fix: skip already-processing UIDs at FETCH level to avoid downloading email content

src/email_client.py

@@ -109,8 +109,10 @@ def _login_and_prepare(account: EmailAccount, timeout: int = 30, select_inbox: b
     return conn
 
 
-def fetch_unseen_emails(account: EmailAccount) -> list[Email]:
+def fetch_unseen_emails(account: EmailAccount, skip_uids: set[bytes] | None = None) -> list[Email]:
     conn = _login_and_prepare(account, select_inbox=False)
+    if skip_uids is None:
+        skip_uids = set()
 
     # 列出所有文件夹
     _, folder_data = conn.list()
@@ -120,8 +122,6 @@ def fetch_unseen_emails(account: EmailAccount) -> list[Email]:
             if item is None:
                 continue
             line = item.decode("utf-8", errors="replace")
-            # IMAP LIST 格式: (flags) "delimiter" "folder_name"
-            # 用正则提取最后一个引号内的内容
             m = re.search(r'"([^"]*)"\s*$', line)
             if m:
                 folders.append(m.group(1))
@@ -130,6 +130,7 @@ def fetch_unseen_emails(account: EmailAccount) -> list[Email]:
     logger.info("扫描文件夹: %s", ", ".join(folders))
 
     emails = []
+    skipped = 0
     for folder in folders:
         try:
             status, _ = conn.select(folder, readonly=True)
@@ -140,9 +141,15 @@ def fetch_unseen_emails(account: EmailAccount) -> list[Email]:
             uids = data[0].split() if data[0] else []
             if not uids:
                 continue
-            logger.info("  %s: %d 封未读", folder, len(uids))
 
-            for uid in uids:
+            # 先过滤掉正在处理的 UID，避免下载不需要的邮件
+            new_uids = [uid for uid in uids if uid not in skip_uids]
+            skipped += len(uids) - len(new_uids)
+            if not new_uids:
+                continue
+            logger.info("  %s: %d 封未读 (%d 封跳过)", folder, len(new_uids), len(uids) - len(new_uids))
+
+            for uid in new_uids:
                 try:
                     _, msg_data = conn.uid("FETCH", uid, "RFC822")
                     if msg_data[0] is None: