# main function bound to scl command
_scl()
{
  local cur prev opts
  COMPREPLY=()

  cur="${COMP_WORDS[COMP_CWORD]}"
  prev="${COMP_WORDS[COMP_CWORD-1]}"
  opts="-l --list"

  # handle options
  if [[ ${cur} == -* ]] ; then
    COMPREPLY=( $(compgen -W "${opts}" -- ${cur}) )
    return 0
  fi

  # handle scriptlets; the first parameter must be a scriptlet if it is not an option
  if ((COMP_CWORD == 1)); then
    # get array of scriptlets found throughout collections
    local scriptlets=($(find /opt/rh/* -maxdepth 1 -type f -exec basename {} \; | sort -u))
    COMPREPLY=( $(compgen -W "${scriptlets[*]}" -- ${cur}) )
    return 0
  fi

  # handle commands; does not handle commands without single or double quotes
  if [[ ${cur} == \'* || ${cur} == \"* ]] ; then
    # it is a command do not reply with anything
    return 0
  fi

  # handle collections; if it is not an option or a command, it must be a collection
  local collections=($(find /etc/scl/prefixes -maxdepth 1 -mindepth 1 -type f -exec basename {} \; | sort -u))
  COMPREPLY=( $(compgen -W "${collections[*]}" -- ${cur}) )
  return 0
}

# bind the scl command to the _scl function for completion
complete -F _scl scl