feat: complete production-quality Model Router AI traffic control platform

backend/main.py

@@ -0,0 +1,94 @@
+import asyncio
+import json
+from contextlib import asynccontextmanager
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+from sse_starlette.sse import EventSourceResponse
+
+from app.config.settings import get_settings
+from app.storage.database import init_db, AsyncSessionLocal
+from app.storage.models import RequestRecord
+from app.api.routes import router as api_router
+from sqlalchemy import select, desc
+
+settings = get_settings()
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    # Initialize SQLite database and seed defaults
+    await init_db()
+    yield
+
+
+app = FastAPI(
+    title="Model Router",
+    description="Intelligent LLM Request Routing Platform — AI Traffic Control Room",
+    version="1.0.0",
+    lifespan=lifespan,
+)
+
+# CORS configuration
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+app.include_router(api_router)
+
+
+@app.get("/api/traffic/stream")
+async def stream_live_traffic():
+    """
+    SSE Live Stream endpoint for the Traffic Control Room visualization.
+    Pushes newly persisted requests to connected frontend clients.
+    """
+    async def event_generator():
+        last_seen_id = None
+        while True:
+            try:
+                async with AsyncSessionLocal() as session:
+                    res = await session.execute(
+                        select(RequestRecord).order_by(desc(RequestRecord.timestamp)).limit(1)
+                    )
+                    latest = res.scalar_one_or_none()
+                    if latest and latest.request_id != last_seen_id:
+                        last_seen_id = latest.request_id
+                        payload = {
+                            "request_id": latest.request_id,
+                            "timestamp": latest.timestamp.isoformat() if latest.timestamp else "",
+                            "prompt": latest.prompt,
+                            "task_type": latest.task_type,
+                            "complexity": latest.complexity,
+                            "selected_model": latest.selected_model,
+                            "provider": latest.provider,
+                            "status": latest.status,
+                            "total_latency_ms": latest.total_latency_ms,
+                            "estimated_cost": latest.estimated_cost,
+                        }
+                        yield {
+                            "event": "traffic_event",
+                            "data": json.dumps(payload),
+                        }
+            except Exception:
+                pass
+            await asyncio.sleep(1.5)
+
+    return EventSourceResponse(event_generator())
+
+
+@app.get("/")
+async def root():
+    return {
+        "message": "Model Router AI Control Room Backend is active.",
+        "docs": "/docs",
+        "health": "/api/health",
+    }
+
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run("main:app", host=settings.HOST, port=settings.PORT, reload=settings.DEBUG)