from fastapi import HTTPException
from db import supabase
from datetime import datetime, timezone

PLAN_CREDITS = {"free": 100, "hobby": 5_000, "team": 25_000,
                "business": 100_000, "enterprise": 999_999_999}

async def check_and_deduct_credits(user_id: str, cost: int) -> int:
    res  = (supabase.table("users")
            .select("credits_remaining,plan,credits_reset_at")
            .eq("id", user_id).single().execute())
    user = res.data
    if not user: raise HTTPException(404, "User not found")

    if user["plan"] == "free":
        reset = datetime.fromisoformat(user["credits_reset_at"])
        now   = datetime.now(timezone.utc)
        if now > reset:
            supabase.table("users").update({
                "credits_remaining": PLAN_CREDITS["free"],
                "credits_reset_at": now.replace(hour=0,minute=0,second=0).isoformat()
            }).eq("id", user_id).execute()
            user["credits_remaining"] = PLAN_CREDITS["free"]

    if user["credits_remaining"] < cost:
        raise HTTPException(429, {
            "error": "Out of credits", "plan": user["plan"],
            "credits_remaining": user["credits_remaining"],
            "upgrade_url": "https://nurricai.com/pricing"})

    new_bal = user["credits_remaining"] - cost
    supabase.table("users").update({"credits_remaining": new_bal}).eq("id", user_id).execute()
    supabase.table("usage_logs").insert({
        "user_id": user_id, "credits_used": cost,
        "timestamp": datetime.now(timezone.utc).isoformat()
    }).execute()
    return new_bal