From c7b8418f1ab86eaa4e353d1c7bb84b9cada5028a Mon Sep 17 00:00:00 2001
From: Nishanth Vijayan <nishanththegr8@gmail.com>
Date: Wed, 17 Aug 2016 18:34:42 +0530
Subject: [PATCH 1/8] Fix linking problems for event and venue commercials

---
 .../versions/_object_desc_and_link.html.haml      | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/app/views/admin/versions/_object_desc_and_link.html.haml b/app/views/admin/versions/_object_desc_and_link.html.haml
index a34f4c4a..1b4f9b83 100644
--- a/app/views/admin/versions/_object_desc_and_link.html.haml
+++ b/app/views/admin/versions/_object_desc_and_link.html.haml
@@ -18,19 +18,18 @@
 
   - case commercial_last_version.commercialable_type
   - when 'Event'
-    =  link_to 'commercial',
-            edit_admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title,
-                id: commercialable_last_version.id, anchor: 'commercials-content')
-    = "in event #{commercialable_last_version.title}"
+    commercial in event
+    =  link_to "#{commercialable_last_version.title}",
+           admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title, id: commercialable_last_version.id)
 
   - when 'Venue'
+    commercial in venue
     - if Venue.find_by(id: commercialable_last_version.id)
-      =  link_to 'commercial',
-              edit_admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title,
+      =  link_to "#{commercialable_last_version.name}",
+              edit_admin_conference_venue_path(conference_id: Conference.find(version.conference_id).short_title,
                   id: commercialable_last_version.id, anchor: 'commercials-content')
     - else
-      = 'commercial'
-    = "in venue #{commercialable_last_version.name}"
+      = commercialable_last_version.name
 
   - when 'Conference'
     = link_to 'commercial',

From b982d18bbb1ebbd1fb070c89ab769f51f1a4245e Mon Sep 17 00:00:00 2001
From: Nishanth Vijayan <nishanththegr8@gmail.com>
Date: Wed, 17 Aug 2016 02:45:10 +0530
Subject: [PATCH 2/8] Use name/title instead of ID for associated object when
 showing changes

---
 app/helpers/application_helper.rb          |  7 +++++
 app/models/role.rb                         |  2 +-
 app/views/shared/_object_changes.html.haml | 30 ++++++++++++++++++----
 spec/features/versions_spec.rb             |  1 +
 4 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 4b7b1699..fcc554c7 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -397,6 +397,7 @@ module ApplicationHelper
   # Returns object as it was before version's change(unless its a create event's version)
   # Else Returns object as it was after version's change
   def get_version_object(version)
+    return nil unless version
     version.item || version.reify || version.next.reify
   end
 
@@ -502,4 +503,10 @@ module ApplicationHelper
       'deleted'
     end
   end
+
+  def object_last_description(model_name, id)
+    object_version = PaperTrail::Version.where(item_type: model_name, item_id: id).last
+    object = (object_version.reify || object_version.item) if object_version
+    object.try(:name) || object.try(:title)
+  end
 end
diff --git a/app/models/role.rb b/app/models/role.rb
index f194ad91..c827d0dd 100644
--- a/app/models/role.rb
+++ b/app/models/role.rb
@@ -3,7 +3,7 @@ class Role < ActiveRecord::Base
   has_many :users_roles
   has_many :users, through: :users_roles
 
-  has_paper_trail on: [:update], only: [:name, :description], meta: { conference_id: :resource_id }
+  has_paper_trail on: [:create, :update], only: [:name, :description], meta: { conference_id: :resource_id }
 
   before_destroy :cancel
   scopify
diff --git a/app/views/shared/_object_changes.html.haml b/app/views/shared/_object_changes.html.haml
index b61d3c83..3a49b631 100644
--- a/app/views/shared/_object_changes.html.haml
+++ b/app/views/shared/_object_changes.html.haml
@@ -12,17 +12,37 @@
         - if can? :revert_attribute, version
           %th Action
     %tbody
-      - if version.event!= 'destroy'
+      - if version.event != 'destroy'
         - version.changeset.reject{ |_, values| values[0].blank? && values[1].blank? }.each do |attribute, values|
           %tr
             %td= attribute
-            - if version.event != 'create'
-              %td= values[0].blank? ?  '-' : values[0]
-            %td= values[1].blank? ?  '-' : values[1]
+
+            - if attribute.include?('_id')
+              - model_name = attribute.chomp('_id').camelize
+              - if version.event != 'create'
+                %td
+                  = object_last_description(model_name, values[0])
+                  = "(ID: #{values[0].blank? ?  '-' : values[0]})"
+              %td
+                = object_last_description(model_name, values[1])
+                = "(ID: #{values[1].blank? ?  '-' : values[1]})"
+
+            - else
+              - if version.event != 'create'
+                %td= values[0].blank? ?  '-' : values[0]
+              %td= values[1].blank? ?  '-' : values[1]
+
             - if can? :revert_attribute, version
               %td= link_to 'Revert', admin_revision_history_revert_attribute_path(id: version.id, attribute: attribute), class: 'btn btn-sm btn-primary', data: { confirm: "Are you sure you want to revert #{attribute}?" }
       - else
         - version.reify.attributes.each do |attribute, value|
           %tr
             %td= attribute
-            %td= value.blank? ?  '-' : value
+
+            - if attribute.include?('_id')
+              - model_name = attribute.chomp('_id').camelize
+              %td
+                = object_last_description(model_name, value)
+                = "(ID: #{value.blank? ?  '-' : value})"
+            - else
+              %td= value.blank? ?  '-' : value
diff --git a/spec/features/versions_spec.rb b/spec/features/versions_spec.rb
index 992061c7..5987b791 100644
--- a/spec/features/versions_spec.rb
+++ b/spec/features/versions_spec.rb
@@ -58,6 +58,7 @@ feature 'Version' do
     new_conference.update_attributes(title: 'New Con', short_title: 'NewCon')
 
