from starlette.middleware.base import BaseHTTPMiddleware
from starlette.responses import JSONResponse

from services.config_service import ConfigService

# Paths that are always accessible, even when DB is not configured
_ALLOWED_PREFIXES = ("/api/setup", "/docs", "/openapi", "/redoc")


class ConfigGuardMiddleware(BaseHTTPMiddleware):
    """Return 503 for all business routes when the database is not configured."""

    async def dispatch(self, request, call_next):
        path = request.url.path

        # Always allow: setup routes, root, docs, OPTIONS (CORS preflight)
        if path == "/" or request.method == "OPTIONS":
            return await call_next(request)
        for prefix in _ALLOWED_PREFIXES:
            if path.startswith(prefix):
                return await call_next(request)

        if not ConfigService.is_db_configured():
            return JSONResponse(
                status_code=503,
                content={
                    "error_code": "SERVICE_NOT_CONFIGURED",
                    "detail": "数据库未配置，请先完成系统初始化",
                },
            )

        return await call_next(request)