defmodule Integrations.Self.Display do
  @moduledoc """
  Dashboard panel for `Integrations.Self` (same package).

  Nested under the monitor's own namespace deliberately — the package's
  top-level module name never changes, and this module's name is
  guaranteed distinct from any separately-published standalone display
  package. `Display.BundledDefault` auto-hooks this whenever
  `Integrations.Self` starts, the same as if they were still one module.
  """

  use CodeNameRaven.Display, category: :system, size_hint: :large

  def display_timezone, do: "America/Chicago"

  @impl true
  def display_name, do: "Application Health"

  @impl true
  def compatible_monitors, do: [Integrations.Self]

  @impl true
  def render(assigns) do
    ~H"""
    <div class="space-y-6">
      <%!-- Header --%>
      <div class="flex items-start justify-between">
        <div>
          <h2 class="text-lg font-semibold text-base-content">Application Health</h2>
          <p class="text-sm text-base-content/50 font-mono"><%= @result && @result.node %></p>
        </div>
        <.status_chip status={@status} />
      </div>

      <%!-- Version / uptime row --%>
      <div :if={@result} class="grid grid-cols-3 gap-4">
        <.info_card label="Elixir" value={"v#{@result.elixir_version}"} />
        <.info_card label="OTP"    value={"v#{@result.otp_version}"} />
        <.info_card label="Uptime" value={format_uptime(@result.uptime_seconds)} />
      </div>

      <%!-- Memory --%>
      <div :if={@result}>
        <p class="text-xs font-semibold uppercase tracking-widest text-base-content/40 mb-3">Memory</p>
        <div class="grid grid-cols-2 gap-3">
          <.memory_row label="Total"     bytes={@result.memory.total} />
          <.memory_row label="Processes" bytes={@result.memory.processes} />
          <.memory_row label="Binary"    bytes={@result.memory.binary} />
          <.memory_row label="ETS"       bytes={@result.memory.ets} />
        </div>
      </div>

      <%!-- Process stats --%>
      <div :if={@result} class="grid grid-cols-2 gap-4">
        <.stat_card label="Processes" value={@result.process_count} />
        <.stat_card label="Run Queue" value={@result.run_queue} />
      </div>

      <%!-- Footer --%>
      <p class="text-xs text-base-content/30">
        Checked <%= CodeNameRaven.Timezone.format_datetime(@last_checked_at, __MODULE__) %>
      </p>
    </div>
    """
  end

  # ---------------------------------------------------------------------------
  # Private components
  # ---------------------------------------------------------------------------

  defp status_chip(%{status: :up} = assigns) do
    ~H"""
    <span class="badge badge-success gap-1 px-3 py-3 text-xs font-semibold">
      <span class="w-1.5 h-1.5 rounded-full bg-current"></span> Up
    </span>
    """
  end

  defp status_chip(%{status: :degraded} = assigns) do
    ~H"""
    <span class="badge badge-warning gap-1 px-3 py-3 text-xs font-semibold">
      <span class="w-1.5 h-1.5 rounded-full bg-current"></span> Degraded
    </span>
    """
  end

  defp status_chip(%{status: :down} = assigns) do
    ~H"""
    <span class="badge badge-error gap-1 px-3 py-3 text-xs font-semibold">
      <span class="w-1.5 h-1.5 rounded-full bg-current"></span> Down
    </span>
    """
  end

  defp status_chip(assigns) do
    ~H"""
    <span class="badge badge-neutral gap-1 px-3 py-3 text-xs font-semibold">
      <span class="w-1.5 h-1.5 rounded-full bg-current"></span> Unknown
    </span>
    """
  end

  defp info_card(assigns) do
    ~H"""
    <div class="bg-base-200 rounded-xl p-3 text-center">
      <p class="text-xs text-base-content/40 mb-1"><%= @label %></p>
      <p class="text-sm font-mono font-semibold text-base-content"><%= @value %></p>
    </div>
    """
  end

  defp memory_row(assigns) do
    ~H"""
    <div class="flex justify-between items-center py-1.5 border-b border-base-200">
      <span class="text-xs text-base-content/50"><%= @label %></span>
      <span class="text-xs font-mono font-medium text-base-content"><%= format_bytes(@bytes) %></span>
    </div>
    """
  end

  defp stat_card(assigns) do
    ~H"""
    <div class="bg-base-200 rounded-xl p-4">
      <p class="text-xs text-base-content/40 mb-1"><%= @label %></p>
      <p class="text-2xl font-mono font-bold text-base-content"><%= @value %></p>
    </div>
    """
  end

  # ---------------------------------------------------------------------------
  # Formatting helpers
  # ---------------------------------------------------------------------------

  defp format_bytes(bytes) when bytes >= 1_073_741_824,
    do: "#{Float.round(bytes / 1_073_741_824, 1)} GB"
  defp format_bytes(bytes) when bytes >= 1_048_576,
    do: "#{Float.round(bytes / 1_048_576, 1)} MB"
  defp format_bytes(bytes) when bytes >= 1_024,
    do: "#{Float.round(bytes / 1_024, 1)} KB"
  defp format_bytes(bytes),
    do: "#{bytes} B"

  defp format_uptime(seconds) do
    days    = div(seconds, 86_400)
    hours   = div(rem(seconds, 86_400), 3_600)
    minutes = div(rem(seconds, 3_600), 60)

    cond do
      days > 0  -> "#{days}d #{hours}h"
      hours > 0 -> "#{hours}h #{minutes}m"
      true      -> "#{minutes}m #{rem(seconds, 60)}s"
    end
  end
end