import { Timestamp, type Transaction } from "firebase-admin/firestore";
import { firestore } from "../firebase";
import { HttpError } from "../middleware/errors";
import { createLedgerEntryTx } from "../repositories/pointLedgerRepository";
import { getWalletTx, walletDocRef } from "../repositories/walletRepository";
import { OP_BY_TYPE, PointLedgerType, type PointChange, type PointLedgerEntry, type WalletDoc } from "../types/points";

const TX_ID = /^[A-Za-z0-9:_-]{1,240}$/;
export function isAlreadyExistsError(err: unknown): boolean { const code = (err as { code?: unknown })?.code; return code === 6 || code === "already-exists" || code === "ALREADY_EXISTS"; }
export async function applyPointChangesTx(tx: Transaction, uid: string, changes: PointChange[]): Promise<WalletDoc | null> {
  for (const c of changes) if (!TX_ID.test(c.txId) || !Number.isSafeInteger(c.amount) || c.amount <= 0) throw new HttpError(400, "invalid point change", "INVALID_POINT_CHANGE");
  const existing = await getWalletTx(tx, uid);
  if (changes.length === 0) return existing;
  const now = Timestamp.now();
  const wallet: WalletDoc = existing ? { ...existing } : { availableBalance: 0, totalEarned: 0, totalSpent: 0, version: 0, createdAt: now, updatedAt: now };
  for (const c of changes) {
    const beforeA = wallet.availableBalance; const op = OP_BY_TYPE[c.type];
    if (op === "credit") {
      wallet.availableBalance += c.amount;
      if (c.type === PointLedgerType.OrderRefund) wallet.totalSpent -= c.amount;
      else wallet.totalEarned += c.amount;
    }
    if (op === "debit") { wallet.availableBalance -= c.amount; wallet.totalSpent += c.amount; }
    if (wallet.availableBalance < 0) throw new HttpError(409, "insufficient balance", "INSUFFICIENT_BALANCE");
    const entry: PointLedgerEntry = { ...c, uid, op, availableBefore: beforeA, availableAfter: wallet.availableBalance, createdAt: now };
    createLedgerEntryTx(tx, uid, entry);
  }
  if (wallet.availableBalance !== wallet.totalEarned - wallet.totalSpent) throw new Error("wallet invariant violated");
  wallet.version += 1; wallet.updatedAt = now;
  tx.set(walletDocRef(uid), wallet);
  return wallet;
}
export async function applyPointChanges(uid: string, changes: PointChange[]) { return firestore.runTransaction((tx) => applyPointChangesTx(tx, uid, changes)); }