#!/bin/bash
set -euo pipefail

# --- Update & Upgrade ---
apt update
apt upgrade -y

# --- Prereqs ---
apt install -y python3 python3-dev git curl \
               gdebi-core software-properties-common dirmngr gnupg apt-transport-https \
               libssl-dev libcurl4-openssl-dev libxml2-dev

# --- R (Ubuntu repo or switch to CRAN later if you want newer) ---
apt install -y r-base

# --- RStudio Server (Jammy build works on Noble) ---
ARCH=amd64
DIST=jammy
VER=2025.09.0-387
BASE_URL="https://download2.rstudio.org/server/${DIST}/${ARCH}"
DEB="rstudio-server-${VER}-${ARCH}.deb"

curl -fL -o "${DEB}" "${BASE_URL}/${DEB}"

# sanity check: fail if the downloaded file is suspiciously small (<50MB)
[ $(stat -c%s "${DEB}") -gt $((50*1024*1024)) ] || { echo "Download looks wrong (file too small)"; exit 1; }

gdebi -n "${DEB}"
rm -f "${DEB}"

# --- The Littlest JupyterHub ---
curl -L https://tljh.jupyter.org/bootstrap.py | sudo -E python3 - --admin anon

# --- Add R to Jupyter (IRkernel) ---
R -e "install.packages('IRkernel', repos='https://cloud.r-project.org')"
R -e "IRkernel::installspec(user = FALSE)"

echo "Done. RStudio Server: http://<server-ip>:8787  (login with a system user)"