     visit admin_revision_history_path
+    select '100', from: 'versionstable_length'
     expect(page).to have_text('Someone (probably via the console) created new conference New Con')
     expect(page).to have_text('Someone (probably via the console) created new event type Talk in conference NewCon')
     expect(page).to have_text('Someone (probably via the console) created new event type Workshop in conference NewCon')

From 7d70f7685e1c07d071b2ca04df887bcbdfa02b34 Mon Sep 17 00:00:00 2001
From: Nishanth Vijayan <nishanththegr8@gmail.com>
Date: Thu, 18 Aug 2016 00:32:16 +0530
Subject: [PATCH 3/8] Track Schedule and EventSchedule

---
 app/helpers/application_helper.rb               | 14 ++++++++------
 app/models/event_schedule.rb                    |  8 ++++++++
 app/models/schedule.rb                          |  8 ++++++++
 .../versions/_object_desc_and_link.html.haml    | 17 +++++++++++++++++
 app/views/admin/versions/index.html.haml        |  3 +++
 5 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index fcc554c7..5e017d8c 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -413,12 +413,6 @@ module ApplicationHelper
       when 'new' then 'resubmitted'
       end
 
-    when version.changeset['start_time'] && version.changeset['start_time'][0].nil?
-      'scheduled'
-
-    when version.changeset['start_time'] && version.changeset['start_time'][1].nil?
-      'unscheduled'
-
     else
       "updated #{updated_attributes(version)} of"
     end
@@ -494,6 +488,14 @@ module ApplicationHelper
     end
   end
 
+  def event_schedule_change_description(version)
+    case version.event
+    when 'create' then 'scheduled'
+    when 'update' then 'rescheduled'
+    when 'destroy' then 'unscheduled'
+    end
+  end
+
   def general_change_description(version)
     if version.event == 'create'
       'created new'
diff --git a/app/models/event_schedule.rb b/app/models/event_schedule.rb
index 4f5e4940..cb630acd 100644
--- a/app/models/event_schedule.rb
+++ b/app/models/event_schedule.rb
@@ -3,6 +3,8 @@ class EventSchedule < ActiveRecord::Base
   belongs_to :event
   belongs_to :room
 
+  has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
+
   validates :schedule, presence: true
   validates :event, presence: true
   validates :room, presence: true
@@ -28,4 +30,10 @@ class EventSchedule < ActiveRecord::Base
   def intersecting_events
     room.event_schedules.where(start_time: start_time, schedule: schedule).where.not(id: id)
   end
+
+  private
+
+  def conference_id
+    schedule.program.conference_id
+  end
 end
diff --git a/app/models/schedule.rb b/app/models/schedule.rb
index 2254ebc9..b14a978c 100644
--- a/app/models/schedule.rb
+++ b/app/models/schedule.rb
@@ -2,4 +2,12 @@ class Schedule < ActiveRecord::Base
   belongs_to :program
   has_many :event_schedules, dependent: :destroy
   has_many :events, through: :event_schedules
+
+  has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
+
+  private
+
+  def conference_id
+    program.conference_id
+  end
 end
diff --git a/app/views/admin/versions/_object_desc_and_link.html.haml b/app/views/admin/versions/_object_desc_and_link.html.haml
index 1b4f9b83..46521439 100644
--- a/app/views/admin/versions/_object_desc_and_link.html.haml
+++ b/app/views/admin/versions/_object_desc_and_link.html.haml
@@ -49,6 +49,23 @@
   - else
     = PaperTrail::Version.where(item_type: 'Target', item_id: version.item_id).last.reify.to_s
 
