defmodule MvWeb.JoinRequestLive.Show do
  @moduledoc """
  LiveView for displaying a single join request and performing approve/reject actions.

  ## Features
  - Show all request data (typed fields + form_data rendered by field)
  - Approve action: transitions to :approved, creates Member
  - Reject action: transitions to :rejected (no Member created)
  - Actions only available when status is :submitted

  ## Security
  - Page access controlled by CheckPagePermission plug and can_access_page? guard
  - Ash policy (HasPermission) enforces JoinRequest update :all for normal_user and admin
  """
  use MvWeb, :live_view

  require Logger

  import MvWeb.LiveHelpers, only: [current_actor: 1]
  import MvWeb.Authorization

  alias Mv.Constants
  alias Mv.Membership
  alias MvWeb.Helpers.DateFormatter
  alias MvWeb.JoinRequestLive.Helpers, as: JoinRequestHelpers
  alias MvWeb.Translations.MemberFields, as: MemberFieldsTranslations

  @impl true
  def mount(_params, _session, socket) do
    if Membership.join_form_enabled?() do
      {:ok,
       socket
       |> assign(:join_request, nil)
       |> assign(:join_form_field_ids, [])
       |> assign(:page_title, gettext("Join request"))}
    else
      {:ok, redirect(socket, to: ~p"/members")}
    end
  end

  @impl true
  def handle_params(%{"id" => id}, _url, socket) do
    actor = current_actor(socket)

    if Membership.join_form_enabled?() and can_access_page?(actor, "/join_requests/:id") do
      case Membership.get_join_request(id, actor: actor) do
        {:ok, nil} ->
          {:noreply,
           socket
           |> put_flash(:error, gettext("Join request not found."))
           |> push_navigate(to: ~p"/join_requests")}

        {:ok, request} ->
          field_ids = Membership.get_join_form_allowlist() |> Enum.map(& &1.id)

          {:noreply,
           socket
           |> assign(:join_request, request)
           |> assign(:join_form_field_ids, field_ids)
           |> assign(:page_title, gettext("Join request – %{email}", email: request.email))}

        {:error, _error} ->
          {:noreply,
           socket
           |> put_flash(:error, gettext("Failed to load join request."))
           |> push_navigate(to: ~p"/join_requests")}
      end
    else
      {:noreply, redirect(socket, to: ~p"/members")}
    end
  end

  @impl true
  def handle_event("approve", _params, socket) do
    actor = current_actor(socket)
    request = socket.assigns.join_request

    case Membership.approve_join_request(request.id, actor: actor) do
      {:ok, _approved} ->
        {:noreply,
         socket
         |> put_flash(:info, gettext("Join request approved. Member created."))
         |> push_navigate(to: ~p"/join_requests")}

      {:error, error} ->
        Logger.warning("Failed to approve join request #{request.id}: #{inspect(error)}")

        {:noreply, put_flash(socket, :error, gettext("Failed to approve join request."))}
    end
  end

  @impl true
  def handle_event("reject", _params, socket) do
    actor = current_actor(socket)
    request = socket.assigns.join_request

    case Membership.reject_join_request(request.id, actor: actor) do
      {:ok, _rejected} ->
        {:noreply,
         socket
         |> put_flash(:info, gettext("Join request rejected."))
         |> push_navigate(to: ~p"/join_requests")}

      {:error, error} ->
        Logger.warning("Failed to reject join request #{request.id}: #{inspect(error)}")

        {:noreply, put_flash(socket, :error, gettext("Failed to reject join request."))}
    end
  end

  @impl true
  def render(assigns) do
    ~H"""
    <Layouts.app flash={@flash} current_user={@current_user}>
      <.header>
        <:leading>
          <.button
            navigate={~p"/join_requests"}
            variant="neutral"
            aria-label={gettext("Back to join requests")}
          >
            <.icon name="hero-arrow-left" class="size-4" />
            {gettext("Back")}
          </.button>
        </:leading>
        {gettext("Join request")}
      </.header>

      <%= if @join_request do %>
        <div class="mt-6 space-y-6 max-w-2xl">
          <%!-- Single block: all applicant-provided data in join form order --%>
          <div>
            <h2 class="text-lg font-semibold mb-2">{gettext("Applicant data")}</h2>
            <div class="border border-base-300 rounded-lg p-4 bg-base-100 space-y-2">
              <%= for {label, value} <- applicant_data_rows(@join_request, @join_form_field_ids || []) do %>
                <.field_row label={label} value={value} empty_text={gettext("Not specified")} />
              <% end %>
            </div>
          </div>

