from sqlalchemy import Column, Integer, String, Text, DateTime, JSON, ForeignKey, func
from sqlalchemy.orm import relationship
from app.database import Base

class Task(Base):
    """Background Task Model"""
    __tablename__ = "tasks"

    id = Column(Integer, primary_key=True, index=True)
    task_type = Column(String(50), nullable=False, comment="Task type (e.g., 'nasa_download')")
    status = Column(String(20), nullable=False, default='pending', index=True, comment="pending, running, completed, failed, cancelled")
    description = Column(String(255), nullable=True)
    params = Column(JSON, nullable=True, comment="Input parameters")
    result = Column(JSON, nullable=True, comment="Output results")
    progress = Column(Integer, default=0, comment="Progress 0-100")
    error_message = Column(Text, nullable=True)
    
    created_by = Column(Integer, nullable=True, comment="User ID")
    
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
    started_at = Column(DateTime(timezone=True), nullable=True)
    completed_at = Column(DateTime(timezone=True), nullable=True)

    def __repr__(self):
        return f"<Task(id={self.id}, type='{self.task_type}', status='{self.status}')>"