Add form helpers

Author: bradgessler

app/views/oxidizer/form.rb

@@ -0,0 +1,53 @@
+module Oxidizer
+  module Form
+    extend ActiveSupport::Concern
+
+    def initialize(model:)
+      @model = model
+    end
+
+    def template
+      form_tag do
+        form_template
+      end
+    end
+
+    def fields
+      form_model.fields.values
+    end
+
+    def field(name)
+      form_model.field(name)
+    end
+
+    def form_tag(**attrs, &)
+      form **form_model.attributes(method: "post", action: action, **attrs) do
+        authenticity_token_field
+        _method_field
+        yield
+      end
+    end
+
+    def action
+      helpers.url_for(action: form_model.resource_action)
+    end
+
+    def authenticity_token_field
+      input(type: :hidden, name: :authenticity_token, value: helpers.form_authenticity_token)
+    end
+
+    def _method_field
+      input(name: "_method", type: :hidden, value: form_model._method_field_value)
+    end
+
+    def default_button_text
+      form_model.button_text
+    end
+
+    private
+
+    def form_model
+      @form_model ||= Form::Model.new(@model)
+    end
+  end
+end

app/views/oxidizer/form/field.rb

@@ -0,0 +1,80 @@
+module Oxidizer
+  module Form
+    # Generates Form attributes for an ActiveRecord model that can be passed into
+    # Phlex tags for fun and for profit.
+    # TODO: This should handle:
+    # * Nested fields
+    class Field
+      include ActionView::Helpers::FormTagHelper
+
+      def initialize(method:, form: nil)
+        @method = method
+        @attribute = method.name
+        @model = method.receiver
+        @form = form
+      end
+
+      def id
+        "#{naming.param_key}_#{@attribute}_#{object_id}"
+      end
+
+      def name
+        field_name naming.param_key, @attribute
+      end
+
+      def value
+        @method.call
+      end
+
+      def label
+        @attribute.to_s.titleize
+      end
+
+      def naming
+        @model.model_name
+      end
+
+      def form
+        @form.id if @form
+      end
+
+      def errors
+        @model.errors[@attribute]
+      end
+
+      def invalid?
+        errors.any?
+      end
+
+      def validators
+        @model.class.validators_on @attribute
+      end
+
+      def validation_attributes(**attrs)
+        validations = validators.each_with_object Hash.new do |validator, attributes|
+          case validator
+          when ActiveRecord::Validations::PresenceValidator
+            attributes[:required] = true
+          end
+        end
+        attrs.merge(**validations)
+      end
+
+      def input_attributes(**attrs)
+        attrs.merge(id: id, name: name, value: value).merge(validation_attributes)
+      end
+
+      def textarea_attributes(**attrs)
+        attrs.merge(id: id, name: name).merge(validation_attributes)
+      end
+
+      def label_attributes(**attrs)
+        attrs.merge(for: id)
+      end
+
+      def self.for(model, attribute, **kwargs)
+        new **kwargs.merge(method: model.method(attribute))
+      end
+    end
+  end
+end

app/views/oxidizer/form/model.rb

@@ -0,0 +1,43 @@
+module Oxidizer
+  module Form
+    class Model
+      attr_reader :fields, :model
+
+      def initialize(model)
+        @model = model
+        @fields ||= Hash.new do | hash, key |
+          hash[key] = Field.for(model, key, form: self)
+        end
+      end
+
+      def field(key)
+        @fields[key]
+      end
+
+      def id
+        "#{naming.param_key}_#{object_id}"
+      end
+
+      def _method_field_value
+        @model.persisted? ? "patch" : "post"
+      end
+
+      def naming
+        @model.model_name
+      end
+
+      def attributes(**attrs)
+        attrs.merge(id: id)
+      end
+
+      def resource_action
+        @model.persisted? ? :update : :create
+      end
+
+      def button_text
+        "#{@model.persisted? ? "Save" : "Create"} #{naming.human.downcase}"
+      end
+      alias :submit_value :button_text
+    end
+  end
+end

app/views/oxidizer/form/strong_params.rb

@@ -0,0 +1,42 @@
+module Oxidizer
+  module Form
+    module StrongParams
+      extend ActiveSupport::Concern
+
+      included do
+        prepend Extensions
+      end
+
+      module Extensions
+        def field(name)
+          if permitted_keys.include? name
+            super(name)
+          else
+            fail "Unpermitted form field: #{name}"
+          end
+        end
+      end
+
+      def permitted_keys
+        self.class.permitted_keys
+      end
+
+      module ClassMethods
+        def permit(*keys)
+          permitted_keys.append *keys
+        end
+
+        def permitted_keys
+          @permitted_keys ||= []
+        end
+
+        def permitted_params(**kwargs)
+          case kwargs.to_a
+            in [[param_key, params]]
+              params.require(param_key).permit(permitted_keys)
+          end
+        end
+      end
+    end
+  end
+end