@spec before_all() :: t()

Return an offset that is guaranteed to be before any real database operations.

@spec first() :: t()

The first possible offset in the log.

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

Parse an offset value from an HTTP header into a %Elixir.Electric.Client.Offset{} struct.

iex> from_string("-1")
{:ok, %Elixir.Electric.Client.Offset{tx: -1, op: 0}}

iex> from_string("1378734_3")
{:ok, %Elixir.Electric.Client.Offset{tx: 1378734, op: 3}}

iex> from_string("not a real offset")
{:error, "has invalid format"}

@spec from_string!(String.t()) :: t() | no_return()

Parse an offset value from an HTTP header into a %Elixir.Electric.Client.Offset{} struct.

Raises if the offset header value is invalid.

iex> from_string!("-1")
%Elixir.Electric.Client.Offset{tx: -1, op: 0}

iex> from_string!("1378734_3")
%Elixir.Electric.Client.Offset{tx: 1378734, op: 3}

iex> from_string!("not a real offset")
** (ArgumentError) has invalid format

A guard to test if the given offset is the first possible (as returned by first/0).

@spec new(non_neg_integer(), non_neg_integer()) :: t()

Create a new Elixir.Electric.Client.Offset struct from the given LSN and operation offsets.

iex> new(2349, 3)
%Elixir.Electric.Client.Offset{tx: 2349, op: 3}

@spec to_string(t()) :: String.t()

Output the an Offset as a string for use in query parameters.

iex> new(2349, 3) |> Elixir.Electric.Client.Offset.to_string()
"2349_3"

iex> before_all() |> Elixir.Electric.Client.Offset.to_string()
"-1"