import pymysql
from datetime import datetime


DB_CONFIG = {
    "host": "192.168.31.105",
    "port": 3306,
    "user": "root",
    "password": "123456",
    "database": "table_comple",
    "charset": "utf8mb4",
}


def fetch_next_task():
    """
    从 app_url_list 获取下一个待处理的任务。
    使用 SELECT ... FOR UPDATE 原子锁，按 finished_at 最早排序。
    获取后立即更新 started_at 为当前时间。

    :return: {"id": int, "url": str, "company": str} 或 None
    """
    conn = pymysql.connect(**DB_CONFIG)
    try:
        conn.begin()
        cursor = conn.cursor(pymysql.cursors.DictCursor)

        cursor.execute("""
            SELECT id, input_url, input_company_name
            FROM app_url_list
            WHERE status != 'processing'
            ORDER BY finished_at ASC, id ASC
            LIMIT 1
            FOR UPDATE
        """)
        row = cursor.fetchone()

        if not row:
            conn.rollback()
            return None

        cursor.execute("""
            UPDATE app_url_list
            SET started_at = %s, status = 'processing'
            WHERE id = %s
        """, (datetime.now(), row["id"]))

        conn.commit()

        return {
            "id": row["id"],
            "url": row["input_url"],
            "company": row["input_company_name"],
        }
    except Exception as e:
        conn.rollback()
        raise e
    finally:
        conn.close()


if __name__ == "__main__":
    import sys
    sys.stdout.reconfigure(encoding="utf-8")

    task = fetch_next_task()
    if task:
        print(f"获取任务成功:")
        print(f"  ID: {task['id']}")
        print(f"  URL: {task['url']}")
        print(f"  公司: {task['company']}")
    else:
        print("没有可用任务")