feat: port basic functionality to elixir

lib/components_elixir/inventory/category.ex

@@ -0,0 +1,44 @@
+defmodule ComponentsElixir.Inventory.Category do
+  @moduledoc """
+  Schema for component categories.
+
+  Categories can be hierarchical with parent-child relationships.
+  """
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  alias ComponentsElixir.Inventory.{Category, Component}
+
+  schema "categories" do
+    field :name, :string
+    field :description, :string
+
+    belongs_to :parent, Category
+    has_many :children, Category, foreign_key: :parent_id
+    has_many :components, Component
+
+    timestamps()
+  end
+
+  @doc false
+  def changeset(category, attrs) do
+    category
+    |> cast(attrs, [:name, :description, :parent_id])
+    |> validate_required([:name])
+    |> validate_length(:name, min: 1, max: 255)
+    |> validate_length(:description, max: 1000)
+    |> unique_constraint([:name, :parent_id])
+    |> foreign_key_constraint(:parent_id)
+  end
+
+  @doc """
+  Returns the full path of the category including parent names.
+  """
+  def full_path(%Category{parent: nil} = category), do: category.name
+  def full_path(%Category{parent: %Category{} = parent} = category) do
+    "#{full_path(parent)} > #{category.name}"
+  end
+  def full_path(%Category{parent: %Ecto.Association.NotLoaded{}} = category) do
+    category.name
+  end
+end