mitgliederverwaltung/lib/mv_web/live/property_live/form.ex

defmodule MvWeb.PropertyLive.Form do
  @moduledoc """
  LiveView form for creating and editing properties.

  ## Features
  - Create new properties with member and type selection
  - Edit existing property values
  - Value input adapts to property type (string, integer, boolean, date, email)
  - Real-time validation

  ## Form Fields
  **Required:**
  - member - Select which member owns this property
  - property_type - Select the type (defines value type)
  - value - The actual value (input type depends on property type)

  ## Value Types
  The form dynamically renders appropriate inputs based on property type:
  - String: text input
  - Integer: number input
  - Boolean: checkbox
  - Date: date picker
  - Email: email input with validation

  ## Events
  - `validate` - Real-time form validation
  - `save` - Submit form (create or update property)

  ## Note
  Properties are typically managed through the member edit form,
  not through this standalone form.
  """
  use MvWeb, :live_view

  @impl true
  def render(assigns) do
    ~H"""
    <Layouts.app flash={@flash} current_user={@current_user}>
      <.header>
        {@page_title}
        <:subtitle>{gettext("Use this form to manage property records in your database.")}</:subtitle>
      </.header>

      <.form for={@form} id="property-form" phx-change="validate" phx-submit="save">
        <!-- Property Type Selection -->
        <.input
          field={@form[:property_type_id]}
          type="select"
          label={gettext("Property type")}
          options={property_type_options(@property_types)}
          prompt={gettext("Choose a property type")}
        />
        
    <!-- Member Selection -->
        <.input
          field={@form[:member_id]}
          type="select"
          label={gettext("Member")}
          options={member_options(@members)}
          prompt={gettext("Choose a member")}
        />
        
    <!-- Value Input - handles Union type -->
        <%= if @selected_property_type do %>
          <.union_value_input form={@form} property_type={@selected_property_type} />
        <% else %>
          <div class="text-sm text-gray-600">
            {gettext("Please select a property type first")}
          </div>
        <% end %>

        <.button phx-disable-with={gettext("Saving...")} variant="primary">
          {gettext("Save Property")}
        </.button>
        <.button navigate={return_path(@return_to, @property)}>{gettext("Cancel")}</.button>
      </.form>
    </Layouts.app>
    """
  end

  # Helper function for Union-Value Input
  defp union_value_input(assigns) do
    # Extract the current value from the Property
    current_value = extract_current_value(assigns.form.data, assigns.property_type.value_type)
    assigns = assign(assigns, :current_value, current_value)

    ~H"""
    <div class="space-y-2">
      <label class="block text-sm font-medium text-gray-700">
        {gettext("Value")}
      </label>

      <%= case @property_type.value_type do %>
        <% :string -> %>
          <.inputs_for :let={value_form} field={@form[:value]}>
            <.input field={value_form[:value]} type="text" label="" value={@current_value} />
            <input type="hidden" name={value_form[:_union_type].name} value="string" />
          </.inputs_for>
        <% :integer -> %>
          <.inputs_for :let={value_form} field={@form[:value]}>
            <.input field={value_form[:value]} type="number" label="" value={@current_value} />
            <input type="hidden" name={value_form[:_union_type].name} value="integer" />
          </.inputs_for>
        <% :boolean -> %>
          <.inputs_for :let={value_form} field={@form[:value]}>
            <.input field={value_form[:value]} type="checkbox" label="" checked={@current_value} />
            <input type="hidden" name={value_form[:_union_type].name} value="boolean" />
          </.inputs_for>
        <% :date -> %>
          <.inputs_for :let={value_form} field={@form[:value]}>
            <.input
              field={value_form[:value]}
              type="date"
              label=""
              value={format_date_value(@current_value)}
            />
            <input type="hidden" name={value_form[:_union_type].name} value="date" />
          </.inputs_for>
        <% :email -> %>
          <.inputs_for :let={value_form} field={@form[:value]}>
            <.input field={value_form[:value]} type="email" label="" value={@current_value} />
            <input type="hidden" name={value_form[:_union_type].name} value="email" />
          </.inputs_for>
        <% _ -> %>
          <div class="text-sm text-red-600">
            {gettext("Unsupported value type: %{type}", type: @property_type.value_type)}
          </div>
      <% end %>
    </div>
    """
  end

