commit 1fe4a43ff8093761e2cfc6db5c9f131174ab2ff0
Author: Zach Daniel <zach@zachdaniel.dev>
Date:   Fri Sep 29 15:38:27 2023 -0400

    WIP

diff --git a/.formatter.exs b/.formatter.exs
new file mode 100644
index 0000000..d2cda26
--- /dev/null
+++ b/.formatter.exs
@@ -0,0 +1,4 @@
+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4a72ba7
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,26 @@
+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+ash_event_source-*.tar
+
+# Temporary files, for example, from tests.
+/tmp/
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..dd9e6df
--- /dev/null
+++ b/README.md
@@ -0,0 +1,20 @@
+# AshEventSource
+
+**TODO: Add description**
+
+## Installation
+
+If [available in Hex](https://hex.pm/docs/publish), the package can be installed
+by adding `ash_event_source` to your list of dependencies in `mix.exs`:
+
+```elixir
+def deps do
+  [
+    {:ash_event_source, "~> 0.1.0"}
+  ]
+end
+```
+
+Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
+and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
+be found at <https://hexdocs.pm/ash_event_source>.
diff --git a/config/config.exs b/config/config.exs
new file mode 100644
index 0000000..7f4576b
--- /dev/null
+++ b/config/config.exs
@@ -0,0 +1,6 @@
+import Config
+
+if Mix.env() == :test do
+  config :ash, :validate_api_resource_inclusion?, false
+  config :ash, :validate_api_config_inclusion?, false
+end
diff --git a/lib/ash_event_source.ex b/lib/ash_event_source.ex
new file mode 100644
index 0000000..eb98504
--- /dev/null
+++ b/lib/ash_event_source.ex
@@ -0,0 +1,20 @@
+defmodule AshEventSource do
+  @event_source %Spark.Dsl.Section{
+    name: :event_source,
+    schema: [
+      event_resource: [
+        type: {:behaviour, Ash.Resource},
+        required: true,
+        doc: "The resource to use to store events."
+      ]
+    ]
+  }
+
+  @sections [@event_source]
+
+  @transformers [
+    AshEventSource.Transformers.RewriteActions
+  ]
+
+  use Spark.Dsl.Extension, transformers: @transformers, sections: @sections
+end
diff --git a/lib/info.ex b/lib/info.ex
new file mode 100644
index 0000000..38ff356
--- /dev/null
+++ b/lib/info.ex
@@ -0,0 +1,3 @@
+defmodule AshEventSource.Info do
+  use Spark.InfoGenerator, extension: AshEventSource, sections: [:event_source]
+end
diff --git a/lib/persist_event.ex b/lib/persist_event.ex
new file mode 100644
index 0000000..d5e3ac3
--- /dev/null
+++ b/lib/persist_event.ex
@@ -0,0 +1,44 @@
+defmodule AshEventSource.PersistEvent do
+  def run(input, opts, context) do
+    event =
+      opts[:event_resource]
+      |> Ash.Changeset.for_create(:create, %{input: input.params, resource: input.resource, action: opts[:action]}, actor: Ash.context_to_opts(context))
+      |> input.api.create!()
+
+    event.resource
+    |> Ash.Changeset.for_create(event.action, event.input)
+    |> input.api.create!()
+
+    event =
+      event
+      |> Ash.Changeset.for_update(:process)
+      |> input.api.update!()
+
+
+    {:ok, :success}
+  end
+
+  # use Ash.Resource.ManualCreate
+  # use Ash.Resource.ManualUpdate
+
+  # @impl Ash.Resource.ManualCreate
+  # def create(changeset, opts, context) do
+  #   input = changeset.input
+
+
+  #   # This is a hack, need to figure this out
+  #   Ash.Changeset.apply_attributes(changeset, force?: true)
+  # end
+
+  # @impl Ash.Resource.ManualUpdate
+  # def update(changeset, opts, context) do
+  #   input = changeset.input
+
+  #   opts[:resource]
+  #   |> Ash.Changeset.for_create(:create, %{input: input}, actor: Ash.context_to_opts(context))
