"""Limit POST /api/v1/events body size (matches nginx client_max_body_size)."""

from __future__ import annotations

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


class IngestBodySizeLimitMiddleware(BaseHTTPMiddleware):
    def __init__(self, app, *, max_bytes: int = 2_097_152) -> None:
        super().__init__(app)
        self._max_bytes = max_bytes

    async def dispatch(self, request: Request, call_next):
        if request.method == "POST" and request.url.path.rstrip("/") == "/api/v1/events":
            content_length = request.headers.get("content-length")
            if content_length:
                try:
                    size = int(content_length)
                except ValueError:
                    size = 0
                if size > self._max_bytes:
                    return JSONResponse(
                        status_code=413,
                        content={"detail": f"Request body too large (max {self._max_bytes} bytes)"},
                    )
        return await call_next(request)