Feature/endgame play (#1)

* create endgame play section

* add cache tests

* normalise FENs - trim and fuill move to 1 on addition

* remove svg on root and allow navbar to exist across all pages

* update nav items

lib/chesstrainer_web/live/endgame_live/play.ex

@@ -0,0 +1,119 @@
+defmodule ChesstrainerWeb.EndgameLive.Play do
+  use ChesstrainerWeb, :live_view
+
+  alias Chesstrainer.Endgames
+
+  @impl true
+  def render(assigns) do
+    ~H"""
+    <Layouts.app flash={@flash}>
+      <.header>
+        Play endgame {@endgame.key}
+        <:subtitle>
+          {@endgame.color} to move · Result: {@endgame.result} · Rating: {@endgame.rating}
+        </:subtitle>
+        <:actions>
+          <.button navigate={~p"/endgames"}>
+            <.icon name="hero-arrow-left" /> Back to endgames
+          </.button>
+        </:actions>
+      </.header>
+
+      <div class="bg-gray-100 p-4 rounded mb-4 flex justify-between items-center shadow-sm">
+        <div>
+          <p class="text-sm text-gray-600 font-semibold">Last Played Move:</p>
+          <p class="text-lg font-mono text-blue-600">{@last_from_to}</p>
+          <p class="text-lg font-mono text-blue-600">{@last_san}</p>
+          <p class="text-lg font-mono text-emerald-600">
+            {if @move_list == [] do
+              "No Moves"
+            else
+              Enum.reverse(@move_list) |> Enum.join(", ")
+            end}
+          </p>
+        </div>
+        <div>
+          <.button phx-click="reset" variant="primary">
+            <.icon name="hero-arrow-path" /> Reset
+          </.button>
+        </div>
+      </div>
+
+      <div class="flex justify-center bg-gray-200 p-4 rounded-xl shadow-inner">
+        <div
+          id="endgame-board"
+          phx-hook="ChessBoard"
+          phx-update="ignore"
+          data-endgame-id={@endgame.id}
+          class="w-[400px] h-[400px]"
+        >
+        </div>
+      </div>
+
+      <.list>
+        <:item title="Fen">{@endgame.fen}</:item>
+        <:item title="Key">{@endgame.key}</:item>
+        <:item title="Color">{@endgame.color}</:item>
+        <:item title="Result">{@endgame.result}</:item>
+        <:item title="Rating">{@endgame.rating}</:item>
+      </.list>
+    </Layouts.app>
+    """
+  end
+
+  @impl true
+  def mount(%{"id" => id}, _session, socket) do
+    endgame = Endgames.get_endgame!(id)
+
+    socket =
+      socket
+      |> assign(:page_title, "Play endgame")
+      |> assign(:endgame, endgame)
+      |> assign(:move_list, [])
+      |> assign(:last_san, "None yet")
+      |> assign(:last_from_to, "None yet")
+      |> push_event("init_board", %{
+        fen: endgame.fen,
+        orientation: Atom.to_string(endgame.color),
+        player_color: Atom.to_string(endgame.color)
+      })
+
+    {:ok, socket}
+  end
+
+  @impl true
+  def handle_event(
+        "endgame_move_played",
+        %{"from" => from, "to" => to, "san" => san},
+        socket
+      ) do
+    # TODO: server-side legality check + tablebase evaluation when wired
+    {:noreply,
+     socket
+     |> assign(:last_from_to, "#{from} ➔ #{to}")
+     |> assign(:last_san, san)
+     |> assign(:move_list, [san | socket.assigns.move_list])}
+  end
+
+  def handle_event("chess_fen_invalid", %{"fen" => fen, "message" => message}, socket) do
+    {:noreply,
+     put_flash(
+       socket,
+       :error,
+       "Endgame FEN is invalid and the board cannot be loaded: #{message} (#{fen})"
+     )}
+  end
+
+  def handle_event("reset", _params, socket) do
+    {:noreply,
+     socket
+     |> assign(:move_list, [])
+     |> assign(:last_san, "None yet")
+     |> assign(:last_from_to, "None yet")
+     |> push_event("init_board", %{
+       fen: socket.assigns.endgame.fen,
+       orientation: Atom.to_string(socket.assigns.endgame.color),
+       player_color: Atom.to_string(socket.assigns.endgame.color)
+     })}
+  end
+end