From 8ca7a349eaa8d8a289f20ab849debf12abb2e557 Mon Sep 17 00:00:00 2001
From: pskl <hello@pascal.cc>
Date: Thu, 6 Feb 2025 18:25:02 +0100
Subject: [PATCH] Add StudentMerger service object to merge students with
 double INE (#1375)

---
 app/services/student_merger.rb                | 64 +++++++++++++++++++
 app/views/pfmps/_pfmp_student_table.html.haml |  2 +-
 config/initializers/version.rb                |  2 +-
 spec/services/student_merger_spec.rb          | 56 ++++++++++++++++
 4 files changed, 122 insertions(+), 2 deletions(-)
 create mode 100644 app/services/student_merger.rb
 create mode 100644 spec/services/student_merger_spec.rb

diff --git a/app/services/student_merger.rb b/app/services/student_merger.rb
new file mode 100644
index 000000000..8bff6dec8
--- /dev/null
+++ b/app/services/student_merger.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+# Service to safely merge duplicate student records (double INE) while preserving data integrity
+class StudentMerger
+  class StudentMergerError < StandardError; end
+  class InvalidStudentsArrayError < StudentMergerError; end
+  class ActiveSchoolingError < StudentMergerError; end
+
+  attr_reader :students
+
+  def initialize(students)
+    @students = students
+  end
+
+  def merge!
+    ActiveRecord::Base.transaction do
+      validate_students!
+      determine_target_and_merge_student!
+      validate_schoolings!
+      transfer_asp_individu_id!
+      transfer_schoolings!
+
+      @student_to_merge.destroy!
+
+      Rails.logger.info(
+        "Merged student #{@student_to_merge.id} into #{@target_student.id}"
+      )
+      true
+    end
+  end
+
+  private
+
+  def validate_students!
+    raise InvalidStudentsArrayError unless students.is_a?(Array) && students.length == 2
+  end
+
+  def determine_target_and_merge_student!
+    sorted_students = students.sort_by do |student|
+      latest_payment_request = student.pfmps.map(&:latest_payment_request).compact.max_by(&:created_at)
+      latest_payment_request&.created_at || Time.zone.at(0)
+    end
+
+    @target_student = sorted_students.last
+    @student_to_merge = sorted_students.first
+  end
+
+  def validate_schoolings!
+    return unless @student_to_merge.schoolings.exists?(end_date: nil)
+
+    raise ActiveSchoolingError, "Cannot merge students with active schoolings"
+  end
+
+  def transfer_asp_individu_id!
+    id = @student_to_merge.asp_individu_id || @target_student.asp_individu_id
+
+    @student_to_merge.update!(asp_individu_id: nil)
+    @target_student.update!(asp_individu_id: id)
+  end
+
+  def transfer_schoolings!
+    @student_to_merge.schoolings.update!(student_id: @target_student.id)
+  end
+end
diff --git a/app/views/pfmps/_pfmp_student_table.html.haml b/app/views/pfmps/_pfmp_student_table.html.haml
index fa8c8a550..5df53b5c6 100644
--- a/app/views/pfmps/_pfmp_student_table.html.haml
+++ b/app/views/pfmps/_pfmp_student_table.html.haml
@@ -1,5 +1,5 @@
+%h2.fr-h4 Scolarités
 - schoolings.sort_by{ |schooling| schooling.classe.school_year.start_year}.reverse.each do |schooling|
-  %h2 Scolarités
   - pfmps = schooling.pfmps
   - classe = schooling.classe
   - school_year = classe.school_year
diff --git a/config/initializers/version.rb b/config/initializers/version.rb
index 39a78d033..0bba69f2f 100644
--- a/config/initializers/version.rb
+++ b/config/initializers/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Aplypro
-  VERSION = "2.1.5"
+  VERSION = "2.2.0"
 end
diff --git a/spec/services/student_merger_spec.rb b/spec/services/student_merger_spec.rb
new file mode 100644
index 000000000..57e7f8901
--- /dev/null
+++ b/spec/services/student_merger_spec.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe StudentMerger do
+  describe "#merge!" do
+    let(:source_student) { create(:schooling, :closed).student }
+    let(:target_student) { create(:schooling, :closed).student }
+    let(:students) { [source_student, target_student] }
+    let(:merger) { described_class.new(students) }
+
+    context "with invalid inputs" do
+      it "raises error when not given exactly two students" do
+        merger = described_class.new([source_student])
+        expect { merger.merge! }.to raise_error(StudentMerger::InvalidStudentsArrayError)
+      end
+    end
+
+    context "when merging students with payment requests" do # rubocop:disable RSpec/MultipleMemoizedHelpers
+      let(:older_payment_request) { create(:asp_payment_request, created_at: 1.month.ago) }
+      let(:newer_payment_request) { create(:asp_payment_request, created_at: 1.day.ago) }
+      let(:source_student) { older_payment_request.student }
+      let(:target_student) { newer_payment_request.student }
+
+      before do
+        source_student.current_schooling.update!(end_date: 2.days.ago)
+      end
+
+      it "keeps the student with the most recent payment request" do
+        merger.merge!
+        expect(Student.exists?(source_student.id)).to be false
+      end
+
+      it "raises error when trying to transfer active schoolings" do
+        create(:schooling, student: source_student)
+        expect { merger.merge! }.to raise_error(StudentMerger::ActiveSchoolingError)
+      end
+    end
+
+    context "when transferring asp_individu_id" do
+      let(:source_student) { create(:schooling, :closed).student }
+      let(:target_student) { create(:schooling, :closed).student }
+
+      before do
+        source_student.update!(asp_individu_id: "123ABC")
+        target_student.update!(asp_individu_id: nil)
+      end
+
+      it "transfers asp_individu_id from source to target student" do
+        merger.merge!
+
+        expect(target_student.reload.asp_individu_id).to eq("123ABC")
+      end
+    end
+  end
+end