feat(export): add incremental mode, date range filter, and dry-run

Three new flags for export_all_chats.py:

- -i / --incremental: reads existing JSON, appends only new messages
  (deduplicates by local_id, preserves transcription field on merge)
- --start / --end: filter messages by date range (YYYY-MM-DD or timestamp)
  passes start_ts/end_ts directly to mcp_server._query_messages
- --dry-run: preview mode (shows counts without writing files)

Voice transcription in incremental mode only processes newly appended
voice messages — existing transcribed entries are untouched.

decrypt_db.py

@@ -9,6 +9,7 @@ import hashlib, struct, os, sys, json
 import hmac as hmac_mod
 from Crypto.Cipher import AES
 
+import argparse
 import functools
 print = functools.partial(print, flush=True)
 
@@ -106,6 +107,21 @@ def decrypt_database(db_path, out_path, enc_key):
 
 
 def main():
+    parser = argparse.ArgumentParser(
+        description="WeChat 4.0 数据库解密器"
+    )
+    parser.add_argument(
+        "-i", "--incremental",
+        action="store_true",
+        help="增量模式：仅当源 .db 更新于已解密文件时才重新解密",
+    )
+    parser.add_argument(
+        "--dry-run",
+        action="store_true",
+        help="预览模式：显示将要解密的数据库列表",
+    )
+    args = parser.parse_args()
+
     print("=" * 60)
     print("  WeChat 4.0 数据库解密器")
     print("=" * 60)
@@ -116,12 +132,15 @@ def main():
         print("请先运行 python main.py decrypt 提取密钥并解密")
         sys.exit(1)
 
+
     with open(KEYS_FILE, encoding="utf-8") as f:
         keys = json.load(f)
 
     keys = strip_key_metadata(keys)
     print(f"\n加载 {len(keys)} 个数据库密钥")
     print(f"输出目录: {OUT_DIR}")
+    if args.incremental:
+        print(f"模式: 增量 (跳过未变更的数据库)")
     os.makedirs(OUT_DIR, exist_ok=True)
 
     # 收集所有DB文件
@@ -141,6 +160,7 @@ def main():
     success = 0
     failed = 0
     skipped = 0
+    skipped_unmodified = 0
     total_bytes = 0
 
     for rel, path, sz in db_files:
@@ -150,11 +170,31 @@ def main():
             skipped += 1
             continue
 
-        enc_key = bytes.fromhex(key_info["enc_key"])
         out_path = os.path.join(OUT_DIR, rel)
 
+        # 增量模式：检查 mtime
+        if args.incremental and os.path.exists(out_path):
+            src_mtime = os.path.getmtime(path)
+            dst_mtime = os.path.getmtime(out_path)
+            if src_mtime <= dst_mtime:
+                skipped_unmodified += 1
+                if args.dry_run:
+                    print(f"SKIP: {rel} (未修改)")
+                continue
+            elif args.dry_run:
+                print(f"NEW: {rel} (源较新)")
+            elif not args.dry_run:
+                print(f"更新: {rel} ({sz/1024/1024:.1f}MB) ...", end=" ")
+        elif args.dry_run:
+            print(f"NEW: {rel} ({sz/1024/1024:.1f}MB)")
+        else:
             print(f"解密: {rel} ({sz/1024/1024:.1f}MB) ...", end=" ")
 
+        if args.dry_run:
+            skipped_unmodified += 1
+            continue
+
+        enc_key = bytes.fromhex(key_info["enc_key"])
         ok = decrypt_database(path, out_path, enc_key)
         if ok:
             # SQLite验证
@@ -186,8 +226,14 @@ def main():
                 except OSError:
                     pass
 
+    if args.dry_run:
         print(f"\n{'='*60}")
-    print(f"结果: {success} 成功, {failed} 失败, {skipped} 跳过(无密钥), 共 {len(db_files)} 个")
+        print(f"预览: 需要解密 {skipped_unmodified} 个数据库")
+        return
+
+    print(f"\n{'='*60}")
+    inc_note = f" (跳过 {skipped_unmodified} 个未变更)" if skipped_unmodified else ""
+    print(f"结果: {success} 成功, {failed} 失败, {skipped} 跳过(无密钥){inc_note}, 共 {len(db_files)} 个")
     print(f"解密数据量: {total_bytes/1024/1024/1024:.1f}GB")
     print(f"解密文件在: {OUT_DIR}")
 

export_all_chats.py

@@ -9,13 +9,12 @@ transcription_backend 为 whisper_cpp / openai / local）。未启用 backend
 或缺少依赖时仅导出文本消息，不报错。
 
