/**
 * Patch: dedup guard in AP syndicator.syndicate() to prevent double-posting.
 *
 * Root cause:
 *   The build CI calls POST /syndicate?source_url=X (force=true) after every
 *   Eleventy build. When syndicateToTargets() records the first syndication, it
 *   issues a Micropub update to save the syndication URL — which commits a new
 *   file to Gitea, triggering another build. That second build's CI call also
 *   hits the syndicate endpoint with force=true.
 *
 *   In force mode with no mp-syndicate-to, syndicateToTargets() re-selects
 *   targets whose origin matches any existing syndication URL. Since the AP
 *   syndicator's UID (publicationUrl, e.g. "https://blog.giersig.eu/") and the
 *   first syndication return value (properties.url, e.g.
 *   "https://blog.giersig.eu/notes/my-post/") share the same origin,
 *   the AP syndicator is matched and called a second time → duplicate Create(Note).
 *
 * Fix:
 *   At the start of syndicate(), query ap_activities for an existing outbound
 *   Create/Announce/Update for properties.url. If found, log and return the
 *   existing URL without re-federating.
 *
 *   This is self-contained (no CI or force-mode changes needed) and correct
 *   regardless of how syndication is triggered.
 */

import { access, readFile, writeFile } from "node:fs/promises";

const MARKER = "// [patch] ap-syndicate-dedup";

const candidates = [
  "node_modules/@rmdes/indiekit-endpoint-activitypub/lib/syndicator.js",
  "node_modules/@indiekit/indiekit/node_modules/@rmdes/indiekit-endpoint-activitypub/lib/syndicator.js",
];

const OLD = `      try {
        const actorUrl = plugin._getActorUrl();`;

const NEW = `      // Dedup: skip re-federation if we've already sent an activity for this URL. ${MARKER}
      // ap_activities is the authoritative record of "already federated".
      try {
        const existingActivity = await plugin._collections.ap_activities?.findOne({
          direction: "outbound",
          type: { $in: ["Create", "Announce", "Update"] },
          objectUrl: properties.url,
        });
        if (existingActivity) {
          console.info(\`[ActivityPub] Skipping duplicate syndication for \${properties.url} — already sent (\${existingActivity.type})\`);
          return properties.url || undefined;
        }
      } catch { /* DB unavailable — proceed */ }

      try {
        const actorUrl = plugin._getActorUrl();`;

async function exists(filePath) {
  try {
    await access(filePath);
    return true;
  } catch {
    return false;
  }
}

let checked = 0;
let patched = 0;

for (const filePath of candidates) {
  if (!(await exists(filePath))) continue;
  checked += 1;

  const source = await readFile(filePath, "utf8");

  if (source.includes(MARKER)) {
    console.log(`[postinstall] patch-ap-syndicate-dedup: already applied to ${filePath}`);
    continue;
  }

  if (!source.includes(OLD)) {
    console.warn(`[postinstall] patch-ap-syndicate-dedup: snippet not found in ${filePath}`);
    continue;
  }

  await writeFile(filePath, source.replace(OLD, NEW), "utf8");
  patched += 1;
  console.log(`[postinstall] Applied patch-ap-syndicate-dedup to ${filePath}`);
}

if (checked === 0) {
  console.log("[postinstall] patch-ap-syndicate-dedup: no target files found");
} else if (patched === 0) {
  console.log("[postinstall] patch-ap-syndicate-dedup: already up to date");
} else {
  console.log(`[postinstall] patch-ap-syndicate-dedup: patched ${patched} file(s)`);
}