#!/bin/sh

# GOHAN
#
# My Arch Linux installation script
# by David T. Sadler <david@davidtsadler.com>
# License: GNU GPLv3

### OPTIONS AND VARIABLES ###

### FUNCTIONS ###

install_from_pacman() {
  pacman --noconfirm --needed -S "$1" >/dev/null 2>&1
}

install_from_repo() {
  progname="$(basename "$1" .git)"
  dir="$3/$progname"

  [ -d "$dir" ] || git clone "$1" "$dir" >/dev/null 2>&1
}

# Install packages required by GOHAN.
install_dependancies() {
  echo "Installing dependancies ..."

  install_from_pacman base-devel
  install_from_pacman git
  install_from_pacman go
}

add_user() {
  get_username_and_password

  if [ -d "/home/$name" ]; then
    echo "Skipping adding of user as $name already exists."
  else
    echo "Adding user $name ..."
    useradd -m -s /bin/zsh "$name" >/dev/null 2>&1
    mkdir -p /home/"$name"
    chown "$name":"$name" /home/"$name"
    usermod -aG wheel "$name"
    echo "$name:$pass1" | chpasswd
  fi

  unset pass1 pass2
}

read_password() {
  PASSWORD="$(
    # always read from the tty even when redirected:
    exec < /dev/tty || exit # || exit only needed for bash

    # save current tty settings:
    tty_settings=$(stty -g) || exit

    # schedule restore of the settings on exit of that subshell
    # or on receiving SIGINT or SIGTERM:
    trap 'stty "$tty_settings"' EXIT INT TERM

    # disable terminal local echo
    stty -echo || exit

    # prompt on tty
    printf "$1" > /dev/tty

    # read password as one line, record exit status
    IFS= read -r password; ret=$?

    # display a newline to visually acknowledge the entered password
    echo > /dev/tty

    # return the password for $REPLY
    printf '%s\n' "$password"
    exit "$ret"
  )"
}

get_username_and_password() {
  printf "Enter a name for the user account: "
  read name
  while ! echo "$name" | grep "^[a-z_][a-z0-9_-]*$" >/dev/null 2>&1; do
    unset name
    printf "Username not valid. Give a username beginning with a letter, with only lowercase letters, - or _.\n\n"
    printf "Enter a name for the user account: "
    read name
  done

  read_password "Enter a password for that user: "
  pass1=$PASSWORD
  read_password "Retype password: "
  pass2=$PASSWORD

  while ! [ "$pass1" = "$pass2" ]; do
    unset pass2
    echo "Passwords do not match."
    read_password "Enter a password again: "
    pass1=$PASSWORD
    read_password "Retype password: "
    pass2=$PASSWORD
  done

  unset PASSWORD
}

configure_sudo() {
  install_from_pacman sudo
  [ -f "/etc/sudoers.d/$name" ] || echo "$name ALL=(ALL) NOPASSWD: ALL" > "/etc/sudoers.d/$name"
}

# Sets up the home directory for the user account.
setup_user_home_directory() {
  echo "Setting up user home directory ..."

  clean_user_home_directory
}

# Remove un-needed files and directories from the home directory.
clean_user_home_directory() {
  [ -f "/home/$name/.bash_history" ] && rm /home/$name/.bash_history
  [ -f "/home/$name/.bash_logout" ] && rm /home/$name/.bash_logout
  [ -f "/home/$name/.bash_profile" ] && rm /home/$name/.bash_profile
  [ -f "/home/$name/.bashrc" ] && rm /home/$name/.bashrc
}

install_yay() {
  [ -f "/usr/bin/yay" ] || (
    echo "Installing yay ..."
    # Use all cores for compilation.
    sed -i "s/-j2/-j$(nproc)/;s/^#MAKEFLAGS/MAKEFLAGS/" /etc/makepkg.conf
    cd /tmp
    rm -rf /tmp/yay
    git clone https://aur.archlinux.org/yay.git
    chown -R "$name":"$name" yay
    cd yay
    sudo -u "$name" makepkg --noconfirm -si >/dev/null 2>&1
    cd /tmp
    rm -rf /tmp/yay
  );
}

install_packages() {
  curl -Ls https://git.davidtsadler.com/gohan/plain/packages.csv?h=version-1.0.0 > /tmp/packages.csv
  total=$(wc -l < /tmp/packages.csv)
  while IFS=, read -r tag program comment; do
    n=$((n+1))
    echo "$comment" | grep "^\".*\"$" >/dev/null 2>&1 && comment="$(echo "$comment" | sed "s/\(^\"\|\"$\)//g")"
    case "$tag" in
      "A") install_from_aur "$program" "$comment" ;;
      "G") install_repo "$program" "$comment" "/usr/local/src" ;;
      "#Tag") ;;
      *) install_package "$program" "$comment" ;;
    esac
  done < /tmp/packages.csv
  rm /tmp/packages.csv
}

install_package() {
  printf  "Installing \`$1\` ($n of $total). $1 $2\n"
  install_from_pacman "$1"
}

install_from_aur() {
  printf "Installing \`$1\` ($n of $total) from the AUR. $1 $2\n"
  sudo -u "$name" yay -S --noconfirm "$1" >/dev/null 2>&1
}

install_repo() {
  progname="$(basename "$1" .git)"
  dir="$3/$progname"

  printf "Installing \`$progname\` ($n of $total) via \`git\` and \`make\`. $(basename "$1") $2\n"

  install_from_repo $1 $2 $3

  [ -d "$dir" ] || (
    cd "$dir"
    make clean install >/dev/null 2>&1
  )
}

### THE ACTUAL SCRIPT ###

install_dependancies

add_user

configure_sudo

setup_user_home_directory

install_yay

install_packages