import os
from contextlib import asynccontextmanager
from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from starlette.middleware.base import BaseHTTPMiddleware
from starlette.requests import Request as StarletteRequest
from starlette.responses import JSONResponse
from slowapi import _rate_limit_exceeded_handler
from slowapi.errors import RateLimitExceeded
from services.limiter import limiter
from fastapi.staticfiles import StaticFiles
from config import get_settings
from database import engine, Base
import models  # noqa: F401
from routers import auth, courseware, animation, exercise, lesson_plan, essay, ai, resource, community, exam, classroom, material, search, admin, mindmap, notification, chat

settings = get_settings()



@asynccontextmanager
async def lifespan(app: FastAPI):
    Base.metadata.create_all(bind=engine)
    os.makedirs(settings.UPLOAD_DIR, exist_ok=True)
    yield


app = FastAPI(
    title=settings.APP_NAME,
    version=settings.APP_VERSION,
    lifespan=lifespan,
)

app.state.limiter = limiter
app.add_exception_handler(RateLimitExceeded, _rate_limit_exceeded_handler)

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


class BodySizeLimitMiddleware(BaseHTTPMiddleware):
    """Reject request bodies exceeding MAX_REQUEST_BODY_SIZE (default 60MB)."""

    async def dispatch(self, request: StarletteRequest, call_next):
        max_size = getattr(settings, "MAX_REQUEST_BODY_SIZE", 60 * 1024 * 1024)
        cl = request.headers.get("content-length")
        if cl and int(cl) > max_size:
            return JSONResponse(
                status_code=413,
                content={"detail": f"请求体过大，最大允许 {max_size // (1024*1024)}MB"},
            )
        return await call_next(request)


app.add_middleware(BodySizeLimitMiddleware)

app.include_router(auth.router)
app.include_router(courseware.router)
app.include_router(animation.router)
app.include_router(exercise.router)
app.include_router(lesson_plan.router)
app.include_router(essay.router)
app.include_router(exam.router)
app.include_router(ai.router)
app.include_router(resource.router)
app.include_router(material.router)
app.include_router(community.router)
app.include_router(classroom.router)
app.include_router(search.router)
app.include_router(admin.router)
app.include_router(mindmap.router)
app.include_router(notification.router)
app.include_router(chat.router)

if os.path.exists(settings.UPLOAD_DIR):
    app.mount("/uploads", StaticFiles(directory=settings.UPLOAD_DIR), name="uploads")


@app.get("/api/health")
def health_check():
    return {"status": "ok", "version": settings.APP_VERSION}


if __name__ == "__main__":
    import uvicorn
    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=settings.DEBUG)