/**
 * `celilo subscribers list` — show registered build-bus subscribers.
 *
 * Reads the static-config subscriber list ([[openspec/changes/build-bus-poll-cd/proposal.md]] Phase
 * 2-lite — registry-server switchboard is deferred). Doesn't print
 * the HMAC secret in cleartext — only a truncated hash so operators
 * can disambiguate subscribers without leaking credentials into
 * terminal history.
 */

import { createHash } from 'node:crypto';
import { loadSubscribers, subscriberStorePath } from '../../services/build-bus';
import type { CommandResult } from '../types';

export function handleSubscribersList(): CommandResult {
  let subscribers: ReturnType<typeof loadSubscribers>;
  try {
    subscribers = loadSubscribers();
  } catch (err) {
    return {
      success: false,
      error: `Could not load subscribers: ${err instanceof Error ? err.message : String(err)}`,
    };
  }

  if (subscribers.length === 0) {
    return {
      success: true,
      message: `No subscribers configured.\n\nStore: ${subscriberStorePath()}\nAdd one with: celilo subscribers add <url> --secret <secret>`,
    };
  }

  const lines: string[] = [`Subscribers (${subscribers.length}) — ${subscriberStorePath()}`, ''];
  for (const s of subscribers) {
    const fingerprint = createHash('sha256').update(s.secret).digest('hex').slice(0, 8);
    const label = s.name ? `${s.name} <${s.url}>` : s.url;
    lines.push(`  ${label}`);
    lines.push(`    secret fingerprint: ${fingerprint}…`);
    const matchParts: string[] = [];
    if (s.match.registry) matchParts.push(`registry=${s.match.registry}`);
    if (s.match.tag) matchParts.push(`tag=${s.match.tag}`);
    if (s.match.packagePattern) matchParts.push(`pkg=${s.match.packagePattern}`);
    lines.push(`    match: ${matchParts.length > 0 ? matchParts.join(', ') : '(any event)'}`);
    lines.push('');
  }

  return { success: true, message: lines.join('\n').trim() };
}