defmodule FreediveWeb.LiliformLive do
  @callback items() :: map
  @callback filters() :: [map]
  @callback search(items :: map, query :: String.t()) :: map

  defmacro __using__(opts) do
    quote location: :keep, bind_quoted: [opts: opts] do
      use FreediveWeb, :live_view
      @behaviour FreediveWeb.LiliformLive
      @filters_all [
        %{
          title: "All",
          icon: "all",
          active: false,
          key: :all
        }
      ]

      def(mount(_params, _session, socket)) do
        items = items()
        filters = filters()
        socket = assign(socket, :opts, Keyword.get(unquote(opts), :opts, []))
        socket = assign(socket, :items_all, items)
        socket = assign(socket, :selected_item, nil)
        socket = assign(socket, :details, nil)

        socket =
          assign(
            socket,
            :items,
            FreediveWeb.LiliformLive.filter(
              items,
              FreediveWeb.LiliformLive.get_active_filter(filters)
            )
          )

        socket = assign(socket, :filters, @filters_all ++ filters)
        socket = assign(socket, :query, "")
        {:ok, socket}
      end

      def(handle_event("search", %{"value" => query}, socket)) do
        filtered_items =
          FreediveWeb.LiliformLive.filter(
            socket.assigns.items_all,
            FreediveWeb.LiliformLive.get_active_filter(socket.assigns.filters)
          )

        searched_items = search(filtered_items, query)
        socket = assign(socket, :items, searched_items)

        socket =
          case Kernel.length(Map.keys(searched_items)) == 1 do
            true ->
              assign(socket, %{
                selected_item: Map.get(searched_items, Map.keys(searched_items) |> List.first()),
                details: true
              })

            false ->
              assign(socket, %{selected_item: nil, details: nil})
          end

        {:noreply, socket}
      end

      def(handle_event("filter", %{"key" => key}, socket)) do
        key = String.to_existing_atom(key)
        items = FreediveWeb.LiliformLive.filter(socket.assigns.items_all, key)
        socket = assign(socket, :items, items)

        socket =
          assign(
            socket,
            :filters,
            FreediveWeb.LiliformLive.update_active_filter(socket.assigns.filters, key)
          )

        {:noreply, socket}
      end

      def(handle_event("tap", %{"name" => item_name}, socket)) do
        # 1 tap to select, 2 taps for details
        item = socket.assigns.items[item_name]

        socket =
          case socket.assigns.selected_item do
            nil ->
              assign(socket, :selected_item, item)

            selected ->
              case selected.name == item_name do
                true ->
                  case socket.assigns.details do
                    nil ->
                      assign(socket, :details, true)

                    _ ->
                      assign(socket, %{selected_item: item, details: nil})
                  end

                false ->
                  assign(socket, %{selected_item: item, details: nil})
              end
          end

        {:noreply, socket}
      end

      def(handle_params(params, _url, socket)) do
        socket = assign(socket, :query, Map.get(params, "search", ""))
        {:noreply, socket}
      end
    end
  end

  def filter(items, key) do
    case key do
      :all ->
        items

      _ ->
        items
        |> Enum.filter(fn {_name, item} -> item[key] == true end)
        |> Enum.into(%{}, fn {name, item} -> {name, item} end)
    end
  end

  def get_active_filter(filters) do
    filters |> Enum.find(& &1.active) |> Map.get(:key)
  end

  def update_active_filter(filters, key) do
    filters
    |> Enum.map(fn filter ->
      Map.put(filter, :active, filter.key == key)
    end)
  end
end