export interface Config {
  port: number;
  publicOrigin: string;
  /** Extra origins accepted for WS/CSRF checks (e.g. Vite dev server). */
  allowedOrigins: string[];
  dbPath: string;
  discord: { clientId: string; clientSecret: string } | null;
  sessionSecret: string;
  secureCookies: boolean;
  /** Trust X-Forwarded-For (only when running behind our reverse proxy). */
  trustProxy: boolean;
  superadminDiscordIds: string[];
}

/** The site owner's Discord ID (docs/14-admin.md §2). */
export const DEFAULT_SUPERADMIN = '293719842274541579';

export function loadConfig(env: Record<string, string | undefined> = process.env): Config {
  const publicOrigin = (env.PUBLIC_ORIGIN ?? 'http://localhost:5173').replace(/\/$/, '');
  const extra = (env.ALLOWED_ORIGINS ?? '').split(',').map((s) => s.trim()).filter(Boolean);
  const clientId = env.DISCORD_CLIENT_ID;
  const clientSecret = env.DISCORD_CLIENT_SECRET;
  const sessionSecret = env.SESSION_SECRET ?? '';
  if (publicOrigin.startsWith('https://') && sessionSecret.length < 32) {
    throw new Error('SESSION_SECRET must be at least 32 characters in production');
  }
  return {
    port: Number(env.PORT ?? 3000),
    publicOrigin,
    allowedOrigins: [publicOrigin, ...extra],
    dbPath: env.DB_PATH ?? './data/app.db',
    discord: clientId && clientSecret ? { clientId, clientSecret } : null,
    sessionSecret: sessionSecret || 'dev-only-insecure-session-secret-change-me',
    secureCookies: publicOrigin.startsWith('https://'),
    trustProxy: env.TRUST_PROXY === '1',
    superadminDiscordIds: (env.SUPERADMIN_DISCORD_IDS ?? DEFAULT_SUPERADMIN).split(',').map((s) => s.trim()).filter(Boolean),
  };
}