validate date and time inputs

app/inputs/date_picker_time_input.rb

@@ -1,7 +1,9 @@
-# DateTime picker using bootstrap-datepicker for the time part
-# requires `date_time_attribute` gem and active on the attribute
-#   http://stackoverflow.com/a/20317763/2866660
-#   https://github.com/einzige/date_time_attribute
+# DateTime picker using bootstrap-datepicker for the time part.
+#
+# Requires +date_time_attribute+ gem (+workaround) and active on the attribute.
+# @see DateTimeAttributeValidate
+# @see http://stackoverflow.com/a/20317763/2866660
+# @see https://github.com/einzige/date_time_attribute
 class DatePickerTimeInput < SimpleForm::Inputs::StringInput
   def input
     # Date format must match datepicker's, see app/assets/application.js .
@@ -9,11 +11,15 @@ class DatePickerTimeInput < SimpleForm::Inputs::StringInput
     # In the future, use html5 date&time inputs. This needs modernizr or equiv. to avoid
     # double widgets, and perhaps conditional css to adjust input width (chrome).
     value = @builder.object.send attribute_name
-    date_options = {as: :string, class: 'input-small datepicker', value: value.try {|e| e.strftime('%Y-%m-%d')}}
-    time_options = {as: :string, class: 'input-mini', value: value.try {|e| e.strftime('%H:%M')}}
-    @builder.input_field("#{attribute_name}_date", input_html_options.merge(date_options)) + ' ' +
-    @builder.input_field("#{attribute_name}_time", input_html_options.merge(time_options))
+    date_options = {as: :string, class: 'input-small datepicker'}
+    time_options = {as: :string, class: 'input-mini'}
+    @builder.input_field("#{attribute_name}_date_value", input_html_options.merge(date_options)) + ' ' +
+    @builder.input_field("#{attribute_name}_time_value", input_html_options.merge(time_options))
     # time_select requires a date_select
     #@builder.time_select("#{attribute_name}_time", {ignore_date: true}, input_html_options.merge(time_options))
   end
+
+  def label_target
+    "#{attribute_name}_date_value"
+  end
 end

app/models/order.rb

@@ -32,7 +32,8 @@ class Order < ActiveRecord::Base
   scope :recent, -> { order('starts DESC').limit(10) }
 
   # Allow separate inputs for date and time
-  include DateTimeAttribute
+  #   with workaround for https://github.com/einzige/date_time_attribute/issues/14
+  include DateTimeAttributeValidate
   date_time_attribute :starts, :ends
 
   def stockit?

lib/date_time_attribute_validate.rb

@@ -0,0 +1,66 @@
+# workaround for https://github.com/einzige/date_time_attribute/issues/14
+require 'date_time_attribute'
+
+module DateTimeAttributeValidate
+  extend ActiveSupport::Concern
+  include DateTimeAttribute
+
+  module ClassMethods
+
+    def date_time_attribute(*attributes)
+      super
+
+      attributes.each do |attribute|
+
+        validate "#{attribute}_datetime_value_valid"
+
+        # allow resetting the field to nil
+        before_validation do
+          if self.instance_variable_get("@#{attribute}_is_set")
+            date = self.instance_variable_get("@#{attribute}_date_value")
+            time = self.instance_variable_get("@#{attribute}_time_value")
+            if date.blank? and time.blank?
+              self.send("#{attribute}=", nil)
+            end
+          end
+        end
+
+        # remember old date and time values
+        define_method("#{attribute}_date_value=") do |val|
+          self.instance_variable_set("@#{attribute}_is_set", true)
+          self.instance_variable_set("@#{attribute}_date_value", val)
+          self.send("#{attribute}_date=", val) rescue nil
+        end
+        define_method("#{attribute}_time_value=") do |val|
+          self.instance_variable_set("@#{attribute}_is_set", true)
+          self.instance_variable_set("@#{attribute}_time_value", val)
+          self.send("#{attribute}_time=", val) rescue nil
+        end
+
+        # fallback to field when values are not set
+        define_method("#{attribute}_date_value") do
+          self.instance_variable_get("@#{attribute}_date_value") || self.send("#{attribute}_date").try {|e| e.strftime('%Y-%m-%d')}
+        end
+        define_method("#{attribute}_time_value") do
+          self.instance_variable_get("@#{attribute}_time_value") || self.send("#{attribute}_time").try {|e| e.strftime('%H:%m')}
+        end
+
+        private
+
+        # validate date and time
+        define_method("#{attribute}_datetime_value_valid") do
+          date = self.instance_variable_get("@#{attribute}_date_value")
+          unless date.blank? or (Date.parse(date) rescue nil)
+            errors.add(attribute, "is not a valid date") # @todo I18n
+          end
+          time = self.instance_variable_get("@#{attribute}_time_value")
+          unless time.blank? or (Time.parse(time) rescue nil)
+            errors.add(attribute, "is not a valid time") # @todo I18n
+          end
+        end
+
+      end
+    end
+
+  end
+end