const fs = require("fs");
const path = require("path");
const zlib = require("zlib");

const INPUT =
  "/Users/lanmu/Desktop/ai-chatbot-main/analysis/qiaodou-extract/app.arm64";
const OUTPUT_ROOT =
  "/Users/lanmu/Desktop/ai-chatbot-main/analysis/qiaodou-extract/extracted";
const MANIFEST =
  "/Users/lanmu/Desktop/ai-chatbot-main/analysis/qiaodou-extract/manifest.json";

const ASSET_REGEX =
  /\/assets\/[A-Za-z0-9 _.@/-]+\.(?:mjs|wasm|webp|png|svg|css|js|ico)(?=[^A-Za-z0-9_.@/-]|$)/g;
const INDEX_HTML_REGEX = /\/index\.html/g;

function collectOffsets(text, regex) {
  const hits = [];
  let match;
  while ((match = regex.exec(text)) !== null) {
    hits.push({
      value: match[0],
      offset: match.index,
    });
  }
  return hits;
}

function uniqueByOffset(items) {
  const seen = new Set();
  return items.filter((item) => {
    if (seen.has(item.offset)) {
      return false;
    }
    seen.add(item.offset);
    return true;
  });
}

function ensureDir(filePath) {
  fs.mkdirSync(path.dirname(filePath), { recursive: true });
}

function main() {
  const buffer = fs.readFileSync(INPUT);
  const text = buffer.toString("latin1");

  const assets = uniqueByOffset(collectOffsets(text, ASSET_REGEX)).sort(
    (a, b) => a.offset - b.offset,
  );
  const indexHtmlHits = uniqueByOffset(collectOffsets(text, INDEX_HTML_REGEX)).sort(
    (a, b) => a.offset - b.offset,
  );

  if (!assets.length) {
    throw new Error("No embedded /assets/* entries were found.");
  }

  const nextBoundaries = [...assets.map((a) => a.offset), ...indexHtmlHits.map((a) => a.offset)]
    .sort((a, b) => a - b);

  const manifest = [];

  for (const asset of assets) {
    const contentStart = asset.offset + Buffer.byteLength(asset.value);
    const nextOffset = nextBoundaries.find((offset) => offset > asset.offset);

    if (!nextOffset) {
      manifest.push({
        asset: asset.value,
        offset: asset.offset,
        status: "skipped_no_boundary",
      });
      continue;
    }

    const compressed = buffer.subarray(contentStart, nextOffset);

    try {
      const decompressed = zlib.brotliDecompressSync(compressed);
      const outputPath = path.join(OUTPUT_ROOT, asset.value.replace(/^\//, ""));
      ensureDir(outputPath);
      fs.writeFileSync(outputPath, decompressed);

      manifest.push({
        asset: asset.value,
        offset: asset.offset,
        nextOffset,
        compressedBytes: compressed.length,
        decompressedBytes: decompressed.length,
        outputPath,
        status: "ok",
      });
    } catch (error) {
      manifest.push({
        asset: asset.value,
        offset: asset.offset,
        nextOffset,
        compressedBytes: compressed.length,
        status: "decompress_failed",
        error: error instanceof Error ? error.message : String(error),
      });
    }
  }

  fs.mkdirSync(OUTPUT_ROOT, { recursive: true });
  fs.writeFileSync(MANIFEST, `${JSON.stringify(manifest, null, 2)}\n`);

  const ok = manifest.filter((item) => item.status === "ok").length;
  const failed = manifest.filter((item) => item.status !== "ok").length;

  console.log(`Extracted: ${ok}`);
  console.log(`Failed: ${failed}`);
  console.log(`Manifest: ${MANIFEST}`);
}

main();