#!/usr/bin/env bash
# Updates the Hub: back up the database, check out the release, install, migrate, build,
# restart PM2 and check it answers. If any step fails, it goes back to the previous version:
# the code, its dependencies and build, and the database too if new migrations had run.
#
# Usage (on the server, as the site user, from the repo folder):
#   bash scripts/deploy.sh            # the latest main
#   bash scripts/deploy.sh v1.2.0     # a tag (or any commit)
#
# Optional settings (environment variables):
#   HUB_BACKUP_DIR     where database dumps go (default ~/backups/events-hub; the newest 10 are kept)
#   HUB_PM2_BACKEND    PM2 name of the backend  (default events-hub-backend)
#   HUB_PM2_FRONTEND   PM2 name of the frontend (default events-hub-frontend)
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 "${HUB_DEPLOY_COPY:-}" ]; then
  COPY="$(mktemp)"
  cp "$0" "$COPY"
  HUB_DEPLOY_COPY=1 HUB_DEPLOY_DIR="$(cd "$(dirname "$0")/.." && pwd)" exec bash "$COPY" "$@"
fi
trap 'rm -f "$0"' EXIT

cd "$HUB_DEPLOY_DIR"
TARGET="${1:-main}"
BACKUP_DIR="${HUB_BACKUP_DIR:-$HOME/backups/events-hub}"
PM2_BACKEND="${HUB_PM2_BACKEND:-events-hub-backend}"
PM2_FRONTEND="${HUB_PM2_FRONTEND:-events-hub-frontend}"
FRONTEND_PORT=3200   # matches "start" in frontend/package.json

describe() { git describe --tags --exact-match 2>/dev/null || git rev-parse --short HEAD; }
PREVIOUS="$(git rev-parse HEAD)"
PREVIOUS_NAME="$(describe)"

if [ -n "$(git status --porcelain --untracked-files=no)" ]; then
  echo "!!> There are local changes to tracked files; deploy would overwrite them:"
  git status --short --untracked-files=no
  exit 1
fi

# The database URL from backend/.env, without Prisma-only options (pg_dump rejects ?schema=).
DB_URL="$(cd backend && node -e "require('dotenv').config(); const u = new URL(process.env.DATABASE_URL); u.search = ''; console.log(u.toString())")"
BACKEND_PORT="$(cd backend && node -e "require('dotenv').config(); console.log(process.env.PORT || 5200)")"

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

echo "==> Backing up the database"
mkdir -p "$BACKUP_DIR"
BACKUP="$BACKUP_DIR/events_hub-$(date +%Y%m%d-%H%M%S)-$PREVIOUS_NAME.dump"
pg_dump --dbname="$DB_URL" -Fc -f "$BACKUP"
echo "    $BACKUP"
ls -1t "$BACKUP_DIR"/events_hub-*.dump | tail -n +11 | xargs -r rm -f

MIGRATED=0
RESTARTED=0
rollback() {
  # set -E passes this trap into ( … ) subshells too; only the script itself rolls back.
  if [ "$BASH_SUBSHELL" -gt 0 ]; then return; fi
  trap - ERR
  set +e
  echo "!!> Deploy failed — going back to $PREVIOUS_NAME"
  git checkout -q -- . 2>/dev/null
  git checkout -q "$PREVIOUS"
  if [ "$MIGRATED" = 1 ]; then
    echo "!!> Restoring the database from $BACKUP"
    pg_restore --clean --if-exists --no-owner --single-transaction --dbname="$DB_URL" "$BACKUP" \
      || echo "!!> Restore failed. Restore by hand: pg_restore --clean --if-exists --no-owner -d \"<DATABASE_URL>\" $BACKUP"
  fi
  (cd backend && npm ci --silent)
  (cd frontend && npm ci --silent && npm run build --silent)
  if [ "$RESTARTED" = 1 ]; then pm2 restart "$PM2_BACKEND" "$PM2_FRONTEND" --update-env; fi
  echo "!!> Back on $PREVIOUS_NAME. Look at the output above for what failed."
  exit 1
}
trap rollback ERR

# A tag or commit as is; main as the latest origin/main (detached, so a local main is never
# in the way).
if [ "$TARGET" = "main" ]; then
  git fetch --quiet origin main
  git checkout -q --detach origin/main
else
  git fetch --tags --quiet origin
  git checkout -q "$TARGET"
fi
DEPLOYED="$(describe)"

echo "==> Backend: install, migrate and generate"
(cd backend && npm ci)
if [ -n "$(git diff --name-only "$PREVIOUS" HEAD -- backend/prisma/migrations)" ]; then MIGRATED=1; fi
(cd backend && npm run prisma:deploy)

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

echo "==> Restarting PM2"
RESTARTED=1
pm2 restart "$PM2_BACKEND" "$PM2_FRONTEND" --update-env

echo "==> Checking it answers"
check() {
  for _ in $(seq 1 30); do
    if curl -fsS -o /dev/null "$1"; then return 0; fi
    sleep 1
  done
  echo "!!> No answer from $1 after 30 seconds"
  return 1
}
check "http://127.0.0.1:$BACKEND_PORT/api/health"
check "http://127.0.0.1:$FRONTEND_PORT/"

trap - ERR
pm2 save --force >/dev/null
echo "==> Deployed $TARGET ($DEPLOYED). Backup: $BACKUP"