"""
Notification model - For system notifications to users
"""
from sqlalchemy import Column, Integer, String, Boolean, DateTime, ForeignKey, JSON, Enum
from sqlalchemy.orm import relationship
from sqlalchemy.sql import func
from config.database import Base
import enum

class NotificationType(enum.Enum):
    STUDENT_CONNECTED = "student_connected"
    STUDENT_COMPLETED_SESSION = "student_completed_session"
    ASSIGNMENT_DUE = "assignment_due"
    INVITATION_ACCEPTED = "invitation_accepted"
    STUDENT_REMOVED = "student_removed"
    SYSTEM = "system"

class Notification(Base):
    __tablename__ = "notifications"
    
    id = Column(Integer, primary_key=True, index=True)
    
    # Who the notification is for
    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    
    # Notification details
    type = Column(Enum(NotificationType), nullable=False)
    title = Column(String(200), nullable=False)
    message = Column(String(1000), nullable=False)
    
    # Additional data (JSON for flexibility)
    data = Column(JSON, nullable=True)
    
    # Status
    is_read = Column(Boolean, default=False)
    read_at = Column(DateTime(timezone=True), nullable=True)
    
    # Timestamps
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    
    # Relationships
    user = relationship("User", backref="notifications")
    
    def mark_as_read(self):
        """Mark notification as read"""
        from datetime import datetime, timezone
        self.is_read = True
        self.read_at = datetime.now(timezone.utc)
    
    def __repr__(self):
        return f"<Notification {self.type.value} for user {self.user_id}>"