+- elsif version.item_type == 'EventSchedule'
+  - event_schedule = get_version_object(version)
+  event
+  =  link_to Event.find(event_schedule.event_id),
+           admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title, id: event_schedule.event_id)
+  in
+  =  link_to "Schedule #{event_schedule.schedule_id}",
+            admin_conference_schedules_path(conference_id: Conference.find(version.conference_id).short_title, id: event_schedule.schedule_id)
+
+- elsif version.item_type == 'Schedule'
+  - schedule = get_version_object(version)
+  - if version.item
+    =  link_to "Schedule #{event_schedule.schedule_id}",
+              admin_conference_schedules_path(conference_id: Conference.find(version.conference_id).short_title, id: event_schedule.schedule_id)
+  - else
+    = "Schedule #{event_schedule.schedule_id}"
+
 - elsif  version.item
   - case version.item_type
   - when 'Conference'
diff --git a/app/views/admin/versions/index.html.haml b/app/views/admin/versions/index.html.haml
index 63244ac4..69af134b 100644
--- a/app/views/admin/versions/index.html.haml
+++ b/app/views/admin/versions/index.html.haml
@@ -41,6 +41,9 @@
             - when 'User'
               = user_change_description(version)
 
+            - when 'EventSchedule'
+              = event_schedule_change_description(version)
+
             - else
               = general_change_description(version)
 

From 75ee1371de034def9fb28ac7227e6c40f59c18be Mon Sep 17 00:00:00 2001
From: Nishanth Vijayan <nishanththegr8@gmail.com>
Date: Thu, 18 Aug 2016 01:28:40 +0530
Subject: [PATCH 4/8] Cleanup obj_desc_and_link

---
 app/helpers/application_helper.rb             |  42 ++--
 .../versions/_object_desc_and_link.html.haml  | 227 +++++++++---------
 app/views/shared/_object_changes.html.haml    |   9 +-
 3 files changed, 138 insertions(+), 140 deletions(-)

diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 5e017d8c..88b89806 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -392,13 +392,22 @@ module ApplicationHelper
     end
   end
 
-  # Recieves a PaperTrail::Version object
+  # Recieves a model_name and id
+  # Returns nil if model_name is invalid
   # Returns object in its current state if its alive
-  # Returns object as it was before version's change(unless its a create event's version)
-  # Else Returns object as it was after version's change
-  def get_version_object(version)
-    return nil unless version
-    version.item || version.reify || version.next.reify
+  # Otherwise Returns object state just before deletion
+  def current_or_last_object_state(model_name, id)
+    begin
+      object = model_name.constantize.find_by(id: id)
+    rescue NameError
+      return nil
+    end
+
+    if object.nil?
+      object_last_version = PaperTrail::Version.where(item_type: model_name, item_id: id).last
+      object = object_last_version.reify if object_last_version
+    end
+    object
   end
 
   def event_change_description(version)
@@ -423,18 +432,17 @@ module ApplicationHelper
   end
 
   def subscription_change_description(version)
-    user = get_version_object(version).user
+    user = current_or_last_object_state(version.item_type, version.item_id).user
     user_name = user.name unless user.id.to_s == version.whodunnit
     version.event == 'create' ? "subscribed #{user_name} to" : "unsubscribed #{user_name} from"
   end
 
   def registration_change_description(version)
     if version.item_type == 'Registration'
-      user = get_version_object(version).user
-    else
-      registration_id = get_version_object(version).registration_id
-      registration_last_version = PaperTrail::Version.where(item_type: 'Registration', item_id: registration_id).last
-      user = get_version_object(registration_last_version).user
+      user = current_or_last_object_state(version.item_type, version.item_id).user
+    elsif version.item_type == 'EventsRegistration'
+      registration_id = current_or_last_object_state(version.item_type, version.item_id).registration_id
+      user = current_or_last_object_state('Registration', registration_id).user
     end
 
     if user.id.to_s == version.whodunnit
@@ -453,7 +461,7 @@ module ApplicationHelper
   end
 
   def comment_change_description(version)
-    user = get_version_object(version).user
+    user = current_or_last_object_state(version.item_type, version.item_id).user
     if version.event == 'create'
       version.previous.nil? ? 'commented on' : "re-added #{user.name}'s comment on"
     else
@@ -462,7 +470,7 @@ module ApplicationHelper
   end
 
   def vote_change_description(version)
-    user = get_version_object(version).user
+    user = current_or_last_object_state(version.item_type, version.item_id).user
     if version.event == 'create'
       version.previous.nil? ? 'voted on' : "re-added #{user.name}'s vote on"
     elsif version.event == 'update'
@@ -506,9 +514,7 @@ module ApplicationHelper
     end
   end
 
