import { fileURLToPath } from 'node:url';
import { randomBytes } from 'node:crypto';
export type Config = {
  production: boolean;
  appUrl: string;
  databasePath: string;
  sessionSecret: string;
  discoverySecret: string;
  discoveryEnabled: boolean;
  trustedProxies: string[];
  port: number;
  host: string;
  guestDays: number;
  requestSeconds: number;
  uploadStartHours: number;
  spaceMinutes: number;
  spaceMax: number;
  offlineGraceMs: number;
  maxUrlBytes: number;
  maxItems: number;
  urlRetentionDays: number;
  sessionRate: number;
  ipRate: number;
  pairRate: number;
  rejectCooldownMs: number;
  uploadDir: string;
  maxFileBytes: number;
  guestQuota: number;
  totalGuestQuota: number;
  minFreeBytes: number;
  fileRetentionDays: number;
  orphanHours: number;
  undoSeconds: number;
  registrationMode: 'open' | 'closed';
  setupToken?: string;
  mailFrom: string;
  resendApiKey?: string;
  userQuota: number;
  emailRequestDays: number;
  webRoot?: string;
};
export function loadConfig(env: NodeJS.ProcessEnv = process.env): Config {
  const production = env.NODE_ENV === 'production';
  const num = (key: string, fallback: number, min = 1) => {
    const n = Number(env[key] ?? fallback);
    if (!Number.isSafeInteger(n) || n < min) throw Error(`Invalid ${key}`);
    return n;
  };
  const secret = (key: string) => {
    const v = env[key];
    if (production && (!v || v.length < 32 || v.startsWith('replace-')))
      throw Error(`${key} must be a random secret (32+ characters)`);
    return v && v.length >= 32 ? v : randomBytes(32).toString('base64url');
  };
  const port = num('PORT', 0, 0);
  if (production && port === 0) throw Error('Set PORT explicitly before deployment');
  const appUrl = env.APP_URL ?? 'http://127.0.0.1';
  if (production && !appUrl.startsWith('https://'))
    throw Error('Production APP_URL must use HTTPS');
  return {
    production,
    appUrl,
    databasePath:
      env.DATABASE_PATH ?? fileURLToPath(new URL('../../../.data/hop.sqlite', import.meta.url)),
    sessionSecret: secret('SESSION_SECRET'),
    discoverySecret: secret('DISCOVERY_SECRET'),
    discoveryEnabled:
      env.SAME_NETWORK_DISCOVERY_ENABLED === undefined
        ? !production
        : env.SAME_NETWORK_DISCOVERY_ENABLED === 'true',
    trustedProxies: (env.TRUSTED_PROXY_CIDRS ?? '')
      .split(',')
      .map((v) => v.trim())
      .filter(Boolean),
    port,
    host: env.HOST ?? '127.0.0.1',
    guestDays: num('GUEST_SESSION_RETENTION_DAYS', 30),
    requestSeconds: num('LOCAL_REQUEST_TIMEOUT_SECONDS', 60),
    uploadStartHours: num('ACCEPTED_UPLOAD_START_HOURS', 24),
    spaceMinutes: num('SPACE_RETENTION_MINUTES', 10),
    spaceMax: num('SPACE_MAX_DEVICES', 10),
    offlineGraceMs: num('OFFLINE_GRACE_MS', 3000, 0),
    maxUrlBytes: num('MAX_URL_PAYLOAD_SIZE_KB', 1024) * 1024,
    maxItems: num('MAX_ITEMS_PER_TRANSFER', 20),
    urlRetentionDays: Math.min(7, num('DEFAULT_URL_RETENTION_DAYS', 7)),
    sessionRate: num('GUEST_REQUESTS_PER_MINUTE', 5),
    ipRate: num('IP_REQUESTS_PER_MINUTE', 20),
    pairRate: num('PAIR_REQUESTS_PER_MINUTE', 2),
    rejectCooldownMs: num('REJECT_COOLDOWN_SECONDS', 300) * 1000,
    uploadDir: env.UPLOAD_DIR ?? fileURLToPath(new URL('../../../.data/uploads', import.meta.url)),
    maxFileBytes: num('MAX_FILE_SIZE_MB', 2048) * 1048576,
    guestQuota: num('GUEST_STORAGE_LIMIT_MB', 2048) * 1048576,
    totalGuestQuota: num('TOTAL_GUEST_STORAGE_LIMIT_MB', 20480) * 1048576,
    minFreeBytes: num('MIN_FREE_DISK_MB', 5120, 0) * 1048576,
    fileRetentionDays: Math.min(7, num('DEFAULT_FILE_RETENTION_DAYS', 7)),
    orphanHours: num('ORPHAN_UPLOAD_RETENTION_HOURS', 24),
    undoSeconds: num('DELETE_UNDO_SECONDS', 5),
    registrationMode: env.REGISTRATION_MODE === 'open' ? 'open' : 'closed',
    setupToken: env.SETUP_TOKEN,
    resendApiKey: env.RESEND_API_KEY?.trim() || undefined,
    mailFrom: env.MAIL_FROM ?? 'hop. <hello@noname.company>',
    userQuota: num('USER_STORAGE_LIMIT_MB', 10240) * 1048576,
    emailRequestDays: num('EMAIL_REQUEST_RETENTION_DAYS', 7),
    webRoot: env.WEB_ROOT,
  };
}