init: add project files and ignore secrets

1 files changed, 85 insertions, 0 deletions

diff --git a/backend/app/main.py b/backend/app/main.py
new file mode 100644
index 0000000..48cb89f
--- /dev/null
+++ b/backend/app/main.py
@@ -0,0 +1,85 @@
+from fastapi import FastAPI, HTTPException
+from fastapi.middleware.cors import CORSMiddleware
+from fastapi.responses import StreamingResponse
+from app.schemas import NodeRunRequest, NodeRunResponse, MergeStrategy, Role, Message, Context
+from app.services.llm import llm_streamer
+from dotenv import load_dotenv
+import os
+
+load_dotenv()
+
+app = FastAPI(title="ContextFlow Backend")
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+@app.get("/")
+def read_root():
+    return {"message": "ContextFlow Backend is running"}
+
+def smart_merge_messages(messages: list[Message]) -> list[Message]:
+    """
+    Merges messages using two steps:
+    1. Deduplication by ID (to handle diamond dependencies).
+    2. Merging consecutive messages from the same role.
+    """
+    if not messages:
+        return []
+
+    # 1. Deduplicate by ID, keeping order
+    seen_ids = set()
+    deduplicated = []
+    for msg in messages:
+        if msg.id not in seen_ids:
+            deduplicated.append(msg)
+            seen_ids.add(msg.id)
+    
+    # 2. Merge consecutive roles
+    if not deduplicated:
+        return []
+        
+    merged = []
+    current_msg = deduplicated[0].model_copy()
+    
+    for next_msg in deduplicated[1:]:
+        if next_msg.role == current_msg.role:
+            # Merge content
+            current_msg.content += f"\n\n{next_msg.content}"
+            # Keep the latest timestamp
+            current_msg.timestamp = next_msg.timestamp
+        else:
+            merged.append(current_msg)
+            current_msg = next_msg.model_copy()
+            
+    merged.append(current_msg)
+    return merged
+
+@app.post("/api/run_node_stream")
+async def run_node_stream(request: NodeRunRequest):
+    """
+    Stream the response from the LLM.
+    """
+    # 1. Concatenate all incoming contexts first
+    raw_messages = []
+    for ctx in request.incoming_contexts:
+        raw_messages.extend(ctx.messages)
+    
+    # 2. Apply Merge Strategy
+    final_messages = []
+    if request.merge_strategy == MergeStrategy.SMART:
+        final_messages = smart_merge_messages(raw_messages)
+    else:
+        # RAW strategy: just keep them as is
+        final_messages = raw_messages
+
+    execution_context = Context(messages=final_messages)
+
+    return StreamingResponse(
+        llm_streamer(execution_context, request.user_prompt, request.config),
+        media_type="text/event-stream"
+    )