script

#!/bin/bash

readonly SUBCOMMAND_PREFIX="subcommand"
readonly DESCRIPTION_PREFIX="desc"
readonly HELP_PREFIX="help"

function _main() {
  readonly SUBCOMMAND="$(echo "$1" | tr "-" "_")"

  if [[ -z "$SUBCOMMAND" ]] ; then
    _usage
    exit
  fi

  if ! type "${SUBCOMMAND_PREFIX}_${SUBCOMMAND}" &>/dev/null ; then
    _usage
    exit 1
  fi

  shift
  eval "${SUBCOMMAND_PREFIX}_${SUBCOMMAND} $@"
  exit $!
}

function _usage() {
  cat <<USAGE >&2

  ./script - one script to rule them all

subcommands:

$(_subcommands)

USAGE
}

function _subcommands() {
 for cmd in $(_cmd_list) ; do
   printf "  $cmd" | tr "_" "-"
   if type "${DESCRIPTION_PREFIX}_${cmd}" &>/dev/null ; then
     printf " $("${DESCRIPTION_PREFIX}_${cmd}")"
   fi
   echo
 done
}

function _cmd_list() {
  compgen -A function | \
    grep -vE "^_.*" | \
    grep "${SUBCOMMAND_PREFIX}" | \
    awk "/^${SUBCOMMAND_PREFIX}_\./{print;next}{sub(/^${SUBCOMMAND_PREFIX}_/,\"\",\$1);print}"
}

# help
function desc_help() { echo "<subcommand> \t- print help text for subcommand" ; }
function subcommand_help() {
  local subcommand="$(echo "$1" | tr "-" "_")"
  if type "${HELP_PREFIX}_${subcommand}" &>/dev/null ; then
    eval "${HELP_PREFIX}_${subcommand}"
  else
    echo "no help text available for subcommand \"$subcommand\""
  fi
}

# -h
function desc__h() { echo "\t\t\t- display this message and exit" ; }
function help__h() { cat <<HELP
This is example help text for the "-h/--help" commands.
HELP
}
function subcommand__h() {
  _usage
}

# --help
function desc___help() { echo "\t\t- display this message and exit" ; }
function help___help() { help__h ; }
function subcommand___help() { subcommand__h ; }

function desc_get() { echo "\t\t\t- download all dependencies" ; }
function help_get() { cat <<HELP

Downloads all dependencies via \`go get\`. Example args might include '-u -d -t'

Help text for \`go help get\`:

$(go help get 2>&1 | awk '{ print "  " $0}')
HELP
}
function subcommand_get() {
  go get "$@" ./...
}

function desc_install() { echo "\t\t- go install this library" ; }
function subcommand_install() {
  go install "$@" ./...
}

function desc_fmtpolice() { echo "\t\t- validate formatting using gofmt and golint" ; }
function help_fmtpolice() { cat <<HELP

Validate formatting using gofmt and golint.  Will download the fmpolice file to ./fmtpolice
if not already present, so please add "fmtpolice" to your \`.gitignore\`
HELP
}
function subcommand_fmtpolice() {
  if [[ ! -s fmtpolice ]] ; then
    curl -sLOf https://raw.githubusercontent.com/rafecolton/fmtpolice/master/fmtpolice
  fi
  bash fmtpolice
}

_main "$@" # this line must always be last