import { chmod, copyFile, cp, mkdir } from "node:fs/promises";
import { builtinModules } from "node:module";
import { dirname, resolve } from "node:path";
import { fileURLToPath, pathToFileURL } from "node:url";

import { build } from "esbuild";

const packageRoot = resolve(dirname(fileURLToPath(import.meta.url)), "..");

export const verifiedProviderEntrypoints = Object.freeze([
  Object.freeze({
    name: "provision-antigravity",
    source: resolve(packageRoot, "scripts/provision-antigravity.mjs"),
    output: resolve(packageRoot, "dist/cli/provision-antigravity.js"),
    verifiedOutput: resolve(packageRoot, "dist/cli/provision-antigravity.cjs"),
  }),
  Object.freeze({
    name: "provision-cursor",
    source: resolve(packageRoot, "scripts/provision-cursor.mjs"),
    output: resolve(packageRoot, "dist/cli/provision-cursor.js"),
    verifiedOutput: resolve(packageRoot, "dist/cli/provision-cursor.cjs"),
  }),
  Object.freeze({
    name: "acpx-runtime-sidecar",
    source: resolve(packageRoot, "src/cli/acpx-runtime-sidecar.ts"),
    output: resolve(packageRoot, "dist/cli/acpx-runtime-sidecar.js"),
    verifiedOutput: resolve(packageRoot, "dist/cli/acpx-runtime-sidecar.cjs"),
  }),
  Object.freeze({
    name: "opencode-app-server-proxy",
    source: resolve(packageRoot, "src/cli/opencode-app-server-proxy.ts"),
    output: resolve(packageRoot, "dist/cli/opencode-app-server-proxy.js"),
    verifiedOutput: resolve(
      packageRoot,
      "dist/cli/opencode-app-server-proxy.cjs",
    ),
  }),
]);

const nodeBuiltins = new Set([
  ...builtinModules,
  ...builtinModules.map((name) => `node:${name}`),
]);

function assertSelfContainedBundle(entrypoint, result) {
  const outputs = Object.entries(result.metafile.outputs).filter(
    ([, output]) => output.entryPoint !== undefined,
  );
  if (outputs.length !== 1) {
    throw new Error(
      `${entrypoint.name} bundle emitted ${outputs.length} entrypoint outputs instead of one`,
    );
  }
  const imports = outputs[0][1].imports;
  for (const dependency of imports) {
    if (!dependency.external || !nodeBuiltins.has(dependency.path)) {
      throw new Error(
        `${entrypoint.name} bundle retained a non-builtin import: ${dependency.path}`,
      );
    }
  }
}

export async function bundleVerifiedProviderEntrypoints({ write = true } = {}) {
  if (write) {
    await mkdir(resolve(packageRoot, "dist/providers"), { recursive: true });
    await cp(resolve(packageRoot, "src/providers"), resolve(packageRoot, "dist/providers"), { recursive: true });
    await copyFile(resolve(packageRoot, "cursor-distributions.json"), resolve(packageRoot, "dist/cursor-distributions.json"));
    await copyFile(resolve(packageRoot, "antigravity-distributions.json"), resolve(packageRoot, "dist/antigravity-distributions.json"));
    await mkdir(resolve(packageRoot, "dist/cli"), { recursive: true });
    await copyFile(resolve(packageRoot, "scripts/patch-antigravity-runtime.admission.py"), resolve(packageRoot, "dist/cli/patch-antigravity-runtime.admission.py"));
  }
  const results = [];
  for (const entrypoint of verifiedProviderEntrypoints) {
    const buildBundle = async (outfile, format) => {
      const result = await build({
        entryPoints: [entrypoint.source],
        outfile,
        bundle: true,
        platform: "node",
        format,
        target: "node24",
        packages: "bundle",
        splitting: false,
        sourcemap: false,
        legalComments: "none",
        metafile: true,
        treeShaking: true,
        write,
        logLevel: "silent",
        banner:
          format === "cjs"
            ? {
                js: 'const __paperclipVerifiedEntrypointUrl = require("node:url").pathToFileURL(__filename).href;',
              }
            : undefined,
        define:
          format === "cjs"
            ? {
                "import.meta.dirname": "__dirname",
                "import.meta.url": "__paperclipVerifiedEntrypointUrl",
              }
            : undefined,
      });
      assertSelfContainedBundle(entrypoint, result);
      return result;
    };
    const result = await buildBundle(entrypoint.output, "esm");
    const verifiedResult = await buildBundle(entrypoint.verifiedOutput, "cjs");
    if (write && process.platform !== "win32") {
      await Promise.all([
        chmod(entrypoint.output, 0o755),
        chmod(entrypoint.verifiedOutput, 0o755),
      ]);
    }
    results.push({ entrypoint, result, verifiedResult });
  }
  await bundlePiProvisioner({ write });
  return results;
}

/** Explicit setup tooling; no provider payload is included in the npm tarball. */
export async function bundlePiProvisioner({ write = true, outputRoot = resolve(packageRoot, "dist/cli") } = {}) {
  const entrypoint = { name: "provision-pi", source: resolve(packageRoot, "scripts/provision-pi.mjs") };
  const result = await build({
    entryPoints: [entrypoint.source], outfile: resolve(outputRoot, "provision-pi.cjs"),
    bundle: true, platform: "node", format: "cjs", target: "node24", packages: "bundle",
    splitting: false, sourcemap: false, legalComments: "none", metafile: true,
    treeShaking: true, write, logLevel: "silent",
    banner: { js: 'const __paperclipVerifiedEntrypointUrl = require("node:url").pathToFileURL(__filename).href;' },
    define: { "import.meta.dirname": "__dirname", "import.meta.url": "__paperclipVerifiedEntrypointUrl" },
  });
  assertSelfContainedBundle(entrypoint, result);
  if (write) {
    const inputs = resolve(outputRoot, "pi-provision-inputs");
    await mkdir(inputs, { recursive: true });
    for (const [source, name] of [
      ["scripts/pi-distribution/package.json", "package.json"],
      ["scripts/pi-distribution/package-lock.json", "package-lock.json"],
      ["../../patches/pi-acp@0.0.33.patch", "pi-acp.patch"],
      ["../../patches/brace-expansion@5.0.9.patch", "brace-expansion.patch"],
      ["src/drivers/acpx/pi-acp-runtime.ts", "pi-acp-runtime.ts"],
      ["src/drivers/acpx/pi-runtime-extension.ts", "pi-runtime-extension.ts"],
    ]) await cp(resolve(packageRoot, source), resolve(inputs, name));
  }
  return result;
}

const invokedPath = process.argv[1]
  ? pathToFileURL(resolve(process.argv[1])).href
  : null;
if (invokedPath === import.meta.url) {
  await bundleVerifiedProviderEntrypoints();
}