Add rake task for migrating deleted adoptions

Occasionally adoptions are deleted when invalid data is corrected within
the source and reimported. This task will automatically move adoptions
that were close to other, unadopted, things as it is likely that the
unadopted thing is actually the one that the user adopted.

.rubocop.yml

@@ -24,10 +24,12 @@ Metrics/AbcSize:
     - 'app/controllers/sessions_controller.rb'
     - 'app/controllers/users_controller.rb'
     - 'lib/thing_importer.rb'
+    - 'lib/adoption_mover.rb'
 
 Metrics/BlockLength:
   Exclude:
     - 'config/initializers/*'
+    - 'lib/adoption_mover.rb' # removing heredocs would decrease readibility
   ExcludedMethods: ['test']
 
 Metrics/BlockNesting:
@@ -43,6 +45,7 @@ Metrics/MethodLength:
   Exclude:
     - 'db/migrate/*.rb'
     - 'lib/thing_importer.rb' # removing heredocs would decrease readibility
+    - 'lib/adoption_mover.rb' # removing heredocs would decrease readibility
 
 Metrics/ParameterLists:
   Max: 4

lib/adoption_mover.rb

@@ -0,0 +1,69 @@
+# class for rectifying adoptions of invalid data
+
+class AdoptionMover
+  class << self
+    # Move adoptions deleted later than `from` to close by unadopted things
+    # within `maximum_movement_in_feet` away
+    #
+    # Returns a hash of {to_id: from_id}
+    def move_close_deleted_adoptions(from, maximum_movement_in_feet)
+      moved_adoptions = {}
+
+      Thing.transaction do
+        records = ActiveRecord::Base.connection.execute <<-SQL.strip_heredoc
+          WITH
+            deleted_adopted_things AS (
+              SELECT *
+              FROM things
+              WHERE
+                user_id IS NOT NULL
+                -- only recently deleted things
+                AND (deleted_at > #{ActiveRecord::Base.sanitize(from)})
+            )
+          SELECT
+            deleted_adopted_things.id AS deleted_adopted_thing_id,
+            closest_unadopted_thing.id AS closest_unadopted_thing_id
+          FROM
+            deleted_adopted_things
+          LEFT JOIN LATERAL (
+              SELECT *,
+              -- Haversine formula
+              -- https://developers.google.com/maps/solutions/store-locator/clothing-store-locator#finding-locations-with-mysql
+                (
+                  3959
+                  * ACOS(
+                    COS(RADIANS(deleted_adopted_things.lat))
+                    * COS(RADIANS(unadopted_things.lat))
+                    * COS(RADIANS(unadopted_things.lng) - RADIANS(deleted_adopted_things.lng))
+                    + SIN(RADIANS(deleted_adopted_things.lat))
+                    * SIN(RADIANS(unadopted_things.lat))
+                  )
+                ) * 5280 AS distance_in_feet
+              FROM things AS unadopted_things
+              WHERE deleted_at IS NULL AND user_id IS NULL
+              ORDER BY distance_in_feet
+              LIMIT 1
+            ) AS closest_unadopted_thing ON 1=1
+          WHERE distance_in_feet < #{ActiveRecord::Base.sanitize(maximum_movement_in_feet)}
+          ORDER BY distance_in_feet
+          ;
+SQL
+
+        records.each do |record|
+          deleted_adopted_thing = Thing.unscoped.find(record['deleted_adopted_thing_id'])
+          closeby_unadopted_thing = Thing.find(record['closest_unadopted_thing_id'])
+
+          closeby_unadopted_thing.update_attributes!(
+            user_id: deleted_adopted_thing.user_id,
+            adopted_name: deleted_adopted_thing.adopted_name,
+          )
+          deleted_adopted_thing.update_attributes!(user_id: nil)
+
+          moved_adoptions[deleted_adopted_thing.id] = closeby_unadopted_thing.id
+        end
+      end
+
+      moved_adoptions
+    end
+  end
+end

