#!/usr/bin/env bash
# Meant to run via the HOST's system crontab on each environment's box (not
# inside a container) — Gitea lives on a separate machine, so rather than
# exposing an inbound webhook receiver on staging/production, each box just
# polls its branch and redeploys when it moves. Silent when there's nothing
# new, so it's safe to run every couple of minutes from cron.
#
# Example crontab line (staging box):
#   */2 * * * * /srv/bookstore/deploy/poll-deploy.sh staging >> /var/log/bookstore-deploy.log 2>&1
set -euo pipefail

ENVIRONMENT="${1:?Usage: poll-deploy.sh <staging|production>}"
REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
cd "$REPO_ROOT"

# A deploy (docker compose up --build + full WP/plugin install) can run
# longer than the cron interval on modest hardware, and the git
# checkout/reset below writes directly onto the live working tree that's
# bind-mounted into the running containers — a second poll firing mid-deploy
# would race the first one's file writes. Non-blocking: if one's already
# running, this run just skips (the next poll picks up wherever HEAD ends up),
# rather than queuing up concurrent deploys.
LOCK_FILE="${REPO_ROOT}/.poll-deploy-${ENVIRONMENT}.lock"
exec 200>"$LOCK_FILE"
if ! flock -n 200; then
  echo "$(date -Is) deploy already in progress for ${ENVIRONMENT}, skipping this poll"
  exit 0
fi

case "$ENVIRONMENT" in
  staging)    BRANCH=staging ;;
  production) BRANCH=main ;;
  *) echo "environment must be 'staging' or 'production'" >&2; exit 1 ;;
esac

BEFORE="$(git rev-parse HEAD)"
git fetch origin "$BRANCH" --quiet
AFTER="$(git rev-parse "origin/${BRANCH}")"

if [[ "$BEFORE" == "$AFTER" ]]; then
  exit 0
fi

echo "$(date -Is) deploying ${ENVIRONMENT} (${BRANCH}): ${BEFORE:0:7} -> ${AFTER:0:7}"
git checkout -f "$BRANCH"
git reset --hard "origin/${BRANCH}"
"$REPO_ROOT/deploy/deploy.sh" "$ENVIRONMENT"