diff --git a/.rubocop.yml b/.rubocop.yml
index e4a51bf6c..881a7b41c 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -11,7 +11,7 @@ Metrics/AbcSize:
 Metrics/ClassLength:
   Max: 200
 Style/BracesAroundHashParameters:
-  EnforcedStyle: context_dependent
+  EnforcedStyle: braces
 Style/RegexpLiteral:
   EnforcedStyle: slashes
 Style/EmptyElse:
diff --git a/lib/fab_manager.rb b/lib/fab_manager.rb
index 96370fbea..56bbfba7e 100644
--- a/lib/fab_manager.rb
+++ b/lib/fab_manager.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_dependency 'plugin/instance'
 
 module FabManager
diff --git a/lib/file_size_validator.rb b/lib/file_size_validator.rb
index 8d80df2be..328e56f93 100644
--- a/lib/file_size_validator.rb
+++ b/lib/file_size_validator.rb
@@ -1,17 +1,20 @@
+# frozen_string_literal: true
+
 # File size validator for CarrierWave
 # https://github.com/jnicklas/carrierwave/wiki/How-to%3A-Validate-attachment-file-size
-
 class FileSizeValidator < ActiveModel::EachValidator
-  MESSAGES  = { :is => :wrong_size, :minimum => :size_too_small, :maximum => :size_too_big }.freeze
-  CHECKS    = { :is => :==, :minimum => :>=, :maximum => :<= }.freeze
+  MESSAGES  = { is: :wrong_size, minimum: :size_too_small, maximum: :size_too_big }.freeze
+  CHECKS    = { is: :==, minimum: :>=, maximum: :<= }.freeze
 
-  DEFAULT_TOKENIZER = lambda { |value| value.split(//) }
-  RESERVED_OPTIONS  = [:minimum, :maximum, :within, :is, :tokenizer, :too_short, :too_long]
+  DEFAULT_TOKENIZER = ->(value) { value.split(//) }
+  RESERVED_OPTIONS  = %i[minimum maximum within is tokenizer too_short too_long].freeze
 
   def initialize(options)
     if range = (options.delete(:in) || options.delete(:within))
-      raise ArgumentError, ":in and :within must be a Range" unless range.is_a?(Range)
-      options[:minimum], options[:maximum] = range.begin, range.end
+      raise ArgumentError, ':in and :within must be a Range' unless range.is_a?(Range)
+
+      options[:minimum] = range.begin
+      options[:maximum] = range.end
       options[:maximum] -= 1 if range.exclude_end?
     end
 
@@ -21,23 +24,19 @@ class FileSizeValidator < ActiveModel::EachValidator
   def check_validity!
     keys = CHECKS.keys & options.keys
 
-    if keys.empty?
-      raise ArgumentError, 'Range unspecified. Specify the :within, :maximum, :minimum, or :is option.'
-    end
+    raise ArgumentError, 'Range unspecified. Specify the :within, :maximum, :minimum, or :is option.' if keys.empty?
 
     keys.each do |key|
       value = options[key]
 
-      unless value.is_a?(Integer) && value >= 0
-        raise ArgumentError, ":#{key} must be a nonnegative Integer"
-      end
+      raise ArgumentError, ":#{key} must be a nonnegative Integer" unless value.is_a?(Integer) && value >= 0
     end
   end
 
   def validate_each(record, attribute, value)
-    raise(ArgumentError, "A CarrierWave::Uploader::Base object was expected") unless value.kind_of? CarrierWave::Uploader::Base
+    raise(ArgumentError, 'A CarrierWave::Uploader::Base object was expected') unless value.is_a? CarrierWave::Uploader::Base
 
-    value = (options[:tokenizer] || DEFAULT_TOKENIZER).call(value) if value.kind_of?(String)
+    value = (options[:tokenizer] || DEFAULT_TOKENIZER).call(value) if value.is_a?(String)
 
     CHECKS.each do |key, validity_check|
       next unless check_value = options[key]
@@ -61,6 +60,7 @@ class FileSizeValidator < ActiveModel::EachValidator
     Helper.instance
   end
 