+  #   |> changeset.api.create!()
+
+  #   # This is a hack, need to figure this out
+  #   Ash.Changeset.apply_attributes(changeset, force?: true)
+  # end
+end
diff --git a/lib/transformers/rewrite_actions.ex b/lib/transformers/rewrite_actions.ex
new file mode 100644
index 0000000..b823b8f
--- /dev/null
+++ b/lib/transformers/rewrite_actions.ex
@@ -0,0 +1,54 @@
+defmodule AshEventSource.Transformers.RewriteActions do
+  @moduledoc "Rewrite each create, update and destroy action into event sourced actions"
+  use Spark.Dsl.Transformer
+
+  def after?(_), do: true
+
+  def transform(dsl) do
+    event_resource = AshEventSource.Info.event_source_event_resource!(dsl)
+
+    dsl
+    |> Ash.Resource.Info.actions()
+    |> Enum.filter(&(&1.type in [:create, :update, :destroy]))
+    |> Enum.reduce({:ok, dsl}, fn action, {:ok, dsl} ->
+      new_name = :"#{action.name}_implementation"
+      copied_action = %{action | name: new_name}
+
+      arguments =
+        action.accept
+        |> Enum.map(fn attr_name ->
+          attr = Ash.Resource.Info.attribute(dsl, attr_name)
+
+          %Ash.Resource.Actions.Argument{
+            name: attr.name,
+            allow_nil?: attr.allow_nil?,
+            type: attr.type,
+            constraints: attr.constraints,
+            default: attr.default,
+            description: attr.description,
+            sensitive?: attr.sensitive?
+          }
+        end)
+
+      arguments =
+        action.arguments
+        |> Enum.concat(arguments)
+        |> Enum.uniq_by(&(&1.name))
+
+      action = %Ash.Resource.Actions.Action{
+        name: action.name,
+        description: action.description,
+        returns: :atom,
+        constraints: [one_of: [:success, :failure]],
+        arguments: arguments,
+        run: {AshEventSource.PersistEvent, [event_resource: event_resource, action: new_name]},
+        transaction?: true
+      }
+
+      {:ok,
+       dsl
+       |> Spark.Dsl.Transformer.replace_entity([:actions], action, &(&1.name == action.name))
+       |> Spark.Dsl.Transformer.add_entity([:actions], copied_action)}
+    end)
+  end
+end
diff --git a/mix.exs b/mix.exs
new file mode 100644
index 0000000..1c26aca
--- /dev/null
+++ b/mix.exs
@@ -0,0 +1,29 @@
+defmodule AshEventSource.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :ash_event_source,
+      version: "0.1.0",
+      elixir: "~> 1.15",
+      start_permanent: Mix.env() == :prod,
+      deps: deps()
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    [
+      extra_applications: [:logger]
+    ]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      {:ash, "~> 2.14"}
+      # {:dep_from_hexpm, "~> 0.3.0"},
+      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+    ]
+  end
+end
diff --git a/mix.lock b/mix.lock
new file mode 100644
index 0000000..0a3da42
--- /dev/null
+++ b/mix.lock
@@ -0,0 +1,16 @@
+%{
+  "ash": {:hex, :ash, "2.14.12", "bb2e3dbe82b49407f07854560ba3174a2c479508da8f33eb296764c6445477fb", [:mix], [{:comparable, "~> 1.0", [hex: :comparable, repo: "hexpm", optional: false]}, {:decimal, "~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:earmark, "~> 1.4", [hex: :earmark, repo: "hexpm", optional: true]}, {:ecto, "~> 3.7", [hex: :ecto, repo: "hexpm", optional: false]}, {:ets, "~> 0.8.0", [hex: :ets, repo: "hexpm", optional: false]}, {:jason, ">= 1.0.0", [hex: :jason, repo: "hexpm", optional: false]}, {:picosat_elixir, "~> 0.2", [hex: :picosat_elixir, repo: "hexpm", optional: false]}, {:plug, ">= 0.0.0", [hex: :plug, repo: "hexpm", optional: true]}, {:spark, ">= 1.1.20 and < 2.0.0-0", [hex: :spark, repo: "hexpm", optional: false]}, {:stream_data, "~> 0.5.0", [hex: :stream_data, repo: "hexpm", optional: false]}, {:telemetry, "~> 1.1", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "799edb6326bd539ede0582b3e62f015a74062d3291e7b2c21ce4b0a2f9ebe88c"},
