Initial commit

app/helpers/errors_helper.rb

@@ -0,0 +1,80 @@
+module ErrorsHelper
+  # Displays an alert containing a list of error messages for a given model attribute
+  def errors_for(model, attribute)
+    ErrorsList.new(self, model, attribute).to_html
+  end
+
+  # Displays an alert containing a list of all the error messages for a given model
+  def errors_summary_for(model)
+    ErrorsSummary.new(self, model).to_html
+  end
+
+  private
+
+  class ErrorsList
+    def initialize(view, model, attribute)
+      @view = view
+      @model = model
+      @attribute = attribute
+    end
+
+    def to_html
+      return if errors.empty?
+
+      error_list_items = errors.map { |error| content_tag(:li, error) }
+
+      content_tag(:div, class: "alert alert-danger text-left") do
+        concat content_tag(:p, message)
+        concat content_tag(:ul, safe_join(error_list_items))
+      end
+    end
+
+    private
+
+    attr_reader :view, :model, :attribute
+
+    delegate :concat, :content_tag, :safe_join, to: :view
+
+    def errors
+      @errors ||= errors = model.errors[attribute]
+    end
+
+    def message
+      "#{attribute.to_s.humanize} is not valid."
+    end
+  end
+
+  class ErrorsSummary
+    def initialize(view, model)
+      @view = view
+      @model = model
+    end
+
+    def to_html
+      return if errors.empty?
+
+      content_tag(:div, class: "alert alert-danger text-left") do
+        concat content_tag(:p, translate("errors_helper.failure_message", model_name: name))
+        concat content_tag(:ul, safe_join(error_list_items))
+      end
+    end
+
+    private
+
+    attr_reader :view, :model
+
+    delegate :concat, :content_tag, :safe_join, :translate, to: :view
+
+    def errors
+      @errors ||= model.errors.full_messages
+    end
+
+    def error_list_items
+      errors.map { |error| content_tag(:li, error) }
+    end
+
+    def name
+      model.model_name.human.downcase
+    end
+  end
+end