From af4f09a1a35d8264ddc40f4c879a25407a15bd4a Mon Sep 17 00:00:00 2001
From: Mayel <git@mayel.space>
Date: Thu, 4 Feb 2021 15:12:05 +0100
Subject: [PATCH 1/2] can use with schemas with @primary_key: false

---
 lib/arbor/tree.ex | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/arbor/tree.ex b/lib/arbor/tree.ex
index db31dcf..f213e49 100644
--- a/lib/arbor/tree.ex
+++ b/lib/arbor/tree.ex
@@ -35,7 +35,12 @@ defmodule Arbor.Tree do
   defmacro __before_compile__(%{module: definition} = _env) do
     arbor_opts = Module.get_attribute(definition, :arbor_opts)
 
-    {primary_key, primary_key_type, _} = Module.get_attribute(definition, :primary_key)
+
+    {primary_key, primary_key_type} = case Module.get_attribute(definition, :primary_key) do
+        {primary_key, primary_key_type, _} -> {primary_key, primary_key_type}
+        _ -> {arbor_opts[:primary_key], arbor_opts[:primary_key_type]}
+      end
+
     struct_fields = Module.get_attribute(definition, :struct_fields)
 
     struct_source = struct_fields[:__meta__].source

From 0f4ae2cdd91d3ca56e53803e9790461771f40afe Mon Sep 17 00:00:00 2001
From: Mayel <git@mayel.space>
Date: Thu, 4 Feb 2021 16:06:07 +0100
Subject: [PATCH 2/2] fallback to :id

---
 lib/arbor/tree.ex | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/lib/arbor/tree.ex b/lib/arbor/tree.ex
index f213e49..2ab71b5 100644
--- a/lib/arbor/tree.ex
+++ b/lib/arbor/tree.ex
@@ -85,13 +85,15 @@ defmodule Arbor.Tree do
         )
       end
 
+      defp id(struct), do: Map.get(struct, unquote(opts[:foreign_key]), Map.get(struct, :id))
+
       def parent(struct) do
         from(
           t in unquote(definition),
           where:
             fragment(
               unquote("#{opts[:primary_key]} = ?"),
-              type(^struct.unquote(opts[:foreign_key]), unquote(opts[:foreign_key_type]))
+              type(^id(struct), unquote(opts[:foreign_key_type]))
             )
         )
       end
@@ -102,7 +104,7 @@ defmodule Arbor.Tree do
           where:
             fragment(
               unquote("#{opts[:foreign_key]} = ?"),
-              type(^struct.unquote(opts[:primary_key]), unquote(opts[:foreign_key_type]))
+              type(^id(struct), unquote(opts[:foreign_key_type]))
             )
         )
       end
@@ -112,7 +114,7 @@ defmodule Arbor.Tree do
           t in unquote(definition),
           where:
             t.unquote(opts[:primary_key]) !=
-              type(^struct.unquote(opts[:primary_key]), unquote(opts[:primary_key_type])),
+              type(^id(struct), unquote(opts[:primary_key_type])),
           where:
             fragment(
               unquote("#{opts[:foreign_key]} = ?"),
@@ -142,7 +144,7 @@ defmodule Arbor.Tree do
             SELECT *
             FROM #{opts[:tree_name]}
           )
-          """), type(^struct.unquote(opts[:primary_key]), unquote(opts[:primary_key_type]))),
+          """), type(^id(struct), unquote(opts[:primary_key_type]))),
           on: t.unquote(opts[:primary_key]) == g.unquote(opts[:foreign_key])
       end
 
@@ -169,7 +171,7 @@ defmodule Arbor.Tree do
               )
               SELECT #{opts[:primary_key]} FROM #{opts[:tree_name]}
               """),
-              type(^struct.unquote(opts[:primary_key]), unquote(opts[:foreign_key_type])),
+              type(^id(struct), unquote(opts[:foreign_key_type])),
               type(^depth, :integer)
             )
         )