From 43717937418ce9a495b64b05392665a73a570fd7 Mon Sep 17 00:00:00 2001
From: chinatsu1124 <23171419+chinatsu1124@users.noreply.github.com>
Date: Tue, 19 May 2026 12:41:32 +0800
Subject: [PATCH] fix: captain-v2 cannot see image attachments shared via email
 (#14449)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

## Description

Inbound email attachments are stored with `file_type: 'file'` regardless
of their actual MIME type. As a result, image screenshots shared by
customers via email are not exposed to Captain V2's multimodal pipeline
— `Captain::OpenAiMessageBuilderService#attachment_parts` selects images
via `attachments.where(file_type: :image)` and emits a placeholder
`"User has shared an attachment"` text part instead of an `image_url`
part. The model never gets the image, so Captain keeps asking the
customer to retype information that is already visible in the
screenshot.

This PR makes the email mailbox derive `file_type` from the blob's
`content_type` using the existing shared `FileTypeHelper`, matching how
every other inbound channel (`twilio`, `sms`, `telegram`, `line`,
`tiktok`, `twitter`, `messenger`) and `MessageBuilder` already classify
attachments.

Fixes #14448

## Type of change

- [x] Bug fix (non-breaking change which fixes an issue)

## How Has This Been Tested?

Reproduced and verified on a self-hosted production instance:

1. Real customer reply via email with a PNG screenshot of an in-app
error.

   Before:
   ```ruby
   a = Message.find(<id>).attachments.first
   a.file_type                # => "file"
   a.file.blob.content_type   # => "image/png"
Captain::OpenAiMessageBuilderService.new(message:
a.message).generate_content
   # => [{type: 'text', text: '...'},
# {type: 'text', text: 'User has shared an attachment'}] ❌ no image_url
   ```
Captain reply: "Please copy and paste the full error text…" (model never
saw the image).

2. After the patch + force-recreate, same conversation:
   ```ruby
   a.file_type                # => "image"
Captain::OpenAiMessageBuilderService.new(message:
a.message).generate_content
   # => [{type: 'text',      text: '...'},
# {type: 'image_url', image_url: {url: 'https://.../<blob>.png'}}] ✅
   ```
Captain reply now correctly references the on-screen error text from the
screenshot via the multimodal vision path — no more deflection.

3. Regression sanity-check on non-image attachments (PDF / Office docs):
`file_type` falls through to `:file`, behavior unchanged.

## Notes for self-hosted operators

Existing email image attachments in the DB will still have `file_type:
'file'`. A one-shot backfill is straightforward and safe (no data loss,
only metadata):

```ruby
Attachment.joins(message: :conversation)
          .where(messages: { content_type: 'incoming_email' })
          .where(file_type: 'file')
          .find_each do |a|
  next unless a.file.attached?
  ct = a.file.blob.content_type.to_s
  next unless ct.start_with?('image/', 'audio/', 'video/')
  new_type = ct.start_with?('image/') ? :image : (ct.start_with?('video/') ? :video : :audio)
  a.update_columns(file_type: Attachment.file_types[new_type])
end
```

## Checklist

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective — happy to add a
`mailbox_helper_spec` example for `process_regular_attachments` if
maintainers prefer; existing specs in that file focus on inline-image
handling.

---------

Co-authored-by: Aakash Bakhle <48802744+aakashb95@users.noreply.github.com>
---
 app/helpers/file_type_helper.rb | 1 +
 app/mailboxes/mailbox_helper.rb | 6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/app/helpers/file_type_helper.rb b/app/helpers/file_type_helper.rb
index 03b807aad..6bae0d3d1 100644
--- a/app/helpers/file_type_helper.rb
+++ b/app/helpers/file_type_helper.rb
@@ -17,6 +17,7 @@ module FileTypeHelper
   def image_file?(content_type)
     [
       'image/jpeg',
+      'image/jpg',
       'image/png',
       'image/gif',
       'image/bmp',
diff --git a/app/mailboxes/mailbox_helper.rb b/app/mailboxes/mailbox_helper.rb
index f7a44ccca..edabfd4ce 100644
--- a/app/mailboxes/mailbox_helper.rb
+++ b/app/mailboxes/mailbox_helper.rb
@@ -1,5 +1,6 @@
 module MailboxHelper
   include MailboxInlineAttachmentHelper
+  include ::FileTypeHelper
 
   private
 
@@ -53,11 +54,12 @@ module MailboxHelper
   def process_regular_attachments(attachments)
     Rails.logger.info "[MailboxHelper] Processing regular attachments for message with ID: #{processed_mail.message_id}"
     attachments.each do |mail_attachment|
+      blob = mail_attachment[:blob]
       attachment = @message.attachments.new(
         account_id: @conversation.account_id,
-        file_type: 'file'
+        file_type: file_type(blob.content_type)
       )
-      attachment.file.attach(mail_attachment[:blob])
+      attachment.file.attach(blob)
     end
   end