feat: Move email attachments from links to file attachments (#11304)

Add ability to send files as attachments instead of links
Fixes: https://github.com/chatwoot/chatwoot/issues/1074


## Changes 
- `emaily_reply` : We will attach the small attachments as attachments
and large ones as links
- `reply_with_summary`, `conversation_transcript`,
`reply_with_out_summary` : We will change the attachment format to the
following instead of the previous `View the attachment here`

```
Attachments:
file_name
file_name2
```


---------

ref: https://github.com/chatwoot/chatwoot/pull/10318/files -> for fixing
: https://github.com/chatwoot/chatwoot/pull/9655#issuecomment-2183962550

---------

Co-authored-by: Marco Marinho <marcomarinho12@gmail.com>
Co-authored-by: Pranav <pranavrajs@gmail.com>

app/mailers/conversation_reply_mailer.rb

@@ -1,4 +1,8 @@
 class ConversationReplyMailer < ApplicationMailer
+  # We needs to expose large attachments to the view as links
+  # Small attachments are linked as mail attachments directly
+  attr_reader :large_attachments
+
   include ConversationReplyMailerHelper
   default from: ENV.fetch('MAILER_SENDER_EMAIL', 'Chatwoot <accounts@chatwoot.com>')
   layout :choose_layout

app/mailers/conversation_reply_mailer_helper.rb

@@ -17,11 +17,44 @@ module ConversationReplyMailerHelper
     google_smtp_settings
     set_delivery_method
 
-    Rails.logger.info("Email sent from #{email_from} to #{to_emails} with subject #{mail_subject}")
-
+    # Email type detection logic:
+    # - email_reply: Sets @message with a single message
+    # - Other actions: Set @messages with a collection of messages
+    #
+    # So this check implicitly determines we're handling an email_reply
+    # and not one of the other email types (summary, transcript, etc.)
+    process_attachments_as_files_for_email_reply if @message&.attachments.present?
     mail(@options)
   end
 
+  def process_attachments_as_files_for_email_reply
+    # Attachment processing for direct email replies (when replying to a single message)
+    #
+    # How attachments are handled:
+    # 1. Total file size (<20MB): Added directly to the email as proper attachments
+    # 2. Total file size (>20MB): Added to @large_attachments to be displayed as links in the email
+
+    @options[:attachments] = []
+    @large_attachments = []
+    current_total_size = 0
+
+    @message.attachments.each do |attachment|
+      raw_data = attachment.file.download
+      attachment_name = attachment.file.filename.to_s
+      file_size = raw_data.bytesize
+
+      # Attach files directly until we hit 20MB total
+      # After reaching 20MB, send remaining files as links
+      if current_total_size + file_size <= 20.megabytes
+        mail.attachments[attachment_name] = raw_data
+        @options[:attachments] << { name: attachment_name }
+        current_total_size += file_size
+      else
+        @large_attachments << attachment
+      end
+    end
+  end
+
   private
 
   def google_smtp_settings

app/views/mailers/conversation_reply_mailer/conversation_transcript.html.erb

@@ -32,9 +32,10 @@
       <% if message.content %>
         <%= ChatwootMarkdownRenderer.new(message.content).render_message %>
       <% end %>
-      <% if message.attachments %>
+      <% if message.attachments.present? %>
+        <p>Attachments:</p>
         <% message.attachments.each do |attachment| %>
-          Attachment [<a href="<%= attachment.file_url %>" _target="blank">Click here to view</a>]
+          <p><a href="<%= attachment.file_url %>" target="_blank"><%= attachment.file.filename.to_s %></a></p>
         <% end %>
       <% end %>
       <p style="font-size: 90%; font-size: 90%;color: #899096;margin-top: -8px; margin-bottom: 0px;">

app/views/mailers/conversation_reply_mailer/email_reply.html.erb

@@ -1,8 +1,9 @@
 <% if @message.content %>
   <%= ChatwootMarkdownRenderer.new(@message.content).render_message %>
 <% end %>
-<% if @message.attachments %>
-  <% @message.attachments.each do |attachment| %>
-    attachment [<a href="<%= attachment.file_url %>" _target="blank">click here to view</a>]
+<% if @large_attachments.present? %>
+  <p>Attachments:</p>
+  <% @large_attachments.each do |attachment| %>
+    <p><a href="<%= attachment.file_url %>" target="_blank"><%= attachment.file.filename.to_s %></a></p>
   <% end %>
 <% end %>

app/views/mailers/conversation_reply_mailer/reply_with_summary.html.erb

@@ -20,9 +20,10 @@
           <% if message.content.present? %>
             <hr style="border: 0; border-bottom: 1px solid #AEC3D5;"/>
           <% end %>
-          This message contains <%= message.attachments.count > 1 ? 'attachments' : 'an attachment' %>.
-          <% message.attachments.each do |attachment| %>
-            <br />- View the attachment <a href="<%= attachment.file_url %>" _target="blank">here</a>.
+          Attachments:
+          <% message.attachments.each_with_index do |attachment, index| %>
+            <% if index > 0 %><br /><% end %>
+            <a href="<%= attachment.file_url %>" target="_blank"><%= attachment.file.filename.to_s %></a>
           <% end %>
         </p>
       <% end %>

app/views/mailers/conversation_reply_mailer/reply_without_summary.html.erb

@@ -3,9 +3,10 @@
     <% if message.content %>
       <%= ChatwootMarkdownRenderer.new(message.content).render_message %>
     <% end %>
-    <% if message.attachments %>
+    <% if message.attachments.present? %>
+      <p>Attachments:</p>
       <% message.attachments.each do |attachment| %>
-        attachment [<a href="<%= attachment.file_url %>" _target="blank">click here to view</a>]
+        <p><a href="<%= attachment.file_url %>" target="_blank"><%= attachment.file.filename.to_s %></a></p>
       <% end %>
     <% end %>
   </p>