From 2e28694b49d9999b341a915c7bd2631f7504c062 Mon Sep 17 00:00:00 2001
From: Jakob Ketterl <jakob.ketterl@gmx.de>
Date: Fri, 5 Mar 2021 19:09:51 +0100
Subject: [PATCH] implement profile removal behaviour

---
 owrx/property/__init__.py               | 12 ++++++++---
 owrx/source/__init__.py                 |  6 ++++++
 test/property/test_property_carousel.py | 27 ++++++++++++++++++++++++-
 3 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/owrx/property/__init__.py b/owrx/property/__init__.py
index d0d92d1..9586cb7 100644
--- a/owrx/property/__init__.py
+++ b/owrx/property/__init__.py
@@ -345,9 +345,13 @@ class PropertyStack(PropertyManager):
 class PropertyCarousel(PropertyDelegator):
     def __init__(self):
         # start with an empty dummy layer
-        super().__init__(PropertyLayer())
+        self.emptyLayer = PropertyLayer().readonly()
+        super().__init__(self.emptyLayer)
         self.layers = {}
 
+    def _getDefaultLayer(self):
+        return self.emptyLayer
+
     def addLayer(self, key, value):
         self.layers[key] = value
 
@@ -355,12 +359,14 @@ class PropertyCarousel(PropertyDelegator):
         return key in self.layers
 
     def removeLayer(self, key):
+        if key in self.layers and self.layers[key] is self.pm:
+            self.switch()
         del self.layers[key]
 
-    def switch(self, key):
+    def switch(self, key=None):
         before = self.pm
         self.subscription.cancel()
-        self.pm = self.layers[key]
+        self.pm = self._getDefaultLayer() if key is None else self.layers[key]
         self.subscription = self.pm.wire(self._fireCallbacks)
         changes = {}
         for key in set(list(before.keys()) + list(self.keys())):
diff --git a/owrx/source/__init__.py b/owrx/source/__init__.py
index 37a713f..97f3d1e 100644
--- a/owrx/source/__init__.py
+++ b/owrx/source/__init__.py
@@ -82,6 +82,12 @@ class SdrProfileCarousel(PropertyCarousel):
             elif not self.hasLayer(profile_id):
                 self.addLayer(profile_id, profile)
 
+    def _getDefaultLayer(self):
+        # return the first available profile, or the default empty layer if we don't have any
+        if self.layers:
+            return next(iter(self.layers.values()))
+        return super()._getDefaultLayer()
+
 
 class SdrSource(ABC):
     def __init__(self, id, props):
diff --git a/test/property/test_property_carousel.py b/test/property/test_property_carousel.py
index b6ae264..29f79ee 100644
--- a/test/property/test_property_carousel.py
+++ b/test/property/test_property_carousel.py
@@ -1,6 +1,6 @@
 from unittest import TestCase
 from unittest.mock import Mock
-from owrx.property import PropertyCarousel, PropertyLayer, PropertyDeleted
+from owrx.property import PropertyCarousel, PropertyLayer, PropertyDeleted, PropertyWriteError
 
 
 class PropertyCarouselTest(TestCase):
@@ -92,3 +92,28 @@ class PropertyCarouselTest(TestCase):
         pc.removeLayer("x")
         with self.assertRaises(KeyError):
             pc.switch("x")
+
+    def testPropertyResetAfterRemoval(self):
+        pc = PropertyCarousel()
+        pl = PropertyLayer(testkey="testvalue")
+        pc.addLayer("x", pl)
+        pc.switch("x")
+        self.assertEqual(pc["testkey"], "testvalue")
+        pc.removeLayer("x")
+        with self.assertRaises(KeyError):
+            x = pc["testkey"]
+
+    def testEmptySwitch(self):
+        pc = PropertyCarousel()
+        pl = PropertyLayer(testkey="testvalue")
+        pc.addLayer("x", pl)
+        pc.switch("x")
+        self.assertEqual(pc["testkey"], "testvalue")
+        pc.switch()
+        with self.assertRaises(KeyError):
+            x = pc["testkey"]
+
+    def testErrorOnWriteOnDefaultLayer(self):
+        pc = PropertyCarousel()
+        with self.assertRaises(PropertyWriteError):
+            pc["testkey"] = "testvalue"