More composable forms (#989)

* Make forms more composable, opt-in to form builder

* Remove unused method

* Simpler money input controls

* Add in new form styling to imports

* Lint fixes

* Small tweak of multi select styles

app/helpers/styled_form_builder.rb

@@ -0,0 +1,55 @@
+class StyledFormBuilder < ActionView::Helpers::FormBuilder
+  # Fields that visually inherit from "text field"
+  class_attribute :text_field_helpers, default: field_helpers - [ :label, :check_box, :radio_button, :fields_for, :fields, :hidden_field, :file_field ]
+
+  # Wraps "text" inputs with custom structure + base styles
+  text_field_helpers.each do |selector|
+    class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
+      def #{selector}(method, options = {})
+        input_html = label_html(method, options) + super(method, merged_options(options))
+        input_html = apply_form_field_wrapper(input_html) unless options[:inline]
+        input_html
+      end
+    RUBY_EVAL
+  end
+
+  def radio_button(method, tag_value, options = {})
+    super(method, tag_value, merged_options(options, "form-field__radio"))
+  end
+
+  def select(method, choices, options = {}, html_options = {})
+    input_html = label_html(method, options) + super(method, choices, options, merged_options(html_options))
+    input_html = apply_form_field_wrapper(input_html, class: "pr-0") unless options[:inline]
+    input_html
+  end
+
+  def collection_select(method, collection, value_method, text_method, options = {}, html_options = {})
+    input_html = label_html(method, options) + super(method, collection, value_method, text_method, options, merged_options(html_options))
+    input_html = apply_form_field_wrapper(input_html, class: "pr-0") unless options[:inline]
+    input_html
+  end
+
+  def submit(value = nil, options = {})
+    value, options = nil, value if value.is_a?(Hash)
+    super(value, merged_options(options, "form-field__submit"))
+  end
+
+  private
+
+    def apply_form_field_wrapper(input_html, **options)
+      @template.form_field_tag(**options) do
+        input_html
+      end
+    end
+
+    def merged_options(options, default_class = "form-field__input")
+      combined_classes = options.fetch(:class, "") + " #{default_class}"
+      style_options = { class: combined_classes }
+      non_custom_options = options.except(:class, :label, :inline)
+      style_options.merge(non_custom_options)
+    end
+
+    def label_html(method, options)
+      options[:label] ? label(method, options[:label], class: "form-field__label") : "".html_safe
+    end
+end