From 409a49ba200be04f1e4ec779e4581a07703e6f1e Mon Sep 17 00:00:00 2001
From: Lance Edgar <lance@edbob.org>
Date: Fri, 12 Aug 2022 14:27:26 -0500
Subject: [PATCH] Standardize merge logic when a handler is defined for it

also adds basic merge support for products view
---
 tailbone/views/master.py   | 33 ++++++++++++++++++++++++++++++++-
 tailbone/views/people.py   | 32 +++++---------------------------
 tailbone/views/products.py |  2 ++
 3 files changed, 39 insertions(+), 28 deletions(-)

diff --git a/tailbone/views/master.py b/tailbone/views/master.py
index 610c2c2e..1915ac83 100644
--- a/tailbone/views/master.py
+++ b/tailbone/views/master.py
@@ -108,6 +108,7 @@ class MasterView(View):
     supports_set_enabled_toggle = False
     populatable = False
     mergeable = False
+    merge_handler = None
     downloadable = False
     cloneable = False
     touchable = False
@@ -1931,17 +1932,34 @@ class MasterView(View):
     def get_merge_fields(self):
         if hasattr(self, 'merge_fields'):
             return self.merge_fields
+
+        if self.merge_handler:
+            fields = self.merge_handler.get_merge_preview_fields()
+            return [field['name'] for field in fields]
+
         mapper = orm.class_mapper(self.get_model_class())
         return mapper.columns.keys()
 
     def get_merge_coalesce_fields(self):
         if hasattr(self, 'merge_coalesce_fields'):
             return self.merge_coalesce_fields
+
+        if self.merge_handler:
+            fields = self.merge_handler.get_merge_preview_fields()
+            return [field['name'] for field in fields
+                    if field.get('coalesce')]
+
         return []
 
     def get_merge_additive_fields(self):
         if hasattr(self, 'merge_additive_fields'):
             return self.merge_additive_fields
+
+        if self.merge_handler:
+            fields = self.merge_handler.get_merge_preview_fields()
+            return [field['name'] for field in fields
+                    if field.get('additive')]
+
         return []
 
     def merge(self):
@@ -1985,8 +2003,15 @@ class MasterView(View):
         the requested merge is valid, in your context.  If it is not - for *any
         reason* - you should raise an exception; the type does not matter.
         """
+        if self.merge_handler:
+            reason = self.merge_handler.why_not_merge(removing, keeping)
+            if reason:
+                raise Exception(reason)
 
     def get_merge_data(self, obj):
+        if self.merge_handler:
+            return self.merge_handler.get_merge_preview_data(obj)
+
         raise NotImplementedError("please implement `{}.get_merge_data()`".format(self.__class__.__name__))
 
     def get_merge_resulting_data(self, remove, keep):
@@ -2008,7 +2033,13 @@ class MasterView(View):
         Merge the two given objects.  You should probably override this;
         default behavior is merely to delete the 'removing' object.
         """
-        self.Session.delete(removing)
+        if self.merge_handler:
+            self.merge_handler.perform_merge(removing, keeping,
+                                             user=self.request.user)
+
+        else:
+            # nb. default "merge" does not update kept object!
+            self.Session.delete(removing)
 
     ##############################
     # Core Stuff
diff --git a/tailbone/views/people.py b/tailbone/views/people.py
index 55f35927..5dc76b73 100644
--- a/tailbone/views/people.py
+++ b/tailbone/views/people.py
@@ -95,10 +95,13 @@ class PersonView(MasterView):
 
     def __init__(self, request):
         super(PersonView, self).__init__(request)
+        app = self.get_rattail_app()
 
         # always get a reference to the People Handler
-        app = self.get_rattail_app()
-        self.handler = app.get_people_handler()
+        self.people_handler = app.get_people_handler()
+        self.merge_handler = self.people_handler
+        # TODO: deprecate / remove this
+        self.handler = self.people_handler
 
     def make_grid_kwargs(self, **kwargs):
         kwargs = super(PersonView, self).make_grid_kwargs(**kwargs)
@@ -396,31 +399,6 @@ class PersonView(MasterView):
             (model.VendorContact, 'person_uuid'),
         ]
 
-    def get_merge_fields(self):
-        fields = self.handler.get_merge_preview_fields()
-        return [field['name'] for field in fields]
-
-    def get_merge_additive_fields(self):
-        fields = self.handler.get_merge_preview_fields()
-        return [field['name'] for field in fields
-                if field.get('additive')]
-
-    def get_merge_coalesce_fields(self):
-        fields = self.handler.get_merge_preview_fields()
-        return [field['name'] for field in fields
-                if field.get('coalesce')]
-
-    def get_merge_data(self, person):
-        return self.handler.get_merge_preview_data(person)
-
-    def validate_merge(self, removing, keeping):
-        reason = self.handler.why_not_merge(removing, keeping)
-        if reason:
-            raise Exception(reason)
-
-    def merge_objects(self, removing, keeping):
-        self.handler.perform_merge(removing, keeping, user=self.request.user)
-
     def view_profile(self):
         """
         View which exposes the "full profile" for a given person, i.e. all
diff --git a/tailbone/views/products.py b/tailbone/views/products.py
index a9376faf..8f1ea545 100644
--- a/tailbone/views/products.py
+++ b/tailbone/views/products.py
@@ -83,6 +83,7 @@ class ProductView(MasterView):
     has_versions = True
     results_downloadable_xlsx = True
     supports_autocomplete = True
+    mergeable = True
     configurable = True
 
     labels = {
@@ -180,6 +181,7 @@ class ProductView(MasterView):
 
         app = self.get_rattail_app()
         self.products_handler = app.get_products_handler()
+        self.merge_handler = self.products_handler
         # TODO: deprecate / remove these
         self.product_handler = self.products_handler
         self.handler = self.products_handler