basics being displayed

lib/cobblemon_ui/cobblemon_fs/pc_store.ex

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+defmodule CobblemonUi.CobblemonFS.PCStore do
+  @moduledoc """
+  Parses a player's PC storage `.dat` file.
+
+  PC layout:
+    Root -> boxes -> box0..boxN -> slot0..slotN
+  """
+
+  alias CobblemonUi.CobblemonFS.{NBT, Pokemon}
+
+  @doc """
+  Reads and parses a PC storage `.dat` file at the given path.
+
+  Returns `{:ok, [%{box: integer, pokemon: list}]}` or `{:error, reason}`.
+  """
+  @spec parse(String.t()) :: {:ok, list(map())} | {:error, term()}
+  def parse(path) do
+    with {:ok, data} <- File.read(path),
+         {:ok, {_name, root}} <- NBT.decode(data) do
+      boxes = Map.get(root, "boxes", %{})
+      {:ok, normalize_boxes(boxes)}
+    else
+      {:error, :enoent} -> {:error, :not_found}
+      {:error, reason} -> {:error, {:corrupt_data, reason}}
+    end
+  end
+
+  defp normalize_boxes(boxes) when is_map(boxes) do
+    boxes
+    |> Enum.filter(fn {key, _} -> String.starts_with?(key, "box") end)
+    |> Enum.sort_by(fn {key, _} -> extract_index(key) end)
+    |> Enum.map(fn {key, box_data} ->
+      %{
+        box: extract_index(key),
+        pokemon: normalize_box_slots(box_data)
+      }
+    end)
+  end
+
+  defp normalize_boxes(_), do: []
+
+  defp normalize_box_slots(box) when is_map(box) do
+    box
+    |> Enum.filter(fn {key, _} -> String.starts_with?(key, "slot") end)
+    |> Enum.sort_by(fn {key, _} -> extract_index(key) end)
+    |> Enum.map(fn {_key, slot_data} -> Pokemon.normalize(slot_data) end)
+  end
+
+  defp normalize_box_slots(_), do: []
+
+  defp extract_index(key) do
+    case Integer.parse(String.replace(key, ~r/[^\d]/, "")) do
+      {n, _} -> n
+      :error -> 0
+    end
+  end
+end