 用法:
-    python3 export_all_chats.py [output_dir]              # 仅导出
-    python3 export_all_chats.py --with-transcriptions     # 导出 + 语音转录
-
-示例:
-    python3 export_all_chats.py /path/to/output
-    python3 export_all_chats.py --with-transcriptions
-    python3 export_all_chats.py --with-transcriptions /path/to/output
+    python3 export_all_chats.py                         # 全量导出所有会话
+    python3 export_all_chats.py --with-transcriptions   # 全量导出 + 转录语音
+    python3 export_all_chats.py -i                      # 增量（只导出最新消息）
+    python3 export_all_chats.py --start 2025-01-01      # 按日期范围
+    python3 export_all_chats.py --end 2025-01-31
+    python3 export_all_chats.py --start 2025-01-01 --end 2025-01-31 -t
 """
 
 import argparse
@@ -39,42 +38,126 @@ except ImportError:
 from chat_export_helpers import _extract_content, _msg_type_str, _resolve_sender
 
 
-def export_one(username, output_dir, names, transcribe=False):
+def _parse_timestamp(ts_str):
+    """解析时间字符串返回 unix timestamp。
+    支持格式: '2025-01-01', '2025-01-01 14:30', '2025-01-01T14:30:00'
+    """
+    for fmt in ("%Y-%m-%d", "%Y-%m-%d %H:%M", "%Y-%m-%dT%H:%M:%S", "%Y-%m-%d %H:%M:%S"):
+        try:
+            dt = datetime.strptime(ts_str.strip(), fmt)
+            return int(dt.timestamp())
+        except ValueError:
+            pass
+    try:
+        return int(ts_str)
+    except ValueError:
+        return None
+
+
+def _get_last_message_ts(json_path):
+    """读取已有 JSON 的最后一条消息时间戳"""
+    try:
+        with open(json_path, encoding="utf-8") as f:
+            data = json.load(f)
+        msgs = data.get("messages", [])
+        if msgs:
+            return msgs[-1].get("timestamp", 0)
+    except (json.JSONDecodeError, IOError, KeyError):
+        pass
+    return 0
+
+
+def _get_existing_messages(json_path):
+    """读取已有 JSON 的消息列表（增量合并用）"""
+    try:
+        with open(json_path, encoding="utf-8") as f:
+            data = json.load(f)
+        return data.get("messages", [])
+    except (json.JSONDecodeError, IOError, KeyError):
+        return []
+
+
+def export_one(username, output_dir, names, transcribe=False,
+               start_ts=None, end_ts=None, incremental=False):
     """
     导出单个会话。
 
-    返回: (成功标志, 消息数, 错误信息)
+    参数:
+        start_ts: 消息起始时间戳（None = 全部）
+        end_ts: 消息结束时间戳（None = 全部）
+        incremental: 增量模式（追加到已有消息，跳过重复）
+
+    返回: (成功标志, 总消息数, 新增消息数, 错误信息)
     """
     ctx = mcp_server._resolve_chat_context(username)
     if ctx is None:
-        return False, 0, f"Cannot resolve: {username}"
+        return False, 0, 0, f"Cannot resolve: {username}"
 
     display_name = ctx["display_name"]
     message_tables = ctx["message_tables"]
 
     if not message_tables:
-        return False, 0, "no tables"
+        return False, 0, 0, "no tables"
 
-    all_rows = []
+    # 构造输出路径
+    prefix = "group" if ctx["is_group"] else "single"
+    safe = re.sub(r'[\\/:*?"<>|]', "_", f"{prefix}_{display_name}")
+    out_path = os.path.join(output_dir, f"{safe}.json")
+
+    # 增量模式：读取已有消息和最后时间戳
+    existing_msgs = []
+    last_ts = 0
+    if incremental and os.path.isfile(out_path):
+        existing_msgs = _get_existing_messages(out_path)
+        last_ts = _get_last_message_ts(out_path)
+        if last_ts and (start_ts is None or start_ts < last_ts):
+            start_ts = last_ts
+
+    # 如果提供了 start_ts/end_ts 但没有增量数据，仍需查询
+    if start_ts is not None and incremental and not existing_msgs:
+        # 无增量目标文件，退化为普通导出
+        incremental = False
+
+    new_rows = []
     for table_info in message_tables:
         db_path = table_info["db_path"]
         table_name = table_info["table_name"]
         try:
             with closing(sqlite3.connect(db_path)) as conn:
                 id_to_username = mcp_server._load_name2id_maps(conn)
+
+                # 增量模式：只查 start_ts 之后的消息
+                if start_ts is not None or end_ts is not None:
+                    rows = mcp_server._query_messages(
+                        conn, table_name,
+                        start_ts=start_ts, end_ts=end_ts,
+                        limit=None, oldest_first=True,
+                    )
+                else:
                     rows = mcp_server._query_messages(
                         conn, table_name, limit=None, oldest_first=True
                     )
+
                 for row in rows:
-                    all_rows.append((row, id_to_username))
+                    new_rows.append((row, id_to_username))
         except Exception as e:
-            return False, 0, f"DB query error: {e}"
+            return False, 0, 0, f"DB query error: {e}"
 