          <%!-- Status and review (submitted_at, status; if decided: approved/rejected at, reviewed by) --%>
          <div>
            <h2 class="text-lg font-semibold mb-2">{gettext("Status and review")}</h2>
            <div class="border border-base-300 rounded-lg p-4 bg-base-100 space-y-2">
              <.field_row
                label={gettext("Submitted at")}
                value={DateFormatter.format_datetime(@join_request.submitted_at, @browser_timezone)}
              />
              <div class="flex gap-2">
                <span class="text-base-content/60 min-w-32 shrink-0">{gettext("Status")}:</span>
                <span>
                  <.badge variant={JoinRequestHelpers.status_badge_variant(@join_request.status)}>
                    {JoinRequestHelpers.format_status(@join_request.status)}
                  </.badge>
                </span>
              </div>
              <%= if @join_request.status in [:approved, :rejected] do %>
                <%= if @join_request.approved_at do %>
                  <.field_row
                    label={gettext("Approved at")}
                    value={
                      DateFormatter.format_datetime(@join_request.approved_at, @browser_timezone)
                    }
                  />
                <% end %>
                <%= if @join_request.rejected_at do %>
                  <.field_row
                    label={gettext("Rejected at")}
                    value={
                      DateFormatter.format_datetime(@join_request.rejected_at, @browser_timezone)
                    }
                  />
                <% end %>
                <.field_row
                  label={gettext("Review by")}
                  value={JoinRequestHelpers.reviewer_display(@join_request)}
                  empty_text="-"
                />
              <% end %>
            </div>
          </div>

          <%= if @join_request.status == :submitted do %>
            <div class="flex flex-wrap items-center justify-between gap-3 pt-2">
              <.button
                variant="danger"
                phx-click="reject"
                data-confirm={gettext("Reject this join request?")}
                data-testid="join-request-reject-btn"
              >
                {gettext("Reject")}
              </.button>
              <.button
                variant="primary"
                phx-click="approve"
                data-confirm={gettext("Approve this join request and create a member?")}
                data-testid="join-request-approve-btn"
              >
                {gettext("Approve")}
              </.button>
            </div>
          <% end %>
        </div>
      <% end %>
    </Layouts.app>
    """
  end

  attr :label, :string, required: true
  attr :value, :any, default: nil
  attr :empty_text, :string, default: nil

  defp field_row(assigns) do
    ~H"""
    <div class="flex gap-2">
      <span class="text-base-content/60 min-w-32 shrink-0">{@label}:</span>
      <span>
        <%= if @value && @value != "" do %>
          {@value}
        <% else %>
          <span class="text-base-content/40 italic">
            {@empty_text || gettext("Not specified")}
          </span>
        <% end %>
      </span>
    </div>
    """
  end

  # Builds a single list of {label, display_value} for all applicant-provided data in join form
  # order. Typed fields (email, first_name, last_name) and form_data are merged; legacy
  # form_data keys (not in current join form config) are appended at the end.
  defp applicant_data_rows(join_request, ordered_field_ids) do
    member_field_strings = Constants.member_fields() |> Enum.map(&Atom.to_string/1)
    form_data = join_request.form_data || %{}

    typed = %{
      "email" => join_request.email,
      "first_name" => join_request.first_name,
      "last_name" => join_request.last_name
    }

    in_order =
      ordered_field_ids
      |> Enum.map(fn key ->
        value = Map.get(typed, key) || Map.get(form_data, key)
        label = field_key_to_label(key, member_field_strings)
        {label, format_applicant_value(value)}
      end)

    legacy_keys =
      form_data
      |> Map.keys()
      |> Enum.reject(fn k ->
        k in ordered_field_ids or k in ["email", "first_name", "last_name"]
      end)
      |> Enum.sort()

    legacy_entries =
      Enum.map(legacy_keys, fn key ->
        label = field_key_to_label(key, member_field_strings)
        {label, format_applicant_value(form_data[key])}
      end)

    in_order ++ legacy_entries
  end

  defp format_applicant_value(nil), do: nil
  defp format_applicant_value(""), do: nil
  defp format_applicant_value(%Date{} = date), do: DateFormatter.format_date(date)

  defp format_applicant_value(value) when is_map(value),
    do: format_applicant_value_from_map(value)

  defp format_applicant_value(value) when is_boolean(value),
    do: if(value, do: gettext("Yes"), else: gettext("No"))

  defp format_applicant_value(value) when is_binary(value) or is_number(value),
    do: to_string(value)

  defp format_applicant_value(value), do: to_string(value)

  defp format_applicant_value_from_map(value) do
    raw = Map.get(value, "_union_value") || Map.get(value, "value")
    type = Map.get(value, "_union_type") || Map.get(value, "type")

    if raw && type in ["date", :date] do
      format_applicant_value(raw)
    else
      format_applicant_value_simple(raw, value)
    end
  end

  defp format_applicant_value_simple(raw, _value) when is_binary(raw), do: raw

  defp format_applicant_value_simple(raw, _value) when is_boolean(raw),
    do: if(raw, do: gettext("Yes"), else: gettext("No"))

  defp format_applicant_value_simple(raw, _value) when is_integer(raw), do: to_string(raw)
  defp format_applicant_value_simple(_raw, value), do: to_string(value)

  defp field_key_to_label(key, member_field_strings) when is_binary(key) do
    if key in member_field_strings,
      do: MemberFieldsTranslations.label(String.to_existing_atom(key)),
      else: key
  end

  defp field_key_to_label(key, _), do: to_string(key)
end