import { unprocessable } from "../errors.js";

const PROBE_CACHE_MAX_ENTRIES = 1024;

/**
 * Process-lifetime cache of Gitea/Forgejo probe results.
 * Keyed by lowercased hostname. Positive and negative results are both cached
 * to avoid re-probing the same host on every import. FIFO-evicted at
 * PROBE_CACHE_MAX_ENTRIES to bound memory.
 */
export const giteaHostProbeCache = new Map<string, boolean>();

function evictProbeCacheIfFull() {
  if (giteaHostProbeCache.size > PROBE_CACHE_MAX_ENTRIES) {
    const oldestKey = giteaHostProbeCache.keys().next().value;
    if (oldestKey !== undefined) giteaHostProbeCache.delete(oldestKey);
  }
}

export function setGiteaHostProbe(hostname: string, isGitea: boolean) {
  giteaHostProbeCache.set(hostname.toLowerCase(), isGitea);
  evictProbeCacheIfFull();
}

export function getGiteaHostProbe(hostname: string): boolean | undefined {
  return giteaHostProbeCache.get(hostname.toLowerCase());
}

/**
 * Gitea/Forgejo API base. There is no dotcom short-circuit — every host uses
 * the same /api/v1 path, including the public gitea.com instance.
 */
export function giteaApiBase(hostname: string) {
  return `https://${hostname}/api/v1`;
}

/**
 * Canonical raw-content URL for Gitea/Forgejo ≥ 1.18.
 * Modern format: `https://{host}/{owner}/{repo}/raw/branch/{ref}/{path}`.
 */
export function resolveRawGiteaUrl(
  hostname: string,
  owner: string,
  repo: string,
  ref: string,
  filePath: string,
) {
  const p = filePath.replace(/^\/+/, "");
  return `https://${hostname}/${owner}/${repo}/raw/branch/${ref}/${p}`;
}

/**
 * Legacy raw-content URL for Gitea < 1.18 and some Forgejo setups.
 * Format: `https://{host}/{owner}/{repo}/raw/{ref}/{path}`.
 */
export function resolveRawGiteaUrlLegacy(
  hostname: string,
  owner: string,
  repo: string,
  ref: string,
  filePath: string,
) {
  const p = filePath.replace(/^\/+/, "");
  return `https://${hostname}/${owner}/${repo}/raw/${ref}/${p}`;
}

export async function giteaFetch(url: string, init?: RequestInit): Promise<Response> {
  try {
    return await fetch(url, init);
  } catch {
    throw unprocessable(
      `Could not connect to ${new URL(url).hostname} — ensure the URL points to a Gitea/Forgejo instance`,
    );
  }
}