"""Job status value object."""
from enum import Enum

class JobStatus(str, Enum):
    """Enumeration of possible job statuses."""
    PENDING = "pending"
    PROCESSING = "processing"
    COMPLETED = "completed"
    FAILED = "failed"
    CANCELLED = "cancelled"
    
    def is_terminal(self) -> bool:
        """Check if status is terminal (no further changes expected)."""
        return self in [self.COMPLETED, self.FAILED, self.CANCELLED]
    
    def is_active(self) -> bool:
        """Check if job is actively being processed."""
        return self == self.PROCESSING
    
    def can_transition_to(self, new_status: 'JobStatus') -> bool:
        """Check if transition to new status is valid."""
        if self.is_terminal():
            return False
        
        valid_transitions = {
            self.PENDING: [self.PROCESSING, self.CANCELLED],
            self.PROCESSING: [self.COMPLETED, self.FAILED, self.CANCELLED]
        }
        
        return new_status in valid_transitions.get(self, [])