"""
动态表管理器
处理分表创建，避免事务冲突
"""
from sqlalchemy import text
from sqlalchemy.orm import Session
from app.core.logging_config import get_logger
from app.models.work_area import WorkArea
from app.models.section_data import SectionData
from app.models.checkpoint import Checkpoint
from app.models.measurement_data import MeasurementData

logger = get_logger(__name__)

class TableManager:
    """动态表管理器"""
    
    # 缓存已创建的表
    _created_tables = set()
    
    @classmethod
    def ensure_table_exists(cls, db: Session, table_type: str, account_id: int) -> bool:
        """
        确保表存在，如果不存在则创建
        使用独立连接创建表，避免与业务事务冲突
        """
        table_name = cls._get_table_name(table_type, account_id)
        cache_key = f"{table_type}_{account_id}"
        
        # 检查缓存
        if cache_key in cls._created_tables:
            return True
        
        try:
            # 检查表是否存在
            result = db.execute(text(f"SHOW TABLES LIKE '{table_name}'"))
            if result.fetchone():
                cls._created_tables.add(cache_key)
                return True
            
            # 获取建表SQL
            create_sql = cls._get_create_sql(table_type, account_id)
            if not create_sql:
                logger.error(f"未知的表类型: {table_type}")
                return False
            
            # 使用独立连接创建表（避免事务冲突）
            connection = db.get_bind().connect()
            try:
                connection.execute(text(create_sql))
                connection.commit()
                cls._created_tables.add(cache_key)
                logger.info(f"动态创建表成功: {table_name}")
                return True
            finally:
                connection.close()
                
        except Exception as e:
            logger.error(f"创建表失败 {table_name}: {e}")
            return False
    
    @classmethod
    def _get_table_name(cls, table_type: str, account_id: int) -> str:
        """获取表名"""
        table_map = {
            "work_area": WorkArea.get_table_name,
            "section_data": SectionData.get_table_name,
            "checkpoint": Checkpoint.get_table_name,
            "measurement_data": MeasurementData.get_table_name,
        }
        return table_map.get(table_type, lambda x: "")(account_id)
    
    @classmethod
    def _get_create_sql(cls, table_type: str, account_id: int) -> str:
        """获取建表SQL"""
        sql_map = {
            "work_area": WorkArea.get_create_sql,
            "section_data": SectionData.get_create_sql,
            "checkpoint": Checkpoint.get_create_sql,
            "measurement_data": MeasurementData.get_create_sql,
        }
        return sql_map.get(table_type, lambda x: "")(account_id)
    
    @classmethod
    def clear_cache(cls):
        """清除表缓存"""
        cls._created_tables.clear()