implement notes

lib/memex/notes/note.ex

@@ -1,22 +1,58 @@
 defmodule Memex.Notes.Note do
+  @moduledoc """
+  Schema for a user-written note
+  """
   use Ecto.Schema
   import Ecto.Changeset
+  alias Ecto.{Changeset, UUID}
+  alias Memex.{Accounts.User, Notes.Note}
 
   @primary_key {:id, :binary_id, autogenerate: true}
   @foreign_key_type :binary_id
   schema "notes" do
     field :content, :string
-    field :tag, {:array, :string}
+    field :tags, {:array, :string}
+    field :tags_string, :string, virtual: true
     field :title, :string
     field :visibility, Ecto.Enum, values: [:public, :private, :unlisted]
 
+    belongs_to :user, User
+
     timestamps()
   end
 
+  @type t :: %Note{}
+  @type id :: UUID.t()
+  @type changeset :: Changeset.t(t())
+
   @doc false
-  def changeset(note, attrs) do
-    note
-    |> cast(attrs, [:title, :content, :tag, :visibility])
-    |> validate_required([:title, :content, :tag, :visibility])
+  @spec create_changeset(attrs :: map(), User.t()) :: changeset()
+  def create_changeset(attrs, %User{id: user_id}) do
+    %Note{}
+    |> cast(attrs, [:title, :content, :tags, :visibility])
+    |> change(user_id: user_id)
+    |> cast_tags_string(attrs)
+    |> validate_required([:title, :content, :user_id, :visibility])
   end
+
+  @spec update_changeset(Note.t(), attrs :: map(), User.t()) :: changeset()
+  def update_changeset(%{user_id: user_id} = note, attrs, %User{id: user_id}) do
+    note
+    |> cast(attrs, [:title, :content, :tags, :visibility])
+    |> cast_tags_string(attrs)
+    |> validate_required([:title, :content, :visibility])
+  end
+
+  defp cast_tags_string(changeset, %{"tags_string" => tags_string})
+       when tags_string |> is_binary() do
+    tags =
+      tags_string
+      |> String.split(",", trim: true)
+      |> Enum.map(fn str -> str |> String.trim() end)
+      |> Enum.sort()
+
+    changeset |> change(tags: tags)
+  end
+
+  defp cast_tags_string(changeset, _attrs), do: changeset
 end