# TODO: refactor this mess
def _args_parse($args; $opts):
  def _parse($args; $flagmap; $r):
    def _parse_with_arg($new_args; $optname; $value; $opt):
      if $opt.object then
        ( ( $value
          | capture("^(?<key>.*?)=(?<value>.*)$")
          // error("\($value): should be key=value")
          ) as {$key, $value}
          # TODO: validate option name key
        | _parse($new_args; $flagmap; ($r | .parsed[$optname][$key] |= $value))
        )
      elif $opt.array then
        _parse($new_args; $flagmap; ($r | .parsed[$optname] += [$value]))
      elif $opt.pairs then
        _parse($new_args; $flagmap; ($r | .parsed[$optname] += [$value]))
      else
        _parse($new_args; $flagmap; ($r | .parsed[$optname] = $value))
      end;
    def _parse_without_arg($new_args; $optname):
      _parse($new_args; $flagmap; ($r | .parsed[$optname] = true));
    # this is to support --arg=VALUE
    ( ($args[0] | index("=")) as $assign_i
    | ( if $assign_i then $args[0][0:$assign_i]
        else $args[0]
        end
      ) as $arg
    | if $arg == null then
        $r
      else
        if $arg == "--" then
          $r | .rest += $args[1:]
        elif $arg | test("^--?[^-]") then
          ( $flagmap[$arg] as $optname
          | ($opts[$optname]? // null) as $opt
          | if $opt == null then
              if $arg | test("^-[^-]") then
                ( $arg[0:2] as $arg
                | $flagmap[$arg] as $optname
                | ($opts[$optname]? // null) as $opt
                | if $opt == null then
                    error("\($arg): no such argument")
                  elif $opt.bool then
                    _parse_without_arg((["-"+$args[0][2:]]+$args[1:]); $optname)
                  else
                    error("\($arg): needs an argument")
                  end
                )
              else
                error("\($arg): no such argument")
              end
            elif $opt.string or $opt.array or $opt.object then
              if $assign_i then
                _parse_with_arg($args[1:]; $optname; $args[0][$assign_i+1:]; $opt)
              elif ($args | length) < 2 then
                error("\($arg): needs an argument")
              else
                _parse_with_arg($args[2:]; $optname; $args[1]; $opt)
              end
            elif $opt.pairs then
              if ($args | length) > 2 then
                _parse_with_arg($args[3:]; $optname; [$args[1], $args[2]]; $opt)
              else
                error("\($arg): needs two argument")
              end
            else
              if $assign_i then error("\($arg): takes no argument")
              else _parse_without_arg($args[1:]; $optname)
              end
            end
          )
        else
          _parse($args[1:]; $flagmap; ($r | .rest += [$args[0]]))
        end
      end
    );
  # build {"-s": "name", "--long": "name", ...}
  def _flagmap:
    ( $opts
    | to_entries
    | map(
        ( . as $opt
        | [.value.short // empty] +
          [.value.long // empty] +
          (.value.aliases // [])
        | map({key: ., value: $opt.key})
        | from_entries
        )
      )
    | add
    );
  def _defaults:
    ( $opts
    | to_entries
    | map(select(.value.default))
    | map({(.key): .value.default})
    | add
    );
  _parse($args; _flagmap; {parsed: _defaults, rest: []});

def args_help_text($opts):
  def _opthelp:
    ( [ .long
      , .short
      ] | map(select(strings)) | join(",")
    ) +
    ( .string // .array // .object // .pairs
    | if . then " \(.)"
      else ""
      end
    );
  def _maxoptlen:
    [ $opts[]
    | (_opthelp | length)
    ] | max;
  def _obj_value:
      if . == null then ""
      elif (. | type) == "string" then tojson | .[1:-1]
      else .
      end;
  ( _maxoptlen as $l
  | $opts
  | to_entries
  | sort_by(.value.long)
  | .[]
  | (.value | .help_default // .default) as $default
  | [ "\(.value | _opthelp | rpad(" "; $l))  \(.value.description)"
    , if $default then
        if .value.object then
          [ "\n"
          , ( [$default | to_entries[] | "\(" "*$l)    \(.key)=\(.value | _obj_value)"]
            | join("\n")
            )
          ]
        else
          " (\($default))"
        end
      else
        empty
      end
    ]
  | flatten
  | join("")
  );