Moving the planting predictions to own service

Gemfile

@@ -136,6 +136,7 @@ end
 
 group :test do
   gem 'codeclimate-test-reporter', require: false
+  gem 'timecop'
 end
 
 group :travis do

Gemfile.lock

@@ -482,6 +482,7 @@ GEM
     thread (0.2.2)
     thread_safe (0.3.6)
     tilt (2.0.7)
+    timecop (0.8.1)
     tins (1.14.0)
     trollop (1.16.2)
     tzinfo (1.2.3)
@@ -589,12 +590,12 @@ DEPENDENCIES
   selenium-webdriver
   sidekiq
   sparkpost_rails
+  timecop
   uglifier (~> 2.7.2)
   unicorn
   webrat
   will_paginate (~> 3.0)
 
-
 RUBY VERSION
    ruby 2.3.4p301
 

app/models/planting.rb

@@ -91,59 +91,27 @@ class Planting < ActiveRecord::Base
     photos.first
   end
 
-  def planted?(current_date = Date.current)
-    planted_at.present? && current_date.to_date >= planted_at
+  def planted?
+    planted_at.present? && planted_at < Date.current
   end
 
   def days_until_finished
-    return 0 if finished?
-    days = (finished_at - Date.current).to_i
-    days.positive? ? days : 0
+    PlantingPredictions.new(self).days_until_finished
   end
 
   def days_until_mature
-    days = ((planted_at + days_before_maturity) - Date.current).to_i
-    days.positive? ? days : 0
+    PlantingPredictions.new(self).days_until_mature
   end
 
-  def percentage_grown(current_date = Date.current)
-    return nil unless days_before_maturity && planted?(current_date)
-
-    days = (current_date.to_date - planted_at.to_date).to_i
-
-    return 0 if current_date < planted_at
-    return 100 if days > days_before_maturity
-    percent = (days / days_before_maturity * 100).to_i
-
-    if percent >= 100
-      percent = 100
-    end
-
-    percent
+  def percentage_grown
+    PlantingPredictions.new(self).percentage_grown
   end
 
   def start_to_finish_diff
-    (finished_at - planted_at).to_i if finished_at && planted_at
-  end
-
-  def self.mean_days_until_maturity(plantings)
-    ## Given a set of finished plantings, calculate the average/mean time from start to finish
-    differences = plantings.collect(&:start_to_finish_diff)
-    differences.compact.sum / differences.compact.size unless differences.compact.empty?
+    PlantingPredictions.new(self).start_to_finish_diff
   end
 
   def calc_and_set_days_before_maturity
-    # calculate the number of days, from planted_at, until maturity
-    if planted_at && finished_at
-      self.days_before_maturity = start_to_finish_diff
-    else
-      self.days_before_maturity = Planting.mean_days_until_maturity other_finished_plantings_same_crop
-    end
-  end
-
-  private
-
-  def other_finished_plantings_same_crop
-    Planting.where(crop_id: crop).where.not(id: id).where.not(finished_at: nil)
+    PlantingPredictions.new(self).calc_and_set_days_before_maturity
   end
 end

