#!/usr/bin/env tsx
// Composes the served `public/` dir for the Archilyzer hub (homepage package)
// ahead of `next build`. Unlike compose-site.ts this is a SINGLE, pool-wide
// build — there is no SITE_ID and no per-site filtering. It produces the data
// files the hub's cross-site landing needs:
//
//   public/stats/{manifest,page-NNNN}.json  <- whole-pool stats (every channel)
//   public/channel-sites.json               <- channel slug -> [siteId, ...]
//   public/homepage-summary.json            <- small cross-site landing summary
//
// None of the three names an unlisted site (site.json `listed: false`) or holds
// a channel only unlisted sites expose (lib/siteSchema.ts isListedSite).
//
// Requires build:index to have populated the cues LMDB first (the homepage
// prebuild chains it), same as the export pipeline.

import path from "node:path";
import { getPaths, type Paths } from "../lib/paths";
import { writeJsonAtomic as writeJsonAtomicShared } from "../lib/jsonFile-server";
import { buildPoolSummary } from "../controller/poolSummary";
import { isListedSite } from "../lib/site";
import { runIfEntryPoint } from "./_cli";

// Where the homepage Next.js app serves static assets from. Overridable for e2e
// test isolation, mirroring EXPORT_PUBLIC_DIR.
function homepagePublicDir(monorepoRoot: string): string {
  return (
    process.env.HOMEPAGE_PUBLIC_DIR ??
    path.join(monorepoRoot, "homepage", "public")
  );
}

// Compact, no trailing newline — the homepage files' historical bytes.
function writeJsonAtomic(filePath: string, value: unknown): Promise<void> {
  return writeJsonAtomicShared(filePath, value, { indent: 0, newline: false });
}

export async function main(opts: { paths?: Paths } = {}): Promise<void> {
  const paths = opts.paths ?? getPaths();
  const publicDir = homepagePublicDir(paths.monorepoRoot);
  const statsDir = path.join(publicDir, "stats");

  // Whole-pool stats (every non-excluded channel) for the cross-site charts,
  // then the summary over them. The hub's cards read a projection of the SAME
  // call (compose-hub.ts, lib/hubSummary.ts) — the input gathering lives in
  // controller/poolSummary.ts so the two cannot drift.
  const { summary, channelSites, sites } = await buildPoolSummary({
    paths,
    statsDir,
  });

  // channel slug -> the ids of the listed content sites that expose it. Drives
  // `groupBy: "site"` in the hub's dashboard (see channelSites.tsx).
  await writeJsonAtomic(
    path.join(publicDir, "channel-sites.json"),
    channelSites,
  );

  // Lightweight cross-site summary for the landing page (pre-binned monthly
  // counts, per-site totals/sparklines, recent additions). Embedded into the
  // SSG HTML so the front page never fetches the full stats dataset.
  await writeJsonAtomic(
    path.join(publicDir, "homepage-summary.json"),
    summary,
  );

  const unlisted = sites.filter((s) => !isListedSite(s)).length;
  console.log(
    `compose-homepage: ${Object.keys(channelSites).length} channel(s) mapped across ${sites.length - unlisted} listed site(s)` +
      (unlisted > 0 ? ` (${unlisted} unlisted left out)` : "") +
      "; " +
      `summary covers ${summary.totals.transcripts} transcription(s) / ${summary.totals.downloads} download(s) ` +
      `across ${summary.sites.length} public site(s) into ${publicDir}.`,
  );
}

runIfEntryPoint(import.meta.url, () => main());