import { createHash } from "node:crypto";
import {
  cp,
  mkdtemp,
  mkdir,
  readFile,
  readdir,
  rm,
  writeFile,
} from "node:fs/promises";
import { tmpdir } from "node:os";
import { dirname, join, resolve } from "node:path";
import { fileURLToPath } from "node:url";
import { spawnSync } from "node:child_process";

const version = "17.0.3";
const expectedSha256 =
  "a0855654b633045ae2337537e77f1bb4361162f7fcd910e613eaab1d6d9c5fca";
const repositoryRoot = resolve(dirname(fileURLToPath(import.meta.url)), "..");
const outputRoot = join(repositoryRoot, "src/markdown/assets/twemoji");
const assetMapPath = join(repositoryRoot, "src/markdown/twemoji-assets.ts");
const temporaryRoot = await mkdtemp(join(tmpdir(), "methanium-twemoji-"));

try {
  const archivePath = join(temporaryRoot, `twemoji-${version}.tar.gz`);
  const response = await fetch(
    `https://codeload.github.com/jdecked/twemoji/tar.gz/refs/tags/v${version}`,
  );
  if (!response.ok) {
    throw new Error(`Could not download Twemoji: ${response.status}`);
  }

  const archive = Buffer.from(await response.arrayBuffer());
  const actualSha256 = createHash("sha256").update(archive).digest("hex");
  if (actualSha256 !== expectedSha256) {
    throw new Error(
      `Twemoji archive checksum mismatch: expected ${expectedSha256}, received ${actualSha256}`,
    );
  }
  await writeFile(archivePath, archive);

  const extractedRoot = join(temporaryRoot, "extracted");
  await mkdir(extractedRoot);
  const extraction = spawnSync(
    "tar",
    ["-xzf", archivePath, "-C", extractedRoot],
    {
      stdio: "inherit",
    },
  );
  if (extraction.status !== 0) throw new Error("Could not extract Twemoji");

  const sourceRoot = join(extractedRoot, `twemoji-${version}`);
  await rm(outputRoot, { force: true, recursive: true });
  await mkdir(outputRoot, { recursive: true });
  await cp(join(sourceRoot, "assets/svg"), join(outputRoot, "svg"), {
    recursive: true,
  });
  await cp(join(sourceRoot, "LICENSE"), join(outputRoot, "LICENSE"));
  await cp(
    join(sourceRoot, "LICENSE-GRAPHICS"),
    join(outputRoot, "LICENSE-GRAPHICS"),
  );
  for (const licenseName of ["LICENSE", "LICENSE-GRAPHICS"]) {
    const licensePath = join(outputRoot, licenseName);
    const license = await readFile(licensePath, "utf8");
    await writeFile(licensePath, license.replace(/[\t ]+(?=\r?$)/gm, ""));
  }
  await writeFile(
    join(outputRoot, "ATTRIBUTION.md"),
    [
      "# Twemoji Attribution",
      "",
      `Twemoji ${version} graphics are provided by the Twemoji project:`,
      "https://github.com/jdecked/twemoji",
      "",
      "Copyright 2023 Twitter, Inc and other contributors.",
      "Graphics licensed under CC-BY 4.0.",
      "Code licensed under the MIT License.",
      "",
    ].join("\n"),
  );

  const files = (await readdir(join(outputRoot, "svg")))
    .filter((file) => file.endsWith(".svg"))
    .sort();
  const entries = files.map((file) => {
    const hexcode = file.slice(0, -4);
    return `  ${JSON.stringify(hexcode)}: new URL(${JSON.stringify(`./assets/twemoji/svg/${file}`)}, import.meta.url).href,`;
  });
  await writeFile(
    assetMapPath,
    [
      `// Generated by scripts/update-twemoji.mjs from Twemoji ${version}.`,
      "export const twemojiAssetUrls: Readonly<Record<string, string>> = {",
      ...entries,
      "};",
      "",
    ].join("\n"),
  );

  const license = await readFile(join(outputRoot, "ATTRIBUTION.md"), "utf8");
  console.log(
    `Vendored ${files.length} Twemoji SVGs. ${license.split("\n")[0]}`,
  );
} finally {
  await rm(temporaryRoot, { force: true, recursive: true });
}