import { resolve, basename, relative } 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) => {
  const assets_flag = dry
    ? ""
    : `--assets-path ${relative(root, resolve(output, "../assets/images/", basename(input.slice(0, -4))))}`;

  // return stdout
  const res = yarn(`--silent typlite ${assets_flag} --root ${root} ${input} -`, "pipe");
  return res.toString();
};

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

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

  const outputContent = `<!-- This file is generated by scripts/link-docs.mjs from ${inp}. Do not edit manually. -->\n${before || ""}${res}\n`;
  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 isCheck = process.argv.includes("--check");

const tasks = [
  {
    input: "docs/tinymist/introduction.typ",
    output: "README.md",
    title: "Tinymist",
  },
  {
    input: "docs/tinymist/release-instruction.typ",
    output: "docs/release-instruction.md",
    title: "Release Instructions",
  },
  {
    input: "docs/tinymist/crates/typlite.typ",
    output: "crates/typlite/README.md",
    title: "Typlite",
  },
  {
    input: "docs/tinymist/frontend/emacs.typ",
    output: "editors/emacs/README.md",
    title: "Tinymist Emacs Support for Typst",
  },
  {
    input: "docs/tinymist/frontend/helix.typ",
    output: "editors/helix/README.md",
    title: "Tinymist Helix Support for Typst",
  },
  {
    input: "docs/tinymist/frontend/neovim.typ",
    output: "editors/neovim/README.md",
    title: "Tinymist Neovim Support for Typst",
  },
  {
    input: "docs/tinymist/frontend/sublime-text.typ",
    output: "editors/sublime-text/README.md",
    title: "Tinymist Sublime Support for Typst",
  },
  {
    input: "docs/tinymist/frontend/vscode.typ",
    output: "editors/vscode/README.md",
    title: "Tinymist Typst VS Code Extension",
  },
  {
    input: "docs/tinymist/frontend/zed.typ",
    output: "editors/zed/README.md",
    title: "Tinymist Zed Support for Typst",
  },
];

const main = async () => {
  await Promise.all([
    ...tasks.map((task) => convert(task.input, task.output, { before: `# ${task.title}\n\n` })),
    maintainerMd(),
  ]);

  if (isCheck) {
    // any dirty git files?
    await Promise.all(
      tasks.map(async (task) => {
        const gitStatus = execSync(`git status --porcelain ${task.output}`, {
          encoding: "utf-8",
        }).trim();
        if (gitStatus) {
          throw new Error(
            `The file ${task.output} is not up to date. Please run \`node scripts/link-docs.mjs\` to update it.`,
          );
        }
      }),
    );
  }
};

main();