Improved drain deletion.

* Send email on deleted drain
* Soft-delete the removed rains

Gemfile

@@ -13,6 +13,7 @@ gem 'rails_admin'
 gem 'validates_formatting_of'
 
 gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw]
+gem 'paranoia', '~> 2.2'
 
 group :assets do
   gem 'sass-rails', '>= 4.0.3'

Gemfile.lock

@@ -110,6 +110,8 @@ GEM
       pkg-config (~> 1.1.7)
     obscenity (1.0.2)
     orm_adapter (0.5.0)
+    paranoia (2.2.0)
+      activerecord (>= 4.0, < 5.1)
     parser (2.3.0.7)
       ast (~> 2.2)
     pg (0.18.4)
@@ -236,6 +238,7 @@ DEPENDENCIES
   haml
   http_accept_language
   obscenity (~> 1.0, >= 1.0.2)
+  paranoia (~> 2.2)
   pg
   puma
   rails (~> 4.2.4)
@@ -255,4 +258,4 @@ RUBY VERSION
    ruby 2.2.3p173
 
 BUNDLED WITH
-   1.13.1
+   1.13.6

app/mailers/thing_mailer.rb

@@ -23,4 +23,9 @@ def reminder(thing)
     @user = thing.user
     mail(to: @user.email, subject: ['Remember to clear your adopted drain'])
   end
+
+  def drain_deleted_notification(thing)
+    @thing = thing
+    mail(to: User.where(admin: true).pluck(:email), subject: 'A drain has been removed.')
+  end
 end

app/models/thing.rb

@@ -2,6 +2,7 @@
 require 'csv'
 
 class Thing < ActiveRecord::Base
+  acts_as_paranoid
   extend Forwardable
   include ActiveModel::ForbiddenAttributesProtection
 
@@ -21,6 +22,7 @@ def self.find_closest(lat, lng, limit = 10)
     query = <<-SQL
       SELECT *, (3959 * ACOS(COS(RADIANS(?)) * COS(RADIANS(lat)) * COS(RADIANS(lng) - RADIANS(?)) + SIN(RADIANS(?)) * SIN(RADIANS(lat)))) AS distance
       FROM things
+      WHERE deleted_at is NULL
       ORDER BY distance
       LIMIT ?
       SQL
@@ -55,7 +57,10 @@ def self._delete_non_existing_drains(drains_from_source)
       drain['PUC_Maximo_Asset_ID'].gsub('N-', '')
     end
 
-    Thing.where.not(city_id: city_ids).delete_all
+    Thing.where.not(city_id: city_ids).find_each do |thing|
+      thing.destroy!
+      ThingMailer.drain_deleted_notification(thing).deliver_now
+    end
   end
 
   def self._drain_params(drain)

app/views/thing_mailer/drain_deleted_notification.html.erb

@@ -0,0 +1,3 @@
+Hi Adopt a drain admin!
+
+Just notifying you that drain with PUC_Maximo_Asset_ID: <%= @thing.city_id %>, and rails id <% @thing.id %>, has been removed from the database.

db/migrate/20161205030306_add_deleted_at_to_things.rb

@@ -0,0 +1,6 @@
+class AddDeletedAtToThings < ActiveRecord::Migration
+  def change
+    add_column :things, :deleted_at, :datetime
+    add_index :things, :deleted_at
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20160326200455) do
+ActiveRecord::Schema.define(version: 20161205030306) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -52,9 +52,11 @@
     t.integer  "city_id"
     t.integer  "user_id"
     t.string   "system_use_code"
+    t.datetime "deleted_at"
   end
 
   add_index "things", ["city_id"], name: "index_things_on_city_id", unique: true, using: :btree
+  add_index "things", ["deleted_at"], name: "index_things_on_deleted_at", using: :btree
 
   create_table "users", force: :cascade do |t|
     t.datetime "created_at"

test/mailers/thing_mailer_test.rb

@@ -39,4 +39,21 @@ class ThingMailerTest < ActionMailer::TestCase
     assert_equal ['[email protected]'], email.to
     assert_equal 'We really do love you, Erik!', email.subject
   end
+
+  test 'drain_deleted_notification' do
+    admin_1 = users(:admin)
+    admin_2 = users(:admin)
+    admin_2.update(email: '[email protected]')
+    thing = things(:thing_1)
+
+    email = nil
+    assert_emails(1) do
+      email = ThingMailer.drain_deleted_notification(thing).deliver_now
+    end
+
+    assert_includes email.to, admin_1.email
+    assert_includes email.to, admin_2.email
+
+    assert_equal email.subject, 'A drain has been removed.'
+  end
 end

test/models/thing_test.rb

@@ -17,6 +17,7 @@ class ThingTest < ActiveSupport::TestCase
   end
 
   test 'loading drains, deletes existing drains not in data set, updates properties on rest' do
+    admin = users(:admin)
     thing_1 = things(:thing_1)
     thing_11 = things(:thing_11)
 
@@ -29,6 +30,10 @@ class ThingTest < ActiveSupport::TestCase
     stub_request(:get, fake_url).to_return(body: fake_response)
 
     Thing.load_drains(fake_url)
+
+    email = ActionMailer::Base.deliveries.last
+    assert_equal email.to, [admin.email]
+    assert_equal email.subject, 'A drain has been removed.'
     thing_11.reload
 
     # Asserts thing_1 is deleted