app/services/planting_predictions.rb

@@ -0,0 +1,59 @@
+class PlantingPredictions
+  def initialize(planting)
+    @planting = planting
+  end
+
+  def days_until_finished
+    return 0 if @planting.finished?
+    days = (@planting.finished_at - Date.current).to_i
+    days.positive? ? days : 0
+  end
+
+  def days_until_mature
+    days = ((@planting.planted_at + @planting.days_before_maturity) - Date.current).to_i
+    days.positive? ? days : 0
+  end
+
+  def percentage_grown
+    current_date = Date.current
+    return nil unless @planting.days_before_maturity && @planting.planted?
+
+    days = (current_date.to_date - @planting.planted_at.to_date).to_i
+
+    return 0 if current_date < @planting.planted_at
+    return 100 if days > @planting.days_before_maturity
+    percent = (days / @planting.days_before_maturity * 100).to_i
+
+    percent = 100 if percent >= 100
+
+    percent
+  end
+
+  def start_to_finish_diff
+    (@planting.finished_at - @planting.planted_at).to_i if @planting.finished_at && @planting.planted_at
+  end
+
+  def calc_and_set_days_before_maturity
+    # calculate the number of days, from planted_at, until maturity
+    if @planting.planted_at && @planting.finished_at
+      @planting.days_before_maturity = start_to_finish_diff
+    else
+      plantings = other_finished_plantings_same_crop
+      @planting.days_before_maturity = PlantingPredictions.mean_days_until_maturity(plantings)
+    end
+  end
+
+  def self.mean_days_until_maturity(plantings)
+    ## Given a set of finished plantings, calculate the average/mean time from start to finish
+    differences = plantings.collect(&:start_to_finish_diff)
+    differences.compact.sum / differences.compact.size unless differences.compact.empty?
+  end
+
+  private
+
+  def other_finished_plantings_same_crop
+    Planting.where(crop_id: @planting.crop.id)
+      .where.not(id: @planting.id)
+      .where.not(finished_at: nil)
+  end
+end

spec/models/planting_spec.rb

@@ -20,9 +20,13 @@ describe Planting do
         8.times { FactoryGirl.create :planting, crop: crop, finished_at: nil }
       end
       let!(:planting_with_diff_crop) { FactoryGirl.create :planting, planted_at: 10.days.ago, finished_at: 2.days.ago }
-      it { expect(planting.send(:other_finished_plantings_same_crop).size).to eq(8) }
-      it { expect(planting.send(:other_finished_plantings_same_crop)).not_to include(planting) }
-      it { expect(planting.send(:other_finished_plantings_same_crop)).not_to include(planting_with_diff_crop) }
+      let(:planting_predictions) { PlantingPredictions.new(planting) }
+      it { expect(planting_predictions.send(:other_finished_plantings_same_crop).size).to eq(8) }
+      it { expect(planting_predictions.send(:other_finished_plantings_same_crop)).not_to include(planting) }
+      it do
+        expect(planting_predictions.send(:other_finished_plantings_same_crop))
+          .not_to include(planting_with_diff_crop)
+      end
     end
 
     describe 'mean_days_until_maturity' do
@@ -30,7 +34,7 @@ describe Planting do
         FactoryGirl.create_list(:planting, 10, crop: crop, planted_at: 12.days.ago, finished_at: 2.days.ago)
       end
       it { expect(plantings.size).to eq(10) }
-      it { expect(Planting.mean_days_until_maturity(plantings)).to eq(10) }
+      it { expect(PlantingPredictions.mean_days_until_maturity(plantings)).to eq(10) }
     end
 
     describe 'saving planting calculates days_before_maturity' do
@@ -88,23 +92,22 @@ describe Planting do
     it 'should not be more than 100%' do
       @planting = FactoryGirl.build(:planting, days_before_maturity: 1, planted_at: 1.day.ago)
 
-      now_later_than_planting = 2.days.from_now
-
-      @planting.percentage_grown(now_later_than_planting).should be 100
+      Timecop.freeze(2.days.from_now) do
+        @planting.percentage_grown.should be 100
+      end
     end
 
     it 'should not be less than 0%' do
       @planting = FactoryGirl.build(:planting, days_before_maturity: 1, planted_at: 1.day.ago)
 
-      now_earlier_than_planting = 2.days.ago
-
-      @planting.percentage_grown(now_earlier_than_planting).should be nil
+      Timecop.freeze(2.days.ago) do
+        @planting.percentage_grown.should be nil
+      end
     end
 
     it 'should reflect the current growth' do
       @planting = FactoryGirl.build(:planting, days_before_maturity: 10, planted_at: 4.days.ago)
-
-      expect(@planting.percentage_grown(Date.current)).to eq 40
+      expect(@planting.percentage_grown).to eq 40
     end
 
     it 'should not be calculated for unplanted plantings' do
@@ -116,7 +119,6 @@ describe Planting do
 
     it 'should not be calculated for plantings with an unknown days before maturity' do
       @planting = FactoryGirl.build(:planting, days_before_maturity: nil)
-
       @planting.percentage_grown.should be nil
     end
   end