#!/usr/bin/env bash
set -Eeuo pipefail

DOTFILES_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
BACKUP_ROOT="${HOME}/.dotfiles-backup/$(date +%Y%m%d-%H%M%S)"
INSTALL_PACKAGES=true
DRY_RUN=false

PACKAGES=(
  sway swaybg swaylock waybar wofi kitty jq curl btop
  greetd greetd-tuigreet
  zsh neovim git base-devel
  grim slurp wl-clipboard mako libnotify brightnessctl playerctl
  pipewire pipewire-pulse wireplumber pavucontrol
  network-manager-applet polkit-gnome xdg-desktop-portal-wlr
  noto-fonts noto-fonts-emoji ttf-jetbrains-mono-nerd
)

usage() {
  cat <<'EOF'
Usage: ./install.sh [--no-packages] [--dry-run] [--help]

  --no-packages  Skip pacman package installation
  --dry-run      Print actions without changing anything
  --help         Show this help
EOF
}

log() { printf '\033[1;34m==>\033[0m %s\n' "$*"; }
run() {
  if "$DRY_RUN"; then printf '    '; printf '%q ' "$@"; printf '\n';
  else "$@"; fi
}

while (($#)); do
  case "$1" in
    --no-packages) INSTALL_PACKAGES=false ;;
    --dry-run) DRY_RUN=true ;;
    --help|-h) usage; exit 0 ;;
    *) printf 'Unknown option: %s\n' "$1" >&2; usage >&2; exit 2 ;;
  esac
  shift
done

link_path() {
  local source=$1 target=$2 relative backup
  if [[ -L "$target" && "$(readlink -f -- "$target")" == "$(readlink -f -- "$source")" ]]; then
    log "Already linked: $target"
    return
  fi
  if [[ -e "$target" || -L "$target" ]]; then
    relative=${target#"${HOME}/"}
    backup="${BACKUP_ROOT}/${relative}"
    log "Backing up $target -> $backup"
    run mkdir -p -- "$(dirname -- "$backup")"
    run mv -- "$target" "$backup"
  fi
  run mkdir -p -- "$(dirname -- "$target")"
  log "Linking $target -> $source"
  run ln -s -- "$source" "$target"
}

install_system_file() {
  local source=$1 target=$2 relative backup
  if [[ -r "$target" ]] && cmp -s -- "$source" "$target"; then
    log "Already installed: $target"
    return
  fi
  if [[ -e "$target" ]]; then
    relative=${target#/}
    backup="${BACKUP_ROOT}/${relative}"
    log "Backing up $target -> $backup"
    run mkdir -p -- "$(dirname -- "$backup")"
    run sudo cp -- "$target" "$backup"
  fi
  log "Installing $target"
  run sudo install -Dm644 -- "$source" "$target"
}

if "$INSTALL_PACKAGES"; then
  command -v pacman >/dev/null || { echo 'pacman was not found; use --no-packages on non-Arch systems.' >&2; exit 1; }
  log "Installing Arch packages"
  run sudo pacman -Syu --needed "${PACKAGES[@]}"

  if ! command -v yay >/dev/null; then
    log "Installing yay from the AUR"
    if "$DRY_RUN"; then
      printf '    git clone https://aur.archlinux.org/yay.git <temporary-directory>/yay\n'
      printf '    cd <temporary-directory>/yay && makepkg -si --noconfirm\n'
    else
      YAY_BUILD_DIR=$(mktemp -d)
      git clone https://aur.archlinux.org/yay.git "$YAY_BUILD_DIR/yay"
      (
        cd "$YAY_BUILD_DIR/yay"
        makepkg -si --noconfirm
      )
      rm -rf -- "$YAY_BUILD_DIR"
      unset YAY_BUILD_DIR
    fi
  fi

  install_system_file "$DOTFILES_DIR/system/greetd/config.toml" /etc/greetd/config.toml
  log "Enabling greetd"
  run sudo systemctl enable greetd.service
fi

for source in "$DOTFILES_DIR"/config/*; do
  [[ -e "$source" ]] || continue
  link_path "$source" "$HOME/.config/$(basename -- "$source")"
done
for source in "$DOTFILES_DIR"/home/.[!.]* "$DOTFILES_DIR"/home/..?*; do
  [[ -e "$source" ]] || continue
  link_path "$source" "$HOME/$(basename -- "$source")"
done

if [[ "${SHELL:-}" != */zsh ]]; then
  log "Zsh is installed. Run 'chsh -s /bin/zsh' to make it your login shell."
fi
log "Installation complete. Reload Sway with Alt+Shift+r."