// esbuild build for @hive/swarm-ui (project-bootstrap scope). Output
// layout (`dist/`):
//
//   dist/index.html              served at GET / — its asset <link>/
//                                 <script> URLs are rewritten below to the
//                                 real hashed filenames esbuild picked
//   dist/static/main-<hash>.js   served at /static/main-<hash>.js (ESM
//                                 bundle, Preact + wouter-preact)
//   dist/static/main-<hash>.js.map  source map sibling
//   dist/static/main-<hash>.css  every component's own `import
//                                 './Foo.css'` (Shell.css, Panel.css, …),
//                                 folded by esbuild into one companion
//                                 output alongside main-<hash>.js — no
//                                 separate build step, this falls out of
//                                 bundling main.tsx with `bundle: true`
//   dist/static/colors.css       served at /static/colors.css — the ONE
//                                 static asset deliberately left UNHASHED:
//                                 nix/host-modules/swarm-ui.nix's stylix
//                                 theming swaps this exact fixed path via
//                                 an `= /static/colors.css` nginx location
//                                 override, with no npm/esbuild rebuild
//                                 involved. Hashing it would silently break
//                                 that swap (the override would stop
//                                 matching anything, and a themed host
//                                 would revert to the default palette). See
//                                 `colors.css`'s own top comment.
//   dist/static/theme-<hash>.css      served at /static/theme-<hash>.css
//   dist/static/swarm-ui-<hash>.css   served at /static/swarm-ui-<hash>.css
//                                 — just the shared base reset now (@import
//                                 resolved from @hive/shared), NOT
//                                 component styles
//   dist/manifest.webmanifest    served at /manifest.webmanifest (PWA)
//   dist/sw.js                   served at /sw.js (PWA) — plain JS, no
//                                 esbuild pass needed (see its own top
//                                 comment for why); its `CACHE_VERSION`
//                                 placeholder and shell-asset URLs are
//                                 rewritten below, same as index.html.
//                                 Filename itself stays fixed/unhashed —
//                                 the browser polls this exact URL to
//                                 detect a SW update, hashing it would
//                                 make every deploy register as a brand
//                                 new, unrelated worker.
//
// main/theme/swarm-ui's filenames are content-hashed so a redeploy's new
// bundle gets a new URL — nginx's Cache-Control (a follow-up, host-side)
// can then mark them `immutable, max-age=1y` for real, instead of caching
// a fixed URL that silently serves stale bytes after a deploy changes the
// nix store path underneath it.
//
// PWA icons (icon-192.png/icon-512.png/icon-512-maskable.png) are NOT
// produced here — like favicon.svg, they're rasterized from
// branding/*.svg and copied in by nix/packages/swarm-ui.nix's
// installPhase, outside the npm tree this script builds. A plain `npm
// run build` here has no `/icon-*.png`, same as it's always had no
// `/favicon.svg`.
//
// Not yet wired into any Rust binary's `ServeDir` — swarm-controller
// only serves `/health` today (see swarm-controller/README.md); this
// just makes `dist/` buildable so nix/packages/swarm-ui.nix has
// something to package. `.tsx` → JS: esbuild transpiles TypeScript
// natively (types stripped, not checked) — run `npm run typecheck`
// (plain `tsc --noEmit`) separately for real type errors; not yet
// wired into CI.

import { build } from "esbuild";
import { mkdirSync, rmSync, readFileSync, writeFileSync } from "node:fs";
import { createHash } from "node:crypto";
import { dirname, relative, resolve } from "node:path";
import { fileURLToPath } from "node:url";

const here = dirname(fileURLToPath(import.meta.url));
const src = (p) => resolve(here, "src", p);
const dist = (p) => resolve(here, "dist", p);
const staticDir = (p) => resolve(here, "dist", "static", p);

// Every metafile path esbuild returns is relative to `absWorkingDir`
// (pinned to `here` on every build call below, regardless of the caller's
// own cwd) and always POSIX-style (`dist/static/main-<hash>.js`) — turn
// one into the URL nginx actually serves it at. A plain prefix strip, not
// `path.relative`: the latter resolves a relative argument against
// `process.cwd()`, which is exactly the caller-cwd dependency pinning
// `absWorkingDir` on every build call below was meant to avoid.
const toUrl = (metafilePath) => "/" + metafilePath.replace(/^dist\//, "");

rmSync(dist(""), { recursive: true, force: true });
mkdirSync(staticDir(""), { recursive: true });

const mainResult = await build({
  absWorkingDir: here,
  entryPoints: [src("main.tsx")],
  outdir: staticDir(""),
  entryNames: "[name]-[hash]",
  bundle: true,
  format: "esm",
  platform: "browser",
  target: ["es2022"],
  sourcemap: true,
  logLevel: "info",
  jsx: "automatic",
  jsxImportSource: "preact",
  metafile: true,
});

