restyle all user notification emails to use a custom html template

app/helpers/user_notifications_helper.rb

@@ -9,4 +9,12 @@ module UserNotificationsHelper
     result
   end
 
+  def correct_top_margin(html, desired)
+    fragment = Nokogiri::HTML.fragment(html)
+    if para = fragment.css("p:first").first
+      para["style"] = "margin-top: #{desired};"
+    end
+    fragment.to_html.html_safe
+  end
+
 end

app/mailers/user_notifications.rb

@@ -96,12 +96,16 @@ class UserNotifications < ActionMailer::Base
 
   def email_post_markdown(post)
     result = "[email-indent]\n"
-    result << "#### #{I18n.t('user_notifications.posted_by', username: post.username, post_date: post.created_at.strftime("%m/%d/%Y"))}\n\n"
     result << "#{post.raw}\n\n"
+    result << "#{I18n.t('user_notifications.posted_by', username: post.username, post_date: post.created_at.strftime("%m/%d/%Y"))}\n\n"
     result << "[/email-indent]\n"
     result
   end
 
+  class UserNotificationRenderer < ActionView::Base
+    include UserNotificationsHelper
+  end
+
   def notification_email(user, opts)
     @notification = opts[:notification]
     return unless @notification.present?
@@ -119,12 +123,19 @@ class UserNotifications < ActionMailer::Base
                         .limit(SiteSetting.email_posts_context)
 
     if context_posts.present?
-      context << "---\n### #{I18n.t('user_notifications.post_history')}\n"
+      context << "---\n*#{I18n.t('user_notifications.previous_discussion')}*\n"
       context_posts.each do |cp|
         context << email_post_markdown(cp)
       end
     end
 
+    html = UserNotificationRenderer.new(Rails.configuration.paths["app/views"]).render(
+          template: 'email/notification',
+          format: :html,
+          locals: { context_posts: context_posts, post: @post }
+    )
+
+
     email_opts = {
       topic_title: @notification.data_hash[:topic_title],
       message: email_post_markdown(@post),
@@ -135,7 +146,8 @@ class UserNotifications < ActionMailer::Base
       username: username,
       add_unsubscribe_link: true,
       allow_reply_by_email: opts[:allow_reply_by_email],
-      template: "user_notifications.user_#{notification_type}"
+      template: "user_notifications.user_#{notification_type}",
+      html_override: html
     }
 
     # If we have a display name, change the from address

app/views/email/_post.html.erb

@@ -0,0 +1,22 @@
+<table cellspacing="0" cellpadding="0" border="0" style='margin-bottom:20px;max-width:761px'>
+  <tbody>
+    <tr>
+      <td style='padding-right:10px;vertical-align:top;'>
+        <img width="45" height="45" src="<%= post.user.small_avatar_url%>" class="avatar" title="<%= post.user.username%>">
+      </td>
+      <td style="width: 100%">
+        <table cellspacing="0" cellpadding="0" border="0">
+          <tbody>
+            <tr>
+              <td style="font-size:13px;font-family:'lucida grande',tahoma,verdana,arial,sans-serif;padding-right:10px;">
+                <a style="color:#3b5998;text-decoration:none;font-weight:bold" href="<%=Discourse.base_url%>/users/<%= post.user.username_lower%>" target="_blank"><%= post.user.username %></a>
+              </td>
+              <td style="text-align:right;color:#999999;padding-right:5px;font-family:'lucida grande',tahoma,verdana,arial,sans-serif;font-size:11px"> <%= l post.created_at, format: :short_no_year %> </td>
+            </tr>
+          </tbody>
+        </table>
+        <%= correct_top_margin post.cooked.html_safe, "5px" %>
+      </td>
+    </tr>
+  </tbody>
+</table>

app/views/email/notification.html.erb

@@ -0,0 +1,12 @@
+<%= render :partial => 'email/post', :locals => {:post => post} %>
+
+<% if context_posts.present? %>
+  <hr>
+  <h4 style='font-size: 17px; color: #444;'><%= t "user_notifications.previous_discussion" %></h4>
+
+  <% context_posts.each do |p| %>
+  <%= render :partial => 'email/post', :locals => {:post => p} %>
+  <% end %>
+<% end %>
+
+<hr>

config/locales/server.en.yml

@@ -934,6 +934,7 @@ en:
   unsubscribe_link: "To unsubscribe from these emails, visit your [user preferences](%{user_preferences_url})."
 
   user_notifications:
+    previous_discussion: "Previous discussion"
     unsubscribe:
       title: "Unsubscribe"
       description: "Not interested in getting these emails? No problem! Click below to unsubscribe instantly:"
@@ -941,7 +942,6 @@ en:
     reply_by_email: "To respond, reply to this email or visit %{base_url}%{url} in your browser."
     visit_link_to_respond: "To respond, visit %{base_url}%{url} in your browser."
 
