import { resolve, basename } from "path";
import * as fs from "fs";
import { execSync } from "child_process";

const root = resolve(import.meta.dirname, "../..");
const dry = process.argv.includes("--dry");

const bytes2utf8 = new TextDecoder();

/**
 * Base64 to UTF-8
 * @param encoded Base64 encoded string
 * @returns UTF-8 string
 */
export const base64Decode = (encoded) =>
  bytes2utf8.decode(Uint8Array.from(atob(encoded), (m) => m.charCodeAt(0)));

const yarn = (cmd, stdio = "inherit") => {
  const script = `yarn run ${cmd}`;
  if (dry) {
    return script;
  }
  return execSync(script, { stdio });
};
const typlite = (input, output = "-") => {
  if (output === "-") {
    // return stdout
    const res = yarn(`--silent typlite ${input} -`, "pipe");
    return res.toString();
  }

  return yarn(`typlite ${input} ${output}`);
};

const convert = async (inp, out, opts) => {
  const input = resolve(root, inp);
  const output = resolve(root, out);
  const { before } = opts || {};

  const res = typlite(input).trim();
  if (dry) {
    console.log(res);
    return;
  }

  const assetsDir = resolve(output, "../assets/images");
  fs.mkdirSync(assetsDir, { recursive: true });

  // outline all data "data:image/svg+xml;base64," to render on GitHub correctly
  const inputName = basename(input);
  let imageCnt = 0;
  const outputContent =
    `<!-- This file is generated by scripts/link-docs.mjs from ${inp}. Do not edit manually. -->\n${before || ""}${res}\n`.replace(
      /\"data\:image\/svg\+xml\;base64,([^\"]*)\"/g,
      (_, content) => {
        const fileName = `${inputName}-inlined${imageCnt}.svg`;
        imageCnt += 1;
        fs.writeFileSync(resolve(assetsDir, fileName), base64Decode(content));
        return `"./assets/images/${fileName}"`;
      },
    );

  await fs.promises.writeFile(output, outputContent);
};

const main = async () => {
  await Promise.all([
    convert("docs/tinymist/introduction.typ", "README.md", {
      before: "# Tinymist\n\n",
    }),
    convert("docs/tinymist/release-instruction.typ", "docs/release-instruction.md", {
      before: "# Release Instructions\n\n",
    }),
    convert("docs/tinymist/frontend/emacs.typ", "editors/emacs/README.md", {
      before: "# Tinymist Emacs Support for Typst\n\n",
    }),
    convert("docs/tinymist/frontend/helix.typ", "editors/helix/README.md", {
      before: "# Tinymist Helix Support for Typst\n\n",
    }),
    convert("docs/tinymist/frontend/neovim.typ", "editors/neovim/README.md", {
      before: "# Tinymist Neovim Support for Typst\n\n",
    }),
    convert("docs/tinymist/frontend/sublime-text.typ", "editors/sublime-text/README.md", {
      before: "# Tinymist Sublime Support for Typst\n\n",
    }),
    convert("docs/tinymist/frontend/vscode.typ", "editors/vscode/README.md", {
      before: "# Tinymist Typst VS Code Extension\n\n",
    }),
    convert("docs/tinymist/frontend/zed.typ", "editors/zed/README.md", {
      before: "# Tinymist Zed Support for Typst\n\n",
    }),
  ]);
};

main().catch(console.error);