Handle invalid random photos before device writes and trace selections

pigway_frame_flow/display/service.py

@@ -132,6 +132,11 @@ class DisplayService:
         )
 
     def update(self, id, status, result=None, error=None):
+        if result:
+            row = self.db.one("SELECT result FROM operations WHERE id=?", (id,))
+            previous = json.loads(row["result"]) if row and row["result"] else {}
+            if "photo_attempts" in previous:
+                result = {**result, "photo_attempts": previous["photo_attempts"]}
         self.db.execute(
             "UPDATE operations SET status=?,updated_at=?,result=COALESCE(?,result),error=? WHERE id=?",
             (
@@ -158,7 +163,7 @@ class DisplayService:
         )
         return self.db.one("SELECT * FROM device_state WHERE device_id=?", (id,))
 
-    def content_asset(self, content, device_id=None):
+    def content_asset(self, content, device_id=None, operation_id=None):
         if isinstance(content, TemplateContent):
             values = self.renderer.resolve(content.template, content.data)
             data = self.renderer.render(content.template, values, content.profile)
@@ -180,22 +185,74 @@ class DisplayService:
                 self.registry.get(device_id or self.settings.device_id).device().display
             )
             size = frame_canvas(display, source.orientation)
-            data, name, caption = self.photo_sources.read(
-                content.source_id, content.item_id, target_size=size
+            import random
+
+            items = self.photo_sources.catalog(content.source_id, target_size=size)
+            candidates = (
+                [item for item in items if item["id"] == content.item_id]
+                if content.item_id
+                else random.SystemRandom().sample(items, min(5, len(items)))
             )
-            rendered = (
-                render_captioned_photo(
-                    data,
-                    caption,
-                    self.renderer.font,
-                    content.fit,
-                    content.profile,
-                    size=size,
+            if not candidates:
+                raise FlowError(
+                    E.NOT_FOUND, "Photo source contains no matching images", 404
                 )
-                if caption
-                else convert(data, content.fit, content.profile, size=size)
+            attempts = []
+            for item in candidates:
+                attempt = {
+                    "source_id": content.source_id,
+                    "item_id": item["id"],
+                    "name": item["name"],
+                    "status": "SELECTED",
+                }
+                attempts.append(attempt)
+                if operation_id:
+                    self.db.execute(
+                        "UPDATE operations SET result=? WHERE id=?",
+                        (encode({"photo_attempts": attempts}), operation_id),
+                    )
+                try:
+                    data, name, caption = self.photo_sources.read(
+                        content.source_id, item["id"], target_size=size
+                    )
+                    rendered = (
+                        render_captioned_photo(
+                            data,
+                            caption,
+                            self.renderer.font,
+                            content.fit,
+                            content.profile,
+                            size=size,
+                        )
+                        if caption
+                        else convert(data, content.fit, content.profile, size=size)
+                    )
+                except FlowError as exc:
+                    attempt["status"] = "SKIPPED"
+                    attempt["code"] = exc.code
+                    if operation_id:
+                        self.db.execute(
+                            "UPDATE operations SET result=? WHERE id=?",
+                            (encode({"photo_attempts": attempts}), operation_id),
+                        )
+                    # Only local preparation can choose another image. No device
+                    # write has begun; explicit selections never change silently.
+                    if content.item_id or exc.code not in (
+                        E.INVALID_REQUEST,
+                        E.NOT_FOUND,
+                    ):
+                        raise
+                    continue
+                attempt["status"] = "PREPARED"
+                if operation_id:
+                    self.db.execute(
+                        "UPDATE operations SET result=? WHERE id=?",
+                        (encode({"photo_attempts": attempts}), operation_id),
+                    )
+                return self.assets.put(rendered, name)
+            raise FlowError(
+                E.INVALID_REQUEST, "No decodable photo found within 5 candidates"
             )
-            return self.assets.put(rendered, name)
         if isinstance(content, URLContent):
             data = self.assets.fetch_url(content.url)
         elif isinstance(content, ImageContent) and content.asset_id:
@@ -322,7 +379,7 @@ class DisplayService:
             from pigway_frame_flow.models import Content
 
             asset = self.content_asset(
-                TypeAdapter(Content).validate_python(payload), device_id
+                TypeAdapter(Content).validate_python(payload), device_id, id
             )
             if action == "local-upload":
                 asset = self.assets.promote(asset["asset_id"])
@@ -402,7 +459,7 @@ class DisplayService:
                     )
                 image_id = matches[0].image_id
         else:
-            asset = self.content_asset(content, device_id)
+            asset = self.content_asset(content, device_id, id)
             image_id = None
         self.db.execute(
             "UPDATE device_state SET previous_image_id=? WHERE device_id=?",