// Look up a build's real output path for one of its entry points, by the
// entry's own source path — rather than guessing esbuild's hash
// algorithm or assuming an output ordering. `entryPoint` in the metafile
// is relative to `absWorkingDir` (`here`, pinned on every build call
// below); `path.relative` with two absolute arguments never touches
// `process.cwd()`, so this is stable regardless of the caller's own cwd.
const outputFor = (result, entrySrcPath) => {
  const wantEntry = relative(here, entrySrcPath);
  const found = Object.entries(result.metafile.outputs).find(
    ([, o]) => o.entryPoint === wantEntry,
  );
  if (!found) {
    throw new Error(
      `esbuild produced no output for entry point ${wantEntry} -- ` +
        "either it failed silently or the metafile's entryPoint " +
        "convention changed; update outputFor() to match.",
    );
  }
  return found;
};

// main.tsx's bundle: the JS entry itself, plus its companion CSS output
// (`cssBundle` — every component's own `import './Foo.css'`, folded into
// one file alongside the JS, same as before this hashed).
const [mainJsPath, mainJsInfo] = outputFor(mainResult, src("main.tsx"));
if (!mainJsInfo.cssBundle) {
  throw new Error(
    "main.tsx produced no companion CSS bundle -- index.html/sw.js still " +
      "reference /static/main.css, so this build can no longer keep that " +
      "promise. Either a component's own CSS import got removed, or " +
      "esbuild's output shape changed; update both the build and the " +
      "files that reference /static/main.css together.",
  );
}
const mainJsUrl = toUrl(mainJsPath);
const mainCssUrl = toUrl(mainJsInfo.cssBundle);

// theme.css / swarm-ui.css: hashed, same as main.tsx above. colors.css is
// deliberately NOT in this list — see the top comment's explanation of
// why it stays at a fixed path.
const hashedCssResult = await build({
  absWorkingDir: here,
  entryPoints: [src("theme.css"), src("swarm-ui.css")],
  outdir: staticDir(""),
  entryNames: "[name]-[hash]",
  bundle: true,
  loader: { ".css": "css" },
  logLevel: "info",
  metafile: true,
});
const themeCssUrl = toUrl(outputFor(hashedCssResult, src("theme.css"))[0]);
const swarmUiCssUrl = toUrl(outputFor(hashedCssResult, src("swarm-ui.css"))[0]);

// colors.css: fixed, unhashed path — see the top comment.
await build({
  absWorkingDir: here,
  entryPoints: [src("colors.css")],
  outfile: staticDir("colors.css"),
  bundle: true,
  loader: { ".css": "css" },
  logLevel: "info",
});

// A build-derived cache-bust version for sw.js's own CACHE_NAME: any
// change to any hashed shell-asset URL (a real content change, or an
// asset added/removed) changes this, which changes CACHE_NAME, which
// makes the SW's own `activate` handler evict the old cache in full —
// no more hand-bumping a CACHE_VERSION const on every shell change.
const buildVersion = createHash("sha256")
  .update(JSON.stringify([mainJsUrl, mainCssUrl, themeCssUrl, swarmUiCssUrl]))
  .digest("hex")
  .slice(0, 12);

const rewriteAssetUrls = (text) =>
  text
    .replaceAll("/static/main.js", mainJsUrl)
    .replaceAll("/static/main.css", mainCssUrl)
    .replaceAll("/static/theme.css", themeCssUrl)
    .replaceAll("/static/swarm-ui.css", swarmUiCssUrl);

writeFileSync(
  dist("index.html"),
  rewriteAssetUrls(readFileSync(src("index.html"), "utf8")),
);
writeFileSync(
  dist("sw.js"),
  rewriteAssetUrls(readFileSync(src("sw.js"), "utf8")).replace(
    '"__BUILD_VERSION__"',
    JSON.stringify(buildVersion),
  ),
);
writeFileSync(
  dist("manifest.webmanifest"),
  readFileSync(src("manifest.webmanifest")),
);

console.log("swarm-ui build ok →", dist(""));