from sqlmodel import Session, select
from uuid import UUID
import uuid
from datetime import timedelta
import models

def generate_referral_link(user_id: UUID) -> str:
    """Generates a unique shortcode for the user to share."""
    # Using a simple deterministic slice for the local sandbox
    shortcode = str(user_id).split("-")[0]
    return f"https://pragativeer.com/join/{shortcode}"

def process_referral_reward(referrer_id: UUID, new_user_id: UUID, session: Session):
    """
    Grants both users 7 days of AI Coach access for free as per PRD Section 3.2.
    """
    referrer = session.get(models.User, referrer_id)
    new_user = session.get(models.User, new_user_id)
    
    if referrer and new_user:
        # Upgrade both to AI Coach
        referrer.tier = models.TierEnum.AI_COACH
        new_user.tier = models.TierEnum.AI_COACH
        
        # Add 7 days to their trial/subscription end dates
        from datetime import datetime
        now = datetime.utcnow()
        
        referrer.subscription_end = (referrer.subscription_end or now) + timedelta(days=7)
        new_user.trial_end = now + timedelta(days=7)
        
        session.add(referrer)
        session.add(new_user)
        session.commit()
        return True
    return False