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);
};

// todo: generate me using typlite.
const maintainerMd = async () => {
  const maintainers = JSON.parse(yarn(`--silent maintainers --input=action=maintainers`, "pipe"));
  const features = JSON.parse(yarn(`--silent maintainers --input=action=features`, "pipe"));

  const output = [];

  output.push("<!-- This file is generated by scripts/link-docs.mjs. Do not edit manually. -->\n");
  output.push("# Tinymist Maintainers\n\n");
  output.push(
    "Tinymist [ˈtaɪni mɪst] is an integrated language service for [Typst](https://typst.app/) [taɪpst].",
  );

  output.push(
    "\nThis page is generated from [./MAINTAINERS.typ](./MAINTAINERS.typ) and renders information of [maintainers](#maintainers) and [features.](#features)\n",
  );

  output.push("## Maintainers\n");

  const italicIt = (it) => `*${it}*`;
  const featureLink = (it) => {
    const feature = features.find((f) => f.name === it);
    if (feature) {
      return `[${it}](#${it.replace(/\s+/g, "-").toLowerCase()})`;
    }
    return it;
  };
  const fsPath = (it) => {
    if (!fs.existsSync(it)) {
      throw new Error(`Path ${it} does not exist!`);
    }
    return `[\`${it}\`](./${it})`;
  };

  for (const maintainer of maintainers) {
    output.push(`- [**${maintainer["name"]}**](https://github.com/${maintainer["github-name"]})`);
    output.push(`  - Email: ${maintainer.email}`);
    if (maintainer.maintains.length > 0) {
      const rendered = maintainer.maintains.map(featureLink).map(italicIt);
      if (rendered.length > 1) {
        const last = rendered.pop();
        output.push(`  - Maintains: ${rendered.join(", ")}, and ${last}`);
      } else {
        output.push(`  - Maintains: ${rendered.join(", ")}`);
      }
    }
    output.push("");
  }

  output.push("## Features\n");
  for (const feature of features) {
    output.push(`### ${feature.name}`);
    output.push(`${feature.description}`);
    output.push(`- Scope: ${feature.scope.map(fsPath).join(", ")}`);
  }

  const outPath = resolve(root, "MAINTAINERS.md");
  const outputContent = output.join("\n");
  if (dry) {
    console.log(content);
    return;
  }

  await fs.promises.writeFile(outPath, 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",
    }),
    maintainerMd(),
  ]);
};

main().catch(console.error);