+  "comparable": {:hex, :comparable, "1.0.0", "bb669e91cedd14ae9937053e5bcbc3c52bb2f22422611f43b6e38367d94a495f", [:mix], [{:typable, "~> 0.1", [hex: :typable, repo: "hexpm", optional: false]}], "hexpm", "277c11eeb1cd726e7cd41c6c199e7e52fa16ee6830b45ad4cdc62e51f62eb60c"},
+  "decimal": {:hex, :decimal, "2.1.1", "5611dca5d4b2c3dd497dec8f68751f1f1a54755e8ed2a966c2633cf885973ad6", [:mix], [], "hexpm", "53cfe5f497ed0e7771ae1a475575603d77425099ba5faef9394932b35020ffcc"},
+  "ecto": {:hex, :ecto, "3.10.3", "eb2ae2eecd210b4eb8bece1217b297ad4ff824b4384c0e3fdd28aaf96edd6135", [:mix], [{:decimal, "~> 1.6 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "44bec74e2364d491d70f7e42cd0d690922659d329f6465e89feb8a34e8cd3433"},
+  "elixir_make": {:hex, :elixir_make, "0.7.7", "7128c60c2476019ed978210c245badf08b03dbec4f24d05790ef791da11aa17c", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}], "hexpm", "5bc19fff950fad52bbe5f211b12db9ec82c6b34a9647da0c2224b8b8464c7e6c"},
+  "ets": {:hex, :ets, "0.8.1", "8ff9bcda5682b98493f8878fc9dbd990e48d566cba8cce59f7c2a78130da29ea", [:mix], [], "hexpm", "6be41b50adb5bc5c43626f25ea2d0af1f4a242fb3fad8d53f0c67c20b78915cc"},
+  "jason": {:hex, :jason, "1.4.1", "af1504e35f629ddcdd6addb3513c3853991f694921b1b9368b0bd32beb9f1b63", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "fbb01ecdfd565b56261302f7e1fcc27c4fb8f32d56eab74db621fc154604a7a1"},
+  "nimble_options": {:hex, :nimble_options, "1.0.2", "92098a74df0072ff37d0c12ace58574d26880e522c22801437151a159392270e", [:mix], [], "hexpm", "fd12a8db2021036ce12a309f26f564ec367373265b53e25403f0ee697380f1b8"},
+  "picosat_elixir": {:hex, :picosat_elixir, "0.2.3", "bf326d0f179fbb3b706bb2c15fbc367dacfa2517157d090fdfc32edae004c597", [:make, :mix], [{:elixir_make, "~> 0.6", [hex: :elixir_make, repo: "hexpm", optional: false]}], "hexpm", "f76c9db2dec9d2561ffaa9be35f65403d53e984e8cd99c832383b7ab78c16c66"},
+  "sourceror": {:hex, :sourceror, "0.13.0", "c6ecc96ee3ae0e042e9082a9550a1989ea40182492dc29024a8d9d2b136e5014", [:mix], [], "hexpm", "d0a819491061cd26bfa4450d1c84301a410c19c1782a6577ce15853fc0e7e4e1"},
+  "spark": {:hex, :spark, "1.1.25", "9a4836520b71a485f5dedfdab1909071c01375b0409eb4cc2e9cfa8cc28c0398", [:mix], [{:nimble_options, "~> 0.5 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:sourceror, "~> 0.1", [hex: :sourceror, repo: "hexpm", optional: false]}], "hexpm", "506dfb6e8a851362ed5bb056644f9f852ec7513df77c65c09ef8f71518a91640"},
+  "stream_data": {:hex, :stream_data, "0.5.0", "b27641e58941685c75b353577dc602c9d2c12292dd84babf506c2033cd97893e", [:mix], [], "hexpm", "012bd2eec069ada4db3411f9115ccafa38540a3c78c4c0349f151fc761b9e271"},
+  "telemetry": {:hex, :telemetry, "1.2.1", "68fdfe8d8f05a8428483a97d7aab2f268aaff24b49e0f599faa091f1d4e7f61c", [:rebar3], [], "hexpm", "dad9ce9d8effc621708f99eac538ef1cbe05d6a874dd741de2e689c47feafed5"},
+  "typable": {:hex, :typable, "0.3.0", "0431e121d124cd26f312123e313d2689b9a5322b15add65d424c07779eaa3ca1", [:mix], [], "hexpm", "880a0797752da1a4c508ac48f94711e04c86156f498065a83d160eef945858f8"},
+}
diff --git a/test/ash_event_source_test.exs b/test/ash_event_source_test.exs
new file mode 100644
index 0000000..084d2b6
--- /dev/null
