import { registerAs } from '@nestjs/config';

export interface ChatConfig {
  enabled: boolean;
  /** Synapse base URL reachable from this container (client + admin APIs). */
  baseUrl: string;
  /** Synapse's public_baseurl — what Element itself is configured to call. Only
   *  used to seed the sso.html handoff; server-to-server calls use {@link baseUrl}. */
  publicBaseUrl: string;
  /** Public Element Web origin — the SSO handoff link points here. */
  webUrl: string;
  /** Matrix server_name — the `:domain` half of every MXID. */
  serverName: string;
  /** HS256 secret. Must exactly match Synapse's jwt_config.secret. */
  jwtSecret: string;
  /** Bearer token for a Synapse server admin account (room/user provisioning). */
  adminToken: string;
}

const REQUIRED_VARS = [
  'MATRIX_BASE_URL',
  'MATRIX_PUBLIC_BASE_URL',
  'MATRIX_CHAT_WEB_URL',
  'MATRIX_SERVER_NAME',
  'MATRIX_JWT_SECRET',
  'MATRIX_ADMIN_TOKEN',
] as const;

export default registerAs('chat', (): ChatConfig => {
  const enabled = (process.env.MATRIX_ENABLED ?? 'false').toLowerCase() === 'true';
  if (!enabled) {
    return {
      enabled: false,
      baseUrl: '',
      publicBaseUrl: '',
      webUrl: '',
      serverName: '',
      jwtSecret: '',
      adminToken: '',
    };
  }

  const missing = REQUIRED_VARS.filter((name) => !process.env[name]);
  if (missing.length > 0) {
    throw new Error(
      `Internal chat is enabled (MATRIX_ENABLED=true) but the following env vars are missing: ${missing.join(', ')}`,
    );
  }

  return {
    enabled: true,
    baseUrl: process.env.MATRIX_BASE_URL!.replace(/\/$/, ''),
    publicBaseUrl: process.env.MATRIX_PUBLIC_BASE_URL!.replace(/\/$/, ''),
    webUrl: process.env.MATRIX_CHAT_WEB_URL!.replace(/\/$/, ''),
    serverName: process.env.MATRIX_SERVER_NAME!,
    jwtSecret: process.env.MATRIX_JWT_SECRET!,
    adminToken: process.env.MATRIX_ADMIN_TOKEN!,
  };
});