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

if [[ $# -gt 1 ]]; then
  echo "Usage: $0 [path/to/.env]" >&2
  exit 2
fi

ENV_FILE="${1:-$(dirname "$0")/.env}"
if [[ ! -f "$ENV_FILE" ]]; then
  echo "Env file not found: $ENV_FILE" >&2
  exit 1
fi

# shellcheck disable=SC1090
source "$ENV_FILE"

required_vars=(
  RSYNC_SOURCE
  RSYNC_TARGET_DIR
  GIT_REPO_DIR
  COMMIT_MESSAGE_PREFIX
)

for var in "${required_vars[@]}"; do
  if [[ -z "${!var:-}" ]]; then
    echo "Missing required env var: $var" >&2
    exit 1
  fi
done

mkdir -p "$RSYNC_TARGET_DIR"

repo_abs="$(cd "$GIT_REPO_DIR" && pwd)"
target_abs="$(cd "$RSYNC_TARGET_DIR" && pwd)"

case "$target_abs" in
  "$repo_abs"/*) ;;
  *)
    echo "RSYNC_TARGET_DIR must be inside GIT_REPO_DIR" >&2
    exit 1
    ;;
esac

rel_target="${target_abs#"$repo_abs"/}"

if [[ -n "${RSYNC_RSH:-}" ]]; then
  rsync -az --delete -e "$RSYNC_RSH" "$RSYNC_SOURCE" "$RSYNC_TARGET_DIR/"
else
  rsync -az --delete "$RSYNC_SOURCE" "$RSYNC_TARGET_DIR/"
fi

git -C "$GIT_REPO_DIR" add -A -- "$rel_target"

if git -C "$GIT_REPO_DIR" diff --cached --quiet -- "$rel_target"; then
  exit 0
fi

timestamp="$(date '+%Y-%m-%d %H:%M:%S')"
git -C "$GIT_REPO_DIR" commit -m "$COMMIT_MESSAGE_PREFIX $timestamp" -- "$rel_target"