FEATURE: Add user location info to spam scanner context (#1076)

This adds registration and last known IP information and email to scanning context.

This provides another hint for spam scanner about possible malicious users.

For example registered in India, replying from Australia or
email is clearly a throwaway email address.

lib/ai_moderation/spam_scanner.rb

@@ -288,11 +288,16 @@ module DiscourseAi
         end
 
         context << "\nPost Author Information:"
-        if post.user # during test we may not have a user
+        if user = post.user # during test we may not have a user
-          context << "- Username: #{post.user.username}"
+          context << "- Username: #{user.username}\n"
-          context << "- Account age: #{(Time.current - post.user.created_at).to_i / 86_400} days"
+          context << "- Email: #{user.email}\n"
-          context << "- Total posts: #{post.user.post_count}"
+          context << "- Account age: #{(Time.current - user.created_at).to_i / 86_400} days\n"
-          context << "- Trust level: #{post.user.trust_level}"
+          context << "- Total posts: #{user.post_count}\n"
+          context << "- Trust level: #{user.trust_level}\n"
+          if info = location_info(user)
+            context << "- Registration Location: #{info[:registration]}\n" if info[:registration]
+            context << "- Last Location: #{info[:last]}\n" if info[:last]
+          end
         end
 
         context << "\nPost Content (first #{MAX_RAW_SCAN_LENGTH} chars):\n"
@@ -300,6 +305,33 @@ module DiscourseAi
         context.join("\n")
       end
 
+      def self.location_info(user)
+        registration, last = nil
+        if user.ip_address.present?
+          info = DiscourseIpInfo.get(user.ip_address, resolve_hostname: true)
+          last = "#{info[:location]} (#{info[:organization]})" if info && info[:location].present?
+        end
+        if user.registration_ip_address.present?
+          info = DiscourseIpInfo.get(user.registration_ip_address, resolve_hostname: true)
+          registration = "#{info[:location]} (#{info[:organization]})" if info &&
+            info[:location].present?
+        end
+
+        rval = nil
+        if registration || last
+          rval = { registration: registration } if registration
+          if last && last != registration
+            rval ||= {}
+            rval[:last] = last
+          end
+        end
+
+        rval
+      rescue => e
+        Discourse.warn_exception(e, message: "Failed to lookup location info")
+        nil
+      end
+
       def self.build_system_prompt(custom_instructions)
         base_prompt = +<<~PROMPT
           You are a spam detection system. Analyze the following post content and context.

spec/lib/modules/ai_moderation/spam_scanner_spec.rb

@@ -289,4 +289,30 @@ RSpec.describe DiscourseAi::AiModeration::SpamScanner do
       expect(post.user.reload.silenced?).to eq(false)
     end
   end
+
+  it "includes location information and email in context" do
+    user.update!(ip_address: "1.2.3.4", registration_ip_address: "5.6.7.8")
+
+    ip_info_registration = { location: "New York", organization: "ISP1" }
+    ip_info_last = { location: "London", organization: "ISP2" }
+
+    DiscourseIpInfo
+      .stubs(:get)
+      .with("5.6.7.8", resolve_hostname: true)
+      .returns(ip_info_registration)
+    DiscourseIpInfo.stubs(:get).with("1.2.3.4", resolve_hostname: true).returns(ip_info_last)
+
+    prompts = nil
+    DiscourseAi::Completions::Llm.with_prepared_responses(
+      ["spam", "just because"],
+    ) do |_, _, _prompts|
+      prompts = _prompts
+      described_class.test_post(post)
+    end
+
+    context = prompts.first.messages[1][:content]
+    expect(context).to include("Registration Location: New York (ISP1)")
+    expect(context).to include("Last Location: London (ISP2)")
+    expect(context).to include(user.email)
+  end
 end