Feature/import download tutorials csv backend

app/api/tutorials_api.rb

@@ -3,6 +3,7 @@
 class TutorialsApi < Grape::API
   helpers AuthenticationHelpers
   helpers AuthorisationHelpers
+  helpers MimeCheckHelpers
 
   before do
     authenticated?
@@ -102,4 +103,38 @@ class TutorialsApi < Grape::API
     tutorial.destroy!
     present true, with: Grape::Presenters::Presenter
   end
+
+  desc 'Upload CSV with tutorials'
+  params do
+    requires :file, type: File, desc: 'CSV upload file.'
+  end
+  post '/csv/tutorials/upload' do
+    unless authorise? current_user, User, :upload_csv
+      error!({ error: 'Not authorised to upload CSV of students of tutorials' }, 403)
+    end
+
+    if params[:file].blank?
+      error!({ error: 'No file uploaded' }, 403)
+    end
+
+    if params[:file][:tempfile].size > 5.megabytes
+      error!({ error: 'CSV file size exceeds the 5MB limit' }, 413)
+    end
+
+    path = params[:file][:tempfile].path
+    Tutorial.import_from_csv(File.new(path))
+  end
+
+  desc 'Download CSV with tutorials'
+  get '/csv/tutorials/download' do
+    unless authorise? current_user, User, :download_tutorial_csv
+      error!({ error: 'Not authorised to download CSV of all tutorials' }, 403)
+    end
+
+    content_type 'application/octet-stream'
+    header['Content-Disposition'] = 'attachment; filename=tutorials.csv'
+    header['Access-Control-Expose-Headers'] = 'Content-Disposition'
+    env['api.format'] = :binary
+    Tutorial.export_to_csv
+  end
 end

app/models/tutorial.rb

@@ -1,4 +1,7 @@
+require 'csv_helper'
+require 'csv'
 class Tutorial < ApplicationRecord
+  include CsvHelper
   # Model associations
   belongs_to :unit, optional: false # Foreign key
   belongs_to :unit_role, optional: true # Foreign key
@@ -73,6 +76,114 @@ def num_students
     projects.where('enrolled = true').count
   end
 
+  def self.missing_headers(row, headers)
+    headers - row.to_hash.keys
+  end
+
+  def self.csv_columns
+    %w[code abbreviation unit_id tutor_id tutorial_stream]
+  end
+
+  def self.import_from_csv(file)
+    success = []
+    errors = []
+    ignored = []
+    data = FileHelper.read_file_to_str(file).gsub('\\n', "\n")
+
+    ActiveRecord::Base.transaction do
+      CSV.parse(data,
+                headers: true,
+                header_converters: [->(i) { i.nil? ? '' : i }, :downcase, ->(hdr) { hdr.strip unless hdr.nil? }],
+                converters: [->(body) { body.encode!('UTF-8', 'binary', invalid: :replace, undef: :replace, replace: '') unless body.nil? }]).each do |row|
+        missing = missing_headers(row, csv_columns)
+        if missing.count > 0
+          errors << { row: row, message: "Missing headers: #{missing.join(', ')}" }
+          raise StandardError, "Critical import error: missing headers"
+        end
+
+        tutorial_code = row['code'].strip unless row['code'].nil?
+        abbreviation = row['abbreviation'].strip unless row['abbreviation'].nil?
+        unit_id = row['unit_id'].strip unless row['unit_id'].nil?
+        user_id = row['tutor_id'].strip unless row['tutor_id'].nil?
+        tutorial_stream_name = row['tutorial_stream'].strip unless row['tutorial_stream'].nil?
+
+        # find unit role using tutor's user_id and unit_id
+        unit_role = UnitRole.find_by(user_id: user_id, unit_id: unit_id)
+
+        if unit_role.nil?
+          errors << { row: row, message: "Tutor with user_id (#{user_id}) not found in unit roles" }
+          raise StandardError, 'Critical import error: missing unit role'
+        end
+
+        # if tutorial is found set it, otherwise leave it blank
+        tutorial_stream = TutorialStream.find_by(name: tutorial_stream_name) if tutorial_stream_name.present?
+
+        # handle missing tutorial stream
+        tutorial_stream = nil if tutorial_stream_name.blank?
+
+        # create a new tutorial
+        tutorial = Tutorial.new(
+          unit_id: unit_id,
+          code: tutorial_code,
+          abbreviation: abbreviation,
+          unit_role_id: unit_role.id,
+          tutorial_stream_id: tutorial_stream&.id
+        )
+
+        if tutorial.save
+          success << { row: row, message: "Created tutorial #{abbreviation} #{unit_id}" }
+        else
+          errors << { row: row, message: "Failed to create tutorial #{abbreviation} #{unit_id}" }
+          raise StandardError, 'Critical import error: failed to save tutorial'
+        end
+      rescue StandardError => e
+        raise ActiveRecord::Rollback
+      end
+
+      raise ActiveRecord::Rollback unless errors.empty?
+    end
+
+    {
+      success: success,
+      ignored: ignored,
+      errors: errors
+    }
+  end
+
+  def self.export_to_csv
+    exportables = %w[code abbreviation unit_id unit_role_id tutorial_stream_id]
+
+    # Generate the CSV file
+    CSV.generate do |csv|
+      # Add header row
+      csv << Tutorial.attribute_names.select { |attribute| exportables.include? attribute }.map do |attribute|
+        if attribute == 'tutorial_stream_id'
+          'tutorial_stream'
+        elsif attribute == 'unit_role_id'
+          'tutor_id'
+        else
+          attribute
+        end
+      end
+
+      # Add data rows
+      Tutorial.order('id').each do |tutorial|
+        csv << tutorial.attributes.select { |attribute| exportables.include? attribute }.map do |key, value|
+          # make the values more readable
+          if key == 'tutorial_stream_id'
+            stream_name = TutorialStream.find_by(id: value)&.name
+            stream_name
+          elsif key == 'unit_role_id'
+            tutor_id = UnitRole.find_by(id: value)&.user_id
+            tutor_id
+          else
+            value
+          end
+        end
+      end
+    end
+  end
+
   private
 
   def can_destroy?

