usage.py

import os
from supabase import create_client, Client

FREE_LIMIT = 8
PLAN_LIMITS = {
    "free": FREE_LIMIT,
    "starter": 80,
    "pro": float("inf"),  # unlimited
}

_supabase_client = None

def get_supabase() -> Client:
    global _supabase_client
    if _supabase_client is None:
        url = os.getenv("SUPABASE_URL")
        key = os.getenv("SUPABASE_SERVICE_ROLE_KEY") or os.getenv("SUPABASE_SERVICE_KEY")
        if not url or not key:
            raise ValueError("Supabase credentials not set.")
        _supabase_client = create_client(url, key)
    return _supabase_client


def get_user_profile(user_id: str) -> dict:
    """Fetch user profile from Supabase."""
    client = get_supabase()
    result = client.table("profiles").select("*").eq("id", user_id).single().execute()
    return result.data


def check_usage_limit(user_id: str) -> dict:
    """
    Check if user has remaining humanizations.
    Returns: { "allowed": bool, "count": int, "limit": int, "plan": str }
    """
    profile = get_user_profile(user_id)
    plan = profile.get("plan", "free")
    count = profile.get("humanization_count", 0)
    limit = PLAN_LIMITS.get(plan, 2)

    return {
        "allowed": count < limit,
        "count": count,
        "limit": limit,
        "plan": plan,
    }


def increment_usage(user_id: str) -> None:
    """Increment humanization count for user atomically."""
    client = get_supabase()
    client.rpc('increment_humanization_count', {'uid': user_id}).execute()

def upgrade_user_plan(user_id: str, plan: str) -> None:
    """Update user plan for a one-time order and reset usage."""
    client = get_supabase()
    client.table("profiles").update({
        "plan": plan,
        "humanization_count": 0
    }).eq("id", user_id).execute()

def cancel_user_subscription(user_id: str) -> None:
    """Revert user to free plan and clear subscription."""
    client = get_supabase()
    client.table("profiles").update({
        "plan": "free",
        "razorpay_subscription_id": None
    }).eq("id", user_id).execute()