fix: Split FromLatestEventOptions into Read and Observe variants (#29)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: goloroden

README.md

@@ -212,7 +212,7 @@ EventSourcingDB.read_events(
   "/books/42",
   %EventSourcingDB.ReadEventsOptions{
     recursive: false,
-    from_latest_event: %EventSourcingDB.FromLatestEventOptions{
+    from_latest_event: %EventSourcingDB.ReadFromLatestEventOptions{
       subject: "/books/42",
       type: "io.eventsourcingdb.library.book-borrowed",
       if_event_is_missing: :read_everything
@@ -297,7 +297,7 @@ EventSourcingDB.observe_events(
   "/books/42",
   %EventSourcingDB.ObserveEventsOptions{
     recursive: false,
-    from_latest_event: %EventSourcingDB.FromLatestEventOptions{
+    from_latest_event: %EventSourcingDB.ObserveFromLatestEventOptions{
       subject: "/books/42",
       type: "io.eventsourcingdb.library.book-borrowed",
       if_event_is_missing: :read_everything

lib/eventsourcingdb.ex

@@ -292,7 +292,7 @@ defmodule EventSourcingDB do
     "/books/42",
     %EventSourcingDB.ReadEventsOptions{
       recursive: false,
-      from_latest_event: %EventSourcingDB.FromLatestEventOptions{
+      from_latest_event: %EventSourcingDB.ReadFromLatestEventOptions{
         subject: "/books/42",
         type: "io.eventsourcingdb.library.book-borrowed",
         if_event_is_missing: :read_everything
@@ -378,7 +378,7 @@ defmodule EventSourcingDB do
     "/books/42",
     %EventSourcingDB.ObserveEventsOptions{
       recursive: false,
-      from_latest_event: %EventSourcingDB.FromLatestEventOptions{
+      from_latest_event: %EventSourcingDB.ObserveFromLatestEventOptions{
         subject: "/books/42",
         type: "io.eventsourcingdb.library.book-borrowed",
         if_event_is_missing: :read_everything

lib/eventsourcingdb/request_options/observe_events.ex

@@ -6,7 +6,7 @@ defmodule EventSourcingDB.ObserveEventsOptions do
 
   typedstruct do
     field :recursive, boolean(), enforce: true
-    field :from_latest_event, EventSourcingDB.FromLatestEventOptions.t()
+    field :from_latest_event, EventSourcingDB.ObserveFromLatestEventOptions.t()
     field :lower_bound, EventSourcingDB.BoundOptions.t()
   end
 

lib/eventsourcingdb/request_options/observe_from_latest_event.ex

@@ -0,0 +1,40 @@
+defmodule EventSourcingDB.ObserveFromLatestEventOptions do
+  @moduledoc """
+  Options for observing events starting from the latest event of a given type.
+  """
+  use TypedStruct
+
+  typedstruct enforce: true do
+    field :if_event_is_missing, :read_everything | :wait_for_event
+    field :subject, String.t()
+    field :type, String.t()
+  end
+
+  @spec new(keyword()) :: t()
+  def new(options) do
+    options =
+      options
+      |> Keyword.validate!([:if_event_is_missing, :subject, :type])
+
+    struct!(__MODULE__, options)
+  end
+
+  defimpl Jason.Encoder do
+    @spec encode(EventSourcingDB.ObserveFromLatestEventOptions.t(), Jason.Encode.opts()) ::
+            iodata()
+    def encode(value, opts) do
+      Jason.Encode.map(
+        %{
+          "ifEventIsMissing" =>
+            case value.if_event_is_missing do
+              :read_everything -> "read-everything"
+              :wait_for_event -> "wait-for-event"
+            end,
+          "subject" => value.subject,
+          "type" => value.type
+        },
+        opts
+      )
+    end
+  end
+end

lib/eventsourcingdb/request_options/read_events.ex

@@ -7,7 +7,7 @@ defmodule EventSourcingDB.ReadEventsOptions do
   typedstruct do
     field :recursive, boolean(), enforce: true
     field :order, :chronological | :antichronological
-    field :from_latest_event, EventSourcingDB.FromLatestEventOptions.t()
+    field :from_latest_event, EventSourcingDB.ReadFromLatestEventOptions.t()
     field :lower_bound, EventSourcingDB.BoundOptions.t()
     field :upper_bound, EventSourcingDB.BoundOptions.t()
   end

