defmodule DashboardWeb.HostsLive do
  @moduledoc """
  LiveView for real-time systant host monitoring.
  """
  use DashboardWeb, :live_view

  alias Phoenix.PubSub

  @pubsub_topic "systant:hosts"

  @impl true
  def mount(_params, _session, socket) do
    if connected?(socket) do
      # Subscribe to host updates from MQTT
      PubSub.subscribe(Dashboard.PubSub, @pubsub_topic)
    end

    # Start with empty hosts - will be populated by MQTT
    hosts = %{}

    socket = 
      socket
      |> assign(:hosts, hosts)
      |> assign(:page_title, "Systant Hosts")

    {:ok, socket}
  end

  @impl true
  def handle_info({:host_update, hostname, host_data}, socket) do
    require Logger
    Logger.info("LiveView received host update for #{hostname}: #{inspect(host_data)}")
    updated_hosts = Map.put(socket.assigns.hosts, hostname, host_data)
    {:noreply, assign(socket, :hosts, updated_hosts)}
  end


  @impl true
  def render(assigns) do
    ~H"""
    <div class="px-4 py-10 sm:px-6 sm:py-28 lg:px-8 xl:px-28 xl:py-32">
      <div class="mx-auto max-w-xl lg:mx-0 lg:max-w-3xl">
        <h1 class="text-brand mt-10 flex items-center text-sm font-semibold leading-6">
          <.icon name="hero-computer-desktop" class="h-4 w-4" />
          Systant Host Monitor
        </h1>
        <p class="text-[2rem] mt-4 font-semibold leading-10 tracking-tighter text-zinc-900">
          Real-time system monitoring across all hosts
        </p>
        <p class="mt-4 text-base leading-7 text-zinc-600">
          Live MQTT-powered dashboard showing statistics from all your systant-enabled hosts.
        </p>
        
        <div class="mt-10 grid gap-6">
          <%= if Enum.empty?(@hosts) do %>
            <div class="rounded-lg border border-zinc-200 p-8 text-center">
              <.icon name="hero-signal-slash" class="mx-auto h-12 w-12 text-zinc-400" />
              <h3 class="mt-4 text-lg font-semibold text-zinc-900">No hosts detected</h3>
              <p class="mt-2 text-sm text-zinc-600">
                Waiting for systant hosts to publish data via MQTT...
              </p>
            </div>
          <% else %>
            <%= for {hostname, host_data} <- @hosts do %>
              <.host_card hostname={hostname} data={host_data} />
            <% end %>
          <% end %>
        </div>
      </div>
    </div>
    """
  end

  attr :hostname, :string, required: true
  attr :data, :map, required: true

  defp host_card(assigns) do
    ~H"""
    <div class="rounded-lg border border-zinc-200 bg-white p-6 shadow-sm">
      <div class="flex items-center justify-between">
        <div class="flex items-center space-x-3">
          <div class="rounded-full bg-green-100 p-2">
            <.icon name="hero-server" class="h-5 w-5 text-green-600" />
          </div>
          <div>
            <h3 class="text-lg font-semibold text-zinc-900"><%= @hostname %></h3>
            <p class="text-sm text-zinc-600">
              Last seen: <%= format_datetime(@data["last_seen"]) %>
            </p>
          </div>
        </div>
        <div class="rounded-full bg-green-100 px-3 py-1">
          <span class="text-xs font-medium text-green-800">Online</span>
        </div>
      </div>
      
      <div class="mt-4">
        <h4 class="text-sm font-medium text-zinc-700 mb-2">Raw Data:</h4>
        <pre class="text-xs bg-zinc-50 p-3 rounded border overflow-x-auto">
          <%= Jason.encode!(@data, pretty: true) %>
        </pre>
      </div>
    </div>
    """
  end

  defp format_datetime(%DateTime{} = datetime) do
    Calendar.strftime(datetime, "%Y-%m-%d %H:%M:%S UTC")
  end

  defp format_datetime(_), do: "Unknown"
end