export function daysAgo(n: number): string {
  const d = new Date();
  d.setDate(d.getDate() - n);
  return d.toISOString().split('T')[0];
}

export function log(...args: unknown[]) {
  console.error(...args);
}

export function sleep(ms: number): Promise<void> {
  return new Promise((r) => setTimeout(r, ms));
}

export async function ghSearch(query: string): Promise<GHRepo[]> {
  const url =
    `https://api.github.com/search/repositories` +
    `?q=${encodeURIComponent(query)}&sort=stars&order=desc&per_page=30`;
  log(`  fetching: ${query}`);

  const res = await fetch(url, {
    headers: { Accept: 'application/vnd.github.v3+json' },
  });

  if (!res.ok) {
    log(`  ⚠ GitHub API ${res.status}: ${await res.text()}`);
    return [];
  }

  const data = (await res.json()) as { items: GHRepo[] };
  return data.items ?? [];
}

export interface GHRepo {
  full_name: string;
  description: string | null;
  stargazers_count: number;
  language: string | null;
  html_url: string;
  created_at: string;
  pushed_at: string;
  topics?: string[];
}

export function formatRepos(repos: GHRepo[], title: string): string {
  if (!repos.length) return `## ${title}\n\n_No results found._\n`;

  const lines = [`## ${title}\n`];
  for (const r of repos) {
    const desc = r.description
      ? r.description.slice(0, 120)
      : '_No description_';
    const lang = r.language ?? '?';
    lines.push(
      `**[${r.full_name}](${r.html_url})** ` +
        `⭐ ${r.stargazers_count.toLocaleString()} | \`${lang}\``
    );
    lines.push(`> ${desc}\n`);
  }
  return lines.join('\n');
}

export function dedupeRepos(repos: GHRepo[]): GHRepo[] {
  const seen = new Set<string>();
  return repos.filter((r) => {
    if (seen.has(r.full_name)) return false;
    seen.add(r.full_name);
    return true;
  });
}