Feature: Installation global config (#839) (#840)

* Renamed concern from Feature to Featurable

* Feature: Installation config (#839)
* Added new model installtion config with corresponding migrations and specs
* Created an installation config yml (key value store model)
* Created a config loader module to load the installaltion configs
* Added this to the config loader seeder
* Changed the account before create hook for default feature enabling to use the feature values from installtion config
* Renamed the feature concern to Featurable to follow the naming pattern for concerns
* Added comments and specs for modules and places that deemed necessary

* Refactored config loader to reduce cognitive complexity (#839)

lib/config_loader.rb

@@ -0,0 +1,84 @@
+class ConfigLoader
+  DEFAULT_OPTIONS = {
+    config_path: nil,
+    reconcile_only_new: true
+  }.freeze
+
+  def process(options = {})
+    options = DEFAULT_OPTIONS.merge(options)
+    # function of the "reconcile_only_new" flag
+    # if true,
+    #   it leaves the existing config and feature flags as it is and
+    #   creates the missing configs and feature flags with their default values
+    # if false,
+    #   then it overwrites existing config and feature flags with default values
+    #   also creates the missing configs and feature flags with their default values
+    @reconcile_only_new = options[:reconcile_only_new]
+
+    # setting the config path
+    @config_path = options[:config_path].presence
+    @config_path ||= Rails.root.join('config')
+
+    # general installation configs
+    reconcile_general_config
+
+    # default account based feature configs
+    reconcile_feature_config
+  end
+
+  private
+
+  def general_configs
+    @general_configs ||= YAML.safe_load(File.read("#{@config_path}/installation_config.yml")).freeze
+  end
+
+  def account_features
+    @account_features ||= YAML.safe_load(File.read("#{@config_path}/features.yml")).freeze
+  end
+
+  def reconcile_general_config
+    general_configs.each do |config|
+      new_config = config.with_indifferent_access
+      existing_config = InstallationConfig.find_by(name: new_config[:name])
+      save_general_config(existing_config, new_config)
+    end
+  end
+
+  def save_general_config(existing_config, new_config)
+    if existing_config
+      # save config only if reconcile flag is false and existing configs value does not match default value
+      save_as_new_config(new_config) if !@reconcile_only_new && existing_config.value != new_config[:value]
+    else
+      save_as_new_config(new_config)
+    end
+  end
+
+  def save_as_new_config(new_config)
+    config = InstallationConfig.new(name: new_config[:name])
+    config.value = new_config[:value]
+    config.save
+  end
+
+  def reconcile_feature_config
+    config = InstallationConfig.find_by(name: 'ACCOUNT_LEVEL_FEATURE_DEFAULTS')
+
+    if config
+      return false if config.value.to_s == account_features.to_s
+
+      compare_and_save(config)
+    else
+      save_as_new_config({ name: 'ACCOUNT_LEVEL_FEATURE_DEFAULTS', value: account_features })
+    end
+  end
+
+  def compare_and_save_feature(config)
+    features = if @reconcile_only_new
+                 # leave the existing feature flag values as it is and add new feature flags with default values
+                 (account_features + config.value).uniq { |h| h['name'] }
+               else
+                 # update the existing feature flag values with default values and add new feature flags with default values
+                 (config.value + account_features).uniq { |h| h['name'] }
+               end
+    save_as_new_config({ name: 'ACCOUNT_LEVEL_FEATURE_DEFAULTS', value: features })
+  end
+end