…gdb/request_options/from_latest_event.ex …equest_options/read_from_latest_event.exlib/eventsourcingdb/request_options/from_latest_event.ex renamed to lib/eventsourcingdb/request_options/read_from_latest_event.ex lib/eventsourcingdb/request_options/from_latest_event.ex renamed to lib/eventsourcingdb/request_options/read_from_latest_event.ex

@@ -1,11 +1,11 @@
-defmodule EventSourcingDB.FromLatestEventOptions do
+defmodule EventSourcingDB.ReadFromLatestEventOptions do
   @moduledoc """
-  Reading events from when a certain event occured.
+  Options for reading events starting from the latest event of a given type.
   """
   use TypedStruct
 
   typedstruct enforce: true do
-    field :if_event_is_missing, :read_everything | :read_nothing | :wait_for_event
+    field :if_event_is_missing, :read_everything | :read_nothing
     field :subject, String.t()
     field :type, String.t()
   end
@@ -20,7 +20,7 @@ defmodule EventSourcingDB.FromLatestEventOptions do
   end
 
   defimpl Jason.Encoder do
-    @spec encode(EventSourcingDB.FromLatestEventOptions.t(), Jason.Encode.opts()) ::
+    @spec encode(EventSourcingDB.ReadFromLatestEventOptions.t(), Jason.Encode.opts()) ::
             iodata()
     def encode(value, opts) do
       Jason.Encode.map(
@@ -29,7 +29,6 @@ defmodule EventSourcingDB.FromLatestEventOptions do
             case value.if_event_is_missing do
               :read_everything -> "read-everything"
               :read_nothing -> "read-nothing"
-              :wait_for_event -> "wait-for-event"
             end,
           "subject" => value.subject,
           "type" => value.type

mix.exs

@@ -70,9 +70,10 @@ defmodule EventSourcingDB.MixProject do
         ],
         "Request Options": [
           EventSourcingDB.BoundOptions,
-          EventSourcingDB.FromLatestEventOptions,
           EventSourcingDB.ObserveEventsOptions,
-          EventSourcingDB.ReadEventsOptions
+          EventSourcingDB.ObserveFromLatestEventOptions,
+          EventSourcingDB.ReadEventsOptions,
+          EventSourcingDB.ReadFromLatestEventOptions
         ],
         Testing: [
           EventSourcingDB.TestContainer

test/observe_events_test.exs

@@ -2,7 +2,7 @@ defmodule EventSourcingDBTest.ObserveEvents do
   alias EventSourcingDB.TestContainer
   alias EventSourcingDB.ObserveEventsOptions
   alias EventSourcingDB.BoundOptions
-  alias EventSourcingDB.FromLatestEventOptions
+  alias EventSourcingDB.ObserveFromLatestEventOptions
   import EventSourcingDBTest.Utils
   use ExUnit.Case, async: true
 
@@ -70,7 +70,7 @@ defmodule EventSourcingDBTest.ObserveEvents do
     events =
       EventSourcingDB.observe_events!(client, "/", %ObserveEventsOptions{
         recursive: true,
-        from_latest_event: %FromLatestEventOptions{
+        from_latest_event: %ObserveFromLatestEventOptions{
           subject: "/test",
           type: "io.eventsourcingdb.test.bar",
           if_event_is_missing: :read_everything

test/read_events_test.exs

@@ -1,7 +1,7 @@
 defmodule EventSourcingDBTest.ReadEvents do
   alias EventSourcingDB.Errors.TransmissionError
   alias EventSourcingDB.Client
-  alias EventSourcingDB.FromLatestEventOptions
+  alias EventSourcingDB.ReadFromLatestEventOptions
   alias EventSourcingDB.BoundOptions
   alias EventSourcingDB.ReadEventsOptions
   alias EventSourcingDB.TestContainer
@@ -181,7 +181,7 @@ defmodule EventSourcingDBTest.ReadEvents do
 
     events =
       EventSourcingDB.read_events!(client, "/test", %ReadEventsOptions{
-        from_latest_event: %FromLatestEventOptions{
+        from_latest_event: %ReadFromLatestEventOptions{
           subject: "/",
           type: "io.eventsourcingdb.test.does-not-exist",
           if_event_is_missing: :read_nothing
@@ -204,7 +204,7 @@ defmodule EventSourcingDBTest.ReadEvents do
 
     events =
       EventSourcingDB.read_events!(client, "/test", %ReadEventsOptions{
-        from_latest_event: %FromLatestEventOptions{
+        from_latest_event: %ReadFromLatestEventOptions{
           subject: "/marker",
           type: "io.eventsourcingdb.test",
           if_event_is_missing: :read_nothing