-  def object_last_description(model_name, id)
-    object_version = PaperTrail::Version.where(item_type: model_name, item_id: id).last
-    object = (object_version.reify || object_version.item) if object_version
-    object.try(:name) || object.try(:title)
+  def link_if_alive(version, link_text, link_url)
+    version.item ? link_to(link_text, link_url) : link_text
   end
 end
diff --git a/app/views/admin/versions/_object_desc_and_link.html.haml b/app/views/admin/versions/_object_desc_and_link.html.haml
index 46521439..ae67bbd7 100644
--- a/app/views/admin/versions/_object_desc_and_link.html.haml
+++ b/app/views/admin/versions/_object_desc_and_link.html.haml
@@ -1,172 +1,161 @@
-- if version.item_type == 'UsersRole'
-  - users_role = get_version_object(version)
+- case version.item_type
+- when 'UsersRole'
+  - users_role = current_or_last_object_state(version.item_type, version.item_id)
   = 'role'
   = link_to users_role.role.name, admin_conference_role_path(conference_id: Conference.find(version.conference_id).short_title, id: users_role.role.name)
   = version.event == 'create' ? 'to' : 'from'
   = 'user'
   = link_to users_role.user.name, admin_user_path(id: users_role.user.id)
 
-- elsif version.item_type == 'Subscription' || version.item_type == 'Registration'
+- when 'Subscription', 'Registration'
   = 'conference'
   = link_to Conference.find(version.conference_id).title,
           admin_conference_registrations_path(conference_id: Conference.find(version.conference_id).short_title)
 
-- elsif version.item_type == 'Commercial'
-  - commercial_last_version = get_version_object(PaperTrail::Version.where(item_type: version.item_type, item_id: version.item_id).last)
-  - commercialable_last_version = get_version_object(PaperTrail::Version.where(item_type: commercial_last_version.commercialable_type,
-                                                          item_id: commercial_last_version.commercialable_id).last)
+- when 'Commercial'
+  - commercial = current_or_last_object_state(version.item_type, version.item_id)
+  - commercialable = current_or_last_object_state(commercial.commercialable_type, commercial.commercialable_id)
 
-  - case commercial_last_version.commercialable_type
+  - case commercial.commercialable_type
   - when 'Event'
     commercial in event
-    =  link_to "#{commercialable_last_version.title}",
-           admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title, id: commercialable_last_version.id)
+    =  link_to commercialable.title,
+           admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title, id: commercialable.id)
 
   - when 'Venue'
     commercial in venue
-    - if Venue.find_by(id: commercialable_last_version.id)
-      =  link_to "#{commercialable_last_version.name}",
-              edit_admin_conference_venue_path(conference_id: Conference.find(version.conference_id).short_title,
-                  id: commercialable_last_version.id, anchor: 'commercials-content')
-    - else
-      = commercialable_last_version.name
+    = link_to commercialable.name,
+          edit_admin_conference_venue_path(conference_id: Conference.find(version.conference_id).short_title,
+                                              id: commercialable.id, anchor: 'commercials-content')
 
   - when 'Conference'
     = link_to 'commercial',
             admin_conference_commercials_path(conference_id: Conference.find(version.conference_id).short_title)
 
-- elsif %w(EventsRegistration Comment Vote).include?(version.item_type)
+- when 'EventsRegistration', 'Comment', 'Vote', 'Event'
   = 'event'
-  - event_id = get_version_object(version).try(:event_id) || get_version_object(version).try(:commentable_id)
-  = link_to Event.find(event_id).title,
+  - object = current_or_last_object_state(version.item_type, version.item_id)
+  - event_id = object.try(:id) || object.try(:event_id) || object.try(:commentable_id)
+  = link_to current_or_last_object_state('Event', event_id).title,
           admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title, id: event_id)
 
-- elsif version.item_type =='Target'
+- when 'Target'
   = 'target'
-  - if version.item
-    = link_to Target.find(version.item_id).to_s,
-            admin_conference_targets_path(conference_id: Conference.find(version.conference_id).short_title)
-  - else
-    = PaperTrail::Version.where(item_type: 'Target', item_id: version.item_id).last.reify.to_s
+  - target = current_or_last_object_state(version.item_type, version.item_id)
+  = link_if_alive version, target.to_s, admin_conference_targets_path(conference_id: Conference.find(version.conference_id).short_title)
 
-- elsif version.item_type == 'EventSchedule'
-  - event_schedule = get_version_object(version)
+- when 'EventSchedule'
+  - event_schedule = current_or_last_object_state(version.item_type, version.item_id)
   event
-  =  link_to Event.find(event_schedule.event_id),
+  =  link_to current_or_last_object_state('Event', event_schedule.event_id).title,
            admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title, id: event_schedule.event_id)
   in
   =  link_to "Schedule #{event_schedule.schedule_id}",
-            admin_conference_schedules_path(conference_id: Conference.find(version.conference_id).short_title, id: event_schedule.schedule_id)
+            admin_conference_schedule_path(conference_id: Conference.find(version.conference_id).short_title, id: event_schedule.schedule_id)
 