lib/tasks/data.rake

@@ -6,4 +6,25 @@ namespace :data do
 
     ThingImporter.load('https://data.sfgov.org/api/views/jtgq-b7c5/rows.csv?accessType=DOWNLOAD')
   end
+
+  # move adoptions to closeby things
+  # useful for rectifying adoptions of inconsistencies in the dataset (things
+  # that are removed during scheduled import)
+  task move_close_deleted_adoptions: :environment do
+    require 'adoption_mover'
+
+    ENV['ADOPTION_DELETION_FROM'] || raise('$ADOPTION_DELETION_FROM required')
+    ENV['MAXIMUM_MOVEMENT_IN_FEET'] || raise('$MAXIMUM_MOVEMENT_IN_FEET required')
+
+    adoption_deletion_from = Time.zone.parse(ENV['ADOPTION_DELETION_FROM'])
+
+    moved_adoptions = AdoptionMover.move_close_deleted_adoptions(adoption_deletion_from, ENV['MAXIMUM_MOVEMENT_IN_FEET'])
+
+    CSV($stdout) do |csv|
+      csv << %w[from to]
+      moved_adoptions.each do |from, to|
+        csv << [from, to]
+      end
+    end
+  end
 end

test/lib/adopted_mover_test.rb

@@ -0,0 +1,71 @@
+require 'test_helper'
+
+require 'adoption_mover'
+
+class AdoptionMoverTest < ActiveSupport::TestCase
+  test 'moves deleted adoptions to close by unadopted things' do
+    deleted_adoption_to_be_moved = things(:thing_1).tap do |thing|
+      thing.update!(user_id: users(:erik).id, adopted_name: 'hello', lat: '37.74092857302200', lng: '-122.422757295129000')
+      thing.destroy!
+    end
+    unadopted_thing_to_be_moved_to = things(:thing_10).tap do |thing|
+      thing.update!(user_id: nil, lat: '37.74093794334370', lng: '-122.42275720139800')
+    end
+
+    moved_adoptions = AdoptionMover.move_close_deleted_adoptions(Time.zone.parse('1 hour ago'), 5)
+
+    assert_equal moved_adoptions[deleted_adoption_to_be_moved.id], unadopted_thing_to_be_moved_to.id
+
+    # assert close deleted adoption moved
+    unadopted_thing_to_be_moved_to.reload
+    assert_equal unadopted_thing_to_be_moved_to.user_id, deleted_adoption_to_be_moved.user_id
+    assert_equal unadopted_thing_to_be_moved_to.adopted_name, deleted_adoption_to_be_moved.adopted_name
+
+    # original adoption removed
+    deleted_adoption_to_be_moved.reload
+    assert_nil deleted_adoption_to_be_moved.user_id
+  end
+
+  test 'does not consider adopted drains when moving deleted adoptions to close by unadopted things' do
+    deleted_adoption_to_be_moved = things(:thing_1).tap do |thing|
+      thing.update!(user_id: users(:erik).id, adopted_name: 'hello', lat: '37.74092857302200', lng: '-122.422757295129000')
+      thing.destroy!
+    end
+    adopted_thing_to_ignore = things(:thing_10).tap do |thing|
+      thing.update!(user_id: users(:dan).id, adopted_name: 'world', lat: '37.74093794334370', lng: '-122.42275720139800')
+    end
+
+    assert_equal AdoptionMover.move_close_deleted_adoptions(Time.zone.parse('1 hour ago'), 5), {}
+
+    # original adoption unchanged
+    deleted_adoption_to_be_moved.reload
+    assert_equal deleted_adoption_to_be_moved.user_id, users(:erik).id
+    assert_equal deleted_adoption_to_be_moved.adopted_name, 'hello'
+
+    # assert close adoption unchanged
+    adopted_thing_to_ignore.reload
+    assert_equal adopted_thing_to_ignore.user_id, users(:dan).id
+    assert_equal adopted_thing_to_ignore.adopted_name, 'world'
+  end
+
+  test 'does not consider unadopted, far away, drains when moving deleted adoptions to close by unadopted things' do
+    deleted_adoption_to_be_moved = things(:thing_1).tap do |thing|
+      thing.update!(user_id: users(:erik).id, adopted_name: 'hello', lat: '37.74092857302200', lng: '-122.422757295129000')
+      thing.destroy!
+    end
+    thing_to_ignore = things(:thing_10).tap do |thing|
+      thing.update!(user_id: nil, lat: '38.74093794334370', lng: '-122.42275720139800')
+    end
+
+    assert_equal AdoptionMover.move_close_deleted_adoptions(Time.zone.parse('1 hour ago'), 5), {}
+
+    # original adoption unchanged
+    deleted_adoption_to_be_moved.reload
+    assert_equal deleted_adoption_to_be_moved.user_id, users(:erik).id
+    assert_equal deleted_adoption_to_be_moved.adopted_name, 'hello'
+
+    # assert far unadopted thing unchanged
+    thing_to_ignore.reload
+    assert_nil thing_to_ignore.user_id
+  end
+end