ELIXIR - Validating a password for length and complexity in Ecto

user.ex

defmodule MyApp.User do
  def changeset(model, params \\ :empty) do
    model
    |> cast(params, @required_fields, @optional_fields)
    |> validate_format(:email, ~r/@/)
    |> validate_length(:password, min: 8)
    |> validate_format(:password, ~r/[0-9]+/, message: "Password must contain a number") # has a number
    |> validate_format(:password, ~r/[A-Z]+/, message: "Password must contain an upper-case letter") # has an upper case letter
    |> validate_format(:password, ~r/[a-z]+/, message: "Password must contain a lower-case letter") # has a lower case letter
    |> validate_format(:password, ~r/[#\!\?&@\$%^&*\(\)]+/, message: "Password must contain a symbol") # Has a symbol
    |> validate_confirmation(:password)    
    # and so on
  end
end