#!/usr/bin/env bash
# Pull the latest LLeMbas and restart the service.
#
# This is what to run after pushing: it fetches, hard-resets the deployment
# checkout to the remote branch, reinstalls dependencies if they changed, and
# restarts. Nothing is ever edited in place at /srv/lembas/app, so a hard reset
# is safe and avoids merge conflicts from a dirty deployment tree.
set -euo pipefail

SERVICE_USER=lembas
PREFIX=/srv/lembas
APP="$PREFIX/app"
VENV="$PREFIX/venv"
BRANCH="${LEMBAS_BRANCH:-main}"

if [[ ! -d "$APP/.git" ]]; then
  echo "No deployment at $APP. Run deploy/install.sh first." >&2
  exit 1
fi

before=$(sudo -u "$SERVICE_USER" git -C "$APP" rev-parse HEAD)

echo "== fetching =="
sudo -u "$SERVICE_USER" git -C "$APP" fetch --quiet origin "$BRANCH"
sudo -u "$SERVICE_USER" git -C "$APP" reset --hard --quiet "origin/$BRANCH"

after=$(sudo -u "$SERVICE_USER" git -C "$APP" rev-parse HEAD)

if [[ "$before" == "$after" ]]; then
  echo "   already at $(git -C "$APP" rev-parse --short HEAD), nothing to pull"
else
  echo "   $(echo "$before" | cut -c1-7) -> $(echo "$after" | cut -c1-7)"
  sudo -u "$SERVICE_USER" git -C "$APP" --no-pager log --oneline "$before..$after" | sed 's/^/     /'
fi

# Cheap and idempotent; catches a dependency added since the last deploy.
echo "== dependencies =="
sudo -u "$SERVICE_USER" "$VENV/bin/pip" install --quiet -e "$APP"

echo "== restart =="
sudo systemctl restart lembas
sleep 2

if systemctl is-active --quiet lembas; then
  echo "   lembas is running at https://chat.lan"
else
  echo "   lembas FAILED to start:" >&2
  sudo journalctl -u lembas -n 30 --no-pager >&2
  exit 1
fi