chore: initial commit — existing single-user document scanner codebase

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/ai/anthropic_provider.py

@@ -0,0 +1,103 @@
+import json
+import re
+import anthropic
+from ai.base import AIProvider, ClassificationResult
+
+MAX_AI_CHARS = 8_000
+
+
+class AnthropicProvider(AIProvider):
+    def __init__(self, api_key: str, model: str = "claude-sonnet-4-6"):
+        self._api_key = api_key
+        self._model = model
+
+    def _client(self):
+        return anthropic.AsyncAnthropic(api_key=self._api_key)
+
+    async def classify(
+        self,
+        document_text: str,
+        existing_topics: list[str],
+        system_prompt: str,
+    ) -> ClassificationResult:
+        topics_str = ", ".join(existing_topics) if existing_topics else "(none yet)"
+        user_msg = (
+            f"Existing topics: [{topics_str}]\n\n"
+            f"Document text:\n{document_text[:MAX_AI_CHARS]}"
+        )
+        client = self._client()
+        response = await client.messages.create(
+            model=self._model,
+            max_tokens=1024,
+            system=system_prompt,
+            messages=[{"role": "user", "content": user_msg}],
+        )
+        raw = response.content[0].text
+        return _parse_classification(raw)
+
+    async def suggest_topics(
+        self,
+        document_text: str,
+        system_prompt: str,
+    ) -> list[str]:
+        user_msg = (
+            "Suggest 3-5 topic names for this document. "
+            "Return ONLY valid JSON: {\"suggested_topics\": [\"topic1\", \"topic2\"]}\n\n"
+            f"Document text:\n{document_text[:MAX_AI_CHARS]}"
+        )
+        client = self._client()
+        response = await client.messages.create(
+            model=self._model,
+            max_tokens=256,
+            system=system_prompt,
+            messages=[{"role": "user", "content": user_msg}],
+        )
+        raw = response.content[0].text
+        return _parse_suggestions(raw)
+
+    async def health_check(self) -> bool:
+        try:
+            client = self._client()
+            await client.messages.create(
+                model=self._model,
+                max_tokens=5,
+                messages=[{"role": "user", "content": "ping"}],
+            )
+            return True
+        except Exception:
+            return False
+
+
+def _strip_code_fences(text: str) -> str:
+    text = re.sub(r"```(?:json)?\s*", "", text)
+    text = re.sub(r"```", "", text)
+    return text.strip()
+
+
+def _parse_classification(raw: str) -> ClassificationResult:
+    raw = _strip_code_fences(raw)
+    # Try to find JSON object
+    match = re.search(r"\{.*\}", raw, re.DOTALL)
+    if match:
+        try:
+            data = json.loads(match.group())
+            return ClassificationResult(
+                topics=data.get("assigned_topics", []),
+                suggested_new_topics=data.get("new_topic_suggestions", []),
+                reasoning=data.get("reasoning", ""),
+            )
+        except json.JSONDecodeError:
+            pass
+    return ClassificationResult()
+
+
+def _parse_suggestions(raw: str) -> list[str]:
+    raw = _strip_code_fences(raw)
+    match = re.search(r"\{.*\}", raw, re.DOTALL)
+    if match:
+        try:
+            data = json.loads(match.group())
+            return data.get("suggested_topics", [])
+        except json.JSONDecodeError:
+            pass
+    return []