#!/usr/bin/env bash

function error_handler() {
  >&2 echo "Exited with BAD EXIT CODE '${2}' in ${0} script at line: ${1}."
  exit "$2"
}
trap 'error_handler ${LINENO} $?' ERR
set -o errtrace -o errexit -o nounset -o pipefail

# HELP: git adds and commits the entire BPMN models directory, including all process groups

bpmn_models_absolute_dir="$1"
git_commit_message="$2"
git_branch="$3"

if [[ -z "${3:-}" ]]; then
  >&2 echo "usage: $(basename "${0}") [bpmn_models_absolute_dir] [git_commit_message] [git_branch]"
  exit 1
fi

function failed_to_get_lock() {
  >&2 echo "ERROR: Failed to get lock."
  exit 1
}

function run() {
  # we are very careful not to run "cd" from python, since it is at the process level and will screw up other threads.
  # we are safe in this case because this entire script is run in a new process.
  cd "${bpmn_models_absolute_dir}"
  git add .

  # https://unix.stackexchange.com/a/155077/456630
  if [ -z "$(git status --porcelain)" ]; then
    echo "No changes to commit"
    return
  fi

  # FIXME: the environment variables may not be working with the root user which we are using in the docker container.
  # we see some evidence with this issue https://stackoverflow.com/questions/68975943/git-config-environment-variables
  # and it didn't seem to work for us either so set them like this for now.
  # One day we should probably not use the root user in the docker container.
  git config --local user.email "$GIT_COMMITTER_EMAIL"
  git config --local user.name "$GIT_COMMITTER_NAME"

  git commit -m "${git_commit_message}"
  git push --set-upstream origin "${git_branch}"
}

lock_directory="/var/lock"
if [[ ! -d "${lock_directory}" ]]; then
  lock_directory="/tmp"
fi

if ! command -v flock >/dev/null 2>&1; then
  if command -v brew >/dev/null 2>&1; then
    # some hero made this available on mac: https://github.com/discoteq/flock
    brew install flock
  else
    >&2 echo "ERROR: flock is not installed and we cannot install it."
    exit 1
  fi
fi

exec {lock_fd}>"${lock_directory}/spiffworkflow-git-lock" || failed_to_get_lock
flock --timeout 60 "${lock_fd}" || failed_to_get_lock
run
flock -u "${lock_fd}"