+  # provides dependencies
   class Helper
     include Singleton
     include ActionView::Helpers::NumberHelper
diff --git a/lib/omni_auth/omni_auth.rb b/lib/omni_auth/omni_auth.rb
index e02cddabc..22fd146ac 100644
--- a/lib/omni_auth/omni_auth.rb
+++ b/lib/omni_auth/omni_auth.rb
@@ -1,5 +1,7 @@
+# frozen_string_literal: true
+
 active_provider = AuthProvider.active
 
 if active_provider.providable_type != DatabaseProvider.name
   require_relative "strategies/sso_#{active_provider.provider_type}_provider"
-end
\ No newline at end of file
+end
diff --git a/lib/omni_auth/strategies/sso_oauth2_provider.rb b/lib/omni_auth/strategies/sso_oauth2_provider.rb
index 5c5aea1d7..6427522b3 100644
--- a/lib/omni_auth/strategies/sso_oauth2_provider.rb
+++ b/lib/omni_auth/strategies/sso_oauth2_provider.rb
@@ -1,115 +1,135 @@
+# frozen_string_literal: true
+
 require 'omniauth-oauth2'
 
-module OmniAuth
-  module Strategies
-    class SsoOauth2Provider < OmniAuth::Strategies::OAuth2
+module OmniAuth::Strategies
+  # Authentication strategy provided trough oAuth 2.0
+  class SsoOauth2Provider < OmniAuth::Strategies::OAuth2
 
-      def self.active_provider
-        active_provider = AuthProvider.active
-        if active_provider.providable_type != OAuth2Provider.name
-          raise "Trying to instantiate the wrong provider: Expected OAuth2Provider, received #{active_provider.providable_type}"
-        end
-        active_provider
+    def self.active_provider
+      active_provider = AuthProvider.active
+      if active_provider.providable_type != OAuth2Provider.name
+        raise "Trying to instantiate the wrong provider: Expected OAuth2Provider, received #{active_provider.providable_type}"
       end
 
-      # Strategy name.
-      option :name, active_provider.strategy_name
+      active_provider
+    end
+
+    # Strategy name.
+    option :name, active_provider.strategy_name
 
 
-      option :client_options, {
-        :site => active_provider.providable.base_url,
-        :authorize_url => active_provider.providable.authorization_endpoint,
-        :token_url => active_provider.providable.token_endpoint
+    option :client_options,
+           { site: active_provider.providable.base_url,
+             authorize_url: active_provider.providable.authorization_endpoint,
+             token_url: active_provider.providable.token_endpoint }
+
+
+    uid { parsed_info['user.uid'.to_sym] }
+
+    info do
+      {
+        mapping: parsed_info
       }
+    end
 
-      uid { parsed_info['user.uid'.to_sym] }
+    extra do
+      {
+        raw_info: raw_info
+      }
+    end
 
-      info do
-        {
-            :mapping => parsed_info
-        }
-      end
-
-      extra do
-        {
-            :raw_info => raw_info
-        }
-      end
-
-      # retrieve data from various url, querying each only once
-      def raw_info
-        @raw_info ||= Hash.new
-        unless @raw_info.size > 0
-          OmniAuth::Strategies::SsoOauth2Provider.active_provider.providable.o_auth2_mappings.each do |mapping|
-            unless @raw_info.has_key?(mapping.api_endpoint.to_sym)
-              @raw_info[mapping.api_endpoint.to_sym] = access_token.get(mapping.api_endpoint).parsed
-            end
+    # retrieve data from various url, querying each only once
+    def raw_info
+      @raw_info ||= {}
+      unless @raw_info.size.positive?
+        OmniAuth::Strategies::SsoOauth2Provider.active_provider.providable.o_auth2_mappings.each do |mapping|
+          unless @raw_info.key?(mapping.api_endpoint.to_sym)
+            @raw_info[mapping.api_endpoint.to_sym] = access_token.get(mapping.api_endpoint).parsed
           end
         end
-        @raw_info
       end
+      @raw_info
+    end
 
+    def parsed_info
+      @parsed_info ||= {}
+      unless @parsed_info.size.positive?
+        OmniAuth::Strategies::SsoOauth2Provider.active_provider.providable.o_auth2_mappings.each do |mapping|
 
-      def parsed_info
-        @parsed_info ||= Hash.new
-        unless @parsed_info.size > 0
-          OmniAuth::Strategies::SsoOauth2Provider.active_provider.providable.o_auth2_mappings.each do |mapping|
+          if mapping.transformation
+            case mapping.transformation['type']
+            ## INTEGER
+            when 'integer'
+              @parsed_info[local_sym(mapping)] = map_integer(mapping.transformation,
+                                                             mapping.api_endpoint.to_sym,
+                                                             mapping.api_field)
 
