@spec fetch_logs(String.t(), String.t(), keyword()) ::
  {:ok, [ExAtlas.Fly.Logs.LogEntry.t()]} | {:error, term()}

Fetches logs for app_name using token.

Options

• :region — filter by Fly region code.
• :instance — filter by machine instance id.
• :start_time — integer nanoseconds-since-epoch, for pagination.
• :base_url — override the endpoint (default: :ex_atlas, :fly, log_endpoint or https://api.machines.dev/v1/apps).
• :timeout_ms — request timeout.

• :http_client — optional (url, headers) -> {:ok, status, body} | {:error, reason} override. When omitted, uses Req.

@spec fetch_logs_with_retry(
  String.t(),
  keyword()
) :: {:ok, [ExAtlas.Fly.Logs.LogEntry.t()]} | {:error, term()}

Fetches logs with a single 401-driven retry.

If the server returns 401, the token is invalidated, a new one is acquired, and the fetch is retried once.

Options

• :token_fn — (app_name -> {:ok, token} | {:error, reason}). Defaults to ExAtlas.Fly.Tokens.get/1.

• :invalidate_fn — (app_name -> :ok). Defaults to ExAtlas.Fly.Tokens.invalidate/1.
• All other options pass through to fetch_logs/3.

@spec next_start_time([ExAtlas.Fly.Logs.LogEntry.t()]) :: non_neg_integer() | nil

Returns the next start_time cursor value for pagination.

Given a list of LogEntry structs, returns the max timestamp in nanoseconds plus 1 (to avoid re-fetching the last entry). Returns nil for an empty list.