app/models/user.rb

@@ -296,6 +296,7 @@ def self.permissions
       :upload_csv,
       :download_system_csv,
       :download_unit_csv,
+      :download_tutorial_csv,
 
       :create_unit,
       :admin_units,

config/routes.rb

@@ -10,4 +10,5 @@
   mount ApiRoot => '/'
   mount GrapeSwaggerRails::Engine => '/api/docs'
   mount Sidekiq::Web => "/sidekiq" # mount Sidekiq::Web in your Rails app
+  mount TutorialsApi => '/api'
 end

test/models/tutorial_model_test.rb

@@ -21,4 +21,104 @@ def test_unit_inconsistency_raises_error
     assert tutorial.invalid?
     assert_equal 'Unit should be same as the unit in the associated tutorial stream', tutorial.errors.full_messages.last
   end
+
+  def test_import_from_valid_csv
+    # Setup
+    unit = FactoryBot.create(:unit)
+    tutor_user = FactoryBot.create(:user, role_id: 3) # role_id 3 for tutor
+    unit_role = FactoryBot.create(:unit_role, user: tutor_user, unit: unit) # Create the unit_role
+    tutorial_stream = FactoryBot.create(:tutorial_stream, unit: unit)
+
+    file = Tempfile.new('tutorials.csv')
+    begin
+      # Writing the test CSV data
+      file.write("code,abbreviation,unit_id,tutor_id,tutorial_stream\n")
+      file.write("CODE123,ABBR,#{unit.id},#{tutor_user.id},#{tutorial_stream.name}\n")
+      file.rewind
+
+      # Perform the CSV import
+      result = Tutorial.import_from_csv(file)
+
+      # Assert the import was successful
+      assert_equal 1, result[:success].length, result[:errors].map { |e| e[:message] }.join(", ")
+      assert_empty result[:errors], "There should be no errors"
+
+      # Check if the tutorial is correctly created
+      tutorial = Tutorial.find_by(code: 'CODE123')
+      assert_not_nil tutorial, "Tutorial should be created"
+      assert_equal 'ABBR', tutorial.abbreviation, "Tutorial abbreviation should match"
+      assert_equal unit.id, tutorial.unit_id, "Tutorial unit should match"
+
+      # Assert that the tutorial's unit_role_id matches the created unit_role
+      assert_equal unit_role.id, tutorial.unit_role_id, "Tutorial's unit_role_id should match the created unit_role"
+    ensure
+      file.close
+      file.unlink
+    end
+  end
+
+  def test_import_with_missing_headers
+    # Prepare a CSV content with a missing header (`tutor_id` is missing)
+    csv_content = <<~CSV
+      code,unit_id
+      TUT102,1
+    CSV
+    # Create a temporary file with the  CSV content
+    file = create_tempfile(csv_content)
+
+    result = Tutorial.import_from_csv(file)
+
+    # Assert that no tutorials were successfully imported
+    assert_equal 0, result[:success].size
+
+    # Assert that one error was raised due to the missing header
+    assert_equal 1, result[:errors].size
+
+    # Assert that the error message contains 'Missing headers', indicating that the import failed
+    assert_match /Missing headers/, result[:errors].first[:message]
+  ensure
+    file.close
+    file.unlink
+  end
+
+  def test_export_to_csv
+    # Ensure no tutorials exist before starting the test
+    Tutorial.delete_all
+
+    # Create necessary objects
+    unit = FactoryBot.create(:unit)
+    unit_role = FactoryBot.create(:unit_role, unit: unit, role_id: 3)  # Ensure this is a tutor role
+    tutorial_stream = FactoryBot.create(:tutorial_stream, unit: unit)
+
+    # Create the tutorial, associating it with the unit_role and tutorial_stream
+    tutorial = Tutorial.create(
+      meeting_day: "Monday",
+      meeting_time: "17:30",
+      meeting_location: "ATC101",
+      unit: unit,
+      unit_role: unit_role,
+      tutorial_stream: tutorial_stream,
+      abbreviation: "ABBR",
+      code: "CODE123"
+    )
+
+    # Export tutorials to CSV
+    csv = Tutorial.export_to_csv
+    data = CSV.parse(csv, headers: true)
+
+    # Check that the exported CSV contains the tutorial that was created
+    assert_includes data.map { |row| row['code'] }, tutorial.code, "Expected tutorial code to be included in the export"
+    assert_includes data.map { |row| row['abbreviation'] }, tutorial.abbreviation, "Expected tutorial abbreviation to be included in the export"
+    assert_includes data.map { |row| row['unit_id'] }, tutorial.unit_id.to_s, "Expected tutorial unit_id to be included in the export"
+    assert_includes data.map { |row| row['tutor_id'] }, tutorial.unit_role.user_id.to_s, "Expected tutor_id to be included in the export"
+  end
+
+  private
+
+  def create_tempfile(content)
+    file = Tempfile.new(['test_csv', '.csv'])
+    file.write(content)
+    file.rewind
+    file
+  end
 end

test_files/csv_test_files/Tutorials.csv

@@ -0,0 +1,3 @@
+code,abbreviation,unit_id,tutor_id,tutorial_stream
+test,CS3,4,8,
+,FX1,1,2,Practical-1