basic admin endgame view and add (#3)

Reviewed-on: #3

lib/chesstrainer/endgames.ex

@@ -0,0 +1,123 @@
+defmodule Chesstrainer.Endgames do
+  @moduledoc """
+  The Endgames context.
+  """
+
+  import Ecto.Query, warn: false
+  alias Chesstrainer.Repo
+
+  alias Chesstrainer.Endgames.Endgame
+
+  @doc """
+  Returns the list of endgames.
+
+  ## Examples
+
+      iex> list_endgames()
+      [%Endgame{}, ...]
+
+  """
+  def list_endgames do
+    Repo.all(Endgame)
+  end
+
+  @doc """
+  Gets a single endgame.
+
+  Raises `Ecto.NoResultsError` if the Endgame does not exist.
+
+  ## Examples
+
+      iex> get_endgame!(123)
+      %Endgame{}
+
+      iex> get_endgame!(456)
+      ** (Ecto.NoResultsError)
+
+  """
+  def get_endgame!(id), do: Repo.get!(Endgame, id)
+
+  @doc """
+  Creates a endgame.
+
+  ## Examples
+
+      iex> create_endgame(%{field: value})
+      {:ok, %Endgame{}}
+
+      iex> create_endgame(%{field: bad_value})
+      {:error, %Ecto.Changeset{}}
+
+  """
+  def create_endgame(attrs) do
+    %Endgame{}
+    |> Endgame.changeset(attrs)
+    |> Repo.insert()
+  end
+
+  @doc """
+  Updates a endgame.
+
+  ## Examples
+
+      iex> update_endgame(endgame, %{field: new_value})
+      {:ok, %Endgame{}}
+
+      iex> update_endgame(endgame, %{field: bad_value})
+      {:error, %Ecto.Changeset{}}
+
+  """
+  def update_endgame(%Endgame{} = endgame, attrs) do
+    # ignore fen on update
+    attrs = Map.delete(attrs, "fen")
+
+    endgame
+    |> Endgame.changeset(attrs)
+    |> Repo.update()
+  end
+
+  @doc """
+  Deletes a endgame.
+
+  ## Examples
+
+      iex> delete_endgame(endgame)
+      {:ok, %Endgame{}}
+
+      iex> delete_endgame(endgame)
+      {:error, %Ecto.Changeset{}}
+
+  """
+  def delete_endgame(%Endgame{} = endgame) do
+    Repo.delete(endgame)
+  end
+
+  @doc """
+  Returns an `%Ecto.Changeset{}` for tracking endgame changes.
+
+  ## Examples
+
+      iex> change_endgame(endgame)
+      %Ecto.Changeset{data: %Endgame{}}
+
+  """
+  def change_endgame(%Endgame{} = endgame, attrs \\ %{}) do
+    Endgame.changeset(endgame, attrs)
+  end
+
+  def add_tag(endgame, tag) do
+    endgame
+    |> Repo.preload(:tags)
+    |> Ecto.Changeset.change()
+    |> Ecto.Changeset.put_assoc(:tags, [tag | endgame.tags])
+    |> Repo.update()
+  end
+
+  def remove_tag(endgame, tag) do
+    endgame
+    |> Repo.preload(:tags)
+    |> Ecto.Changeset.change()
+    |> Ecto.Changeset.put_assoc(:tags, endgame.tags -- [tag])
+    |> Repo.update()
+  end
+end