defmodule Mv.DataCase do
  @moduledoc """
  This module defines the setup for tests requiring
  access to the application's data layer.

  You may define functions here to be used as helpers in
  your tests.

  Finally, if the test case interacts with the database,
  we enable the SQL sandbox, so changes done to the database
  are reverted at the end of every test. If you are using
  PostgreSQL, you can even run database tests asynchronously
  by setting `use Mv.DataCase, async: true`, although
  this option is not recommended for other databases.
  """

  use ExUnit.CaseTemplate

  require Ash.Query

  using do
    quote do
      alias Mv.Repo

      import Ecto
      import Ecto.Changeset
      import Ecto.Query
      import Mv.DataCase
    end
  end

  setup tags do
    Mv.DataCase.setup_sandbox(tags)
    # Ensure "Mitglied" role exists for default role assignment to work in tests
    # Note: This runs in every test because each test runs in a sandboxed database.
    # The check is fast (single query) and idempotent (skips if role exists).
    Mv.DataCase.ensure_default_role()
    :ok
  end

  @doc """
  Sets up the sandbox based on the test tags.
  Returns the owner pid for use with Phoenix.Ecto.SQL.Sandbox.
  """
  def setup_sandbox(tags) do
    pid = Ecto.Adapters.SQL.Sandbox.start_owner!(Mv.Repo, shared: not tags[:async])
    on_exit(fn -> Ecto.Adapters.SQL.Sandbox.stop_owner(pid) end)
    pid
  end

  @doc """
  Ensures the default "Mitglied" role exists in the test database.

  This is necessary because the role_id attribute's default function expects this role to exist.
  Tests run in sandbox mode, so the role needs to be created for each test.
  """
  def ensure_default_role do
    # Check if "Mitglied" role already exists
    case Mv.Authorization.Role.get_mitglied_role() do
      {:ok, nil} ->
        # Create the role if it doesn't exist
        Mv.Authorization.Role
        |> Ash.Changeset.for_create(:create_role_with_system_flag, %{
          name: "Mitglied",
          description: "Default member role with access to own data only",
          permission_set_name: "own_data",
          is_system_role: true
        })
        |> Ash.create!(authorize?: false, domain: Mv.Authorization)

      {:ok, _role} ->
        # Role already exists, do nothing
        :ok

      {:error, _error} ->
        # Ignore errors (e.g., in tests that don't need roles)
        :ok
    end
  end

  @doc """
  A helper that transforms changeset errors into a map of messages.

      assert {:error, changeset} = Accounts.create_user(%{password: "short"})
      assert "password is too short" in errors_on(changeset).password
      assert %{password: ["password is too short"]} = errors_on(changeset)

  """
  def errors_on(changeset) do
    Ecto.Changeset.traverse_errors(changeset, fn {message, opts} ->
      Regex.replace(~r"%{(\w+)}", message, fn _, key ->
        opts |> Keyword.get(String.to_existing_atom(key), key) |> to_string()
      end)
    end)
  end
end