  # Helper function to extract the current value from the Property
  defp extract_current_value(
         %Mv.Membership.Property{value: %Ash.Union{value: value}},
         _value_type
       ) do
    value
  end

  defp extract_current_value(_data, _value_type) do
    nil
  end

  # Helper function to format Date values for HTML input
  defp format_date_value(%Date{} = date) do
    Date.to_iso8601(date)
  end

  defp format_date_value(nil), do: ""

  defp format_date_value(date) when is_binary(date) do
    case Date.from_iso8601(date) do
      {:ok, parsed_date} -> Date.to_iso8601(parsed_date)
      _ -> ""
    end
  end

  defp format_date_value(_), do: ""

  @impl true
  def mount(params, _session, socket) do
    property =
      case params["id"] do
        nil -> nil
        id -> Ash.get!(Mv.Membership.Property, id) |> Ash.load!([:property_type])
      end

    action = if is_nil(property), do: "New", else: "Edit"
    page_title = action <> " " <> "Property"

    # Load all PropertyTypes and Members for the selection fields
    property_types = Ash.read!(Mv.Membership.PropertyType)
    members = Ash.read!(Mv.Membership.Member)

    {:ok,
     socket
     |> assign(:return_to, return_to(params["return_to"]))
     |> assign(property: property)
     |> assign(:page_title, page_title)
     |> assign(:property_types, property_types)
     |> assign(:members, members)
     |> assign(:selected_property_type, property && property.property_type)
     |> assign_form()}
  end

  defp return_to("show"), do: "show"
  defp return_to(_), do: "index"

  @impl true
  def handle_event("validate", %{"property" => property_params}, socket) do
    # Find the selected PropertyType
    selected_property_type =
      case property_params["property_type_id"] do
        "" -> nil
        nil -> nil
        id -> Enum.find(socket.assigns.property_types, &(&1.id == id))
      end

    # Set the Union type based on the selected PropertyType
    updated_params =
      if selected_property_type do
        union_type = to_string(selected_property_type.value_type)
        put_in(property_params, ["value", "_union_type"], union_type)
      else
        property_params
      end

    {:noreply,
     socket
     |> assign(:selected_property_type, selected_property_type)
     |> assign(form: AshPhoenix.Form.validate(socket.assigns.form, updated_params))}
  end

  def handle_event("save", %{"property" => property_params}, socket) do
    # Set the Union type based on the selected PropertyType
    updated_params =
      if socket.assigns.selected_property_type do
        union_type = to_string(socket.assigns.selected_property_type.value_type)
        put_in(property_params, ["value", "_union_type"], union_type)
      else
        property_params
      end

    case AshPhoenix.Form.submit(socket.assigns.form, params: updated_params) do
      {:ok, property} ->
        notify_parent({:saved, property})

        action =
          case socket.assigns.form.source.type do
            :create -> gettext("create")
            :update -> gettext("update")
            other -> to_string(other)
          end

        socket =
          socket
          |> put_flash(:info, gettext("Property %{action} successfully", action: action))
          |> push_navigate(to: return_path(socket.assigns.return_to, property))

        {:noreply, socket}

      {:error, form} ->
        {:noreply, assign(socket, form: form)}
    end
  end

  defp notify_parent(msg), do: send(self(), {__MODULE__, msg})

  defp assign_form(%{assigns: %{property: property}} = socket) do
    form =
      if property do
        # Determine the Union type based on the property_type
        union_type = property.property_type && property.property_type.value_type

        params =
          if union_type do
            %{"value" => %{"_union_type" => to_string(union_type)}}
          else
            %{}
          end

        AshPhoenix.Form.for_update(property, :update, as: "property", params: params)
      else
        AshPhoenix.Form.for_create(Mv.Membership.Property, :create, as: "property")
      end

    assign(socket, form: to_form(form))
  end

  defp return_path("index", _property), do: ~p"/properties"
  defp return_path("show", property), do: ~p"/properties/#{property.id}"

  # Helper functions for selection options
  defp property_type_options(property_types) do
    Enum.map(property_types, &{&1.name, &1.id})
  end

  defp member_options(members) do
    Enum.map(members, &{"#{&1.first_name} #{&1.last_name}", &1.id})
  end
end