import { init } from "@nulo/apkit";
import { execFile as _execFile } from "node:child_process";
import {
  chmod,
  mkdir,
  mkdtemp,
  readFile,
  readdir,
  rm,
  symlink,
  writeFile,
} from "node:fs/promises";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { promisify } from "node:util";
const execFile = promisify(_execFile);

const root = await mkdtemp(join(tmpdir(), "fireactions-rootfs."));
const alpine = await init(root);
await alpine.install(["dropbear", "util-linux", "dropbear-dbclient", "dhcpcd"]);

// gotta go fast
await append(r("/etc/rc.conf"), 'rc_parallel="YES"');

await mkdirp(r("/usr/local/sbin"));
console.debug(
  await execFile("go", [
    "build",
    "-tags=netgo",
    "-o",
    r("/usr/local/sbin/fireactions-agent"),
    "./agent",
  ])
);
// https://github.com/OpenRC/openrc/blob/master/service-script-guide.md
await writeFile(
  r("/etc/init.d/fireactions-agent"),
  `#!/sbin/openrc-run
pidfile="/run/\${RC_SVCNAME}.pid"
command_background=true
command=/usr/local/sbin/fireactions-agent
output_log=/dev/stdout
error_log=/dev/stdout
`
);
await chmod(r("/etc/init.d/fireactions-agent"), 0o700);
await alpine.rcUpdate("default", "fireactions-agent");

await alpine.rcUpdate("boot", "devfs");
await alpine.rcUpdate("boot", "procfs");
await alpine.rcUpdate("boot", "sysfs");
// alpine.rcUpdate('default', 'dhcpcd')
await alpine.rcUpdate("default", "dropbear");

await writeFile(r("/etc/securetty"), "ttyS0");
await symlink("agetty", r("/etc/init.d/agetty.ttyS0"));
await alpine.rcUpdate("default", "agetty.ttyS0");

await mkdirp(r("/etc/dropbear"));
for (const t of ["rsa", "dss", "ed25519", "ecdsa"]) {
  await execFile("dropbearkey", [
    "-t",
    t,
    "-f",
    r(`/etc/dropbear/dropbear_${t}_host_key`),
  ]);
}

await execFile("sudo", ["mkdir", "-p", r("/root/.ssh")]);
await writeFile(
  "authorized_keys",
  "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIEhrcTPMrhrOdwpgFkRFjTt8rdxt3gg16LJvBCZENRWa user@personal"
);
await execFile("sudo", [
  "mv",
  "authorized_keys",
  r("/root/.ssh/authorized_keys"),
]);

await alpine.rcUpdate("default", "networking");
await writeFile(
  r("/etc/network/interfaces"),
  `auto lo
iface lo inet loopback`
);

const ext4 = "rootfs.ext4";
await rm(ext4);
await execFile("fallocate", ["--length", "1G", ext4]);
await execFile("mkfs.ext4", [ext4]);

const mountpoint = await mkdtemp(join(tmpdir(), "tmp.fireactions-mountpoint."));
try {
  await mkdirp(mountpoint);
  await execFile("sudo", ["mount", ext4, mountpoint]);
  try {
    for (const dir of await readdir(root)) {
      await execFile("sudo", ["cp", "-r", r(dir), mountpoint]);
    }
  } finally {
    await execFile("sudo", ["umount", mountpoint]);
  }
} finally {
  await rm(mountpoint, { recursive: true });
}

// # sudo rm -rf "$dir"

// helpers
/**
 * @param {import("node:fs").PathLike} path
 * @param {string} content
 * @returns {Promise<void>}
 */
async function append(path, content) {
  const file = await readFile(path, "utf-8");
  await writeFile(path, file + "\n" + content);
}
/**
 * @param {import("node:fs").PathLike} path
 * @returns {Promise<void>}
 */
async function mkdirp(path) {
  await mkdir(path, { recursive: true });
}
/**
 * @param {string} path
 */
function r(path) {
  return join(root, path);
}