-            if mapping.transformation
-              case mapping.transformation['type']
-                ## INTEGER
-                when 'integer'
-                  mapping.transformation['mapping'].each do |m|
-                    if m['from'] == raw_info[mapping.api_endpoint.to_sym][mapping.api_field]
-                      @parsed_info[local_sym(mapping)] = m['to']
-                      break
-                    end
-                  end
-                  # if no transformation had set any value, set the raw value
-                  unless @parsed_info[local_sym(mapping)]
-                    @parsed_info[local_sym(mapping)] = raw_info[mapping.api_endpoint.to_sym][mapping.api_field]
-                  end
+            ## BOOLEAN
+            when 'boolean'
+              @parsed_info[local_sym(mapping)] = map_boolean(mapping.transformation,
+                                                             mapping.api_endpoint.to_sym,
+                                                             mapping.api_field)
 
-                ## BOOLEAN
-                when 'boolean'
-                  @parsed_info[local_sym(mapping)] = !(raw_info[mapping.api_endpoint.to_sym][mapping.api_field] == mapping.transformation['false_value'])
-                  @parsed_info[local_sym(mapping)] = (raw_info[mapping.api_endpoint.to_sym][mapping.api_field] == mapping.transformation['true_value'])
+            ## DATE
+            when 'date'
+              @params[local_sym(mapping)] = map_date(mapping.transformation,
+                                                     mapping.api_endpoint.to_sym,
+                                                     mapping.api_field)
 
-                ## DATE
-                when 'date'
-                  case mapping.transformation['format']
-                    when 'iso8601'
-                      @parsed_info[local_sym(mapping)] = DateTime.iso8601(raw_info[mapping.api_endpoint.to_sym][mapping.api_field])
-                    when 'rfc2822'
-                      @parsed_info[local_sym(mapping)] = DateTime.rfc2822(raw_info[mapping.api_endpoint.to_sym][mapping.api_field])
-                    when 'rfc3339'
-                      @parsed_info[local_sym(mapping)] = DateTime.rfc3339(raw_info[mapping.api_endpoint.to_sym][mapping.api_field])
-                    when 'timestamp-s'
-                      @parsed_info[local_sym(mapping)] = DateTime.strptime(raw_info[mapping.api_endpoint.to_sym][mapping.api_field],'%s')
-                    when 'timestamp-ms'
-                      @parsed_info[local_sym(mapping)] = DateTime.strptime(raw_info[mapping.api_endpoint.to_sym][mapping.api_field],'%Q')
-                    else
-                      @parsed_info[local_sym(mapping)] = DateTime.parse(raw_info[mapping.api_endpoint.to_sym][mapping.api_field])
-                  end
-
-                ## OTHER TRANSFORMATIONS (not supported)
-                else
-                  @parsed_info[local_sym(mapping)] = raw_info[mapping.api_endpoint.to_sym][mapping.api_field]
-              end
-
-            ## NO TRANSFORMATION
+            ## OTHER TRANSFORMATIONS (not supported)
             else
               @parsed_info[local_sym(mapping)] = raw_info[mapping.api_endpoint.to_sym][mapping.api_field]
             end
+
+          ## NO TRANSFORMATION
+          else
+            @parsed_info[local_sym(mapping)] = raw_info[mapping.api_endpoint.to_sym][mapping.api_field]
           end
         end
-        @parsed_info
       end
+      @parsed_info
+    end
 
