#!/usr/bin/env bash
# Generates a private CA and a mutual-TLS cert/key pair for the Provisioner <-> rn-lab-host-01
# Docker Engine connection (docs/PRODUCTION_NETWORK_SECURITY.md §7). The application already
# supports this (platform/provisioner/src/docker.js buildClient() has required mTLS since
# Phase 1) — this script only ever needed to exist for the CERTIFICATES, not new app code.
#
# Output goes to $OUT_DIR (default ./out, gitignored) — never into a tracked path. Deploy the
# resulting files with the `docker-tls` Ansible role, which places:
#   rn-lab-host-01:  ca.pem, server-cert.pem, server-key.pem  -> dockerd's --tlsverify config
#   rn-platform-01:   ca.pem, provisioner-client-cert.pem, provisioner-client-key.pem
#                      -> /etc/rootnode/docker-tls/ (referenced by lab-hosts.yaml)
#
# Usage:
#   ./generate-docker-tls.sh [--out-dir DIR] [--lab-host-ip IP] [--lab-host-dns NAME] [--days N]
set -euo pipefail

OUT_DIR="./out"
LAB_HOST_IP="127.0.0.1"
LAB_HOST_DNS="rn-lab-host-01.internal"
DAYS=825   # ~2.25 years — matches modern browser/OS max cert lifetime conventions; see rotation runbook for cadence

while [ $# -gt 0 ]; do
  case "$1" in
    --out-dir) OUT_DIR="$2"; shift 2 ;;
    --lab-host-ip) LAB_HOST_IP="$2"; shift 2 ;;
    --lab-host-dns) LAB_HOST_DNS="$2"; shift 2 ;;
    --days) DAYS="$2"; shift 2 ;;
    *) echo "Unknown argument: $1" >&2; exit 1 ;;
  esac
done

mkdir -p "$OUT_DIR"
cd "$OUT_DIR"
umask 077   # private keys must never be group/world readable, from the moment they're written

echo "==> Generating CA"
openssl genrsa -out ca-key.pem 4096
openssl req -new -x509 -days "$DAYS" -key ca-key.pem -sha256 -out ca.pem \
  -subj "/O=RootNode Academy/CN=RootNode Docker TLS CA"

echo "==> Generating server cert for rn-lab-host-01 (dockerd)"
openssl genrsa -out server-key.pem 4096
openssl req -subj "/CN=$LAB_HOST_DNS" -sha256 -new -key server-key.pem -out server.csr

cat > server-extfile.cnf <<EOF
subjectAltName = DNS:$LAB_HOST_DNS,IP:$LAB_HOST_IP
extendedKeyUsage = serverAuth
EOF

openssl x509 -req -days "$DAYS" -sha256 -in server.csr -CA ca.pem -CAkey ca-key.pem \
  -CAcreateserial -out server-cert.pem -extfile server-extfile.cnf

echo "==> Generating client cert for the Provisioner"
openssl genrsa -out provisioner-client-key.pem 4096
openssl req -subj "/CN=rootnode-provisioner" -new -key provisioner-client-key.pem -out client.csr

cat > client-extfile.cnf <<EOF
extendedKeyUsage = clientAuth
EOF

openssl x509 -req -days "$DAYS" -sha256 -in client.csr -CA ca.pem -CAkey ca-key.pem \
  -CAcreateserial -out provisioner-client-cert.pem -extfile client-extfile.cnf

rm -f server.csr client.csr server-extfile.cnf client-extfile.cnf
chmod 0400 ca-key.pem server-key.pem provisioner-client-key.pem
chmod 0444 ca.pem server-cert.pem provisioner-client-cert.pem

echo "==> Done. Generated in $OUT_DIR:"
ls -la
echo
echo "Deploy server-{cert,key}.pem + ca.pem to rn-lab-host-01 (docker-tls Ansible role)."
echo "Deploy provisioner-client-{cert,key}.pem + ca.pem to rn-platform-01 (same role)."
echo "Verify with: ../verify-docker-tls.sh $OUT_DIR <lab-host-ip>"