feat: migrate core data stores to MySQL with compatibility fixes

db/chat_log_db.py

@@ -16,6 +16,51 @@ _MYSQL_USER = os.getenv("MYSQL_USER", "root")
 _MYSQL_PASSWORD = os.getenv("MYSQL_PASSWORD", "")
 _MYSQL_DATABASE = os.getenv("MYSQL_DATABASE", "ai_cs")
 
+
+class _CompatResult:
+    def __init__(self, rows=None, rowcount: int = 0, lastrowid: int = 0):
+        self._rows = rows or []
+        self.rowcount = rowcount
+        self.lastrowid = lastrowid
+
+    def fetchall(self):
+        return self._rows
+
+    def fetchone(self):
+        return self._rows[0] if self._rows else None
+
+
+class _PyMySQLCompatConn:
+    """让 pymysql 连接兼容 sqlite 的 conn.execute 用法。"""
+
+    def __init__(self, conn):
+        self._conn = conn
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc, tb):
+        if exc_type:
+            try:
+                self._conn.rollback()
+            except Exception:
+                pass
+        self._conn.close()
+
+    def execute(self, query: str, args=None):
+        cur = self._conn.cursor()
+        cur.execute(query, args or ())
+        rows = cur.fetchall() if cur.description else []
+        res = _CompatResult(rows=rows, rowcount=cur.rowcount, lastrowid=getattr(cur, "lastrowid", 0))
+        cur.close()
+        return res
+
+    def commit(self):
+        self._conn.commit()
+
+    def close(self):
+        self._conn.close()
+
 def _is_mysql() -> bool:
     return _DB_TYPE in ("mysql", "mariadb")
 
@@ -26,7 +71,7 @@ def _sql(query: str) -> str:
 def _get_conn() -> sqlite3.Connection:
     if _is_mysql():
         import pymysql
-        return pymysql.connect(
+        conn = pymysql.connect(
             host=_MYSQL_HOST,
             port=_MYSQL_PORT,
             user=_MYSQL_USER,
@@ -36,6 +81,7 @@ def _get_conn() -> sqlite3.Connection:
             cursorclass=pymysql.cursors.DictCursor,
             autocommit=False,
         )
+        return _PyMySQLCompatConn(conn)
     os.makedirs(os.path.dirname(_DB_PATH), exist_ok=True)
     conn = sqlite3.connect(_DB_PATH)
     conn.row_factory = sqlite3.Row
@@ -59,9 +105,14 @@ def init_db():
                     timestamp   DATETIME NOT NULL
                 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4
             """)
-            conn.execute("CREATE INDEX IF NOT EXISTS idx_customer ON chat_logs(customer_id)")
-            conn.execute("CREATE INDEX IF NOT EXISTS idx_ts ON chat_logs(timestamp)")
-            conn.execute("CREATE INDEX IF NOT EXISTS idx_acc ON chat_logs(acc_id)")
+            idx_rows = conn.execute("SHOW INDEX FROM chat_logs").fetchall()
+            exists = {str(r.get("Key_name", "")) for r in idx_rows}
+            if "idx_customer" not in exists:
+                conn.execute("CREATE INDEX idx_customer ON chat_logs(customer_id)")
+            if "idx_ts" not in exists:
+                conn.execute("CREATE INDEX idx_ts ON chat_logs(timestamp)")
+            if "idx_acc" not in exists:
+                conn.execute("CREATE INDEX idx_acc ON chat_logs(acc_id)")
         else:
             conn.execute("""
                 CREATE TABLE IF NOT EXISTS chat_logs (