import crypto from "node:crypto";
import { generateSecret, verify, generateURI } from "otplib";
import QRCode from "qrcode";
import { encryptCredential, decryptCredential } from "@/lib/crypto/credentials";

const ISSUER = "top-tickets";
const RECOVERY_CODE_COUNT = 8;

export function generateTotpSecret(): string {
  return generateSecret();
}

export function encryptTotpSecret(secret: string): string {
  return encryptCredential(secret);
}

export function decryptTotpSecret(encrypted: string): string {
  return decryptCredential(encrypted);
}

export async function buildTotpQrCode(secret: string, email: string): Promise<string> {
  const uri = generateURI({ issuer: ISSUER, label: email, secret });
  return QRCode.toDataURL(uri);
}

export async function verifyTotpCode(secret: string, code: string): Promise<boolean> {
  const result = await verify({ secret, token: code.trim() });
  return result.valid;
}

/** Human-typeable: groups of 5 lowercase hex chars, e.g. "a1b2c-d3e4f". */
function formatRecoveryCode(): string {
  const raw = crypto.randomBytes(5).toString("hex");
  return `${raw.slice(0, 5)}-${raw.slice(5, 10)}`;
}

export function generateRecoveryCodes(count = RECOVERY_CODE_COUNT): string[] {
  return Array.from({ length: count }, formatRecoveryCode);
}

export function hashRecoveryCode(code: string): string {
  return crypto.createHash("sha256").update(code.trim().toLowerCase()).digest("hex");
}