From ea849a715d1409b0225789c4f6dc70c682f5a950 Mon Sep 17 00:00:00 2001
From: Anders Ejlersen <anders@ejlersen.info>
Date: Sun, 5 Dec 2021 10:31:29 +0100
Subject: [PATCH] 1.2.0: Added AssignIfNull which allows for fields to get
 components from self or children

---
 .../AssignIfNullAttributeDrawer.cs            | 39 +++++++++++++++++++
 .../AssignIfNullAttributeDrawer.cs.meta       |  3 ++
 README.md                                     |  4 +-
 .../ValueModifiers/AssignIfNullAttribute.cs   | 36 +++++++++++++++++
 .../AssignIfNullAttribute.cs.meta             | 11 ++++++
 package.json                                  |  2 +-
 6 files changed, 93 insertions(+), 2 deletions(-)
 create mode 100644 Editor/ValueModifiers/AssignIfNullAttributeDrawer.cs
 create mode 100644 Editor/ValueModifiers/AssignIfNullAttributeDrawer.cs.meta
 create mode 100644 Runtime/ValueModifiers/AssignIfNullAttribute.cs
 create mode 100644 Runtime/ValueModifiers/AssignIfNullAttribute.cs.meta

diff --git a/Editor/ValueModifiers/AssignIfNullAttributeDrawer.cs b/Editor/ValueModifiers/AssignIfNullAttributeDrawer.cs
new file mode 100644
index 0000000..021544b
--- /dev/null
+++ b/Editor/ValueModifiers/AssignIfNullAttributeDrawer.cs
@@ -0,0 +1,39 @@
+using System;
+using UnityEditor;
+using UnityEngine;
+using Object = UnityEngine.Object;
+
+namespace Module.Inspector.Editor
+{
+    [CustomPropertyDrawer(typeof(AssignIfNullAttribute))]
+    internal sealed class AssignIfNullAttributeDrawer : ValueModifierPropertyDrawer
+    {
+        public override void Modify(ValueModifierPropertyAttribute attribute, SerializedProperty property)
+        {
+            if (property.propertyType != SerializedPropertyType.ObjectReference)
+                return;
+            if (property.objectReferenceValue != null)
+                return;
+            
+            var att = (AssignIfNullAttribute)attribute;
+            Type type = att.useType ? att.type : property.GetValueType();
+
+            if (!typeof(Component).IsAssignableFrom(type))
+                return;
+
+            for (var i = 0; i < property.serializedObject.targetObjects.Length; i++)
+            {
+                Object obj = property.serializedObject.targetObjects[i];
+
+                if (!(obj is Component component))
+                    continue;
+
+                Component c = att.includeChildren 
+                                  ? component.gameObject.GetComponentInChildren(type) 
+                                  : component.gameObject.GetComponent(type);
+
+                property.objectReferenceValue = c;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Editor/ValueModifiers/AssignIfNullAttributeDrawer.cs.meta b/Editor/ValueModifiers/AssignIfNullAttributeDrawer.cs.meta
new file mode 100644
index 0000000..fd1013c
--- /dev/null
+++ b/Editor/ValueModifiers/AssignIfNullAttributeDrawer.cs.meta
@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: e029b0d7c1384ab2b961e74a2bf23fe0
+timeCreated: 1638695373
\ No newline at end of file
diff --git a/README.md b/README.md
index 7910d06..06fbaff 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,7 @@ There are six different kinds of attributes:
     * Validate field (if invalid, draws as red)
 * Decorator
     * Adds additional information or styling to a field/method (E.g. Header displays a title/category to fields after attribute)
-
+    
 
 ## Access
 
@@ -121,6 +121,8 @@ List of all value attributes:
     * If value is less than min value, then set value to min value 
 * `SmallerThanField`
     * If value is less than other fields value, then set value to other fields value
+* `AssignIfNull`
+    * If value is null will either use field or custom type to get from self or children 
 
 
 ## Validate
diff --git a/Runtime/ValueModifiers/AssignIfNullAttribute.cs b/Runtime/ValueModifiers/AssignIfNullAttribute.cs
new file mode 100644
index 0000000..81d71f7
--- /dev/null
+++ b/Runtime/ValueModifiers/AssignIfNullAttribute.cs
@@ -0,0 +1,36 @@
+using System;
+
+namespace Module.Inspector
+{
+    [AttributeUsage(AttributeTargets.Field, AllowMultiple = false, Inherited = true)]
+    public sealed class AssignIfNullAttribute : ValueModifierPropertyAttribute
+    {
+        public readonly bool useType;
+        public readonly Type type;
+        public readonly bool includeChildren;
+
+        public AssignIfNullAttribute()
+        {
+            useType = false;
+        }
+
+        public AssignIfNullAttribute(bool includeChildren)
+        {
+            useType = false;
+            this.includeChildren = includeChildren;
+        }
+
+        public AssignIfNullAttribute(Type type)
+        {
+            this.type = type;
+            useType = true;
+        }
+
+        public AssignIfNullAttribute(Type type, bool includeChildren)
+        {
+            this.type = type;
+            this.includeChildren = includeChildren;
+            useType = true;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Runtime/ValueModifiers/AssignIfNullAttribute.cs.meta b/Runtime/ValueModifiers/AssignIfNullAttribute.cs.meta
new file mode 100644
index 0000000..687a964
--- /dev/null
+++ b/Runtime/ValueModifiers/AssignIfNullAttribute.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: dfd8ecaea012b084f994832dd519d850
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/package.json b/package.json
index 51aeec5..7bf7670 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "com.module.inspector",
-  "version": "1.1.1",
+  "version": "1.2.0",
   "displayName": "Module.Inspector",
   "description": "Custom inspector with various useful property drawers",
   "unity": "2019.2",