#!/usr/bin/env bash

## CONSTANTS

BASEDIR=$(dirname $0)

## FUNCTIONS

function assert_debian13 {
  test -f /etc/debian_version &&
    grep --quiet ^13\. /etc/debian_version ||
    echo "assert: Debian 13 missing!"
}

function assert_gnome_desktop {
  [[ $XDG_SESSION_DESKTOP == "gnome" ]] ||
    echo "assert: Gnome Shell missing!"
}

function install_ghostty {

  if ! command -v ghostty >/dev/null; then
    curl -sS https://debian.griffo.io/EA0F721D231FDD3A0A17B9AC7808B4DD62C41256.asc |
      sudo gpg --dearmor --yes -o /etc/apt/trusted.gpg.d/debian.griffo.io.gpg

    echo "deb https://debian.griffo.io/apt $(lsb_release -sc 2>/dev/null) main" |
      sudo tee /etc/apt/sources.list.d/debian.griffo.io.list

    sudo apt-get update &&
      sudo apt-get install -y ghostty
  else
    echo Ghostty already installed!
  fi

  if ! systemctl is-enabled --user --quiet app-com.mitchellh.ghostty; then
    systemctl enable --user app-com.mitchellh.ghostty.service
  else
    echo "Ghostty service already enabled!"
  fi
}

function install_homebrew {

  bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
}

function raise_error {
  message=${1:-an undefined error has occured!}
  code=${2:-1}
  echo "error ${code}: ${message}" >&2
  exit "${code}"
}

function set_alternative {
  local key command path_to_command path_to_key
  key=$1
  [[ -f /etc/alternatives/$key ]] || raise_error "alternative <${key}> not found!" 11

  path_to_key=$(readlink "/etc/alternatives/$key")

  command=$2
  path_to_command=$(command -v "${command}")

  if [[ "${path_to_key}" != "${path_to_command}" ]]; then
    echo "$key: $path_to_key != $path_to_command"
    sudo -vp 'sudo for update-alternatives: '
    sudo update-alternatives --install "/usr/bin/${key}" "${key}" "${path_to_command}" 100
    sudo update-alternatives --set "${key}" "${path_to_command}"
  else
    echo "alternative ${key} => ${command}"
  fi

}

function configure_default {
  # CAPS LOCK means ESC()
  gsettings set org.gnome.desktop.input-sources xkb-options "['caps:escape']"

  set_alternative editor nvim
  set_alternative vi nvim
  set_alternative vim nvim

  [[ ! -f $HOME/.vimrc ]] &&
    cp "$BASEDIR/resources/vimrc" "$HOME/.vimrc" ||
    echo vimrc defined!

  [[ ! -f $HOME/.config/nvim/init.vim ]] &&
    cp "$BASEDIR/resources/init.vim" "$HOME/.config/nvim/init.vim" ||
    echo nvim init.vim defined!

  [[ ! -f $HOME/.config/nvim-vanilla/init.vim ]] &&
    cp "$BASEDIR/resources/init.vim" "$HOME/.config/nvim-vanilla/init.vim" ||
    echo nvim-vanilla init.vim defined!
}

function install_neovim {
  local shellrc alias_expr
  shellrc="$HOME/.bashrc"
  if ! grep -q nvim-vanilla "$shellrc"; then
    alias_expr="alias nvim-vanilla='NVIM_APPNAME=nvim-vanilla nvim'"
    echo "$alias_expr" >>"$shellrc"
    eval "$alias_expr"
    echo 'nvim-vanilla created!'
  else
    echo 'nvim-vanilla ready!'
  fi
}
## MAIN
set -Eue

assert_debian13
assert_gnome_desktop

echo "MIAOU-DESKTOP installation..."

install_ghostty
# install_homebrew
install_neovim
configure_default
echo SUCCESS