From 5bfd4ecbbfde36b49f4f1bbf2e17c62393c5b87d Mon Sep 17 00:00:00 2001
From: simon lehericey <mail@simon.lehericey.net>
Date: Wed, 21 Apr 2021 12:02:57 +0200
Subject: [PATCH] add DossierProjectionService

---
 app/services/dossier_projection_service.rb    |  88 ++++++++++
 .../dossier_projection_service_spec.rb        | 157 ++++++++++++++++++
 2 files changed, 245 insertions(+)
 create mode 100644 app/services/dossier_projection_service.rb
 create mode 100644 spec/services/dossier_projection_service_spec.rb

diff --git a/app/services/dossier_projection_service.rb b/app/services/dossier_projection_service.rb
new file mode 100644
index 000000000..a53905cec
--- /dev/null
+++ b/app/services/dossier_projection_service.rb
@@ -0,0 +1,88 @@
+class DossierProjectionService
+  class DossierProjection < Struct.new(:dossier, :columns)
+  end
+
+  TABLE = 'table'
+  COLUMN = 'column'
+
+  # Returns [DossierProjection(dossier, columns)] ordered by dossiers_ids
+  # and the columns orderd by fields.
+  #
+  # It tries to be fast by using `pluck` (or at least `select`)
+  # to avoid deserializing entire records.
+  #
+  # It stores its intermediary queries results in an hash in the corresponding field.
+  # ex: field_email[:id_value_h] = { dossier_id_1: email_1, dossier_id_3: email_3 }
+  #
+  # Those hashes are needed because:
+  # - the order of the intermediary query results are unknown
+  # - some values can be missing (if a revision added or removed them)
+  def self.project(dossiers_ids, fields)
+    champ_fields, other_fields = fields
+      .partition { |f| ['type_de_champ', 'type_de_champ_private'].include?(f[TABLE]) }
+
+    if champ_fields.present?
+      Champ
+        .includes(:type_de_champ)
+        .where(
+          # as querying the champs table is costly
+          # we fetch all the requested champs at once
+          types_de_champ: { stable_id: champ_fields.map { |f| f[COLUMN] } },
+          dossier_id: dossiers_ids
+        )
+        .select(:dossier_id, :value, :type_de_champ_id, :stable_id) # we cannot pluck :value, as we need the champ.to_s method
+        .group_by(&:stable_id) # the champs are redispatched to their respective fields
+        .map do |stable_id, champs|
+        field = champ_fields.find { |f| f[COLUMN] == stable_id.to_s }
+        field[:id_value_h] = champs.to_h { |c| [c.dossier_id, c.to_s] }
+      end
+    end
+
+    other_fields.each do |field|
+      field[:id_value_h] = case field[TABLE]
+      when 'self'
+        Dossier
+          .where(id: dossiers_ids)
+          .pluck(:id, field[COLUMN].to_sym)
+          .to_h { |id, col| [id, col&.strftime('%d/%m/%Y')] }
+      when 'user'
+        Dossier
+          .joins(:user)
+          .where(id: dossiers_ids)
+          .pluck('dossiers.id, users.email')
+          .to_h
+      when 'individual'
+        Individual
+          .where(dossier_id: dossiers_ids)
+          .pluck(:dossier_id, field[COLUMN].to_sym)
+          .to_h
+      when 'etablissement'
+        Etablissement
+          .where(dossier_id: dossiers_ids)
+          .pluck(:dossier_id, field[COLUMN].to_sym)
+          .to_h
+      when 'groupe_instructeur'
+        Dossier
+          .joins(:groupe_instructeur)
+          .where(id: dossiers_ids)
+          .pluck('dossiers.id, groupe_instructeurs.label')
+          .to_h
+      when 'followers_instructeurs'
+        Follow
+          .active
+          .joins(instructeur: :user)
+          .where(dossier_id: dossiers_ids)
+          .pluck('dossier_id, users.email')
+          .group_by { |dossier_id, _| dossier_id }
+          .to_h { |dossier_id, dossier_id_emails| [dossier_id, dossier_id_emails.map { |_, email| email }&.join(', ')] }
+      end
+    end
+
+    Dossier
+      .select(:id, :state, :archived) # the dossier object is needed in the view
+      .find(dossiers_ids) # keeps dossiers_ids order and raise exception if one is missing
+      .map do |dossier|
+      DossierProjection.new(dossier, fields.map { |f| f[:id_value_h][dossier.id] })
+    end
+  end
+end
diff --git a/spec/services/dossier_projection_service_spec.rb b/spec/services/dossier_projection_service_spec.rb
new file mode 100644
index 000000000..aef955f73
--- /dev/null
+++ b/spec/services/dossier_projection_service_spec.rb
@@ -0,0 +1,157 @@
+describe DossierProjectionService do
+  describe '#project' do
+    subject { described_class.project(dossiers_ids, fields) }
+
+    context 'with multiple dossier' do
+      let!(:procedure) { create(:procedure, :with_type_de_champ) }
+      let!(:dossier_1) { create(:dossier, procedure: procedure) }
+      let!(:dossier_2) { create(:dossier, procedure: procedure) }
+      let!(:dossier_3) { create(:dossier, procedure: procedure) }
+
+      let(:dossiers_ids) { [dossier_3.id, dossier_1.id, dossier_2.id] }