-      private
-        def local_sym(mapping)
-          (mapping.local_model+'.'+mapping.local_field).to_sym
+    private
+
+    def local_sym(mapping)
+      (mapping.local_model + '.' + mapping.local_field).to_sym
+    end
+
+    def map_integer(transformation, api_endpoint, api_field)
+      value = nil
+      transformation['mapping'].each do |m|
+        if m['from'] == raw_info[api_endpoint][api_field]
+          value = m['to']
+          break
         end
+      end
+      # if no transformation had set any value, return the raw value
+      value || raw_info[api_endpoint.to_sym][api_field]
+    end
+
+    def map_boolean(transformation, api_endpoint, api_field)
+      return false if raw_info[api_endpoint][api_field] == transformation['false_value']
+
+      true if raw_info[api_endpoint][api_field] == transformation['true_value']
+    end
+
+    def map_date(transformation, api_endpoint, api_field)
+      case transformation['format']
+      when 'iso8601'
+        DateTime.iso8601(raw_info[api_endpoint][api_field])
+      when 'rfc2822'
+        DateTime.rfc2822(raw_info[api_endpoint][api_field])
+      when 'rfc3339'
+        DateTime.rfc3339(raw_info[api_endpoint][api_field])
+      when 'timestamp-s'
+        DateTime.strptime(raw_info[api_endpoint][api_field], '%s')
+      when 'timestamp-ms'
+        DateTime.strptime(raw_info[api_endpoint][api_field], '%Q')
+      else
+        DateTime.parse(raw_info[api_endpoint][api_field])
+      end
     end
   end
-end
\ No newline at end of file
+end
diff --git a/lib/plugin/instance.rb b/lib/plugin/instance.rb
index 965e16028..fe6911288 100644
--- a/lib/plugin/instance.rb
+++ b/lib/plugin/instance.rb
@@ -1,98 +1,97 @@
+# frozen_string_literal: true
+
 require 'fileutils'
 require 'plugin_registry'
 
-module Plugin
-  class Instance
-    attr_accessor :path#, :directory
+class Plugin::Instance
+  attr_accessor :path
 
-    [:assets, :initializers, :javascripts, :styles].each do |att|
-      class_eval %Q{
-        def #{att}
-          @#{att} ||= []
-        end
-      }
-    end
-
-    def self.find_all(parent_path)
-      [].tap { |plugins|
-        # also follows symlinks - http://stackoverflow.com/q/357754
-        Dir["#{parent_path}/**/*/**/plugin.rb"].sort.each do |path|
-
-          source = File.read(path)
-  #        metadata = Plugin::Metadata.parse(source)
-          plugins << self.new(nil, path)
-        end
-      }
-    end
-
-    def initialize(metadata=nil, path=nil)
-      @metadata = metadata
-      @path = path
-      #@directory = path.match(/(.*)\/plugin.rb/)[1]
-      @idx = 0
-    end
-
-    def activate!
-      if @path
-        root_path = "#{File.dirname(@path)}/assets/javascripts"
-        PluginRegistry.register_glob(root_path, 'coffee.erb')
+  %i[assets initializers javascripts styles].each do |att|
+    class_eval %(
+      def #{att}
+        @#{att} ||= []
       end
+    ), __FILE__, __LINE__ - 4
+  end
 
-      self.instance_eval File.read(path), path # execute all code of the plugin main file ! (named plugin.rb)
+  def self.find_all(parent_path)
+    [].tap { |plugins|
+      # also follows symlinks - http://stackoverflow.com/q/357754
+      Dir["#{parent_path}/**/*/**/plugin.rb"].sort.each do |path|
+        plugins << new(nil, path)
+      end
+    }
+  end
 
-      register_assets! unless assets.blank?
+  def initialize(metadata=nil, path=nil)
+    @metadata = metadata
+    @path = path
+    @idx = 0
+  end
 
-      Rails.configuration.assets.paths << File.dirname(path) + "/assets"
-
-      Rails.configuration.assets.precompile += [lambda do |filename, path|
-        (Dir["plugins/*/assets/templates"].any? { |p| path.include?(p) }) # useless because already included in application.css/js || (%w(.js).include?(File.extname(filename)) && Dir["plugins/*/assets/javascripts"].any? { |p| path.include?(p) }) || (%w(.css).include?(File.extname(filename)) && Dir["plugins/*/assets/stylesheets"].any? { |p| path.include?(p) })
-      end] #
-
-      Rails.configuration.sass.load_paths += Dir["plugins/*/assets/stylesheets"]
-
-
-      # Automatically include rake tasks
-      Rake.add_rakelib(File.dirname(path) + "/lib/tasks")
-
-      # Automatically include migrations
-      Rails.configuration.paths["db/migrate"] << File.dirname(path) + "/db/migrate"
+  def activate!
+    if @path
+      root_path = "#{File.dirname(@path)}/assets/javascripts"
+      PluginRegistry.register_glob(root_path, 'coffee.erb')
     end
 
-    def register_asset(file, opts=nil) # to be used by the plugin !
-      full_path = File.dirname(path) << "/assets/" << file
-      assets << [full_path, opts]
-    end
+    instance_eval File.read(path), path # execute all code of the plugin main file ! (named plugin.rb)
 
-    def register_code_insertion(key, code)
-      PluginRegistry.code_insertions[key] ||= []
-      PluginRegistry.code_insertions[key] << code
-    end
+    register_assets! unless assets.blank?
 
