#!/usr/bin/env bash
# shebang for syntax detection, not a command
# do *not* set executable!

declare -Ag _modules_

shopt -s expand_aliases
alias _args_='(( $# ))'
alias _to_args_='set --'

module.already_loaded () {
  declare -Ag _modules_
  [[ -v _modules_[${BASH_SOURCE[1]}] ]]
}

_blank_ () {
  [[ -z ${1:-} ]]
}

_defined_ () {
  [[ -v $1 ]]
}

_eq_ () {
  [[ $1 == "${2:-}" ]]
}

_functions_ () {
  env -i bash <<END
    shopt -s expand_aliases
    alias source=:
    \\source $1 &>/dev/null
    compgen -A function;:
END
}

_in_ () {
  [[ $IFS$1$IFS == *"$IFS$2$IFS"* ]]
}

_pop_ () {
  local -n ref1=$1
  local ref2=${2:-}

  _present_ $ref2 && printf -v $ref2 %s "${ref1[-1]}"
  unset -v $1[-1]
}

_present_ () {
  [[ -n ${1:-} ]]
}

_push_ () {
  local -n ref=$1

  ref+=( "$2" )
}

_parent_=${BASH_SOURCE[1]:-}

[[ ${1:-} != module ]] && return
set -- ${*:2}

_numargs_+=( $# )

{ ! _args_ && _present_ ${_file_:-} && _eq_ $_parent_ $_file_ ;} && return

{ ! _args_ && _present_ $_parent_ && ! _eq_ ${_parent_##*/} module ;} && {
  _in_ "${_ancestors_[*]:-}" $_parent_ && return
  _push_ _ancestors_ $_parent_
}

! _args_ && _to_args_ $_parent_

for _file_; do
  _module_=${_file_%%=*}
  _file_=${_file_#*=}

  _defined_ _modules_[$_file_] && continue

  _eq_ $_module_ $_file_ && {
    _module_=${_module_##*/}
    _module_=${_module_%.*}
  }

  _prefixes_+=( $_module_ )

  _push_ _aliases_ "$(alias)"
  unalias -a

  _functions_=$(_functions_ $_file_)

  for _function_ in $_functions_; do
    printf -v _prefix_ %s. ${_prefixes_[*]}
    alias $_function_=$_prefix_$_function_
  done

  _push_ _files_ $_file_
  _push_ _funcs_ "$_functions_"

  set --
  source $_file_

  unset -v _prefixes_[-1]

  _pop_ _files_ _file_
  _pop_ _funcs_ _functions_

  _modules_[$_file_]=''

  for _function_ in $_functions_; do
    unalias $_function_
  done

  eval "${_aliases_[-1]}"
  _pop_ _aliases_
done

! (( ${#_files_[*]} )) && {
  unalias _args_
  unalias _to_args_
  unset -f _blank_
  unset -f _defined_
  unset -f _eq_
  unset -f _in_
  unset -f _pop_
  unset -f _present_
  unset -f _push_
  unset -v _file_
  unset -v _funcs_
  unset -v _function_
  unset -v _functions_
  unset -v _module_
  unset -v _name_
  unset -v _parent_
  unset -v _prefix_
  unset -v _prefixes_
}
{ ! (( _numargs_[-1] )) && [[ -n ${BASH_SOURCE[1]} && ${BASH_SOURCE[1]##*/} != module ]] ;} && unset -v _ancestors_[-1]
unset -v _numargs_[-1]