/**
 * Build script for the markdown-review MCP server.
 *
 * Produces two self-contained artifacts in dist/ with ZERO runtime node_modules:
 *   - dist/index.js     Node MCP server, all deps inlined (run: node dist/index.js --stdio)
 *   - dist/mcp-app.html Single-file webview app (HTML + inlined JS/CSS)
 *
 * Build-time deps live in node_modules; runtime needs only `node`. Commit dist/
 * so a fresh install runs without `npm install`.
 */
import { build, context } from "esbuild";
import { readFile, writeFile, mkdir } from "node:fs/promises";
import path from "node:path";
import { fileURLToPath } from "node:url";

const root = path.dirname(fileURLToPath(import.meta.url));
const dist = path.join(root, "dist");
const watch = process.argv.includes("--watch");

const serverOpts = {
  entryPoints: [path.join(root, "src/main.ts")],
  outfile: path.join(dist, "index.js"),
  bundle: true,
  platform: "node",
  format: "esm",
  target: "node20",
  // ESM output that bundles CJS deps needs createRequire shimmed in.
  banner: {
    js: [
      "#!/usr/bin/env node",
      "import { createRequire as __cr } from 'node:module';",
      "const require = __cr(import.meta.url);",
    ].join("\n"),
  },
  logLevel: "info",
};

/** Bundle the browser app to a string of JS, then inline it into the HTML shell. */
async function buildApp() {
  const result = await build({
    entryPoints: [path.join(root, "src/app/mcp-app.ts")],
    bundle: true,
    platform: "browser",
    format: "iife",
    target: "es2022",
    minify: !watch,
    sourcemap: watch ? "inline" : false,
    write: false,
    logLevel: "info",
  });
  const js = result.outputFiles[0].text;
  // Escape any literal "</script>" inside the bundle, or the HTML parser closes
  // the inline <script> early and the whole bundle fails to parse. (markdown-it
  // and friends ship such strings.) "<\/script>" is identical JS, inert to HTML.
  const safeJs = js.replace(/<\/script>/gi, "<\\/script>");
  const shell = await readFile(path.join(root, "src/app/index.html"), "utf-8");
  // Use a replacer FUNCTION, not a string: a string replacement interprets "$&",
  // "$`", etc., and the minified bundle is full of "$" — which silently
  // duplicates/mangles the shell. A function replacement is taken verbatim.
  const html = shell.replace("<!--APP_BUNDLE-->", () => `<script>${safeJs}</script>`);
  await writeFile(path.join(dist, "mcp-app.html"), html, "utf-8");
  console.log("[build] dist/mcp-app.html");
}

async function run() {
  await mkdir(dist, { recursive: true });
  if (watch) {
    const ctx = await context(serverOpts);
    await ctx.watch();
    await buildApp();
    console.log("[build] watching server; rebuild app manually on change");
  } else {
    await build(serverOpts);
    await buildApp();
    console.log("[build] done");
  }
}

run().catch((e) => {
  console.error(e);
  process.exit(1);
});