#!/usr/bin/env bash

function print_help_and_exit() {
  cat <<EOF
Open a shell inside the docker container
Usage: docker_shell.sh [OPTIONS] [CONTAINER]

Options:
  -u,--user         The user to login with in the container (defaults to the current user)
  -c,--container    The container name (may also be specified as positional arg)
  -h,--help         Print this help message and exit

EOF
  exit "$1"
}


declare docker_user=""
declare cont_name=""

while [[ $# -gt 0 ]]; do
  case "$1" in
    -u)
      ;&
    --user)
      if [[ -z "$2" ]]; then
        echo "User (-u,--user) must be non-empty"
        print_help_and_exit 1
      fi
      docker_user="$2"
      shift 2
      ;;
    -h)
      ;&
    --help)
      print_help_and_exit 0
      ;;
    -c)
      ;&
    --container)
      shift 1
      ;&
    *)
      if [[ ! -z "$cont_name" ]]; then
        echo "Unexpected argument '$1'"
        print_help_and_exit 1
      fi
      cont_name="$1"
      shift 1
      ;;
  esac
done


if [[ -z "$cont_name" ]]; then
  echo "Please specify the container ([-c,--container])"
  print_help_and_exit 1
fi

if [[ -z "$docker_user" ]]; then
  docker_user="$USER"
fi

docker exec -u "$docker_user" -it "$cont_name" bash