#!/usr/bin/env bash
#
# Install / update the Theta42 proxy on a fresh or existing host.
#
# This script is idempotent: run it to install, and re-run it to update. It
# installs system dependencies (Node, OpenResty, Redis, Lua modules), checks
# out (or fast-forwards) the repo at $REPO_DIR, and symlinks the OpenResty and
# systemd config straight from the repo. Because the config is symlinked, an
# update is just "git pull + reload" -- the files under /etc always track the
# repo, so there is nothing to re-copy.
#
# Usage: sudo ./install.sh
set -euo pipefail

REPO_URL="https://github.com/theta42/proxy.git"
REPO_DIR="/var/www/proxy"
BRANCH="${BRANCH:-master}"
NODE_MAJOR=22

if [ "$(id -u)" -ne 0 ]; then
	echo "This script must be run as root (try: sudo $0)" >&2
	exit 1
fi

# Symlink $1 -> $2, replacing whatever is already at $2 (idempotent).
link(){
	ln -sfn "$1" "$2"
	echo "linked $2 -> $1"
}

echo "==> Base packages"
apt-get update
apt-get install -y --no-install-recommends \
	libpam0g-dev build-essential redis-server luarocks \
	wget gnupg ca-certificates curl git lsb-release

echo "==> Node.js ${NODE_MAJOR}.x apt source"
install -d -m 0755 /etc/apt/keyrings
curl -fsSL https://deb.nodesource.com/gpgkey/nodesource-repo.gpg.key \
	| gpg --dearmor --yes -o /etc/apt/keyrings/nodesource.gpg
echo "deb [signed-by=/etc/apt/keyrings/nodesource.gpg] https://deb.nodesource.com/node_${NODE_MAJOR}.x nodistro main" \
	> /etc/apt/sources.list.d/nodesource.list

echo "==> OpenResty apt source"
wget -qO- https://openresty.org/package/pubkey.gpg \
	| gpg --dearmor --yes -o /usr/share/keyrings/openresty.gpg
echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/openresty.gpg] http://openresty.org/package/ubuntu $(lsb_release -sc) main" \
	> /etc/apt/sources.list.d/openresty.list

echo "==> Install Node.js + OpenResty"
apt-get update
apt-get install -y nodejs openresty

echo "==> Lua modules"
luarocks install lua-resty-auto-ssl
luarocks install luasocket

echo "==> Fallback SSL cert"
install -d /etc/ssl
if [ ! -f /etc/ssl/resty-auto-ssl-fallback.crt ]; then
	openssl req -new -newkey rsa:2048 -days 3650 -nodes -x509 \
		-subj '/CN=sni-support-required-for-valid-ssl' \
		-keyout /etc/ssl/resty-auto-ssl-fallback.key \
		-out /etc/ssl/resty-auto-ssl-fallback.crt
else
	echo "fallback cert already present, skipping"
fi

echo "==> Repo checkout at ${REPO_DIR} (branch ${BRANCH})"
install -d "$(dirname "$REPO_DIR")"
if [ -d "$REPO_DIR/.git" ]; then
	git -C "$REPO_DIR" fetch --prune origin
	git -C "$REPO_DIR" checkout "$BRANCH"
	git -C "$REPO_DIR" pull --ff-only origin "$BRANCH"
else
	git clone --branch "$BRANCH" "$REPO_URL" "$REPO_DIR"
fi

echo "==> Symlink config from the repo"
install -d /etc/openresty/sites-enabled /var/log/nginx
link "$REPO_DIR/ops/nginx_conf/nginx.conf"     /etc/openresty/nginx.conf
link "$REPO_DIR/ops/nginx_conf/autossl.conf"   /etc/openresty/autossl.conf
link "$REPO_DIR/ops/nginx_conf/proxy.conf"     /etc/openresty/sites-enabled/000-proxy
link "$REPO_DIR/ops/nginx_conf/targetinfo.lua" /usr/local/openresty/lualib/targetinfo.lua
link "$REPO_DIR/ops/proxy.service"             /etc/systemd/system/proxy.service

echo "==> Node dependencies"
( cd "$REPO_DIR/nodejs" && npm install )

echo "==> Services"
systemctl daemon-reload
systemctl enable --now proxy.service
systemctl restart proxy.service

# Validate the OpenResty config before (re)starting so a bad edit can't take
# the proxy down; reload if already running, otherwise start it.
if openresty -t; then
	systemctl reload openresty 2>/dev/null || systemctl restart openresty
else
	echo "openresty config test FAILED -- not reloading" >&2
	exit 1
fi

echo "==> Done. Update later with: sudo BRANCH=${BRANCH} $0"