threading.Thread(target=_bg_mark, daemon=True).start()
    logger.info(f"  TG 发送成功，标记已读已提交后台")