+      let(:fields) do
+        [
+          {
+            "table" => "type_de_champ",
+            "column" => procedure.types_de_champ[0].stable_id.to_s
+          }
+        ]
+      end
+
+      before do
+        dossier_1.champs.first.update(value: 'champ_1')
+        dossier_2.champs.first.update(value: 'champ_2')
+        dossier_3.champs.first.destroy
+      end
+
+      let(:result) { subject }
+
+      it 'respects the dossiers_ids order and returns nil for empty result' do
+        expect(result.length).to eq(3)
+        expect(result[0].dossier.id).to eq(dossier_3.id)
+        expect(result[1].dossier.id).to eq(dossier_1.id)
+        expect(result[2].dossier.id).to eq(dossier_2.id)
+
+        expect(result[0].columns[0]).to be nil
+        expect(result[1].columns[0]).to eq('champ_1')
+        expect(result[2].columns[0]).to eq('champ_2')
+      end
+    end
+
+    context 'attributes by attributes' do
+      let(:fields) { [{ "table" => table, "column" => column }] }
+      let(:dossiers_ids) { [dossier.id] }
+
+      subject { super()[0].columns[0] }
+
+      context 'for self table' do
+        let(:table) { 'self' }
+
+        context 'for created_at column' do
+          let(:column) { 'created_at' }
+          let(:dossier) { Timecop.freeze(Time.zone.local(1992, 3, 22)) { create(:dossier) } }
+
+          it { is_expected.to eq('22/03/1992') }
+        end
+
+        context 'for en_construction_at column' do
+          let(:column) { 'en_construction_at' }
+          let(:dossier) { create(:dossier, :en_construction, en_construction_at: Time.zone.local(2018, 10, 17)) }
+
+          it { is_expected.to eq('17/10/2018') }
+        end
+
+        context 'for updated_at column' do
+          let(:column) { 'updated_at' }
+          let(:dossier) { create(:dossier) }
+
+          before { dossier.touch(time: Time.zone.local(2018, 9, 25)) }
+
+          it { is_expected.to eq('25/09/2018') }
+        end
+      end
+
+      context 'for user table' do
+        let(:table) { 'user' }
+        let(:column) { 'email' }
+
+        let(:dossier) { create(:dossier, user: create(:user, email: 'bla@yopmail.com')) }
+
+        it { is_expected.to eq('bla@yopmail.com') }
+      end
+
+      context 'for individual table' do
+        let(:table) { 'individual' }
+        let(:procedure) { create(:procedure, :for_individual, :with_type_de_champ, :with_type_de_champ_private) }
+        let(:dossier) { create(:dossier, procedure: procedure, individual: create(:individual, nom: 'Martin', prenom: 'Jacques', gender: 'M.')) }
+
+        context 'for prenom column' do
+          let(:column) { 'prenom' }
+
+          it { is_expected.to eq('Jacques') }
+        end
+
+        context 'for nom column' do
+          let(:column) { 'nom' }
+
+          it { is_expected.to eq('Martin') }
+        end
+
+        context 'for gender column' do
+          let(:column) { 'gender' }
+
+          it { is_expected.to eq('M.') }
+        end
+      end
+
+      context 'for etablissement table' do
+        let(:table) { 'etablissement' }
+        let(:column) { 'code_postal' } # All other columns work the same, no extra test required
+
+        let!(:dossier) { create(:dossier, etablissement: create(:etablissement, code_postal: '75008')) }
+
+        it { is_expected.to eq('75008') }
+      end
+
+      context 'for groupe_instructeur table' do
+        let(:table) { 'groupe_instructeur' }
+        let(:column) { 'label' }
+
+        let!(:dossier) { create(:dossier) }
+
+        it { is_expected.to eq('défaut') }
+      end
+
+      context 'for followers_instructeurs table' do
+        let(:table) { 'followers_instructeurs' }
+        let(:column) { 'email' }
+
+        let(:dossier) { create(:dossier) }
+        let!(:follow1) { create(:follow, dossier: dossier, instructeur: create(:instructeur, email: 'user1@host')) }
+        let!(:follow2) { create(:follow, dossier: dossier, instructeur: create(:instructeur, email: 'user2@host')) }
+
+        it { is_expected.to eq "user1@host, user2@host" }
+      end
+
+      context 'for type_de_champ table' do
+        let(:table) { 'type_de_champ' }
+        let(:dossier) { create(:dossier) }
+        let(:column) { dossier.procedure.types_de_champ.first.stable_id.to_s }
+
+        before { dossier.champs.first.update(value: 'kale') }
+
+        it { is_expected.to eq('kale') }
+      end
+
+      context 'for type_de_champ_private table' do
+        let(:table) { 'type_de_champ_private' }
+        let(:dossier) { create(:dossier) }
+        let(:column) { dossier.procedure.types_de_champ_private.first.stable_id.to_s }
+
+        before { dossier.champs_private.first.update(value: 'quinoa') }
+
+        it { is_expected.to eq('quinoa') }
+      end
+    end
+  end
+end