"""Config Executor for ERP AI Assistant.

This module provides the ConfigExecutor class for validating and executing
SQL configuration statements with safety checks.
"""

import re
from typing import List, Tuple, Dict, Any

from loguru import logger

from app.core.db_engine import DatabaseEngine


class ConfigExecutor:
    """Executor for SQL configuration statements with safety validation.

    This class validates SQL statements against dangerous operations before
    execution and provides transaction-based execution with rollback support.
    """

    # Dangerous SQL keywords that should be blocked
    DANGEROUS_KEYWORDS = [
        r"DROP\s+DATABASE",
        r"DROP\s+TABLE",
        r"TRUNCATE\s+TABLE",
        r"DELETE\s+FROM",
        r"UPDATE\s+.*\s+SET",
        r"ALTER\s+TABLE\s+.*\s+DROP"
    ]

    def __init__(self) -> None:
        """Initialize executor with database engine."""
        self.db_engine = DatabaseEngine()
        logger.info("ConfigExecutor initialized")

    def validate_sql(self, sql: str) -> Tuple[bool, str]:
        """Validate SQL statement for safety.

        Checks SQL against a list of dangerous keywords/patterns to prevent
        destructive operations.

        Args:
            sql: SQL statement to validate

        Returns:
            Tuple of (is_valid, message) where is_valid indicates if SQL is safe
        """
        if not sql or not sql.strip():
            return False, "SQL语句为空"

        sql_upper = sql.upper().strip()

        # Check for dangerous operations
        for pattern in self.DANGEROUS_KEYWORDS:
            if re.search(pattern, sql_upper):
                # Extract matched keyword for error message
                match = re.search(pattern, sql_upper)
                matched_keyword = match.group(0) if match else pattern
                logger.warning(f"SQL validation failed: dangerous operation '{matched_keyword}' detected")
                return False, f"危险操作被拦截: {matched_keyword}"

        logger.debug(f"SQL validation passed: {sql[:50]}...")
        return True, "SQL验证通过"

    def execute_config(
        self,
        sql_list: List[str],
        session_id: str
    ) -> Dict[str, Any]:
        """Execute a list of SQL statements in a transaction.

        Validates all SQL statements before execution. If any validation fails,
        no statements are executed.

        Args:
            sql_list: List of SQL statements to execute
            session_id: Session ID for logging and tracking

        Returns:
            Dictionary containing:
                - success: Boolean indicating overall success
                - executed: List of executed SQL statements
                - failed: Error message if execution failed, None otherwise
                - message: Human-readable result message
        """
        logger.info(f"[{session_id}] Starting config execution with {len(sql_list)} SQL statements")

        results: Dict[str, Any] = {
            "success": True,
            "executed": [],
            "failed": None,
            "message": ""
        }

        try:
            # Step 1: Validate all SQL statements
            logger.debug(f"[{session_id}] Validating {len(sql_list)} SQL statements")
            for i, sql in enumerate(sql_list):
                is_valid, msg = self.validate_sql(sql)
                if not is_valid:
                    error_msg = f"SQL #{i+1} 验证失败: {msg}"
                    logger.error(f"[{session_id}] {error_msg}")
                    raise ValueError(error_msg)

            # Step 2: Execute transaction
            logger.debug(f"[{session_id}] Executing transaction")
            self.db_engine.execute_transaction(sql_list)

            # Step 3: Record success
            results["executed"] = sql_list
            results["message"] = f"成功执行 {len(sql_list)} 条SQL"
            logger.success(f"[{session_id}] {results['message']}")

        except ValueError as e:
            # Validation failure
            results["success"] = False
            results["failed"] = str(e)
            results["message"] = f"执行失败: {e}"
            logger.error(f"[{session_id}] {results['message']}")

        except Exception as e:
            # Execution failure
            results["success"] = False
            results["failed"] = str(e)
            results["message"] = f"执行失败: {e}"
            logger.error(f"[{session_id}] {results['message']}")

        return results

    def rollback(self, session_id: str) -> Dict[str, Any]:
        """Rollback executed operations for a session.

        This is a placeholder for rollback functionality. Actual implementation
        would require recording inverse SQL operations during execution.

        Args:
            session_id: Session ID to rollback

        Returns:
            Dictionary with success status and message
        """
        logger.warning(f"[{session_id}] Rollback requested but not yet implemented")
        return {
            "success": False,
            "message": "回滚功能待实现"
        }