import { NextRequest, NextResponse } from "next/server";
import { auth } from "@/auth";
import { prisma } from "@/lib/prisma";
import { generateServerSeed, deriveInt } from "@/lib/provably-fair";
import { creditWalletCredits, debitWalletCredits, INSUFFICIENT_CREDITS } from "@/lib/wallet-safety";

export const dynamic = "force-dynamic";

const SYMBOLS = ["🍒", "🍋", "🍊", "🍇", "💎", "7️⃣"];
const SYMBOL_WEIGHTS = [30, 25, 20, 15, 7, 3]; // out of 100

// Paytable: 3 of a kind multipliers
const PAYTABLE: Record<string, number> = {
  "🍒": 2,
  "🍋": 3,
  "🍊": 5,
  "🍇": 10,
  "💎": 25,
  "7️⃣": 50,
};

function weightedSymbol(roll: number): string {
  let cumulative = 0;
  for (let i = 0; i < SYMBOLS.length; i++) {
    cumulative += SYMBOL_WEIGHTS[i];
    if (roll < cumulative) return SYMBOLS[i];
  }
  return SYMBOLS[SYMBOLS.length - 1];
}

export async function POST(req: NextRequest) {
  const session = await auth();
  if (!session?.user?.id) return NextResponse.json({ error: "Unauthorized" }, { status: 401 });

  const body = await req.json();
  const { wageBLW, clientSeed } = body as { wageBLW: number; clientSeed?: string };

  if (!Number.isInteger(wageBLW) || wageBLW < 1) return NextResponse.json({ error: "Invalid wager" }, { status: 400 });

  const serverSeed = generateServerSeed();
  const cs = clientSeed ?? "default";

  const reels = [
    weightedSymbol(deriveInt(serverSeed, cs, 0, 0, 99)),
    weightedSymbol(deriveInt(serverSeed, cs, 1, 0, 99)),
    weightedSymbol(deriveInt(serverSeed, cs, 2, 0, 99)),
  ];

  let multiplier = 0;
  let outcome = "loss";

  if (reels[0] === reels[1] && reels[1] === reels[2]) {
    multiplier = PAYTABLE[reels[0]] ?? 2;
    outcome = "win";
  } else if (reels[0] === reels[1] || reels[1] === reels[2] || reels[0] === reels[2]) {
    multiplier = 1.5;
    outcome = "win";
  }

  const payout = outcome === "win" ? Math.floor(wageBLW * multiplier) : 0;

  try {
    await prisma.$transaction(async (tx) => {
      await debitWalletCredits(tx, session.user.id, wageBLW);
      await tx.ledgerEntry.create({
        data: { userId: session.user.id, delta: -wageBLW, type: "DEBIT_GAME_BET", memo: "SLOTS bet" },
      });
      if (payout > 0) {
        await creditWalletCredits(tx, session.user.id, payout);
        await tx.ledgerEntry.create({
          data: { userId: session.user.id, delta: payout, type: "CREDIT_GAME_WIN", memo: "SLOTS payout" },
        });
      }
      await tx.gameSession.create({
        data: {
          userId: session.user.id,
          gameType: "SLOTS",
          wageredBLW: wageBLW,
          payoutBLW: payout,
          multiplier,
          outcome,
          serverSeed,
          clientSeed: cs,
          resultData: { reels, multiplier },
        },
      });
    });
  } catch (e) {
    if (e instanceof Error && e.message === INSUFFICIENT_CREDITS) {
      return NextResponse.json({ error: "Insufficient balance" }, { status: 402 });
    }
    console.error(e);
    return NextResponse.json({ error: "Could not settle slots game" }, { status: 500 });
  }

  return NextResponse.json({ reels, multiplier, payout, outcome, serverSeed });
}