Calculate merge request status

app/models/merge_request.rb

@@ -4,6 +4,7 @@ class MergeRequest < ApplicationRecord
   belongs_to :absorbing_organisation, class_name: "Organisation", optional: true
   has_many :merging_organisations, through: :merge_request_organisations, source: :merging_organisation
   belongs_to :requester, class_name: "User", optional: true
+  before_save :update_status!
 
   STATUS = {
     "merge_issues" => 0,
@@ -11,6 +12,7 @@ class MergeRequest < ApplicationRecord
     "ready_to_merge" => 2,
     "processing" => 3,
     "request_merged" => 4,
+    "deleted" => 5,
   }.freeze
   enum status: STATUS
 
@@ -21,6 +23,8 @@ class MergeRequest < ApplicationRecord
     merged.where("merge_requests.merge_date >= ?", open_collection_period_start_date).or(not_merged).where(discarded_at: nil)
   }
 
+  attr_accessor :skip_update_status
+
   def absorbing_organisation_name
     absorbing_organisation&.name || ""
   end
@@ -32,4 +36,27 @@ class MergeRequest < ApplicationRecord
   def discard!
     update!(discarded_at: Time.zone.now)
   end
+
+  def update_status!
+    return if skip_update_status
+
+    self.status = calculate_status
+  end
+
+  def calculate_status
+    return "deleted" if discarded_at.present?
+    return "request_merged" if status == "request_merged"
+    return "processing" if status == "processing"
+    return "incomplete" unless required_questions_answered?
+    return "ready_to_merge" if absorbing_organisation.data_protection_confirmed?
+
+    "merge_issues"
+  end
+
+  def required_questions_answered?
+    absorbing_organisation_id.present? &&
+      merge_date.present? &&
+      merging_organisations.count.positive? &&
+      errors.empty?
+  end
 end

spec/factories/merge_request_organisation.rb

@@ -0,0 +1,6 @@
+FactoryBot.define do
+  factory :merge_request_organisation do
+    association :merging_organisation, factory: :organisation
+    association :merge_request, factory: :merge_request
+  end
+end

spec/models/merge_request_spec.rb

@@ -42,4 +42,51 @@ RSpec.describe MergeRequest, type: :model do
       expect(described_class.visible).not_to include(merge_request)
     end
   end
+
+  describe "#calculate_status" do
+    it "returns the correct status for deleted merge request" do
+      merge_request = build(:merge_request, id: 1, discarded_at: Time.zone.today)
+      expect(merge_request.calculate_status).to eq "deleted"
+    end
+
+    it "returns the correct status for a merged request" do
+      merge_request = build(:merge_request, id: 1, status: "request_merged")
+      expect(merge_request.calculate_status).to eq "request_merged"
+    end
+
+    it "returns the correct status for a ready to merge request" do
+      merge_request = build(:merge_request, id: 1, absorbing_organisation: create(:organisation), merge_date: Time.zone.today)
+      create(:merge_request_organisation, merge_request:)
+      expect(merge_request.calculate_status).to eq "ready_to_merge"
+    end
+
+    it "returns the merge issues if dsa is not signed for absorbing organisation" do
+      merge_request = build(:merge_request, id: 1, absorbing_organisation: create(:organisation, with_dsa: false), merge_date: Time.zone.today)
+      create(:merge_request_organisation, merge_request:)
+      expect(merge_request.calculate_status).to eq "merge_issues"
+    end
+
+    it "returns the incomplete if absorbing organisation is missing" do
+      merge_request = build(:merge_request, id: 1, absorbing_organisation: nil, merge_date: Time.zone.today)
+      create(:merge_request_organisation, merge_request:)
+      expect(merge_request.calculate_status).to eq "incomplete"
+    end
+
+    it "returns the incomplete if merge requests organisation is missing" do
+      merge_request = build(:merge_request, id: 1, absorbing_organisation: create(:organisation), merge_date: Time.zone.today)
+      expect(merge_request.calculate_status).to eq "incomplete"
+    end
+
+    it "returns the incomplete if merge date is missing" do
+      merge_request = build(:merge_request, id: 1, absorbing_organisation: create(:organisation))
+      create(:merge_request_organisation, merge_request:)
+      expect(merge_request.calculate_status).to eq "incomplete"
+    end
+
+    it "returns processing if merge is processing" do
+      merge_request = build(:merge_request, id: 1, absorbing_organisation: create(:organisation), status: "processing")
+      create(:merge_request_organisation, merge_request:)
+      expect(merge_request.calculate_status).to eq "processing"
+    end
+  end
 end