dotfiles/scripts/installs/prerequisites.sh

#!/usr/bin/env bash

######################################################################
# Core Dependency Install Script                                     #
######################################################################
# Installs essential pre-requsite packages, when using new systems   #
# Intended to be run before install.sh, if packages not yet present. #
# All other package installs are managed in system-specific scripts  #
# For docs and more info, see: https://github.com/lissy93/dotfiles   #
# IMPORTANT: Before running, read through everything very carefully! #
######################################################################
# Licensed under MIT (C) Alicia Sykes 2022 <https://aliciasykes.com> #
######################################################################

# List of apps to install
core_packages=(
  'git' # Needed to fetch dotfiles
  'vim' # Needed to edit files
  'zsh' # Needed as bash is crap
)

# Color variables
PURPLE='\033[0;35m'
YELLOW='\033[0;93m'
LIGHT='\x1b[2m'
RESET='\033[0m'

# Shows help menu / introduction
function print_usage () {
  echo -e "${PURPLE}Prerequisite Dependency Installation Script${LIGHT}\n"\
  "There's a few packages that are needed in order to continue with setting up dotfiles.\n"\
  "This script will detect distro and use appropriate package manager to install apps.\n"\
  "Elavated permissions may be required. Ensure you've read the script before proceeding."\
  "\n${RESET}"
}

function install_debian () {
  echo -e "${PURPLE}Installing ${1} via apt-get${RESET}"
  sudo apt install $1
}
function install_arch () {
  echo -e "${PURPLE}Installing ${1} via Pacman${RESET}"
  sudo pacman -S $1
}
function install_mac () {
  echo -e "${PURPLE}Installing ${1} via Homebrew${RESET}"
  brew install $1
}
function get_homebrew () {
  echo -e "${PURPLE}Setting up Homebrew${RESET}"
  /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
  export PATH=/opt/homebrew/bin:$PATH
}

# Detect OS type, then triggers install using appropriate package manager
function multi_system_install () {
  app=$1
  if [ "$(uname -s)" = "Darwin" ]; then
    if ! hash brew 2> /dev/null; then get_homebrew; fi
    install_mac $app # MacOS via Homebrew
  elif [ -f "/etc/arch-release" ] && hash pacman 2> /dev/null; then 
    install_arch $app # Arch Linux via Pacman
  elif ! [ -f "/etc/debian_version" ] && hash apt 2> /dev/null; then
    install_debian $app # Debian via apt-get
  else
    echo -e "${YELLOW}Skipping ${app}, as couldn't detect system type ${RESET}"
  fi
}

# Show usage instructions, help menu
print_usage
if [[ $* == *"--help"* ]]; then exit; fi

# Ask user if they'd like to proceed
if [[ ! $* == *"--auto-yes"* ]] ; then
  echo -e "${PURPLE}Are you happy to continue? (y/N)${RESET}"
  read -t 15 -n 1 -r
  echo
  if [[ ! $REPLY =~ ^[Yy]$ ]]; then
    echo -e "${YELLOW}Proceeding was rejected by user, exiting...${RESET}"
    exit 0
  fi
fi

# For each app, check if not present and install
for app in ${core_packages[@]}; do
  if ! hash "${app}" 2> /dev/null; then
    multi_system_install $app
  else
    echo -e "${YELLOW}${app} is already installed, skipping${RESET}"
  fi
done

# All done
echo -e "\n${PURPLE}Jobs complete, exiting${RESET}"
exit 0