defmodule MicrowavepropWeb.BackfillLive do
  @moduledoc false
  use MicrowavepropWeb, :live_view

  import Ecto.Query

  alias Microwaveprop.Radio.Contact
  alias Microwaveprop.Repo
  alias Microwaveprop.Workers.ContactWeatherEnqueueWorker

  @refresh_interval 2_000

  @impl true
  def mount(_params, _session, socket) do
    if connected?(socket) do
      Process.send_after(self(), :refresh_stats, @refresh_interval)
    end

    stats = fetch_stats()
    unprocessed = count_unprocessed()

    {:ok,
     assign(socket,
       page_title: "Backfill",
       limit: 500,
       stats: stats,
       unprocessed: unprocessed,
       last_enqueued: nil,
       enqueuing: false
     )}
  end

  @impl true
  def handle_event("enqueue", %{"limit" => limit_str}, socket) do
    limit = String.to_integer(limit_str)

    # Run in a task to not block the LiveView
    pid = self()

    Task.start(fn ->
      count = enqueue_batch(limit)
      send(pid, {:enqueued, count})
    end)

    {:noreply, assign(socket, enqueuing: true)}
  end

  @impl true
  def handle_info({:enqueued, count}, socket) do
    {:noreply,
     assign(socket,
       last_enqueued: count,
       enqueuing: false,
       stats: fetch_stats(),
       unprocessed: count_unprocessed()
     )}
  end

  def handle_info(:refresh_stats, socket) do
    Process.send_after(self(), :refresh_stats, @refresh_interval)

    {:noreply,
     assign(socket,
       stats: fetch_stats(),
       unprocessed: count_unprocessed()
     )}
  end

  defp enqueue_batch(limit) do
    contacts =
      from(c in Contact,
        where:
          not is_nil(c.pos1) and
            (c.hrrr_queued == false or c.weather_queued == false or
               c.terrain_queued == false or c.iemre_queued == false),
        order_by: [desc: c.qso_timestamp],
        limit: ^limit
      )
      |> Repo.all()

    Enum.each(contacts, &ContactWeatherEnqueueWorker.enqueue_for_contact/1)
    length(contacts)
  end

  defp count_unprocessed do
    Repo.one(
      from(c in Contact,
        where:
          not is_nil(c.pos1) and
            (c.hrrr_queued == false or c.weather_queued == false or
               c.terrain_queued == false or c.iemre_queued == false),
        select: count(c.id)
      )
    )
  end

  defp fetch_stats do
    jobs =
      Repo.all(
        from(j in "oban_jobs",
          where: j.state in ["available", "executing", "scheduled", "retryable"],
          group_by: [j.worker, j.state],
          select: {j.worker, j.state, count(j.id)}
        )
      )

    by_worker =
      Enum.group_by(jobs, &elem(&1, 0), fn {_, state, count} -> {state, count} end)
      |> Enum.map(fn {worker, states} ->
        short_name = worker |> String.split(".") |> List.last()
        total = Enum.reduce(states, 0, fn {_, c}, acc -> acc + c end)
        executing = Enum.find_value(states, 0, fn {s, c} -> if s == "executing", do: c end)
        available = Enum.find_value(states, 0, fn {s, c} -> if s == "available", do: c end)
        retryable = Enum.find_value(states, 0, fn {s, c} -> if s == "retryable", do: c end)

        %{
          worker: short_name,
          total: total,
          executing: executing,
          available: available,
          retryable: retryable
        }
      end)
      |> Enum.sort_by(& &1.total, :desc)

    completed_1h =
      Repo.one(
        from(j in "oban_jobs",
          where: j.state == "completed" and j.completed_at > ago(1, "hour"),
          select: count(j.id)
        )
      )

    %{by_worker: by_worker, completed_1h: completed_1h}
  end

  @impl true
  def render(assigns) do
    ~H"""
    <Layouts.app flash={@flash}>
      <.header>
        Backfill Dashboard
        <:subtitle>Enqueue and monitor contact enrichment jobs</:subtitle>
      </.header>

      <div class="grid grid-cols-1 md:grid-cols-3 gap-4 my-6">
        <div class="stat bg-base-200 rounded-box p-4">
          <div class="text-xs opacity-60">Contacts Needing Enrichment</div>
          <div class="text-2xl font-bold">{@unprocessed}</div>
        </div>
        <div class="stat bg-base-200 rounded-box p-4">
          <div class="text-xs opacity-60">Active/Queued Jobs</div>
          <div class="text-2xl font-bold">
            {Enum.reduce(@stats.by_worker, 0, fn w, acc -> acc + w.total end)}
          </div>
        </div>
        <div class="stat bg-base-200 rounded-box p-4">
          <div class="text-xs opacity-60">Completed (last hour)</div>
          <div class="text-2xl font-bold">{@stats.completed_1h}</div>
        </div>
      </div>

      <div class="bg-base-200 rounded-box p-4 mb-6">
        <form phx-submit="enqueue" class="flex items-end gap-4">
          <div>
            <label class="label text-sm">Contacts to enqueue</label>
            <input
              type="number"
              name="limit"
              value={@limit}
              min="1"
              max="5000"
              class="input input-bordered w-32"
            />
          </div>
          <button class="btn btn-primary" disabled={@enqueuing}>
            <%= if @enqueuing do %>
              <span class="loading loading-spinner loading-sm"></span> Enqueuing...
            <% else %>
              Enqueue Backfill
            <% end %>
          </button>
          <%= if @last_enqueued do %>
            <span class="text-sm text-success">
              Enqueued {@last_enqueued} contacts
            </span>
          <% end %>
        </form>
      </div>

      <h2 class="text-base font-semibold mb-2">Job Queue Status</h2>
      <%= if @stats.by_worker == [] do %>
        <p class="text-sm text-base-content/50 italic">No active jobs.</p>
      <% else %>
        <div class="overflow-x-auto">
          <table class="table table-sm table-zebra">
            <thead>
              <tr>
                <th>Worker</th>
                <th>Executing</th>
                <th>Available</th>
                <th>Retryable</th>
                <th>Total</th>
              </tr>
            </thead>
            <tbody>
              <%= for w <- @stats.by_worker do %>
                <tr>
                  <td class="font-semibold">{w.worker}</td>
                  <td>
                    <%= if w.executing > 0 do %>
                      <span class="flex items-center gap-1">
                        <span class="loading loading-spinner loading-xs"></span> {w.executing}
                      </span>
                    <% else %>
                      0
                    <% end %>
                  </td>
                  <td>{w.available}</td>
                  <td>
                    <%= if w.retryable > 0 do %>
                      <span class="text-warning">{w.retryable}</span>
                    <% else %>
                      0
                    <% end %>
                  </td>
                  <td>{w.total}</td>
                </tr>
              <% end %>
            </tbody>
          </table>
        </div>
      <% end %>

      <p class="text-xs text-base-content/50 mt-4">Auto-refreshes every 2 seconds.</p>
    </Layouts.app>
    """
  end
end