defmodule EctoPSQLExtras.TableSchema do
  @behaviour EctoPSQLExtras

  def info do
    %{
      title: "Column names and types",
      columns: [
        %{name: :column_name, type: :string},
        %{name: :data_type, type: :string},
        %{name: :is_nullable, type: :boolean},
        %{name: :column_default, type: :string},
        %{name: :table_name, type: :string}
      ]
    }
  end

  def query(args \\ []) do
    if args[:table_name] do
      """
      /* ECTO_PSQL_EXTRAS: Table column names and types */

      SELECT column_name, data_type, is_nullable, column_default, table_name
      FROM information_schema.columns
      WHERE table_name = '<%= table_name %>';
      """
      |> EEx.eval_string(args)
    else
      """
      /* ECTO_PSQL_EXTRAS: All database column names and types */

      SELECT column_name, data_type, is_nullable, column_default, table_name
      FROM information_schema.columns;
      """
    end
  end
end