defmodule ToweropsWeb.MobileQRLive do
  @moduledoc """
  LiveView for displaying QR code for mobile app authentication.

  Shows a QR code containing a temporary token that can be scanned by the mobile app.
  Automatically polls to detect when the token has been used and shows success message.
  """
  use ToweropsWeb, :live_view

  alias Towerops.MobileSessions

  @impl true
  def mount(_params, _session, socket) do
    user = socket.assigns.current_scope.user

    # Create QR login token
    {:ok, qr_token} = MobileSessions.create_qr_login_token(user.id)

    # Start polling to check if token has been completed
    timer_ref =
      if connected?(socket) do
        schedule_check()
      end

    socket =
      socket
      |> assign(:page_title, t("Mobile App"))
      |> assign(:qr_token, qr_token)
      |> assign(:completed, false)
      |> assign(:mobile_session, nil)
      |> assign(:timer_ref, timer_ref)

    {:ok, socket}
  end

  @impl true
  def handle_info(:check_completion, socket) do
    token = socket.assigns.qr_token.token

    case MobileSessions.check_qr_login_completed(token) do
      nil ->
        # Not completed yet, check if expired
        if DateTime.after?(DateTime.utc_now(), socket.assigns.qr_token.expires_at) do
          # Token expired, create a new one
          user = socket.assigns.current_scope.user
          {:ok, qr_token} = MobileSessions.create_qr_login_token(user.id)

          timer_ref = schedule_check()

          socket =
            socket
            |> assign(:qr_token, qr_token)
            |> assign(:timer_ref, timer_ref)
            |> put_flash(:info, t("QR code expired, generated a new one"))

          {:noreply, socket}
        else
          # Still valid, check again
          timer_ref = schedule_check()
          {:noreply, assign(socket, :timer_ref, timer_ref)}
        end

      mobile_session ->
        # Token was completed! Cancel timer since we're done
        cancel_timer(socket.assigns.timer_ref)

        socket =
          socket
          |> assign(:completed, true)
          |> assign(:mobile_session, mobile_session)
          |> assign(:timer_ref, nil)
          |> put_flash(:info, t("Mobile device authenticated successfully!"))

        {:noreply, socket}
    end
  end

  # Catch-all for unexpected messages
  @impl true
  def handle_info(_msg, socket), do: {:noreply, socket}

  @impl true
  def terminate(_reason, socket) do
    cancel_timer(socket.assigns[:timer_ref])
    :ok
  end

  defp schedule_check do
    Process.send_after(self(), :check_completion, 2000)
  end

  defp cancel_timer(nil), do: :ok

  defp cancel_timer(timer_ref) when is_reference(timer_ref) do
    Process.cancel_timer(timer_ref)
    :ok
  end

  # Generate QR code data URL using qrcode.show API (public service)
  defp qr_code_url(token) do
    # Base URL for the mobile app to handle the token
    # In production, this would be your custom URL scheme like towerops://qr-login?token=...
    # For now, we'll just use the token directly
    data = URI.encode(token)
    "https://qrcode.tec-it.com/API/QRCode?data=#{data}&backcolor=%23ffffff"
  end

  @impl true
  def render(assigns) do
    ~H"""
    <Layouts.authenticated flash={@flash} current_scope={@current_scope}>
      <div class="mx-auto max-w-4xl">
        <.header>
          Link Mobile App
          <:subtitle>
            Scan this QR code with the Towerops app on your phone to link it to your account
          </:subtitle>
        </.header>

        <div :if={!@completed} class="mt-8">
          <div class="rounded-lg bg-white p-8 shadow-sm ring-1 ring-gray-200 dark:bg-gray-800/50 dark:ring-white/10">
            <div class="flex flex-col items-center space-y-6">
              <div class="rounded-lg bg-white p-4">
                <img
                  src={qr_code_url(@qr_token.token)}
                  alt="QR Code for mobile login"
                  class="h-64 w-64"
                />
              </div>

              <div class="text-center">
                <p class="text-xs text-gray-500 dark:text-gray-400">
                  This QR code expires in 5 minutes
                </p>
              </div>

              <div class="flex items-center space-x-2">
                <div class="h-2 w-2 animate-pulse rounded-full bg-blue-500"></div>
                <span class="text-sm text-gray-600 dark:text-gray-400">
                  Waiting for mobile app to scan...
                </span>
              </div>
            </div>
          </div>

