Notify users that their email is bouncing when they log in

[sebbacon]

Currently we just silently disable email sending. We should let them know.

From a user email:

I have not been receiving emails since around mid-December. Looking
back at previous correspondence it seems this might be due to a
delivery failure, but that I should have been informed of this when
logging in to the site. I have logged in several times and checked
all my settings I am able and have discovered nothing amiss, nor
been informed of any email address errors.

Please could you investigate and restart my email delivery.

[robinhouston]

I have found a (possibly incomplete) attempt at doing this:

diff --git a/app/controllers/user_controller.rb b/app/controllers/user_controller.rb
index d3c42c7..86173cc 100644
--- a/app/controllers/user_controller.rb
+++ b/app/controllers/user_controller.rb
@@ -102,6 +102,10 @@ class UserController < ApplicationController
                 return
             else
                 # Successful login
+                if !@user_signin.email_bounced_at.nil?
+                    flash[:email_bounced] = true
+                end
+
                 if @user_signin.email_confirmed
                     session[:user_id] = @user_signin.id
                     session[:user_circumstance] = nil
diff --git a/app/views/general/_email_bounced.rhtml b/app/views/general/_email_bounced.rhtml
new file mode 100644
index 0000000..894ef9c
--- /dev/null
+++ b/app/views/general/_email_bounced.rhtml
@@ -0,0 +1,10 @@
+<div id="email_bounced">
+    <h1>Your email has bounced</h1>
+    <p>Last time we tried to email you at <%= @user.email %>, the message bounced.
+       Because of this, we will not send you any more emails until you reconfirm
+       your address.
+    </p>
+    <form method="post" action="">
+      <input type="submit" name="action" value="Reconfirm">
+    </form>
+</div>
diff --git a/app/views/layouts/default.rhtml b/app/views/layouts/default.rhtml
index 94ec5a9..0fff955 100644
--- a/app/views/layouts/default.rhtml
+++ b/app/views/layouts/default.rhtml
@@ -116,6 +116,9 @@
             <% if flash[:error] %>
                 <div id="error"><%= flash[:error] %></div>
             <% end %>
+            <% if flash[:email_bounced] %>
+                <%= render :partial => 'general/email_bounced' %>
+            <% end %>

             <div id="<%= controller.controller_name + "_" + controller.action_name %>" class="controller_<%= controller.controller_n
             <%= yield :layout %>