Deduplicate online references returned by chat API to clients

This will ensure only unique online references are shown in all
clients.

The duplication issue was exacerbated in research mode as even with
different online search queries, you can get previously seen results.

This change does a global deduplication across all online results seen
across research iterations before returning them in client reponse.

src/khoj/processor/tools/online_search.py

@@ -367,3 +367,25 @@ async def search_with_jina(query: str, location: LocationData) -> Tuple[str, Dic
                 for item in response_json["data"]
             ]
             return query, {"organic": parsed_response}
+
+
+def deduplicate_organic_results(online_results: dict) -> dict:
+    """Deduplicate organic search results based on links across all queries."""
+    # Keep track of seen links to filter out duplicates across queries
+    seen_links = set()
+    deduplicated_results = {}
+
+    # Process each query's results
+    for query, results in online_results.items():
+        # Filter organic results keeping only first occurrence of each link
+        filtered_organic = []
+        for result in results.get("organic", []):
+            link = result.get("link")
+            if link and link not in seen_links:
+                seen_links.add(link)
+                filtered_organic.append(result)
+
+        # Update results with deduplicated organic entries
+        deduplicated_results[query] = {**results, "organic": filtered_organic}
+
+    return deduplicated_results

src/khoj/routers/api_chat.py

@@ -28,7 +28,11 @@ from khoj.processor.conversation.prompts import help_message, no_entries_found
 from khoj.processor.conversation.utils import defilter_query, save_to_conversation_log
 from khoj.processor.image.generate import text_to_image
 from khoj.processor.speech.text_to_speech import generate_text_to_speech
-from khoj.processor.tools.online_search import read_webpages, search_online
+from khoj.processor.tools.online_search import (
+    deduplicate_organic_results,
+    read_webpages,
+    search_online,
+)
 from khoj.processor.tools.run_code import run_code
 from khoj.routers.api import extract_references_and_questions
 from khoj.routers.email import send_query_feedback
@@ -1026,12 +1030,13 @@ async def chat(
                 )
 
         ## Send Gathered References
+        unique_online_results = deduplicate_organic_results(online_results)
         async for result in send_event(
             ChatEvent.REFERENCES,
             {
                 "inferredQueries": inferred_queries,
                 "context": compiled_references,
-                "onlineContext": online_results,
+                "onlineContext": unique_online_results,
                 "codeContext": code_results,
             },
         ):