Behaviour for form layout templates.

Templates define how the form is structured:

• Standard — single-page form with groups
• Wizard — multi-step form with progress indicator
• Tabs — tabbed form layout

Templates pair with UI adapters along orthogonal axes:

• Template — where things go (structure / layout)
• UIAdapter — how things look (styling / CSS)

Two ways to implement

Bare behaviour — implement every required callback yourself. The default template MishkaGervaz.Form.Templates.Standard follows this path:

defmodule MyApp.Form.Templates.Custom do
  @behaviour MishkaGervaz.Form.Behaviours.Template
  use Phoenix.Component

  @impl true
  def name, do: :custom

  @impl true
  def label, do: "Custom Form"

  @impl true
  def icon, do: "hero-document-text"

  @impl true
  def render(assigns) do
    ~H"""
    <div class="my-custom-form">...</div>
    """
  end

  # render_loading/1, render_field/1, render_group/1,
  # render_step_indicator/1 must be implemented or `use`-d below.
end

Or use this module to inherit Standard's implementations of the optional callbacks (overridable). Most custom templates only need to override render/1:

defmodule MyApp.Form.Templates.Sidebar do
  use MishkaGervaz.Form.Behaviours.Template

  @impl true
  def name,  do: :sidebar
  @impl true
  def label, do: "Sidebar"
  @impl true
  def icon,  do: "hero-bars-3"

  @impl true
  def render(assigns), do: ~H"<aside>...</aside>"

  # render_loading, render_field, render_group, render_step_indicator
  # delegate to Standard. Override any of them as needed.
end

See MishkaGervaz.Form.Templates.Standard, MishkaGervaz.Form.Behaviours.FieldType, and MishkaGervaz.Behaviours.UIAdapter.