@spec validate(NaiveDateTime.t()) :: {:ok, NaiveDateTime.t()} | {:error, String.t()}

Validates invoice creation datetime.

Rules

• Must be a NaiveDateTime
• Must not be in the future (cannot create invoices with future timestamps)

Examples

iex> past = ~N[2025-01-01 12:00:00]
iex> QRNBU.Validators.InvoiceCreation.validate(past)
{:ok, past}

iex> now = NaiveDateTime.utc_now()
iex> QRNBU.Validators.InvoiceCreation.validate(now)
{:ok, now}

iex> future = NaiveDateTime.add(NaiveDateTime.utc_now(), 86400, :second)
iex> QRNBU.Validators.InvoiceCreation.validate(future)
{:error, "Invoice creation cannot be in the future"}

iex> QRNBU.Validators.InvoiceCreation.validate("2025-01-01")
{:error, "Invoice creation must be a NaiveDateTime"}