import { randomInt } from "crypto";
import { v4 as uuidv4 } from "uuid";
import { config } from "../config.js";
import { getDb } from "../db/index.js";
import { getWalletBalanceSats } from "./lnbits.js";

const QUOTE_TTL_SECONDS = 60;

/**
 * Random payout between FAUCET_MIN_SATS and FAUCET_MAX_SATS (inclusive),
 * capped by daily budget remaining.
 */
export function computePayoutForClaim(todayPaidSats: number): number {
  const remaining = Math.max(0, config.dailyBudgetSats - todayPaidSats);
  if (remaining < config.faucetMinSats) return 0;
  const min = Math.max(config.faucetMinSats, 1);
  const max = Math.min(config.faucetMaxSats, remaining);
  if (max < min) return 0;
  return randomInt(min, max + 1);
}

export interface CreateQuoteResult {
  quoteId: string;
  payoutSats: number;
  expiresAt: number;
}

export async function createQuote(pubkey: string, lightningAddress: string): Promise<CreateQuoteResult | null> {
  const db = getDb();
  const now = Math.floor(Date.now() / 1000);
  const dayStart = now - (now % 86400);
  const todayPaid = await db.getPaidSatsSince(dayStart);
  let payout = computePayoutForClaim(todayPaid);
  if (payout <= 0) return null;

  const walletBalance = await getWalletBalanceSats();
  payout = Math.min(payout, Math.max(0, walletBalance));
  if (payout < config.faucetMinSats) return null;

  const quoteId = uuidv4();
  const expiresAt = now + QUOTE_TTL_SECONDS;
  await db.createQuote(quoteId, pubkey, payout, lightningAddress, expiresAt);
  return { quoteId, payoutSats: payout, expiresAt };
}