from datetime import datetime, timezone
from app import db


def format_datetime(dt: datetime) -> str:
    """Format datetime to ISO format with UTC timezone indicator"""
    if dt is None:
        return None
    # If datetime is naive (no timezone), assume it's UTC
    if dt.tzinfo is None:
        dt = dt.replace(tzinfo=timezone.utc)
    return dt.isoformat()


class Report(db.Model):
    """Report model for generated Word documents"""
    __tablename__ = 'reports'
    
    id = db.Column(db.Integer, primary_key=True)
    task_id = db.Column(db.Integer, db.ForeignKey('tasks.id'), nullable=False, unique=True)
    file_name = db.Column(db.String(255), nullable=False)
    file_path = db.Column(db.String(500), nullable=False)
    file_size = db.Column(db.Integer)
    created_at = db.Column(db.DateTime, default=datetime.utcnow, index=True)
    
    # Relationships
    task = db.relationship('Task', back_populates='report')
    
    def to_dict(self) -> dict:
        """Convert report to dictionary"""
        return {
            'id': self.id,
            'task_id': self.task_id,
            'file_name': self.file_name,
            'file_size': self.file_size,
            'created_at': format_datetime(self.created_at),
            'download_url': f'/api/reports/download?id={self.id}'
        }
    
    def __repr__(self):
        return f'<Report {self.id} {self.file_name}>'