defmodule Commanded.ExampleDomain.MoneyTransfer do
  defstruct [
    transfer_uuid: nil,
    debit_account: nil,
    credit_account: nil,
    amount: 0,
    state: nil,
  ]

  alias Commanded.ExampleDomain.MoneyTransfer

  defmodule Commands do
    defmodule TransferMoney, do: defstruct [transfer_uuid: nil, debit_account: nil, credit_account: nil, amount: nil]
  end

  defmodule Events do
    defmodule MoneyTransferRequested, do: defstruct [transfer_uuid: nil, debit_account: nil, credit_account: nil, amount: nil]
  end

  alias Commands.{TransferMoney}
  alias Events.{MoneyTransferRequested}

  def transfer_money(%MoneyTransfer{state: nil}, %TransferMoney{transfer_uuid: transfer_uuid, debit_account: debit_account, credit_account: credit_account, amount: amount})
    when amount > 0
  do
    %MoneyTransferRequested{transfer_uuid: transfer_uuid, debit_account: debit_account, credit_account: credit_account, amount: amount}
  end

  # state mutatators

  def apply(%MoneyTransfer{} = state, %MoneyTransferRequested{} = transfer_requested) do
    %MoneyTransfer{state |
      transfer_uuid: transfer_requested.transfer_uuid,
      debit_account: transfer_requested.debit_account,
      credit_account: transfer_requested.credit_account,
      amount: transfer_requested.amount,
      state: :requested,
    }
  end
end