-- elsif version.item_type == 'Schedule'
-  - schedule = get_version_object(version)
-  - if version.item
-    =  link_to "Schedule #{event_schedule.schedule_id}",
-              admin_conference_schedules_path(conference_id: Conference.find(version.conference_id).short_title, id: event_schedule.schedule_id)
-  - else
-    = "Schedule #{event_schedule.schedule_id}"
+- when 'Schedule'
+  = link_if_alive version, "Schedule #{version.item_id}",
+            admin_conference_schedule_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item_id)
 
-- elsif  version.item
-  - case version.item_type
-  - when 'Conference'
-    = 'conference'
-    = link_to Conference.find(version.conference_id).title,
-            edit_admin_conference_path(id: Conference.find(version.conference_id).short_title)
+- when 'Conference'
+  = 'conference'
+  = link_to Conference.find(version.conference_id).title,
+          edit_admin_conference_path(id: Conference.find(version.conference_id).short_title)
 
-  - when 'RegistrationPeriod'
-    = link_to 'registration period',
-            admin_conference_registration_period_path(conference_id: Conference.find(version.conference_id).short_title)
+- when 'RegistrationPeriod'
+  = link_if_alive version, 'registration period',
+          admin_conference_registration_period_path(conference_id: Conference.find(version.conference_id).short_title)
 
-  - when 'Contact'
-    = link_to 'contact details',
-            edit_admin_conference_contact_path(conference_id: Conference.find(version.conference_id).short_title)
+- when 'Contact'
+  = link_if_alive version, 'contact details',
+          edit_admin_conference_contact_path(conference_id: Conference.find(version.conference_id).short_title)
 
-  - when 'Program'
-    = link_to 'program',
-            admin_conference_program_path(conference_id: Conference.find(version.conference_id).short_title)
+- when 'Program'
+  = link_if_alive version, 'program',
+          admin_conference_program_path(conference_id: Conference.find(version.conference_id).short_title)
 
-  - when 'Cfp'
-    = link_to 'cfp',
-            admin_conference_program_cfp_path(conference_id: Conference.find(version.conference_id).short_title)
+- when 'Cfp'
+  = link_if_alive version, 'cfp',
+          admin_conference_program_cfp_path(conference_id: Conference.find(version.conference_id).short_title)
 
-  - when 'Track'
-    = 'track'
-    = link_to Track.find(version.item_id).name,
-            admin_conference_program_track_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item_id)
+- when 'Track'
+  = 'track'
+  - track = current_or_last_object_state(version.item_type, version.item_id)
+  = link_if_alive version, track.name,
+          admin_conference_program_track_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item_id)
 
-  - when 'Event'
-    = 'event'
-    = link_to Event.find(version.item_id).title,
-            admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item_id)
+- when 'EventType'
+  = 'event type'
+  - event_type = current_or_last_object_state(version.item_type, version.item_id)
+  = link_if_alive version, event_type.title,
+          admin_conference_program_event_types_path(conference_id: Conference.find(version.conference_id).short_title)
 
-  - when 'EventType'
-    = 'event type'
-    = link_to EventType.find(version.item_id).title,
-            admin_conference_program_event_types_path(conference_id: Conference.find(version.conference_id).short_title)
+- when 'Role'
+  = 'role'
+  - role = current_or_last_object_state(version.item_type, version.item_id)
+  = link_if_alive version, role.name,
+          admin_conference_role_path(conference_id: Conference.find(version.conference_id).short_title, id: role.name)
 
-  - when 'Role'
-    = 'role'
-    = link_to Role.find(version.item_id).name,
-            admin_conference_role_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item.name)
+- when 'Venue'
+  = 'venue'
+  - venue = current_or_last_object_state(version.item_type, version.item_id)
+  = link_if_alive version, venue.name,
+          admin_conference_venue_path(conference_id: Conference.find(version.conference_id).short_title)
 
-  - when 'Venue'
-    = 'venue'
-    = link_to Venue.find(version.item_id).name,
-            admin_conference_venue_path(conference_id: Conference.find(version.conference_id).short_title)
+- when 'Lodging'
+  = 'lodging'
+  - lodging = current_or_last_object_state(version.item_type, version.item_id)
+  = link_if_alive version, lodging.name,
+          admin_conference_lodgings_path(conference_id: Conference.find(version.conference_id).short_title)
 