-    def register_css(style) # useless ?
-      styles << style
-    end
+    Rails.configuration.assets.paths << "#{File.dirname(path)}/assets"
 
-    def after_initialize(&block)
-      initializers << block
-    end
+    Rails.configuration.assets.precompile += [lambda do |_filename, path|
+      (Dir['plugins/*/assets/templates'].any? { |p| path.include?(p) })
+    end]
 
-    def notify_after_initialize
-      initializers.each do |callback|
-        begin
-          callback.call(self)
-        rescue ActiveRecord::StatementInvalid => e
-          # When running db:migrate for the first time on a new database, plugin initializers might
-          # try to use models. Tolerate it.
-          raise e unless e.message.try(:include?, "PG::UndefinedTable")
-        end
+    Rails.configuration.sass.load_paths += Dir['plugins/*/assets/stylesheets']
+
+
+    # Automatically include rake tasks
+    Rake.add_rakelib("#{File.dirname(path)}/lib/tasks")
+
+    # Automatically include migrations
+    Rails.configuration.paths['db/migrate'] << "#{File.dirname(path)}/db/migrate"
+  end
+
+  # to be used by the plugin !
+  def register_asset(file, opts=nil)
+    full_path = File.dirname(path) << '/assets/' << file
+    assets << [full_path, opts]
+  end
+
+  def register_code_insertion(key, code)
+    PluginRegistry.code_insertions[key] ||= []
+    PluginRegistry.code_insertions[key] << code
+  end
+
+  # useless ?
+  def register_css(style)
+    styles << style
+  end
+
+  def after_initialize(&block)
+    initializers << block
+  end
+
+  def notify_after_initialize
+    initializers.each do |callback|
+      begin
+        callback.call(self)
+      rescue ActiveRecord::StatementInvalid => e
+        # When running db:migrate for the first time on a new database, plugin initializers might
+        # try to use models. Tolerate it.
+        raise e unless e.message.try(:include?, 'PG::UndefinedTable')
       end
     end
+  end
 
-    protected
-      def register_assets!
-        assets.each do |asset, opts|
-          PluginRegistry.register_asset(asset, opts)
-        end
-      end
+  protected
+
+  def register_assets!
+    assets.each do |asset, opts|
+      PluginRegistry.register_asset(asset, opts)
+    end
   end
 end
diff --git a/lib/plugin_registry.rb b/lib/plugin_registry.rb
index 079401fa2..40a4d1323 100644
--- a/lib/plugin_registry.rb
+++ b/lib/plugin_registry.rb
@@ -21,38 +21,18 @@ class PluginRegistry
   end
 
   def self.register_glob(root, extension, options=nil)
-    self.asset_globs << [root, extension, options || {}]
+    asset_globs << [root, extension, options || {}]
   end
 
-  def self.register_asset(asset, opts=nil)
+  def self.register_asset(asset, _opts = nil)
     if asset =~ /\.js$|\.js\.erb$|\.js\.es6$|\.coffee$|\.coffee\.erb/
-      # if opts == :admin
-      #   self.admin_javascripts << asset
-      # else
-      #   if opts == :server_side
-      #     self.server_side_javascripts << asset
-      #   end
-      self.javascripts << asset
-      # end
+      javascripts << asset
     elsif asset =~ /\.css$|\.scss$/
-      # if opts == :mobile
-      #   self.mobile_stylesheets << asset
-      # elsif opts == :desktop
-      #   self.desktop_stylesheets << asset
-      # elsif opts == :variables
-      #   self.sass_variables << asset
-      # else
-        self.stylesheets << asset
-      # end
-
-    # elsif asset =~ /\.hbs$/
-    #   self.handlebars << asset
-    # elsif asset =~ /\.js\.handlebars$/
-    #   self.handlebars << asset
+      stylesheets << asset
     end
   end
 
   def self.insert_code(key)
-    self.code_insertions[key]&.join('\n')
+    code_insertions[key]&.join('\n')
   end
 end