add openai pdf upload support

enterprise/app/models/captain/document.rb

@@ -26,10 +26,13 @@ class Captain::Document < ApplicationRecord
   belongs_to :assistant, class_name: 'Captain::Assistant'
   has_many :responses, class_name: 'Captain::AssistantResponse', dependent: :destroy, as: :documentable
   belongs_to :account
+  has_one_attached :pdf_file
 
-  validates :external_link, presence: true
-  validates :external_link, uniqueness: { scope: :assistant_id }
+  validates :external_link, presence: true, unless: -> { pdf_file.attached? }
+  validates :external_link, uniqueness: { scope: :assistant_id }, allow_blank: true
   validates :content, length: { maximum: 200_000 }
+  validates :pdf_file, presence: true, if: :pdf_document?
+  validate :validate_pdf_format, if: :pdf_document?
   before_validation :ensure_account_id
 
   enum status: {
@@ -47,6 +50,20 @@ class Captain::Document < ApplicationRecord
   scope :for_account, ->(account_id) { where(account_id: account_id) }
   scope :for_assistant, ->(assistant_id) { where(assistant_id: assistant_id) }
 
+  def pdf_document?
+    (external_link&.ends_with?('.pdf')) || (pdf_file.attached? && pdf_file.content_type == 'application/pdf')
+  end
+
+  def openai_file_id
+    metadata = self[:content].is_a?(Hash) ? self[:content] : {}
+    metadata['openai_file_id']
+  end
+
+  def store_openai_file_id(file_id)
+    current_metadata = self[:content].is_a?(Hash) ? self[:content] : {}
+    update!(content: current_metadata.merge('openai_file_id' => file_id).to_json)
+  end
+
   private
 
   def enqueue_crawl_job
@@ -73,4 +90,16 @@ class Captain::Document < ApplicationRecord
     limits = account.usage_limits[:captain][:documents]
     raise LimitExceededError, 'Document limit exceeded' unless limits[:current_available].positive?
   end
+
+  def validate_pdf_format
+    return unless pdf_file.attached?
+
+    unless pdf_file.content_type == 'application/pdf'
+      errors.add(:pdf_file, 'must be a PDF file')
+    end
+
+    if pdf_file.byte_size > 512.megabytes
+      errors.add(:pdf_file, 'must be less than 512MB')
+    end
+  end
 end