Add ApplyCropJobTemplate service and for_crop scope to CropJobTemplate model

app/models/crop_job_template.rb

@@ -14,6 +14,10 @@ class CropJobTemplate < ApplicationRecord
 
   validates :name, presence: true
 
+  # Those written for the crop itself or, if it is a variety, for the crop it
+  # is a variety of.
+  scope :for_crop, ->(crop) { where(crop_id: [crop.id, crop.parent_id].compact) }
+
   accepts_nested_attributes_for :steps, allow_destroy: true, reject_if: :all_blank
 
   def to_s

app/services/apply_crop_job_template.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+# Makes jobs for a planting from a crop job template: one for each step that
+# falls today or later. A step the planting already has a job for is not made
+# again, so applying a template twice does nothing the second time. A step
+# repeating weekly, fortnightly or monthly is made once, for its first day.
+class ApplyCropJobTemplate
+  def initialize(template, planting, today: Time.zone.today)
+    @template = template
+    @planting = planting
+    @today = today
+  end
+
+  # The jobs made, in the order of the template's steps.
+  def call
+    return [] if @planting.planted_at.blank?
+
+    entries.filter_map { |entry| create_job(entry) }
+  end
+
+  private
+
+  def entries
+    schedule = CropJobSchedule.new(@template, planting_out_on: @planting.planted_at.to_date, today: @today)
+    schedule.entries.select { |entry| entry.date && !entry.past? && applied_step_ids.exclude?(entry.step.id) }
+  end
+
+  # Steps of the template that already have a job for this planting.
+  def applied_step_ids
+    @applied_step_ids ||= Job.where(jobbable: @planting, crop_job_step: @template.steps).pluck(:crop_job_step_id)
+  end
+
+  def create_job(entry)
+    Job.create!(name: entry.step.name, due_date: entry.date, owner: @planting.owner, garden: @planting.garden,
+                jobbable: @planting, crop_job_step: entry.step)
+  end
+end

spec/models/crop_job_template_spec.rb

@@ -43,4 +43,27 @@ describe CropJobTemplate do
       expect { template.destroy }.to change(CropJobStep, :count).by(-2)
     end
   end
+
+  describe '.for_crop' do
+    subject(:found) { described_class.for_crop(crop) }
+
+    let(:parent) { create(:crop) }
+    let(:crop) { create(:crop, parent:) }
+
+    it 'has templates written for the crop' do
+      expect(found).to include(create(:crop_job_template, crop:))
+    end
+
+    it 'has templates written for its parent' do
+      expect(found).to include(create(:crop_job_template, crop: parent))
+    end
+
+    it 'leaves out templates for other crops' do
+      expect(found).not_to include(create(:crop_job_template))
+    end
+
+    it 'leaves out templates for a sibling variety' do
+      expect(found).not_to include(create(:crop_job_template, crop: create(:crop, parent:)))
+    end
+  end
 end

spec/services/apply_crop_job_template_spec.rb

@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe ApplyCropJobTemplate do
+  subject(:apply) { described_class.new(template, planting, today:) }
+
+  let(:today) { Date.new(2026, 10, 23) }
+  let(:planting) { create(:planting, planted_at: Date.new(2026, 10, 20)) }
+  let(:template) { create(:crop_job_template, crop: planting.crop) }
+  let!(:stake) { create(:crop_job_step, crop_job_template: template, name: 'Stake', offset_amount: 2, offset_unit: 'weeks') }
+
+  describe '#call' do
+    it 'makes a job for a step' do
+      expect(apply.call.map(&:name)).to eq ['Stake']
+    end
+
+    it 'dates the job from the planting' do
+      expect(apply.call.first.due_date).to eq Date.new(2026, 11, 3)
+    end
+
+    it 'makes the job the planting owner\'s' do
+      expect(apply.call.first.owner).to eq planting.owner
+    end
+
+    it 'makes the job about the planting' do
+      expect(apply.call.first.jobbable).to eq planting
+    end
+
+    it 'puts the job in the planting\'s garden' do
+      expect(apply.call.first.garden).to eq planting.garden
+    end
+
+    it 'records the step the job came from' do
+      expect(apply.call.first.crop_job_step).to eq stake
+    end
+
+    context 'when applied a second time' do
+      before { described_class.new(template, planting, today:).call }
+
+      it 'makes no more jobs' do
+        expect(apply.call).to be_empty
+      end
+    end
+
+    context 'with a step that fell before today' do
+      before { create(:crop_job_step, crop_job_template: template, name: 'Harden off', offset_amount: 1, offset_unit: 'days') }
+
+      it 'leaves it out' do
+        expect(apply.call.map(&:name)).not_to include 'Harden off'
+      end
+    end
+
+    context 'with a step on the first harvest and no harvest date known' do
+      before { create(:crop_job_step, crop_job_template: template, name: 'Pick', anchor: 'first_harvest') }
+
+      it 'leaves it out' do
+        expect(apply.call.map(&:name)).not_to include 'Pick'
+      end
+    end
+
+    context 'with a planting that has no planting date' do
+      let(:planting) { create(:planting, planted_at: nil) }
+
+      it 'makes no jobs' do
+        expect(apply.call).to be_empty
+      end
+    end
+  end
+end