-    post_history: "Post History"
     posted_by: "Posted by %{username} on %{post_date}"
 
     user_invited_to_private_message:
@@ -954,8 +954,6 @@ en:
     user_replied:
       subject_template: "[%{site_name}] new reply to your post in '%{topic_title}'"
       text_body_template: |
-        %{username} replied to your post in '%{topic_title}' on %{site_name}:
-
         %{message}
 
         %{context}
@@ -966,8 +964,6 @@ en:
     user_quoted:
       subject_template: "[%{site_name}] %{username} quoted you in '%{topic_title}'"
       text_body_template: |
-        %{username} quoted you in '%{topic_title}' on %{site_name}:
-
         %{message}
 
         %{context}
@@ -978,8 +974,6 @@ en:
     user_mentioned:
       subject_template: "[%{site_name}] %{username} mentioned you in '%{topic_title}'"
       text_body_template: |
-        ### %{username} mentioned you in '%{topic_title}' on %{site_name}:
-
         %{message}
 
         %{context}
@@ -990,8 +984,6 @@ en:
     user_posted:
       subject_template: "[%{site_name}] new post in '%{topic_title}'"
       text_body_template: |
-        %{username} posted in '%{topic_title}' on %{site_name}:
-
         %{message}
 
         %{context}

lib/email/message_builder.rb

@@ -6,7 +6,9 @@ module Email
     def build_email(*builder_args)
       builder = Email::MessageBuilder.new(*builder_args)
       headers(builder.header_args) if builder.header_args.present?
-      mail(builder.build_args)
+      mail(builder.build_args).tap { |message|
+        message.html_part = builder.html_part if message
+      }
     end
   end
 
@@ -22,10 +24,11 @@ module Email
                         user_preferences_url: "#{Discourse.base_url}/user_preferences" }.merge!(@opts)
 
       if @template_args[:url].present?
+        @template_args[:respond_instructions] =
           if allow_reply_by_email?
-          @template_args[:respond_instructions] = I18n.t('user_notifications.reply_by_email', @template_args)
+            I18n.t('user_notifications.reply_by_email', @template_args)
           else
-          @template_args[:respond_instructions] = I18n.t('user_notifications.visit_link_to_respond', @template_args)
+            I18n.t('user_notifications.visit_link_to_respond', @template_args)
           end
       end
     end
@@ -36,6 +39,27 @@ module Email
       subject
     end
 
+    def html_part
+      return unless html_override = @opts[:html_override]
+      if @opts[:add_unsubscribe_link]
+        html_override  << "<br>".html_safe
+
+        if response_instructions = @template_args[:respond_instructions]
+          html_override << PrettyText.cook(response_instructions).html_safe
+        end
+
+        html_override << PrettyText.cook(I18n.t('unsubscribe_link', template_args)).html_safe
+      end
+
+      styled = Email::Styles.new(html_override)
+      styled.format_basic
+
+      Mail::Part.new do
+        content_type 'text/html; charset=UTF-8'
+        body styled.to_html
+      end
+    end
+
     def body
       body = @opts[:body]
       body = I18n.t("#{@opts[:template]}.text_body_template", template_args) if @opts[:template]

lib/email/sender.rb

@@ -32,14 +32,15 @@ module Email
 
       renderer = Email::Renderer.new(@message, opts)
 
+      unless @message.html_part
         @message.html_part = Mail::Part.new do
           content_type 'text/html; charset=UTF-8'
           body renderer.html
         end
+      end
 
       @message.parts[0].body = @message.parts[0].body.to_s.gsub!(/\[\/?email-indent\]/, '')
 
-
       @message.text_part.content_type = 'text/plain; charset=UTF-8'
 
       # Set up the email log