implement pdf for google ai

lib/chat_models/chat_google_ai.ex

@@ -311,6 +311,26 @@ defmodule LangChain.ChatModels.ChatGoogleAI do
     }
   end
 
+  def for_api(%ContentPart{type: :file, options: opts} = part) do
+    media = Keyword.get(opts || [], :media, nil)
+
+    mime_type =
+      if is_nil(media) do
+        message = "Received no media type for ContentPart"
+        Logger.error(message)
+        raise LangChainError, message
+      else
+        "#{media}"
+      end
+
+    %{
+      "inline_data" => %{
+        "mime_type" => mime_type,
+        "data" => part.content
+      }
+    }
+  end
+
   def for_api(%ToolCall{} = call) do
     %{
       "functionCall" => %{

test/chat_models/chat_google_ai_test.exs

@@ -196,6 +196,39 @@
              } = msg1
     end
 
+    test "turns a file ContentPart into the expected JSON format" do
+      file_base64_data = "some_file_base64_data"
+      mime_type = "application/pdf"
+
+      expected = %{
+        "inline_data" => %{
+          "mime_type" => mime_type,
+          "data" => file_base64_data
+        }
+      }
+
+      result =
+        ChatGoogleAI.for_api(
+          ChatGoogleAI.new!(),
+          ContentPart.file!(file_base64_data, media: "application/pdf")
+        )
+
+      assert result == expected
+    end
+
+    test "throws an exception when no media type supplied" do
+      file_base64_data = "some_file_base64_data"
+
+      assert_raise(
+        LangChainError,
+        "Received no media type for ContentPart",
+        ChatGoogleAI.for_api(
+          ChatGoogleAI.new!(),
+          ContentPart.file!(file_base64_data)
+        )
+      )
+    end
+
     test "translates a Message with function results to the expected structure" do
       expected =
         %{