-  - when 'Lodging'
-    = 'lodging'
-    = link_to Lodging.find(version.item_id).name,
-            admin_conference_lodgings_path(conference_id: Conference.find(version.conference_id).short_title)
+- when 'Room'
+  = 'room'
+  - room = current_or_last_object_state(version.item_type, version.item_id)
+  = link_if_alive version, room.name,
+          admin_conference_venue_rooms_path(conference_id: Conference.find(version.conference_id).short_title)
 
-  - when 'Room'
-    = 'room'
-    = link_to Room.find(version.item_id).name,
-            admin_conference_venue_rooms_path(conference_id: Conference.find(version.conference_id).short_title)
+- when 'Sponsor'
+  = 'sponsor'
+  - sponsor = current_or_last_object_state(version.item_type, version.item_id)
+  = link_if_alive version, sponsor.name,
+          admin_conference_sponsors_path(conference_id: Conference.find(version.conference_id).short_title)
 
-  - when 'Sponsor'
-    = 'sponsor'
-    = link_to Sponsor.find(version.item_id).name,
-            admin_conference_sponsors_path(conference_id: Conference.find(version.conference_id).short_title)
+- when 'SponsorshipLevel'
+  = 'sponsorship level'
+  - sponsorship_level = current_or_last_object_state(version.item_type, version.item_id)
+  = link_if_alive version, sponsorship_level.title,
+          admin_conference_sponsorship_levels_path(conference_id: Conference.find(version.conference_id).short_title)
 
-  - when 'SponsorshipLevel'
-    = 'sponsorship level'
-    = link_to SponsorshipLevel.find(version.item_id).title,
-            admin_conference_sponsorship_levels_path(conference_id: Conference.find(version.conference_id).short_title)
+- when 'Ticket'
+  = 'ticket'
+  - ticket = current_or_last_object_state(version.item_type, version.item_id)
+  = link_if_alive version, ticket.title,
+          admin_conference_ticket_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item_id)
 
-  - when 'Ticket'
-    = 'ticket'
-    = link_to Ticket.find(version.item_id).title,
-            admin_conference_ticket_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item_id)
+- when 'Campaign'
+  = 'campaign'
+  - campaign = current_or_last_object_state(version.item_type, version.item_id)
+  = link_if_alive version, campaign.name,
+          admin_conference_campaigns_path(conference_id: Conference.find(version.conference_id).short_title)
 
-  - when 'Campaign'
-    = 'campaign'
-    = link_to Campaign.find(version.item_id).name,
-            admin_conference_campaigns_path(conference_id: Conference.find(version.conference_id).short_title)
+- when 'DifficultyLevel'
+  = 'difficulty level'
+  - difficulty_level = current_or_last_object_state(version.item_type, version.item_id)
+  = link_if_alive version, difficulty_level.title,
+          admin_conference_program_difficulty_level_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item_id)
 
-  - when 'DifficultyLevel'
-    = 'difficulty level'
-    = link_to DifficultyLevel.find(version.item_id).title,
-            admin_conference_program_difficulty_level_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item_id)
+- when 'Splashpage'
+  = link_if_alive version, 'splashpage',
+          admin_conference_splashpage_path(conference_id: Conference.find(version.conference_id).short_title)
 
-  - when 'Splashpage'
-    = link_to 'splashpage',
-            admin_conference_splashpage_path(conference_id: Conference.find(version.conference_id).short_title)
+- when 'EmailSettings'
+  = link_if_alive version, 'email settings',
+          admin_conference_emails_path(conference_id: Conference.find(version.conference_id).short_title)
 
-  - when 'EmailSettings'
-    = link_to 'email settings',
-            admin_conference_emails_path(conference_id: Conference.find(version.conference_id).short_title)
-
-  - when 'User'
-    - if version.event == 'update'
-      = 'user'
-      = link_to User.find(version.item_id).name, admin_user_path(id: version.item_id)
-
-- else
-  = version.item_type.underscore.tr('_', ' ')
-  / The last deleted version's name/title is used to describe all the changes in object
-  - last_deleted_version = PaperTrail::Version.where(item_type: version.item_type, item_id: version.item_id).last.reify
-  = last_deleted_version.try(:title) || last_deleted_version.try(:name)
+- when 'User'
+  - if version.event == 'update'
+    = 'user'
+    = link_to current_or_last_object_state('User', version.item_id).name, admin_user_path(id: version.item_id)
 
