feat: add pure notification message helpers

surfsense_backend/app/notifications/service/messages/document_processing.py

@@ -0,0 +1,64 @@
+"""Pure presentation logic for document-processing notifications."""
+
+from __future__ import annotations
+
+import hashlib
+from datetime import UTC, datetime
+from typing import Any
+
+
+def operation_id(document_type: str, filename: str, search_space_id: int) -> str:
+    """Build a unique id for a document processing run."""
+    timestamp = datetime.now(UTC).strftime("%Y%m%d_%H%M%S_%f")
+    filename_hash = hashlib.md5(filename.encode()).hexdigest()[:8]
+    return f"doc_{document_type}_{search_space_id}_{timestamp}_{filename_hash}"
+
+
+def progress(
+    stage: str,
+    stage_message: str | None = None,
+    chunks_count: int | None = None,
+) -> tuple[str, dict[str, Any]]:
+    """Compute the progress message and metadata updates for a processing run."""
+    stage_messages = {
+        "parsing": "Reading your file",
+        "chunking": "Preparing for search",
+        "embedding": "Preparing for search",
+        "storing": "Finalizing",
+    }
+
+    message = stage_message or stage_messages.get(stage, "Processing")
+
+    metadata_updates: dict[str, Any] = {"processing_stage": stage}
+    if chunks_count is not None:
+        metadata_updates["chunks_count"] = chunks_count
+
+    return message, metadata_updates
+
+
+def completion(
+    document_name: str,
+    error_message: str | None = None,
+    document_id: int | None = None,
+    chunks_count: int | None = None,
+) -> tuple[str, str, str, dict[str, Any]]:
+    """Compute the final title, message, status, and metadata for a finished run."""
+    if error_message:
+        title = f"Failed: {document_name}"
+        message = f"Processing failed: {error_message}"
+        status = "failed"
+    else:
+        title = f"Ready: {document_name}"
+        message = "Now searchable!"
+        status = "completed"
+
+    metadata_updates: dict[str, Any] = {
+        "processing_stage": "completed" if not error_message else "failed",
+        "error_message": error_message,
+    }
+    if document_id is not None:
+        metadata_updates["document_id"] = document_id
+    if chunks_count is not None:
+        metadata_updates["chunks_count"] = chunks_count
+
+    return title, message, status, metadata_updates