fix: Add display messages for cases, when use can fix input (#182)

aidial_adapter_bedrock/llm/model/stability/v2.py

@@ -17,6 +17,7 @@
 from aidial_adapter_bedrock.dial_api.resource import (
     AttachmentResource,
     DialResource,
+    UnsupportedContentType,
     URLResource,
 )
 from aidial_adapter_bedrock.dial_api.storage import (
@@ -26,13 +27,26 @@
 from aidial_adapter_bedrock.dial_api.token_usage import TokenUsage
 from aidial_adapter_bedrock.llm.chat_model import ChatCompletionAdapter
 from aidial_adapter_bedrock.llm.consumer import Attachment, Consumer
-from aidial_adapter_bedrock.llm.errors import ValidationError
+from aidial_adapter_bedrock.llm.errors import UserError, ValidationError
 from aidial_adapter_bedrock.llm.model.stability.storage import save_to_storage
 from aidial_adapter_bedrock.llm.truncate_prompt import DiscardedMessages
 from aidial_adapter_bedrock.utils.json import remove_nones
 from aidial_adapter_bedrock.utils.resource import Resource
 
 SUPPORTED_IMAGE_TYPES = ["image/jpeg", "image/png", "image/webp"]
+SUPPORTED_IMAGE_EXTENSIONS = ["jpeg", "jpe", "jpg", "png", "webp"]
+
+
+async def _download_resource(
+    dial_resource: DialResource, storage: FileStorage | None
+) -> Resource:
+    try:
+        return await dial_resource.download(storage)
+    except UnsupportedContentType as e:
+        raise UserError(
+            error_message=f"Unsupported image type: {e.type}",
+            usage_message=f"Supported image types: {', '.join(SUPPORTED_IMAGE_EXTENSIONS)}",
+        )
 
 
 def _validate_image_size(
@@ -202,20 +216,23 @@ async def chat(
             )
 
         if not self.image_to_image_supported and image_resources:
-            raise ValidationError(
-                f"Image-to-image is not supported for {self.model}"
-            )
+            raise UserError("Image-to-Image is not supported")
         if len(image_resources) > 1:
-            raise ValidationError("Only one input image is supported")
+            raise UserError("Only one input image is supported")
 
         if self.image_to_image_supported and image_resources:
-            image_resource = await image_resources[0].download(self.storage)
+            image_resource = await _download_resource(
+                image_resources[0], self.storage
+            )
             _validate_image_size(
                 image_resource, self.width_constraints, self.height_constraints
             )
         else:
             image_resource = None
 
+        if not text_prompt:
+            raise UserError("Text prompt is required")
+
         response, _ = await self.client.ainvoke_non_streaming(
             self.model,
             remove_nones(