The behaviour for Tuix applications, modeled after Phoenix LiveView.

An app holds its state in assigns, reacts to events and messages, and declaratively describes its UI in render/1. Tuix re-renders after every callback and writes only the changed terminal cells.

Example

defmodule Counter do
  use Tuix.App

  @impl true
  def mount(_opts, app), do: {:ok, assign(app, count: 0)}

  @impl true
  def handle_event(%Tuix.Event.Key{key: :up}, app),
    do: {:noreply, update(app, :count, &(&1 + 1))}

  def handle_event(%Tuix.Event.Key{key: :down}, app),
    do: {:noreply, update(app, :count, &(&1 - 1))}

  def handle_event(%Tuix.Event.Key{key: "q"}, app),
    do: {:stop, :normal, app}

  def handle_event(_event, app), do: {:noreply, app}

  @impl true
  def render(assigns) do
    box border: :rounded, padding: 1 do
      text("Count: #{assigns.count}", fg: :green)
    end
  end
end

Tuix.run(Counter)

Because the runtime is a regular process, any Elixir message — timer ticks, Task results, PubSub broadcasts — can drive the UI through handle_info/2.