 - unless %w(Conference Subscription Registration User).include?(version.item_type)
   = "in conference"
diff --git a/app/views/shared/_object_changes.html.haml b/app/views/shared/_object_changes.html.haml
index 3a49b631..d01f35b6 100644
--- a/app/views/shared/_object_changes.html.haml
+++ b/app/views/shared/_object_changes.html.haml
@@ -21,10 +21,12 @@
               - model_name = attribute.chomp('_id').camelize
               - if version.event != 'create'
                 %td
-                  = object_last_description(model_name, values[0])
+                  - associated_object = current_or_last_object_state(model_name, values[0])
+                  = associated_object.try(:title) || associated_object.try(:name)
                   = "(ID: #{values[0].blank? ?  '-' : values[0]})"
               %td
-                = object_last_description(model_name, values[1])
+                - associated_object = current_or_last_object_state(model_name, values[1])
+                = associated_object.try(:title) || associated_object.try(:name)
                 = "(ID: #{values[1].blank? ?  '-' : values[1]})"
 
             - else
@@ -42,7 +44,8 @@
             - if attribute.include?('_id')
               - model_name = attribute.chomp('_id').camelize
               %td
-                = object_last_description(model_name, value)
+                - associated_object = current_or_last_object_state(model_name, value)
+                = associated_object.try(:title) || associated_object.try(:name)
                 = "(ID: #{value.blank? ?  '-' : value})"
             - else
               %td= value.blank? ?  '-' : value

From b30afccfba8be17b572108889766fead45b8ec4c Mon Sep 17 00:00:00 2001
From: Nishanth Vijayan <nishanththegr8@gmail.com>
Date: Sat, 20 Aug 2016 15:45:53 +0530
Subject: [PATCH 5/8] When displaying changes, use '-' if id of associated
 object is blank

---
 app/helpers/application_helper.rb          | 1 +
 app/views/shared/_object_changes.html.haml | 6 +++---
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 88b89806..1d3e4bea 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -397,6 +397,7 @@ module ApplicationHelper
   # Returns object in its current state if its alive
   # Otherwise Returns object state just before deletion
   def current_or_last_object_state(model_name, id)
+    return nil unless id.present? && model_name.present?
     begin
       object = model_name.constantize.find_by(id: id)
     rescue NameError
diff --git a/app/views/shared/_object_changes.html.haml b/app/views/shared/_object_changes.html.haml
index d01f35b6..69a9dd80 100644
--- a/app/views/shared/_object_changes.html.haml
+++ b/app/views/shared/_object_changes.html.haml
@@ -23,11 +23,11 @@
                 %td
                   - associated_object = current_or_last_object_state(model_name, values[0])
                   = associated_object.try(:title) || associated_object.try(:name)
-                  = "(ID: #{values[0].blank? ?  '-' : values[0]})"
+                  = values[0].blank? ? '-' : "(ID: #{values[0]})"
               %td
                 - associated_object = current_or_last_object_state(model_name, values[1])
                 = associated_object.try(:title) || associated_object.try(:name)
-                = "(ID: #{values[1].blank? ?  '-' : values[1]})"
+                = (values[1].blank? ? '-' : "(ID: #{values[1]})")
 
             - else
               - if version.event != 'create'
@@ -46,6 +46,6 @@
               %td
                 - associated_object = current_or_last_object_state(model_name, value)
                 = associated_object.try(:title) || associated_object.try(:name)
-                = "(ID: #{value.blank? ?  '-' : value})"
+                = value.blank? ? '-' : "(ID: #{value})"
             - else
               %td= value.blank? ?  '-' : value

From 5a5b6868304afc5aeea85f66fa1e84feddcf1c09 Mon Sep 17 00:00:00 2001
From: Nishanth Vijayan <nishanththegr8@gmail.com>
Date: Mon, 22 Aug 2016 01:10:37 +0530
Subject: [PATCH 6/8] Display event,user title/name only if they exists or when
 they have versions

---
 .../admin/versions/_object_desc_and_link.html.haml | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/app/views/admin/versions/_object_desc_and_link.html.haml b/app/views/admin/versions/_object_desc_and_link.html.haml
index ae67bbd7..07f19002 100644
--- a/app/views/admin/versions/_object_desc_and_link.html.haml
+++ b/app/views/admin/versions/_object_desc_and_link.html.haml
@@ -1,11 +1,13 @@
 - case version.item_type
 - when 'UsersRole'
   - users_role = current_or_last_object_state(version.item_type, version.item_id)
+  - user = current_or_last_object_state('User', users_role.user_id)
   = 'role'
   = link_to users_role.role.name, admin_conference_role_path(conference_id: Conference.find(version.conference_id).short_title, id: users_role.role.name)
   = version.event == 'create' ? 'to' : 'from'
   = 'user'
-  = link_to users_role.user.name, admin_user_path(id: users_role.user.id)
+
+  = link_to (user.try(:name) || 'deleted user'), admin_user_path(id: users_role.user.id)
 
 - when 'Subscription', 'Registration'
   = 'conference'
@@ -19,7 +21,7 @@
   - case commercial.commercialable_type
   - when 'Event'
     commercial in event
-    =  link_to commercialable.title,
+    =  link_to (commercialable.try(:title) || 'deleted event'),
            admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title, id: commercialable.id)
 
