Setup the glow markdown viewer

setup_glow

#!/bin/bash

# Functionalise 'command -v' to allow 'if get_command [command]' idiom
get_command() { command -v "${1}" &>/dev/null; }

# TO-DO: Update environment to ensure a sane $ARCH variable
# This will allow us to make this portable to various arm implementations
setup_glow() {
  # If it's already present, there's nothing to do here
  if get_command glow; then
    printf -- '%s\n' "'glow' already exists in PATH"
    return 0
  fi

  # Otherwise, check for our required commands
  for command in curl jq; do
    if ! get_command "${command}"; then
      printf -- '%s\n' "setup_glow(): '${command}' required but not found in PATH"
      return 1
    fi
  done

  case "$(uname -s)" in
    (Darwin*)
      # OSX without 'brew'?  I don't need that kind of negativity in my life.
      if ! get_command brew; then
        printf -- '%s\n' "setup_glow(): 'brew' is required but not found in PATH"
        return 1
      else
        brew install charmbracelet/homebrew-tap/glow
      fi
    ;;
    ("Linux"|"linux-gnu"|"GNU"*)
      # Setup this helper function
      get_glow_target() {
        curl -s https://api.github.com/repos/charmbracelet/glow/releases/latest |
          jq -r --arg url_test "${1:?No target specified}" '
            .assets[] 
            | select(.browser_download_url | test($url_test)) 
            | .browser_download_url'
      }
      (
        cd /tmp || return 1
        if get_command dpkg; then
          target_url="$(get_glow_target linux_amd64.deb)"
          printf -- '%s\n' "Downloading ${target_url}..."
          curl -sLO "${target_url}"
          sudo dpkg -i glow_*_linux_amd64.deb
        elif get_command rpm; then
          target_url="$(get_glow_target linux_amd64.rpm)"
          printf -- '%s\n' "Downloading ${target_url}..."
          curl -sLO "${target_url}"
          sudo rpm -ivh glow_*_linux_amd64.rpm
        else
          target_url="$(get_glow_target linux_x86_64.tar.gz)"
          printf -- '%s\n' "Downloading ${target_url}..."
          curl -sLO "${target_url}"
          tar xzf glow_*_x86_64.tar.gz glow
          sudo install -g root -o root -m 755 glow /usr/local/bin
          rm -f glow
        fi
        rm -f glow_*_linux_*
      )
    ;;
  esac
}

setup_glow