# shellcheck shell=bash

usage() {
  echo "Usage: $0 flake -m install|repair -h host [-k key] [-p password_file] [-c] [-r]"
  echo
  echo "Options:"
  echo "  flake               Directory containing the flake.nix file."
  echo "  -m mode             Mode: 'install' or 'repair'."
  echo "  -h host             Host to configure."
  echo "  -k key              Key file to copy to user config."
  echo "  -p password_file    LUKS password file to use for encryption."
  echo "  -c                  Copy configuration to target."
  echo "  -r                  Reboot after completion."
  exit 1
}

check_root() {
  if [[ "$EUID" -ne 0 ]]; then
    echo "Please run the script as root."
    exit 1
  fi
}

check_network() {
  if ! ping -c 1 google.com &>/dev/null; then
    echo "Connect to a network before proceeding."
    exit 1
  fi
}

check_flake() {
  if [[ ! -f "$flake/flake.nix" ]]; then
    echo "flake.nix not found in $flake."
    exit 1
  fi
}

check_host() {
  if ! nix flake show --quiet --json "$flake" 2>/dev/null | jq -e ".nixosConfigurations[\"$host\"]" &>/dev/null; then
    echo "Host '$host' not found in flake."
    exit 1
  fi
}

check_key() {
  if [[ -n "$key" ]] && [[ ! -f "$flake/secrets/$key/key.txt" ]]; then
    echo "Key '$key' not found."
    exit 1
  fi
}

set_password_file() {
  if [[ -n "$password_file" ]]; then
    if [[ ! -f "$password_file" ]]; then
      echo "LUKS key file '$password_file' not found."
      exit 1
    fi

    ln -sf "$(realpath "$password_file")" /tmp/installer.key
  else
    echo "Enter password for LUKS encryption:"
    IFS= read -r -s password
    echo "Enter password again to confirm: "
    IFS= read -r -s password_check
    [ "$password" != "$password_check" ]
    echo -n "$password" > /tmp/installer.key
    unset password password_check
  fi
}

prepare_disk() {
  local disko_mode="$1"
  mkdir -p /mnt
  root=$(mktemp -d /mnt/install.XXXXXX)
  disko -m "$disko_mode" --yes-wipe-all-disks --root-mountpoint "$root" "$flake/hosts/$host/format.nix"
}

copy_keys() {
  mkdir -p "$root/persist/etc/ssh"
  cp "$flake/hosts/$host/secrets/ssh_host_ed25519_key" "$root/persist/etc/ssh/ssh_host_ed25519_key"

  for path in "$flake/hosts/$host/users"/*; do
    if [[ -z "$key" ]]; then
      continue
    fi

    local user
    user=$(basename "$path")
    mkdir -p "$root/persist/home/$user/.config/sops-nix"
    cp "$flake/secrets/$key/key.txt" "$root/persist/home/$user/.config/sops-nix/key.txt"
    chown -R "$(cat "$flake/hosts/$host/users/$user/uid"):100" "$root/persist/home/$user"
  done
}

install() {
  nixos-install --root "$root" --flake "$flake#$host" --no-root-passwd
}

copy_config() {
  echo "Copying configuration..."
  rm -rf "$root/persist/etc/nixos"
  cp -r "$flake" "$root/persist/etc/nixos"
}

finish() {
  echo "Rebooting system..."
  trap - EXIT
  cleanup
  reboot
}

cleanup() {
  rm -f /tmp/installer.key
  if [[ -n "$host" ]]; then disko -m "unmount" "$flake/hosts/$host/format.nix"; fi
  if [[ -d "$root" ]]; then rmdir "$root"; fi
}

check_root
check_network

if [[ "$#" -lt 1 ]]; then
  usage
fi

flake="$(realpath "$1")"
check_flake
shift

mode=""
host=""
key=""
password_file=""
copy_config_flag="false"
reboot_flag="false"

while getopts "m:h:k:p:cr" opt; do
  case "$opt" in
    m) mode="$OPTARG" ;;
    h) host="$OPTARG" ;;
    k) key="$OPTARG" ;;
    p) password_file="$OPTARG" ;;
    c) copy_config_flag="true" ;;
    r) reboot_flag="true" ;;
    *) usage ;;
  esac
done

if [[ -z "$mode" || -z "$host" ]]; then
  usage
fi

check_host
check_key
until set_password_file; do echo "Passwords did not match, please try again."; done

case "$mode" in
  install)
    prepare_disk "destroy,format,mount"
    copy_keys
    install
    if [[ "$copy_config_flag" == "true" ]]; then copy_config; fi
    if [[ "$reboot_flag" == "true" ]]; then finish; fi
    ;;
  repair)
    prepare_disk "mount"
    install
    if [[ "$reboot_flag" == "true" ]]; then finish; fi
    ;;
  *)
    echo "Invalid mode: $mode"
    usage
    ;;
esac