From 2eab92a76acbeda5d3127f50f697b3c852269b70 Mon Sep 17 00:00:00 2001
From: James Harton <james@harton.nz>
Date: Mon, 2 Oct 2023 15:36:56 +1300
Subject: [PATCH] feat: Support destroying records.

---
 README.md                           |  2 +-
 lib/ash_cub_db/data_layer.ex        | 16 ++++++++++++++++
 test/ash_cub_db/data_layer_test.exs | 11 ++++++++++-
 test/support/post.ex                |  4 ++--
 4 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index fa1843f..25c5dc6 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ AshCubDb is still a work in progress.  Feel free to give it a go.
 | Read (calculations)     | ❌     |
 | Read (aggregates)       | ❌     |
 | Update                  | ✅     |
-| Destroy                 | ❌     |
+| Destroy                 | ✅     |
 
 ## Github Mirror
 
diff --git a/lib/ash_cub_db/data_layer.ex b/lib/ash_cub_db/data_layer.ex
index 4676c50..fc24c48 100644
--- a/lib/ash_cub_db/data_layer.ex
+++ b/lib/ash_cub_db/data_layer.ex
@@ -53,6 +53,7 @@ defmodule AshCubDB.DataLayer do
   def can?(resource, :create), do: Dir.writable?(resource)
   def can?(resource, :update), do: Dir.writable?(resource)
   def can?(resource, :upsert), do: Dir.writable?(resource)
+  def can?(resource, :destroy), do: Dir.writable?(resource)
   def can?(resource, :read), do: Dir.readable?(resource)
   def can?(_, :multitenancy), do: true
   def can?(_, :filter), do: true
@@ -136,6 +137,21 @@ defmodule AshCubDB.DataLayer do
     end
   end
 
+  @doc false
+  @impl true
+  def destroy(resource, changeset) do
+    with :ok <- validate_tenant_configuration(resource, changeset.tenant),
+         {:ok, db} <- start(resource),
+         {:ok, key, _data} <- Serde.serialise(changeset.data),
+         {:ok, key} <- maybe_wrap_in_tenant(key, changeset),
+         true <- CubDB.has_key?(db, key) do
+      CubDB.delete(db, key)
+    else
+      false -> {:error, StaleRecord.exception(resource: resource)}
+      {:error, reason} -> {:error, reason}
+    end
+  end
+
   @doc false
   @impl true
   def run_query(query, resource, parent \\ nil) do
diff --git a/test/ash_cub_db/data_layer_test.exs b/test/ash_cub_db/data_layer_test.exs
index 4aa894e..a5ec942 100644
--- a/test/ash_cub_db/data_layer_test.exs
+++ b/test/ash_cub_db/data_layer_test.exs
@@ -1,6 +1,6 @@
 defmodule AshCubDB.DataLayerTest do
   use ExUnit.Case, async: true
-  alias Ash.Query
+  alias Ash.{Error.Query.NotFound, Query}
   alias AshCubDB.Info
   alias Support.{Api, Author, Post}
   import Support.Factory
@@ -157,6 +157,15 @@ defmodule AshCubDB.DataLayerTest do
     end
   end
 
+  describe "destroy" do
+    test "records can be destroyed" do
+      post = insert!(Post)
+
+      assert :ok = Post.destroy(post)
+      assert {:error, %NotFound{}} = Post.get(post.id)
+    end
+  end
+
   defp dump(resource) do
     resource
     |> via()
diff --git a/test/support/post.ex b/test/support/post.ex
index ffac374..15a0b58 100644
--- a/test/support/post.ex
+++ b/test/support/post.ex
@@ -16,8 +16,7 @@ defmodule Support.Post do
   end
 
   actions do
-    # defaults ~w[create read update destroy]a
-    defaults ~w[create read update]a
+    defaults ~w[create read update destroy]a
   end
 
   relationships do
@@ -31,5 +30,6 @@ defmodule Support.Post do
     define :read
     define :update
     define :get, action: :read, get_by: [:id]
+    define :destroy
   end
 end