   - when 'Venue'
@@ -35,8 +37,8 @@
 - when 'EventsRegistration', 'Comment', 'Vote', 'Event'
   = 'event'
   - object = current_or_last_object_state(version.item_type, version.item_id)
-  - event_id = object.try(:id) || object.try(:event_id) || object.try(:commentable_id)
-  = link_to current_or_last_object_state('Event', event_id).title,
+  - event_id = object.try(:id) || object.try(:event_id) || object.commentable_id
+  = link_to (current_or_last_object_state('Event', event_id).try(:title) || 'deleted event'),
           admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title, id: event_id)
 
 - when 'Target'
@@ -47,7 +49,7 @@
 - when 'EventSchedule'
   - event_schedule = current_or_last_object_state(version.item_type, version.item_id)
   event
-  =  link_to current_or_last_object_state('Event', event_schedule.event_id).title,
+  = link_to (current_or_last_object_state('Event', event_schedule.event_id).try(:title) || 'deleted event'),
            admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title, id: event_schedule.event_id)
   in
   =  link_to "Schedule #{event_schedule.schedule_id}",
@@ -155,7 +157,7 @@
 - when 'User'
   - if version.event == 'update'
     = 'user'
-    = link_to current_or_last_object_state('User', version.item_id).name, admin_user_path(id: version.item_id)
+    = link_to (current_or_last_object_state('User', version.item_id).try(:name) || 'deleted user'), admin_user_path(id: version.item_id)
 
 - unless %w(Conference Subscription Registration User).include?(version.item_type)
   = "in conference"

From 1c42bf92c03a74543485106ff841477518dae5ea Mon Sep 17 00:00:00 2001
From: Nishanth Vijayan <nishanththegr8@gmail.com>
Date: Wed, 28 Sep 2016 18:42:18 +0530
Subject: [PATCH 7/8] Link commercialable only if it exists else just display
 title/name

---
 .../versions/_object_desc_and_link.html.haml  | 20 +++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/app/views/admin/versions/_object_desc_and_link.html.haml b/app/views/admin/versions/_object_desc_and_link.html.haml
index 07f19002..53f5a22d 100644
--- a/app/views/admin/versions/_object_desc_and_link.html.haml
+++ b/app/views/admin/versions/_object_desc_and_link.html.haml
@@ -17,18 +17,26 @@
 - when 'Commercial'
   - commercial = current_or_last_object_state(version.item_type, version.item_id)
   - commercialable = current_or_last_object_state(commercial.commercialable_type, commercial.commercialable_id)
+  - commercialable_last_version = PaperTrail::Version.where(item_type: commercial.commercialable_type, item_id: commercial.commercialable_id).last
 
   - case commercial.commercialable_type
   - when 'Event'
-    commercial in event
-    =  link_to (commercialable.try(:title) || 'deleted event'),
-           admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title, id: commercialable.id)
+    commercial in
+    - if commercialable_last_version.item
+      event
+      =  link_to commercialable.title,
+             admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title, id: commercialable.id)
+    - else
+      = commercialable.title
 
   - when 'Venue'
     commercial in venue
-    = link_to commercialable.name,
-          edit_admin_conference_venue_path(conference_id: Conference.find(version.conference_id).short_title,
-                                              id: commercialable.id, anchor: 'commercials-content')
+    - if commercialable_last_version.item
+      = link_to commercialable.name,
+            edit_admin_conference_venue_path(conference_id: Conference.find(version.conference_id).short_title,
+                                                id: commercialable.id, anchor: 'commercials-content')
+    - else
+      = commercialable.name
 
   - when 'Conference'
     = link_to 'commercial',

From 5100bf4c13fdc609d6d657c6f43098796044d89b Mon Sep 17 00:00:00 2001
From: Nishanth Vijayan <nishanththegr8@gmail.com>
Date: Wed, 28 Sep 2016 18:50:40 +0530
Subject: [PATCH 8/8] Add comment about displaying associated model object name
 in _object_changes

---
 app/views/shared/_object_changes.html.haml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/app/views/shared/_object_changes.html.haml b/app/views/shared/_object_changes.html.haml
index 69a9dd80..247f0461 100644
--- a/app/views/shared/_object_changes.html.haml
+++ b/app/views/shared/_object_changes.html.haml
@@ -17,6 +17,9 @@
           %tr
             %td= attribute
 
+            / If the attribute is an associated model, show the value of the record it corresponds to, not just the ID.
+            / Eg. when the version is of an Event, if the attribute is event_type_id it shows
+            / Workshop (ID: 116) instead of just 116
             - if attribute.include?('_id')
               - model_name = attribute.chomp('_id').camelize
               - if version.event != 'create'