from enum import Enum
from dataclasses import dataclass
from typing import Optional, Any

class DBErrorType(Enum):
    """Classified error categories."""
    SUCCESS = "success"
    NEED_MIGRATION = "need_migration"
    MIGRATION_FAILED = "migration_failed"
    OLD_CLIENT_NEW_API = "old_client_new_api"
    MALFORMED_SQL = "malformed_sql_file"
    MISSING_SQL = "missing_sql_file"
    MISSING_DEPENDENCY = "missing_dependency"
    INTEGRITY_ERROR = "integrity_error"
    PERMISSION_ERROR = "permission_error"
    FILESYSTEM_FULL = "filesystem_full"
    DATABASE_LOCKED = "database_locked"
    CORRUPTED_DATABASE = "corrupted_database"
    PYTHON_MODEL_STRUCTURE = "python_model_structure"
    UNKNOWN = "unknown"

@dataclass
class DatabaseOperation:
    valid: bool
    error_type: DBErrorType = DBErrorType.SUCCESS
    data: Optional[Any] = None
    message: Optional[str] = None
    tried_migration: bool = False
    tried_filtered: bool = False
    
    def is_recoverable(self) -> bool:
        """Can the caller attempt a retry or manual fix?"""
        return self.db_error_type in {
            DBErrorType.OLD_CLIENT_NEW_API,
            DBErrorType.NEED_MIGRATION
        }
    
    def user_message(self) -> str:
        """Human-readable error for the UI."""
        messages = {
            DBErrorType.SUCCESS: "Operation completed successfully.",
            DBErrorType.NEED_MIGRATION: "Database schema needs update. Contact admin.",
            DBErrorType.OLD_CLIENT_NEW_API: "Client version incompatible. Please upgrade.",
            DBErrorType.MALFORMED_SQL: "Migration file is corrupted. Contact admin.",
            DBErrorType.MISSING_SQL: "Migration file missing. Contact admin.",
            DBErrorType.MISSING_DEPENDENCY: "Database dependency missing. Contact admin.",
            DBErrorType.UNKNOWN: f"Unexpected error: {self.message}",
        }
        return messages.get(self.error_type, "Unknown error")