Implement FileSystem wide semantic file search engine with temporal awareness using LEANN. (#103)

* system wide semantic file search with temporal awareness

* ruff checking passed

* graceful exit for empty dump

* error thrown for time only search

* fixes

apps/semantic_file_search/leann_index_builder.py

@@ -0,0 +1,82 @@
+#!/usr/bin/env python3
+import json
+import sys
+from pathlib import Path
+
+from leann import LeannBuilder
+
+
+def process_json_items(json_file_path):
+    """Load and process JSON file with metadata items"""
+
+    with open(json_file_path, encoding="utf-8") as f:
+        items = json.load(f)
+
+    # Guard against empty JSON
+    if not items:
+        print("⚠️  No items found in the JSON file. Exiting gracefully.")
+        return
+
+    INDEX_PATH = str(Path("./").resolve() / "demo.leann")
+    builder = LeannBuilder(backend_name="hnsw", is_recompute=False)
+
+    total_items = len(items)
+    items_added = 0
+    print(f"Processing {total_items} items...")
+
+    for idx, item in enumerate(items):
+        try:
+            # Create embedding text sentence
+            embedding_text = f"{item.get('Name', 'unknown')} located at {item.get('Path', 'unknown')} and size {item.get('Size', 'unknown')} bytes with content type {item.get('ContentType', 'unknown')} and kind {item.get('Kind', 'unknown')}"
+
+            # Prepare metadata with dates
+            metadata = {}
+            if "CreationDate" in item:
+                metadata["creation_date"] = item["CreationDate"]
+            if "ContentChangeDate" in item:
+                metadata["modification_date"] = item["ContentChangeDate"]
+
+            # Add to builder
+            builder.add_text(embedding_text, metadata=metadata)
+            items_added += 1
+
+        except Exception as e:
+            print(f"\n⚠️  Warning: Failed to process item {idx}: {e}")
+            continue
+
+        # Show progress
+        progress = (idx + 1) / total_items * 100
+        sys.stdout.write(f"\rProgress: {idx + 1}/{total_items} ({progress:.1f}%)")
+        sys.stdout.flush()
+
+    print()  # New line after progress
+
+    # Guard against no successfully added items
+    if items_added == 0:
+        print("⚠️  No items were successfully added to the index. Exiting gracefully.")
+        return
+
+    print(f"\n✅ Successfully processed {items_added}/{total_items} items")
+    print("Building index...")
+
+    try:
+        builder.build_index(INDEX_PATH)
+        print(f"✓ Index saved to {INDEX_PATH}")
+    except ValueError as e:
+        if "No chunks added" in str(e):
+            print("⚠️  No chunks were added to the builder. Index not created.")
+        else:
+            raise
+
+
+if __name__ == "__main__":
+    if len(sys.argv) != 2:
+        print("Usage: python build_index.py <json_file>")
+        sys.exit(1)
+
+    json_file = sys.argv[1]
+    if not Path(json_file).exists():
+        print(f"Error: File {json_file} not found")
+        sys.exit(1)
+
+    process_json_items(json_file)