          <div class="mt-6 rounded-lg bg-white p-6 shadow-sm ring-1 ring-gray-200 dark:bg-gray-800/50 dark:ring-white/10">
            <h3 class="text-sm font-semibold text-gray-900 dark:text-white">
              How to link your phone
            </h3>
            <ol class="mt-4 space-y-3">
              <li class="flex items-start gap-3">
                <span class="flex h-6 w-6 shrink-0 items-center justify-center rounded-full bg-indigo-600 text-xs font-bold text-white">
                  1
                </span>
                <span class="text-sm text-gray-600 dark:text-gray-400">
                  Open the <span class="font-medium text-gray-900 dark:text-white">Towerops</span>
                  app on your iPhone
                </span>
              </li>
              <li class="flex items-start gap-3">
                <span class="flex h-6 w-6 shrink-0 items-center justify-center rounded-full bg-indigo-600 text-xs font-bold text-white">
                  2
                </span>
                <span class="text-sm text-gray-600 dark:text-gray-400">
                  Tap <span class="font-medium text-gray-900 dark:text-white">"Scan QR Code"</span>
                  on the login screen
                </span>
              </li>
              <li class="flex items-start gap-3">
                <span class="flex h-6 w-6 shrink-0 items-center justify-center rounded-full bg-indigo-600 text-xs font-bold text-white">
                  3
                </span>
                <span class="text-sm text-gray-600 dark:text-gray-400">
                  Point your camera at the QR code above
                </span>
              </li>
            </ol>
          </div>

          <div class="mt-4 rounded-lg bg-blue-50 p-4 dark:bg-blue-900/20">
            <div class="flex">
              <div class="flex-shrink-0">
                <.icon name="hero-information-circle" class="h-5 w-5 text-blue-400" />
              </div>
              <div class="ml-3">
                <h3 class="text-sm font-medium text-blue-800 dark:text-blue-300">
                  Don't have the app yet?
                </h3>
                <p class="mt-1 text-sm text-blue-700 dark:text-blue-400">
                  Download Towerops from the App Store on your iPhone.
                </p>
              </div>
            </div>
          </div>
        </div>

        <div :if={@completed} class="mt-8">
          <div class="rounded-lg bg-green-50 p-8 shadow-sm ring-1 ring-green-200 dark:bg-green-900/20 dark:ring-green-700">
            <div class="flex flex-col items-center space-y-4">
              <div class="flex h-16 w-16 items-center justify-center rounded-full bg-green-100 dark:bg-green-900">
                <.icon name="hero-check" class="h-10 w-10 text-green-600 dark:text-green-400" />
              </div>

              <div class="text-center">
                <h3 class="text-lg font-semibold text-green-900 dark:text-green-100">
                  Mobile Device Authenticated!
                </h3>
                <p class="mt-2 text-sm text-green-700 dark:text-green-300">
                  Your mobile device has been successfully authenticated.
                </p>
              </div>

              <div class="mt-4 w-full max-w-md rounded-lg bg-white p-4 dark:bg-gray-800/50">
                <dl class="space-y-2 text-sm">
                  <div>
                    <dt class="font-medium text-gray-700 dark:text-gray-300">Device Name</dt>
                    <dd class="mt-1 text-gray-900 dark:text-white">
                      {@mobile_session.device_name || "Unknown"}
                    </dd>
                  </div>
                  <div>
                    <dt class="font-medium text-gray-700 dark:text-gray-300">Device OS</dt>
                    <dd class="mt-1 text-gray-900 dark:text-white">
                      {@mobile_session.device_os || "Unknown"}
                    </dd>
                  </div>
                  <div>
                    <dt class="font-medium text-gray-700 dark:text-gray-300">App Version</dt>
                    <dd class="mt-1 text-gray-900 dark:text-white">
                      {@mobile_session.app_version || "Unknown"}
                    </dd>
                  </div>
                </dl>
              </div>

              <.link
                navigate={~p"/users/settings"}
                class="text-sm font-medium text-blue-600 hover:text-blue-500 dark:text-blue-400"
              >
                Manage mobile sessions →
              </.link>
            </div>
          </div>
        </div>

        <div class="mt-6">
          <.link
            navigate={~p"/orgs"}
            class="text-sm font-medium text-gray-600 hover:text-gray-900 dark:text-gray-400 dark:hover:text-white"
          >
            ← Back to Organizations
          </.link>
        </div>
      </div>
    </Layouts.authenticated>
    """
  end
end