// Bundle-Budget fuer den lazy geladenen Beute-3D-Chunk.
// Spec: docs/superpowers/specs/2026-10-15-beute-3d-design.md (§9.9 / L3).
// Laeuft nach `next build`; Exit 1, wenn der three.js-Chunk das Budget
// ueberschreitet oder gar kein three.js-Chunk gefunden wird.
import { readdirSync, readFileSync } from "node:fs";
import path from "node:path";
import { fileURLToPath } from "node:url";
import { gzipSync } from "node:zlib";

// Spec §9.9: hoechstens 320 kB gzip fuer den 3D-Chunk (1 kB = 1000 Byte).
export const BUDGET_BYTES = 320_000;

// Stabile Marker, die three.js auch minifiziert im Chunk behaelt (String-
// Literale): der Renderer-Name und die globale Mehrfach-Import-Markierung.
const THREE_MARKERS = ["WebGLRenderer", "__THREE__"];

export function isThreeChunk(source) {
  return THREE_MARKERS.every((marker) => source.includes(marker));
}

/**
 * Misst den groessten three.js-Chunk (gzip level 9) unter chunksDir.
 * @returns {{ ok: boolean, file: string | null, gzipBytes: number, budget: number, message: string }}
 */
export function checkBudget(chunksDir, budget = BUDGET_BYTES) {
  let largest = null;
  for (const name of readdirSync(chunksDir)) {
    if (!name.endsWith(".js")) continue;
    const source = readFileSync(path.join(chunksDir, name));
    if (!isThreeChunk(source.toString("latin1"))) continue;
    const gzipBytes = gzipSync(source, { level: 9 }).length;
    if (!largest || gzipBytes > largest.gzipBytes) largest = { file: name, gzipBytes };
  }
  if (!largest) {
    return {
      ok: false,
      file: null,
      gzipBytes: 0,
      budget,
      message: `Kein three.js-Chunk in ${chunksDir} gefunden (Marker: ${THREE_MARKERS.join(", ")}). Check kaputt oder Bundle umgebaut?`,
    };
  }
  const ok = largest.gzipBytes <= budget;
  return {
    ok,
    ...largest,
    budget,
    message: `3D-Chunk ${largest.file}: ${largest.gzipBytes} Byte gzip, Budget ${budget} Byte${ok ? "" : " UEBERSCHRITTEN"}`,
  };
}

if (process.argv[1] && path.resolve(process.argv[1]) === fileURLToPath(import.meta.url)) {
  const chunksDir = path.resolve(process.cwd(), ".next/static/chunks");
  let result;
  try {
    result = checkBudget(chunksDir);
  } catch (error) {
    console.error(`check-3d-budget: ${chunksDir} nicht lesbar (zuerst next build?): ${error.message}`);
    process.exit(1);
  }
  (result.ok ? console.log : console.error)(result.message);
  process.exit(result.ok ? 0 : 1);
}