#!/usr/bin/env bash
# Updates this install: back up the database, check out the release, install, migrate,
# build, and reload PM2. If anything fails before the reload, the previous version keeps
# running and the checkout goes back to it.
#
# Usage (on the server, from the repo folder):
#   bash scripts/deploy.sh            # the latest main
#   bash scripts/deploy.sh v1.37.3    # a tagged release
# CI runs it with the tag over SSH when a v* tag is pushed (see .gitea/workflows/ci.yml).
#
# PM2 uses this install's own ecosystem.config.js (app names, ports). It isn't in git, so
# deploys never change it; the first deploy creates it from ecosystem.config.example.js.
set -Eeuo pipefail

# The checkout below replaces this file, and bash reads a script as it runs — so run from a
# copy that can't change underneath us.
if [ -z "${HOPE_DEPLOY_COPY:-}" ]; then
  COPY="$(mktemp)"
  cp "$0" "$COPY"
  HOPE_DEPLOY_COPY=1 HOPE_DEPLOY_DIR="$(cd "$(dirname "$0")/.." && pwd)" exec bash "$COPY" "$@"
fi

cd "$HOPE_DEPLOY_DIR"
TARGET="${1:-main}"
PREVIOUS="$(git describe --tags --exact-match 2>/dev/null || git rev-parse --short HEAD)"

# Keep this install's PM2 config safe across the checkout (older releases tracked it in git).
PM2_CONFIG="ecosystem.config.js"
PM2_KEEP="$(mktemp)"
HAVE_PM2_CONFIG=0
if [ -f "$PM2_CONFIG" ]; then cp "$PM2_CONFIG" "$PM2_KEEP"; HAVE_PM2_CONFIG=1; fi
trap 'rm -f "$0" "$PM2_KEEP"' EXIT
# Out of the way before a checkout: back to the committed version if git tracks it in this
# release, otherwise removed (a release that still tracks it would refuse to overwrite it).
clear_pm2_config() {
  git checkout -q -- "$PM2_CONFIG" 2>/dev/null || rm -f "$PM2_CONFIG"
}
restore_pm2_config() {
  if [ "$HAVE_PM2_CONFIG" = 1 ]; then cp "$PM2_KEEP" "$PM2_CONFIG"; fi
}

# Check out a tag, or the latest main (detached, so local main is never in the way).
checkout() {
  clear_pm2_config
  if [ "$1" = "main" ]; then
    git fetch --quiet origin main
    git checkout -q --detach origin/main
  else
    git fetch --tags --quiet origin
    git checkout -q "$1"
  fi
  restore_pm2_config
}

echo "==> Deploying $TARGET (currently $PREVIOUS)"

echo "==> Backing up the database"
(cd backend && node -e "require('dotenv').config(); require('./src/utils/backupUtils').runBackup().then(r => console.log('   ', r.filename)).catch(e => { console.error('    Backup failed:', e.message); process.exit(1); })")

rollback() {
  # set -E passes this trap into ( … ) subshells too; only the script itself rolls back.
  if [ "$BASH_SUBSHELL" -gt 0 ]; then return; fi
  echo "!!> Deploy failed — going back to $PREVIOUS (the running version was not touched)"
  clear_pm2_config
  git checkout -q "$PREVIOUS"
  restore_pm2_config
  (cd backend && npm ci --silent) || true
  (cd frontend && npm ci --silent && npm run build --silent) || true
}
trap rollback ERR

checkout "$TARGET"
DEPLOYED="$(git describe --tags --exact-match 2>/dev/null || git rev-parse --short HEAD)"

if [ ! -f "$PM2_CONFIG" ]; then
  cp ecosystem.config.example.js "$PM2_CONFIG"
  echo "    Created $PM2_CONFIG from the example — check its app names and port."
fi

echo "==> Backend: install and migrate"
(cd backend && npm ci && npm run prisma:deploy)

echo "==> Frontend: install and build"
(cd frontend && npm ci && npm run build)

trap - ERR
echo "==> Reloading PM2"
pm2 reload "$PM2_CONFIG" --update-env

echo "==> Deployed $TARGET ($DEPLOYED)"