#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
临时脚本：读取 configs/settings.json 里的 IMAP 配置，从指定的 Sent 邮箱抓取所有邮件，
把其中出现过的收件人邮箱写入 configs/curator_status.json 的 sent_emails 字段。

使用方式（在仓库根目录）：
  python backfill_sent_emails.py
"""

import os
import json
import sys
import imaplib
import email
from email.utils import getaddresses

SETTINGS_PATH = os.path.join("configs", "settings.json")

def load_settings(path: str) -> dict:
    if not os.path.exists(path):
        print(f"ERROR: settings file not found: {path}", file=sys.stderr)
        sys.exit(2)
    with open(path, "r", encoding="utf-8") as f:
        data = json.load(f)
    files = data.get("files", {})
    for key, val in list(files.items()):
        if not os.path.isabs(val):
            files[key] = os.path.abspath(val)
    data["files"] = files
    return data

def load_state(path: str) -> dict:
    if not os.path.exists(path):
        return {"_path": path, "mailboxes": {}, "sent_emails": []}
    with open(path, "r", encoding="utf-8") as f:
        data = json.load(f)
    if "sent_emails" not in data or not isinstance(data["sent_emails"], list):
        data["sent_emails"] = []
    data["_path"] = path
    return data

def save_state(state: dict) -> None:
    path = state.get("_path")
    if not path:
        return
    os.makedirs(os.path.dirname(path), exist_ok=True)
    tmp = path + ".tmp"
    with open(tmp, "w", encoding="utf-8") as f:
        json.dump({k: v for k, v in state.items() if k != "_path"}, f, ensure_ascii=False, indent=2)
    os.replace(tmp, path)

def fetch_sent_addresses(imap_conf: dict) -> set[str]:
    host = imap_conf.get("host")
    port = int(imap_conf.get("port", 993))
    user = imap_conf.get("user")
    pwd = imap_conf.get("pass")
    mailbox = imap_conf.get("sent_mailbox") or imap_conf.get("mailbox") or "Sent"
    if not (host and user and pwd):
        print("ERROR: settings.json 缺少 IMAP 登录配置", file=sys.stderr)
        sys.exit(2)

    conn = imaplib.IMAP4_SSL(host, port)
    conn.login(user, pwd)
    typ, _ = conn.select(mailbox, readonly=True)
    if typ != "OK":
        print(f"ERROR: 无法选择邮箱 {mailbox}", file=sys.stderr)
        conn.logout()
        sys.exit(3)

    typ, data = conn.search(None, "ALL")
    if typ != "OK" or not data or not data[0]:
        conn.close(); conn.logout()
        return set()

    addresses: set[str] = set()
    uids = data[0].split()
    for idx, uid in enumerate(uids, 1):
        typ, msg_data = conn.fetch(uid, "(RFC822.HEADER)")
        if typ != "OK" or not msg_data:
            continue
        raw = msg_data[0][1]
        msg = email.message_from_bytes(raw)
        fields = []
        target_headers = [
            "To", "Cc", "Bcc", "Resent-To", "Resent-Cc", "Resent-Bcc",
            "X-Original-To", "Delivered-To", "X-Real-To", "X-Forwarded-To"
        ]
        for field in target_headers:
            values = msg.get_all(field, [])
            if not values:
                continue
            if isinstance(values, str):
                fields.append(values)
            else:
                fields.extend(values)
        for _, addr in getaddresses(fields):
            if addr:
                addresses.add(addr.strip().lower())
        if idx % 200 == 0:
            print(f"[INFO] processed {idx}/{len(uids)} messages ...")

    try:
        conn.close()
    except Exception:
        pass
    conn.logout()
    return addresses

def main() -> None:
    settings = load_settings(SETTINGS_PATH)
    files = settings.get("files", {})
    state_path = os.path.abspath(files.get("state", os.path.join("configs", "curator_status.json")))
    imap_conf = settings.get("imap", {})

    new_addresses = fetch_sent_addresses(imap_conf)
    print(f"[INFO] collected {len(new_addresses)} address(es) from Sent mailbox.")

    state = load_state(state_path)
    existing = {addr.strip().lower() for addr in state.get("sent_emails", []) if addr}
    merged = sorted(existing.union(new_addresses))
    state["sent_emails"] = merged
    save_state(state)
    print(f"[DONE] sent_emails updated to {len(merged)} unique entries in {state_path}.")

if __name__ == "__main__":
    main()