const FIX_WORDS =
  /\b(fix(?:e[ds])?|bug|broken|race|crash|regression|rollback|restore[ds]?|duplicate[ds]?|auth|fail(?:ed|ure|ing)?)\b/i;
const validRepo = (value) => /^[a-z0-9_.-]+\/[a-z0-9_.-]+$/i.test(value);
export async function scanGiteaCandidates({
  baseUrl,
  repositories,
  token = '',
  limit = 100,
  fetchImpl = fetch,
}) {
  const candidates = [],
    errors = [],
    headers = { accept: 'application/json' };
  if (token) headers.authorization = `token ${token}`;
  for (const repo of repositories) {
    if (!validRepo(repo)) {
      errors.push({ repo, error: 'invalid owner/repository identifier' });
      continue;
    }
    const [owner, name] = repo.split('/');
    let seen = 0;
    try {
      for (let page = 1; seen < limit; page++) {
        const count = Math.min(50, limit - seen),
          url = `${baseUrl.replace(/\/$/, '')}/api/v1/repos/${encodeURIComponent(owner)}/${encodeURIComponent(name)}/commits?limit=${count}&page=${page}`;
        const response = await fetchImpl(url, { headers, signal: AbortSignal.timeout(5000) });
        if (!response.ok) throw new Error(`Gitea returned ${response.status}`);
        const commits = await response.json();
        if (!Array.isArray(commits)) throw new Error('unexpected Gitea response');
        for (const commit of commits) {
          seen++;
          const subject = String(commit.commit?.message || '')
              .split('\n')[0]
              .trim(),
            match = subject.match(FIX_WORDS);
          if (!match) continue;
          let paths = '';
          try {
            const detail = await fetchImpl(
              `${baseUrl.replace(/\/$/, '')}/api/v1/repos/${encodeURIComponent(owner)}/${encodeURIComponent(name)}/git/commits/${encodeURIComponent(commit.sha)}`,
              { headers, signal: AbortSignal.timeout(5000) },
            );
            if (detail.ok) {
              const data = await detail.json();
              paths = (data.files || [])
                .map((file) => file.filename)
                .filter(Boolean)
                .join('\n');
            }
          } catch {}
          candidates.push({
            repo,
            sha: commit.sha,
            committedAt:
              commit.commit?.committer?.date ||
              commit.commit?.author?.date ||
              commit.created ||
              new Date().toISOString(),
            subject,
            paths,
            reason: `Gitea subject keyword: ${match[0].toLowerCase()}`,
          });
        }
        if (commits.length < count) break;
      }
    } catch (error) {
      errors.push({ repo, error: error.message });
    }
  }
  return { candidates, errors };
}