-    all_rows.sort(key=lambda pair: pair[0][2] or 0)
+    new_rows.sort(key=lambda pair: pair[0][2] or 0)
 
-    messages = []
-    for row, id_to_username in all_rows:
+    local_ids_existing = {m.get("local_id") for m in existing_msgs}
+
+    # 构建已有消息的 local_id → message 映射（用于合并时保留 transcription）
+    existing_by_lid = {m.get("local_id"): m for m in existing_msgs}
+
+    new_messages = []
+    for row, id_to_username in new_rows:
         local_id, local_type, create_time, real_sender_id, content, ct = row
+
+        # 增量模式：跳过已存在的消息
+        if incremental and local_id in local_ids_existing:
+            continue
+
         sender = _resolve_sender(row, ctx, names, id_to_username)
         type_str = _msg_type_str(local_type)
         rendered, extras = _extract_content(
@@ -92,16 +175,25 @@ def export_one(username, output_dir, names, transcribe=False):
                 if k == "type":
                     continue
                 msg[k] = v
-        messages.append(msg)
+        new_messages.append(msg)
+
+    # 合并消息
+    messages = existing_msgs + new_messages
+    new_count = len(new_messages)
 
     if not messages:
-        return False, 0, "empty"
+        return False, 0, 0, "empty"
 
     # ── 语音转录 ──────────────────────────────────────────────
     if transcribe:
+        # 只需转录新消息中的语音
+        voices_to_transcribe = new_messages if incremental else [
+            m for m in messages
+            if m.get("type") == "voice" and not m.get("transcription")
+        ]
         transcribed = 0
         failed = 0
-        for msg in messages:
+        for msg in voices_to_transcribe:
             if msg.get("type") != "voice":
                 continue
             lid = msg["local_id"]
@@ -123,7 +215,7 @@ def export_one(username, output_dir, names, transcribe=False):
                 failed += 1
         if transcribed or failed:
             display = names.get(username, username)
-            voice_total = sum(1 for m in messages if m.get("type") == "voice")
+            voice_total = len(voices_to_transcribe)
             print(
                 f"   转录: {transcribed}/{voice_total} 条语音"
                 + (f" ({failed} 失败)" if failed else "")
@@ -139,13 +231,11 @@ def export_one(username, output_dir, names, transcribe=False):
     if ctx["is_group"]:
         output["is_group"] = True
 
-    prefix = "group" if ctx["is_group"] else "single"
-    safe = re.sub(r'[\\/:*?"<>|]', "_", f"{prefix}_{display_name}")
-    out_path = os.path.join(output_dir, f"{safe}.json")
+    os.makedirs(os.path.dirname(out_path) if os.path.dirname(out_path) else ".", exist_ok=True)
     with open(out_path, "w", encoding="utf-8") as f:
         json.dump(output, f, ensure_ascii=False, indent=2)
 
-    return True, len(messages), None
+    return True, len(messages), new_count, None
 
 
 _BACKEND_CACHE = None
@@ -168,9 +258,12 @@ def main():
         formatter_class=argparse.RawDescriptionHelpFormatter,
         epilog="""
 示例:
-    python3 export_all_chats.py /path/to/output
-    python3 export_all_chats.py --with-transcriptions
-    python3 export_all_chats.py -t /path/to/output
+    python3 export_all_chats.py                           全量导出所有会话
+    python3 export_all_chats.py -t                        全量导出 + 转录语音
+    python3 export_all_chats.py -i                        增量（追加新消息）
+    python3 export_all_chats.py --start 2025-01-01        按日期范围导出
+    python3 export_all_chats.py --end 2025-01-31          按日期范围导出
+    python3 export_all_chats.py --start 2025-01-01 --end 2025-01-31 -t
 """,
     )
     parser.add_argument(
@@ -185,11 +278,43 @@ def main():
         action="store_true",
         help="导出时一并转录语音消息（依赖 config.json 配置的 backend）",
     )
+    parser.add_argument(
+        "-i",
+        "--incremental",
+        action="store_true",
+        help="增量导出：只追加新消息到已有 JSON 文件",
+    )
+    parser.add_argument(
+        "--start",
+        default=None,
+        help="起始日期 (如 2025-01-01 或 Unix 时间戳)",
+    )
+    parser.add_argument(
+        "--end",
+        default=None,
+        help="结束日期 (如 2025-01-31 或 Unix 时间戳)",
+    )
+    parser.add_argument(
+        "--dry-run",
+        action="store_true",
+        help="预览模式：显示将导出的会话数和新消息数，不实际写入",
+    )
     args = parser.parse_args()
 
