import re

from fastapi import Request, Response
from starlette.middleware.base import BaseHTTPMiddleware, RequestResponseEndpoint
from starlette.responses import JSONResponse

from app.config import settings

BLOCKED_UA_PATTERNS = [
    re.compile(r"(?i)(curl|wget|python-requests|scrapy|httpx|go-http-client|java/)"),
]


class AntiCrawlerMiddleware(BaseHTTPMiddleware):
    async def dispatch(
        self, request: Request, call_next: RequestResponseEndpoint
    ) -> Response:
        # Skip health/docs
        if request.url.path in ("/health", "/api-docs", "/openapi.json", "/api-redoc"):
            return await call_next(request)

        # Skip callback endpoints
        if request.url.path.startswith("/api/callbacks/"):
            return await call_next(request)

        user_agent = request.headers.get("user-agent", "")

        # Block empty User-Agent
        if not user_agent:
            return JSONResponse(status_code=403, content={"detail": "Forbidden"})

        # Block known bot User-Agents (unless they have an API key)
        api_key = request.headers.get("x-api-key")
        if not api_key:
            for pattern in BLOCKED_UA_PATTERNS:
                if pattern.search(user_agent):
                    return JSONResponse(
                        status_code=403, content={"detail": "Forbidden"}
                    )

        return await call_next(request)