#!/usr/bin/env node
// Unified entry point for the Codex CLI.

import path from "path";
import os from "os";
import fs from "fs";
import { createRequire } from "module";
import { fileURLToPath } from "url";

// __dirname equivalent in ESM
const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const { platform, arch } = process;

let targetTriple = null;
switch (platform) {
  case "linux":
  case "android":
    switch (arch) {
      case "x64":
        targetTriple = "x86_64-unknown-linux-musl";
        break;
      case "arm64":
        targetTriple = "aarch64-unknown-linux-musl";
        break;
      default:
        break;
    }
    break;
  case "darwin":
    switch (arch) {
      case "x64":
        targetTriple = "x86_64-apple-darwin";
        break;
      case "arm64":
        targetTriple = "aarch64-apple-darwin";
        break;
      default:
        break;
    }
    break;
  case "win32":
    switch (arch) {
      case "x64":
        targetTriple = "x86_64-pc-windows-msvc.exe";
        break;
      case "arm64":
      // We do not build this today, fall through...
      default:
        break;
    }
    break;
  default:
    break;
}

if (!targetTriple) {
  throw new Error(`Unsupported platform: ${platform} (${arch})`);
}

const pkgRoot = path.join(__dirname, "..");
const pkgBinDir = path.join(pkgRoot, "bin");
const binaryPath = path.join(pkgBinDir, `codex-${targetTriple}`);

// Use an asynchronous spawn instead of spawnSync so that Node is able to
// respond to signals (e.g. Ctrl-C / SIGINT) while the native binary is
// executing. This allows us to forward those signals to the child process
// and guarantees that when either the child terminates or the parent
// receives a fatal signal, both processes exit in a predictable manner.
const { spawn } = await import("child_process");

async function tryImport(moduleName) {
  try {
    // eslint-disable-next-line node/no-unsupported-features/es-syntax
    return await import(moduleName);
  } catch (err) {
    return null;
  }
}

async function resolveRgDir() {
  const ripgrep = await tryImport("@vscode/ripgrep");
  if (!ripgrep?.rgPath) {
    return null;
  }
  return path.dirname(ripgrep.rgPath);
}

function getUpdatedPath(newDirs) {
  const pathSep = process.platform === "win32" ? ";" : ":";
  const existingPath = process.env.PATH || "";
  const updatedPath = [
    ...newDirs,
    ...existingPath.split(pathSep).filter(Boolean),
  ].join(pathSep);
  return updatedPath;
}

const additionalDirs = [];
// 1) Make packaged bin directory available on PATH for any helper binaries.
additionalDirs.push(pkgBinDir);
const rgDir = await resolveRgDir();
if (rgDir) {
  additionalDirs.push(rgDir);
}
// 2) Ensure an `apply_patch` helper exists in $CODEX_HOME/<version>/ and add that directory to PATH.
try {
  const require = createRequire(import.meta.url);
  // Load package.json to read the version string.
  const { version } = require("../package.json");
  const codexHome = process.env.CODEX_HOME || path.join(os.homedir(), ".codex");
  const versionDir = path.join(codexHome, version);
  fs.mkdirSync(versionDir, { recursive: true });
  const isWindows = platform === "win32";
  const destName = isWindows ? "apply_patch.exe" : "apply_patch";
  const destPath = path.join(versionDir, destName);
  const srcPath = path.join(pkgBinDir, `apply-patch-${targetTriple}`);
  // Only copy if missing; keep it simple and fast.
  if (!fs.existsSync(destPath)) {
    fs.copyFileSync(srcPath, destPath);
    if (!isWindows) {
      fs.chmodSync(destPath, 0o755);
    }
  }
  additionalDirs.push(versionDir);
} catch {
  // Best-effort: if anything fails, continue without the helper.
}
const updatedPath = getUpdatedPath(additionalDirs);

const child = spawn(binaryPath, process.argv.slice(2), {
  stdio: "inherit",
  env: { ...process.env, PATH: updatedPath, CODEX_MANAGED_BY_NPM: "1" },
});

child.on("error", (err) => {
  // Typically triggered when the binary is missing or not executable.
  // Re-throwing here will terminate the parent with a non-zero exit code
  // while still printing a helpful stack trace.
  // eslint-disable-next-line no-console
  console.error(err);
  process.exit(1);
});

// Forward common termination signals to the child so that it shuts down
// gracefully. In the handler we temporarily disable the default behavior of
// exiting immediately; once the child has been signaled we simply wait for
// its exit event which will in turn terminate the parent (see below).
const forwardSignal = (signal) => {
  if (child.killed) {
    return;
  }
  try {
    child.kill(signal);
  } catch {
    /* ignore */
  }
};

["SIGINT", "SIGTERM", "SIGHUP"].forEach((sig) => {
  process.on(sig, () => forwardSignal(sig));
});

// When the child exits, mirror its termination reason in the parent so that
// shell scripts and other tooling observe the correct exit status.
// Wrap the lifetime of the child process in a Promise so that we can await
// its termination in a structured way. The Promise resolves with an object
// describing how the child exited: either via exit code or due to a signal.
const childResult = await new Promise((resolve) => {
  child.on("exit", (code, signal) => {
    if (signal) {
      resolve({ type: "signal", signal });
    } else {
      resolve({ type: "code", exitCode: code ?? 1 });
    }
  });
});

if (childResult.type === "signal") {
  // Re-emit the same signal so that the parent terminates with the expected
  // semantics (this also sets the correct exit code of 128 + n).
  process.kill(process.pid, childResult.signal);
} else {
  process.exit(childResult.exitCode);
}