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 pathlib import Path
import os

from backend.core.database import init_db
from backend.api.api import api_router

@asynccontextmanager
async def lifespan(app: FastAPI):
    # Startup
    try:
        await init_db()
    except Exception as e:
        print(f"WARNING: Database initialization failed. Running in MOCK mode. Error: {e}")
    yield
    # Shutdown

app = FastAPI(
    title="GeoQuery API", 
    description="Geospatial Analysis Agent API", 
    version="0.1.0",
    lifespan=lifespan
)

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"], # Allow all for dev
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

app.include_router(api_router, prefix="/api/v1")

# Serve static files (Frontend)
static_dir = Path(__file__).parent / "static"

if static_dir.exists():
    app.mount("/_next", StaticFiles(directory=static_dir / "_next"), name="next")
    # app.mount("/assets", StaticFiles(directory=static_dir / "assets"), name="assets") # Standard Next.js Output might not use this top-level
    
    @app.get("/{full_path:path}")
    async def serve_frontend(full_path: str):
        # API requests are already handled by include_router above (because specific routes take precedence? No, order matters).
        # Wait, explicit routes define earlier take precedence. 
        # But include_router adds routes. 
        # A catch-all route /{full_path:path} will capture everything NOT matched by previous routes.
        # Since api_router is included first (implicitly? No, verify order).
        # FastAPI router priority: First declared wins.
        # So app.include_router MUST be before this catch-all. It is.
        
        file_path = static_dir / full_path
        if file_path.exists() and file_path.is_file():
            return FileResponse(file_path)
            
        # Fallback to index.html for SPA routing
        index_path = static_dir / "index.html"
        if index_path.exists():
            return FileResponse(index_path)
        return {"error": "Frontend not found"}
else:
    @app.get("/")
    def read_root():
        return {"message": "GeoQuery API is running (Frontend not built)"}