import { resolve } from 'node:path';

import {
  CANARY_DEFAULT_PORT,
  CANARY_DEFAULT_UPSTREAM_PORT,
  createCanaryGateway,
} from './canary-gateway.ts';

function environmentPort(name: string, fallback: number): number {
  const value = process.env[name];
  if (value === undefined || value === '') return fallback;
  const port = Number(value);
  if (!Number.isInteger(port)) throw new Error(`${name} must be an integer port`);
  return port;
}

const gateway = createCanaryGateway({
  distDir: resolve(process.env.CANARY_DIST_DIR ?? 'apps/web/dist'),
  port: environmentPort('CANARY_PORT', CANARY_DEFAULT_PORT),
  upstreamPort: environmentPort('CANARY_UPSTREAM_PORT', CANARY_DEFAULT_UPSTREAM_PORT),
});

let stopping = false;
async function stop(signal: string): Promise<void> {
  if (stopping) return;
  stopping = true;
  process.stdout.write(`Stopping canary gateway (${signal})\n`);
  await gateway.stop();
}

process.once('SIGINT', () => void stop('SIGINT'));
process.once('SIGTERM', () => void stop('SIGTERM'));

try {
  await gateway.start();
  process.stdout.write(`Canary gateway listening at ${gateway.origin}\n`);
} catch (error) {
  process.stderr.write(`${error instanceof Error ? error.message : String(error)}\n`);
  process.exitCode = 1;
}