#!/usr/bin/env bash
# Launch the hsa-app binary with its environment loaded from an env file.
#
# Usage:
#   hsa-app.sh [ENV_FILE]
#
# ENV_FILE resolves to, in order: the first argument, then $HSA_ENV_FILE, then
# /etc/hsa-app/hsa-app.env. The binary defaults to ./hsa next to this script;
# override with $HSA_BIN (e.g. HSA_BIN=/usr/local/bin/hsa).
#
# Designed as a systemd ExecStart: it exports every KEY=VALUE in the env file and
# then exec's the binary, so the binary becomes the unit's main process (signals
# and exit codes propagate correctly). The env file should use ABSOLUTE paths for
# DB_PATH / STORAGE_DIR / BACKUP_DIR / CONFIG_PATH, since the app resolves relative
# paths from the working directory.
set -euo pipefail

ENV_FILE="${1:-${HSA_ENV_FILE:-/etc/hsa-app/hsa-app.env}}"
HERE="$(cd "$(dirname "$(readlink -f "$0")")" && pwd)"
BIN="${HSA_BIN:-$HERE/hsa}"

if [[ ! -r "$ENV_FILE" ]]; then
  echo "hsa-app: env file not found or unreadable: $ENV_FILE" >&2
  exit 1
fi
if [[ ! -x "$BIN" ]]; then
  echo "hsa-app: binary not found or not executable: $BIN" >&2
  exit 1
fi

# Export every assignment in the env file (KEY=VALUE lines; '#' comments and blank
# lines are fine). set -a marks all subsequently-set vars for export.
set -a
# shellcheck disable=SC1090
source "$ENV_FILE"
set +a

exec "$BIN"