#!/usr/bin/env bash
set -Eeuo pipefail

deploy_root="${1:?deployment root is required}"
release_id="${2:?release id is required}"
archive="${3:?release archive is required}"

if [[ "$deploy_root" != /* || "$deploy_root" == "/" ]]; then
  echo "DEPLOY_PATH must be an absolute directory other than /." >&2
  exit 2
fi

if [[ ! "$release_id" =~ ^[0-9a-f]{7,64}$ ]]; then
  echo "The release id must be a Git commit SHA." >&2
  exit 2
fi

if [[ ! -f "$archive" ]]; then
  echo "Release archive not found: $archive" >&2
  exit 2
fi

releases_dir="$deploy_root/releases"
release_dir="$releases_dir/$release_id"
current_link="$deploy_root/current"
staging_dir="$releases_dir/.incoming-$release_id-$$"

cleanup() {
  rm -f -- "$archive"
  if [[ -d "$staging_dir" ]]; then
    rm -rf -- "$staging_dir"
  fi
}
trap cleanup EXIT

mkdir -p -- "$releases_dir"

if [[ ! -d "$release_dir" ]]; then
  mkdir -- "$staging_dir"
  tar -xzf "$archive" -C "$staging_dir"
  mv -- "$staging_dir" "$release_dir"
fi

if [[ ! -f "$release_dir/compose.yaml" ]]; then
  echo "The release does not contain compose.yaml." >&2
  exit 2
fi

previous_release=""
if [[ -L "$current_link" ]]; then
  previous_release="$(readlink -f -- "$current_link" || true)"
fi

compose() {
  local directory="$1"
  shift
  docker compose \
    --project-name portfolio \
    --file "$directory/compose.yaml" \
    "$@"
}

wait_until_healthy() {
  local directory="$1"
  local container_id status

  container_id="$(compose "$directory" ps -q portfolio-app)"
  if [[ -z "$container_id" ]]; then
    echo "The portfolio-app container was not created." >&2
    return 1
  fi

  for _ in {1..30}; do
    status="$(docker inspect --format '{{if .State.Health}}{{.State.Health.Status}}{{else}}{{.State.Status}}{{end}}' "$container_id")"
    case "$status" in
      healthy|running)
        return 0
        ;;
      unhealthy|exited|dead)
        echo "Container entered state: $status" >&2
        return 1
        ;;
    esac
    sleep 2
  done

  echo "Container did not become healthy within 60 seconds." >&2
  return 1
}

deploy() {
  local directory="$1"
  compose "$directory" config --quiet
  compose "$directory" up --detach --build --remove-orphans
  wait_until_healthy "$directory"
}

if deploy "$release_dir"; then
  new_link="$deploy_root/.current-$release_id-$$"
  ln -s -- "$release_dir" "$new_link"
  mv -Tf -- "$new_link" "$current_link"
  echo "Deployment succeeded: $release_id"
  exit 0
fi

echo "Deployment failed; attempting rollback." >&2
if [[ -n "$previous_release" && -f "$previous_release/compose.yaml" ]]; then
  deploy "$previous_release"
  echo "Rollback succeeded: $(basename "$previous_release")" >&2
else
  echo "No previous release is available to roll back to." >&2
fi

exit 1