+++ b/test/ash_event_source_test.exs
@@ -0,0 +1,153 @@
+defmodule AshEventSourceTest do
+  use ExUnit.Case
+
+  require Ash.Query
+
+  defmodule Api do
+    use Ash.Api
+
+    resources do
+      allow_unregistered?(true)
+    end
+  end
+
+  defmodule Event do
+    use Ash.Resource,
+      data_layer: Ash.DataLayer.Ets
+
+    actions do
+      defaults [:read, :create, :update, :destroy]
+
+      update :process do
+        change set_attribute(:processed, true)
+      end
+    end
+
+    ets do
+      private?(true)
+    end
+
+    attributes do
+      uuid_primary_key(:id)
+      attribute :input, :map, allow_nil?: false
+      attribute :resource, :atom, allow_nil?: false
+      attribute :action, :atom, allow_nil?: false
+      attribute :processed, :boolean, allow_nil?: false, default: false
+      attribute :timestamp, :utc_datetime_usec do
+        default &DateTime.utc_now/0
+        allow_nil? false
+        writable? false
+      end
+    end
+  end
+
+  defmodule Profile do
+    use Ash.Resource,
+      data_layer: Ash.DataLayer.Ets,
+      extensions: [AshEventSource]
+
+    event_source do
+      event_resource(Event)
+    end
+
+    actions do
+      defaults [:create, :read, :update, :destroy]
+    end
+
+    ets do
+      private?(true)
+    end
+
+    attributes do
+      uuid_primary_key :id
+      attribute :bio, :string
+    end
+
+    relationships do
+      belongs_to :user, AshEventSourceTest.User do
+        allow_nil? false
+        attribute_writable? true
+      end
+    end
+
+    code_interface do
+      define_for Api
+      define :create
+    end
+  end
+
+  defmodule User do
+    use Ash.Resource,
+      data_layer: Ash.DataLayer.Ets,
+      extensions: [AshEventSource]
+
+    event_source do
+      event_resource(Event)
+    end
+
+    ets do
+      private?(true)
+    end
+
+    attributes do
+      uuid_primary_key(:id)
+      attribute(:username, :string, allow_nil?: false)
+    end
+
+    actions do
+      defaults([:read, :update, :destroy])
+      create :create do
+        primary? true
+
+        change after_action(fn _changeset, result ->
+          Profile.create!(%{user_id: result.id, bio: "Initial Bio!"})
+
+          {:ok, result}
+        end)
+      end
+    end
+
+    code_interface do
+      define_for(Api)
+      define(:create)
+    end
+
+    relationships do
+      has_one :profile, Profile
+    end
+  end
+
+  test "test" do
+    User.create!(%{username: "fred"})
+    # IO.inspect("FIRST EVENT CREATED")
+    Api.read!(Event) |> IO.inspect()
+    Api.read!(User) |> IO.inspect()
+    Api.read!(Profile) |> IO.inspect()
+    # process()
+    # IO.inspect("FIRST EVENT PROCESSED")
+    # Api.read!(Event) |> IO.inspect()
+    # Api.read!(User) |> IO.inspect()
+    # Api.read!(Profile) |> IO.inspect()
+    # process()
+    # IO.inspect("SECOND EVENT PROCESSED")
+    # Api.read!(Event) |> IO.inspect()
+    # Api.read!(User) |> IO.inspect()
+    # Api.read!(Profile) |> IO.inspect()
+  end
+
+  defp process() do
+    Event
+    |> Ash.Query.sort(timestamp: :asc, id: :desc)
+    |> Ash.Query.filter(processed == false)
+    |> Api.read!()
+    |> Enum.each(fn event ->
+      event.resource
+      |> Ash.Changeset.for_create(event.action, event.input)
+      |> Api.create!()
+
+      event
+      |> Ash.Changeset.for_update(:process)
+      |> Api.update!()
+    end)
+  end
+end
diff --git a/test/test_helper.exs b/test/test_helper.exs
new file mode 100644
index 0000000..869559e
--- /dev/null
+++ b/test/test_helper.exs
@@ -0,0 +1 @@
+ExUnit.start()