cmdc_tui

defmodule CmdcTui.Panels.StatusBar do
  @moduledoc """
  底部状态栏 — 三区域布局：左（状态 + Throbber）/ 中（session + model）/ 右（快捷键）。

  ## 宽度适应

  - ≥80 列：三区域全显
  - 40~79 列：隐藏快捷键区域
  - <40 列：仅显示状态指示
  """

  alias ExRatatui.{Layout, Style}
  alias ExRatatui.Layout.Rect
  alias ExRatatui.Widgets.{Paragraph, Throbber}

  @doc "渲染状态栏（返回 1~3 个 widget）。"
  @spec render(CmdcTui.State.t(), Rect.t()) :: [{ExRatatui.widget(), Rect.t()}]
  def render(state, area) do
    cond do
      area.width >= 80 -> render_full(state, area)
      area.width >= 40 -> render_compact(state, area)
      true -> render_minimal(state, area)
    end
  end

  # ==========================================================================
  # 三区域完整布局
  # ==========================================================================

  defp render_full(state, area) do
    [left_area, mid_area, right_area] =
      Layout.split(area, :horizontal, [
        {:percentage, 30},
        {:percentage, 40},
        {:percentage, 30}
      ])

    left_widgets = render_left(state, left_area)
    mid_widget = render_mid(state, mid_area)
    right_widget = render_right(right_area)

    left_widgets ++ [mid_widget, right_widget]
  end

  # -----
  # 左侧：状态 + Throbber（active 时）
  # -----

  defp render_left(%{agent_status: s} = state, area) when s in [:running, :streaming] do
    [throbber_area, text_area] =
      Layout.split(area, :horizontal, [
        {:length, 3},
        {:min, 1}
      ])

    throbber = %Throbber{
      label: "",
      step: state.throbber_step,
      throbber_set: :braille,
      style: %Style{fg: :yellow},
      throbber_style: %Style{fg: :yellow, modifiers: [:bold]}
    }

    label_text = if s == :streaming, do: " streaming", else: " thinking…"

    label = %Paragraph{
      text: label_text,
      style: %Style{fg: :yellow}
    }

    [{throbber, throbber_area}, {label, text_area}]
  end

  defp render_left(_state, area) do
    widget = %Paragraph{
      text: " ● idle",
      style: %Style{fg: :dark_gray}
    }

    [{widget, area}]
  end

  # -----
  # 中间：token / cost / session_id / model
  # -----

  defp render_mid(state, area) do
    tokens = format_number(state.total_tokens)
    cost = format_cost(state.cost_usd)
    mid_text = " #{tokens} tok  $#{cost}"

    extra =
      cond do
        state.model_name ->
          " │ #{shorten_model(state.model_name)}"

        state.session_id ->
          " │ #{String.slice(state.session_id, 0, 12)}"

        true ->
          ""
      end

    widget = %Paragraph{
      text: mid_text <> extra,
      style: %Style{fg: :dark_gray}
    }

    {widget, area}
  end

  # -----
  # 右侧：快捷键提示
  # -----

  defp render_right(area) do
    widget = %Paragraph{
      text: "Enter:发送  S-Enter:换行  Tab:切换  Ctrl+C:退出 ",
      style: %Style{fg: :dark_gray},
      alignment: :right
    }

    {widget, area}
  end

  # ==========================================================================
  # 精简布局（隐藏右侧）
  # ==========================================================================

  defp render_compact(state, area) do
    [left_area, right_area] =
      Layout.split(area, :horizontal, [
        {:percentage, 40},
        {:percentage, 60}
      ])

    left_widgets = render_left(state, left_area)
    mid = render_mid(state, right_area)
    left_widgets ++ [mid]
  end

  # ==========================================================================
  # 最小布局
  # ==========================================================================

  defp render_minimal(state, area) do
    text = status_text(state)

    widget = %Paragraph{
      text: text,
      style: %Style{fg: :dark_gray, bg: :black}
    }

    [{widget, area}]
  end

  defp status_text(%{agent_status: :streaming}), do: " ◉ streaming"
  defp status_text(%{agent_status: :running}), do: " ◉ thinking"
  defp status_text(_), do: " ● idle"

  # ==========================================================================
  # 格式化辅助
  # ==========================================================================

  defp format_number(n) when n >= 1_000_000, do: "#{div(n, 1_000_000)}M"
  defp format_number(n) when n >= 1_000, do: "#{Float.round(n / 1000.0, 1)}K"
  defp format_number(n), do: "#{n}"

  defp format_cost(cost) when cost < 0.0001, do: "0.0000"
  defp format_cost(cost), do: :erlang.float_to_binary(cost, decimals: 4)

  # anthropic:claude-sonnet-4-5 → sonnet-4-5
  defp shorten_model(name) do
    name
    |> String.split(":")
    |> List.last()
    |> String.replace("claude-", "")
    |> String.slice(0, 14)
  end
end