import logging
import os
from typing import Any, Callable, Iterable, List, Optional, TypeVar

import pymysql
from dbutils.pooled_db import PooledDB
from pymysql.cursors import DictCursor

logger = logging.getLogger(__name__)

T = TypeVar("T")

# 连接池公共参数（可自行调大 maxconnections 等）
_POOL_COMMON = {
    "maxconnections": 10,
    "mincached": 2,
    "maxcached": 5,
    "blocking": True,
}


def _create_pool(
    host: str,
    port: int,
    user: str,
    password: str,
    database: str,
) -> PooledDB:
    return PooledDB(
        creator=pymysql,
        cursorclass=DictCursor,
        charset="utf8mb4",
        host=host,
        port=port,
        user=user,
        password=password,
        database=database,
        **_POOL_COMMON,
    )


class _MySQLPoolBase:
    """共用的取连接、写库、读库逻辑，避免两套类复制粘贴。"""

    def __init__(self, pool: PooledDB) -> None:
        self.pool = pool

    def get_conn(self):
        return self.pool.connection()

    def _close(self, conn, cursor) -> None:
        try:
            if cursor:
                cursor.close()
        finally:
            if conn:
                conn.close()

    def _write(self, fn: Callable[..., T], *args, **kwargs) -> Optional[T]:
        conn = self.get_conn()
        cursor = conn.cursor()
        try:
            result = fn(cursor, *args, **kwargs)
            conn.commit()
            return result
        except Exception as e:
            logger.error("SQL 执行错误: %s", e)
            conn.rollback()
            return None
        finally:
            self._close(conn, cursor)

    def execute_many(self, sql: str, data: Iterable) -> None:
        rows = list(data)
        if not rows:
            return

        def _do(c, s, d):
            c.executemany(s, d)

        self._write(_do, sql, rows)

    def execute_one(self, sql: str, data) -> None:
        def _do(c, s, d):
            c.execute(s, d)

        self._write(_do, sql, data)

    def update_data(self, sql: str, data) -> None:
        self.execute_one(sql, data)

    def select_data(self, sql: str) -> List[Any]:
        """只读查询，不应 commit。"""
        conn = self.get_conn()
        cursor = conn.cursor()
        try:
            cursor.execute(sql)
            return cursor.fetchall()
        except Exception as e:
            logger.error("SQL 查询错误: %s", e)
            return []
        finally:
            self._close(conn, cursor)

    def execute(self, sql: str, data: Any = None) -> int:
        """通用写操作，返回受影响行数；失败返回 0。"""

        def _do(c, s, d):
            if d is not None:
                return c.execute(s, d)
            return c.execute(s)

        result = self._write(_do, sql, data)
        return result if isinstance(result, int) else 0


class MySQLPool(_MySQLPoolBase):
    """test2 库（可通过环境变量覆盖，便于部署；未设置则沿用原默认）。"""

    def __init__(self) -> None:
        pool = _create_pool(
            host=os.environ.get("MYSQL_TEST2_HOST", "47.119.164.65"),
            port=int(os.environ.get("MYSQL_TEST2_PORT", "3306")),
            user=os.environ.get("MYSQL_TEST2_USER", "test_c"),
            password=os.environ.get("MYSQL_TEST2_PASSWORD", "Dfwy@2025"),
            database=os.environ.get("MYSQL_TEST2_DB", "test2"),
        )
        super().__init__(pool)


class MySQLPool39(_MySQLPoolBase):
    """drug_retrieve 库。"""

    def __init__(self) -> None:
        pool = _create_pool(
            host=os.environ.get("MYSQL_DRUG_HOST", "39.108.116.125"),
            port=int(os.environ.get("MYSQL_DRUG_PORT", "3306")),
            user=os.environ.get("MYSQL_DRUG_USER", "drug_retrieve"),
            password=os.environ.get("MYSQL_DRUG_PASSWORD", "Pem287cwM58jNpe2"),
            database=os.environ.get("MYSQL_DRUG_DB", "drug_retrieve"),
        )
        super().__init__(pool)

class MySQLPoolOnline(_MySQLPoolBase):
    """drug_retrieve 库。"""

    def __init__(self) -> None:
        pool = _create_pool(
            host=os.environ.get("MYSQL_DRUG_HOST", "120.24.49.2"),
            port=int(os.environ.get("MYSQL_DRUG_PORT", "3306")),
            user=os.environ.get("MYSQL_DRUG_USER", "drug_retrieve"),
            password=os.environ.get("MYSQL_DRUG_PASSWORD", "ksCt3xm6chzdkafj"),
            database=os.environ.get("MYSQL_DRUG_DB", "drug_retrieve"),
        )
        super().__init__(pool)



if __name__ == "__main__":
    pool = MySQLPool()
    rows = pool.select_data("SELECT 1 AS one")
    print(rows)