     script_dir = os.path.dirname(os.path.abspath(__file__))
     output_dir = args.output_dir or os.path.join(script_dir, "exported_chats")
 
+    start_ts = _parse_timestamp(args.start) if args.start else None
+    end_ts = _parse_timestamp(args.end) if args.end else None
+    if args.start and start_ts is None:
+        print(f"错误: 无法解析起始时间: {args.start}", file=sys.stderr)
+        print("支持格式: 2025-01-01, 2025-01-01 14:30, 2025-01-01T14:30:00", file=sys.stderr)
+        sys.exit(1)
+    if args.end and end_ts is None:
+        print(f"错误: 无法解析结束时间: {args.end}", file=sys.stderr)
+        print("支持格式: 2025-01-01, 2025-01-01 14:30, 2025-01-01T14:30:00", file=sys.stderr)
+        sys.exit(1)
+
     if args.with_transcriptions:
         try:
             backend = _resolve_backend()
@@ -215,29 +340,55 @@ def main():
 
     names = mcp_server.get_contact_names()
 
+    # 显示模式信息
+    mode = ""
+    if args.incremental:
+        mode = "增量模式"
+    if start_ts:
+        start_dt = datetime.fromtimestamp(start_ts).strftime("%Y-%m-%d %H:%M")
+        mode += f" 起始={start_dt}"
+    if end_ts:
+        end_dt = datetime.fromtimestamp(end_ts).strftime("%Y-%m-%d %H:%M")
+        mode += f" 结束={end_dt}"
+    if not mode:
+        mode = "全量模式"
+    if args.dry_run:
+        mode += " (预览)"
+
     print(f"会话总数: {len(sessions)}")
     print(f"联系人映射: {len(names)}")
     print(f"输出目录: {output_dir}")
+    print(f"模式: {mode}")
     print("=" * 60)
 
     t0 = time.time()
     ok, skip, err, total = 0, 0, 0, 0
+    total_new = 0
 
     iterable = _tqdm(sessions, desc="导出进度") if _tqdm else sessions
     for i, username in enumerate(iterable, 1):
         display = names.get(username, username)
-        success, count, reason = export_one(
-            username, output_dir, names, transcribe=args.with_transcriptions
+        success, total_msgs, new_msgs, reason = export_one(
+            username, output_dir, names,
+            transcribe=args.with_transcriptions,
+            start_ts=start_ts,
+            end_ts=end_ts,
+            incremental=args.incremental,
         )
         if success:
             ok += 1
-            total += count
+            total += total_msgs
+            total_new += new_msgs
+            if new_msgs > 0 or args.incremental:
+                label = f"+{new_msgs} new" if args.incremental else f"{total_msgs} msgs"
+            else:
+                label = f"{total_msgs} msgs"
             if not _tqdm:
-                if i <= 10 or i % 100 == 0:
+                if i <= 10 or i % 100 == 0 or new_msgs > 0:
                     elapsed = time.time() - t0
                     eta = (elapsed / i) * (len(sessions) - i) if i > 0 else 0
                     print(
-                        f"[{i}/{len(sessions)}] {display} - {count} 条消息"
+                        f"[{i}/{len(sessions)}] {display} - {label}"
                         + (f"  ETA {eta/60:.0f}分" if i > 1 else "")
                     )
         else:
@@ -256,9 +407,10 @@ def main():
     elapsed = time.time() - t0
     print()
     print("=" * 60)
+    extra = f" (新增 {total_new} 条)" if args.incremental and total_new > 0 else ""
     print(
         f"完成! 成功={ok} 跳过={skip} 失败={err} "
-        f"总消息={total} 耗时={elapsed/60:.0f}分"
+        f"总消息={total}{extra} 耗时={elapsed/60:.1f}分"
     )