import sys
import os

sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from contextlib import asynccontextmanager
from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from fastapi.staticfiles import StaticFiles
from fastapi.responses import FileResponse
from app.routes.predict import router as predict_router
from app.routes.weather import router as weather_router
from app.routes.holiday import router as holiday_router
from app.routes.city    import router as city_router
from app.models.loader  import ModelLoader


@asynccontextmanager
async def lifespan(app: FastAPI):
    print("🔄 Loading ML model...")
    ModelLoader.get_model()
    ModelLoader.get_feature_columns()
    print("✅ CrowdRoute API is ready!")
    yield
    print("🛑 Shutting down...")


app = FastAPI(
    title="🚌 CrowdRoute API",
    description="Predict crowd levels across public transport options",
    version="1.0.0",
    lifespan=lifespan
)

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# ── API Routes ────────────────────────────────────────────
app.include_router(predict_router, prefix="/api/v1", tags=["Predictions"])
app.include_router(weather_router, prefix="/api/v1", tags=["Weather"])
app.include_router(holiday_router, prefix="/api/v1", tags=["Holiday"])
app.include_router(city_router,    prefix="/api/v1", tags=["City"])

# ── Serve React Frontend ──────────────────────────────────
FRONTEND_DIR  = os.path.join(os.path.dirname(os.path.dirname(os.path.abspath(__file__))), "static")
ASSETS_DIR    = os.path.join(FRONTEND_DIR, "assets")
INDEX_FILE    = os.path.join(FRONTEND_DIR, "index.html")

# Only mount static files if they exist
if os.path.exists(ASSETS_DIR):
    app.mount("/assets", StaticFiles(directory=ASSETS_DIR), name="assets")
    print(f"✅ Serving frontend from: {FRONTEND_DIR}")
else:
    print(f"⚠️  No frontend found at {FRONTEND_DIR} — API only mode")

@app.get("/")
async def root():
    if os.path.exists(INDEX_FILE):
        return FileResponse(INDEX_FILE)
    return {
        "message": "🚌 CrowdRoute API",
        "docs":    "/docs",
        "health":  "/api/v1/health",
        "version": "1.0.0"
    }

@app.get("/{full_path:path}")
async def catch_all(full_path: str):
    # Don't intercept API routes
    if full_path.startswith("api/") or full_path.startswith("docs") or full_path.startswith("openapi"):
        from fastapi import HTTPException
        raise HTTPException(status_code=404, detail="Not found")
    # Serve React app for all other routes
    if os.path.exists(INDEX_FILE):
        return FileResponse(INDEX_FILE)
    return {"message": "🚌 CrowdRoute API — Frontend not deployed yet"}