import crypto from 'node:crypto';
import bcrypt from 'bcrypt';
import { env } from '../config/env.js';

const ALGORITHM = 'aes-256-gcm';
const IV_LENGTH = 16;
const TAG_LENGTH = 16;

export function generateApiKey(): string {
  return `bc_${crypto.randomBytes(24).toString('hex')}`;
}

export function generateApiSecret(): string {
  return crypto.randomBytes(32).toString('hex');
}

export async function hashPassword(password: string): Promise<string> {
  return bcrypt.hash(password, 12);
}

export async function verifyPassword(password: string, hash: string): Promise<boolean> {
  return bcrypt.compare(password, hash);
}

export function generateWebhookSecret(): string {
  return `whsec_${crypto.randomBytes(24).toString('hex')}`;
}

export function signWebhookPayload(payload: string, secret: string): string {
  const hmac = crypto.createHmac('sha256', secret);
  hmac.update(payload);
  return `sha256=${hmac.digest('hex')}`;
}

export function verifyWebhookSignature(payload: string, signature: string, secret: string): boolean {
  const expected = signWebhookPayload(payload, secret);
  return crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected));
}

export function encrypt(text: string): string {
  const key = Buffer.from(env.encryption.key, 'hex');
  const iv = crypto.randomBytes(IV_LENGTH);
  const cipher = crypto.createCipheriv(ALGORITHM, key, iv);

  let encrypted = cipher.update(text, 'utf8', 'hex');
  encrypted += cipher.final('hex');

  const tag = cipher.getAuthTag();

  return `${iv.toString('hex')}:${tag.toString('hex')}:${encrypted}`;
}

export function decrypt(encryptedText: string): string {
  const key = Buffer.from(env.encryption.key, 'hex');
  const parts = encryptedText.split(':');
  if (parts.length !== 3) throw new Error('Invalid encrypted text format');

  const iv = Buffer.from(parts[0], 'hex');
  const tag = Buffer.from(parts[1], 'hex');
  const encrypted = parts[2];

  const decipher = crypto.createDecipheriv(ALGORITHM, key, iv);
  decipher.setAuthTag(tag);

  let decrypted = decipher.update(encrypted, 'hex', 'utf8');
  decrypted += decipher.final('utf8');

  return decrypted;
}

export function generateSlug(name: string): string {
  return name
    .toLowerCase()
    .replace(/[çÇ]/g, 'c')
    .replace(/[ğĞ]/g, 'g')
    .replace(/[ıİ]/g, 'i')
    .replace(/[öÖ]/g, 'o')
    .replace(/[şŞ]/g, 's')
    .replace(/[üÜ]/g, 'u')
    .replace(/[^a-z0-9]+/g, '-')
    .replace(/^-|-$/g, '');
}