from django.utils.crypto import get_random_string

from analytics.models import Attribution, UTMVisit


CORRELATION_COOKIE = "ms_cid"


class UTMTrackingMiddleware:
    """Capture UTM params into UTMVisit and stash a correlation id cookie."""

    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        cid = request.COOKIES.get(CORRELATION_COOKIE) or get_random_string(32)
        request.utm_correlation_id = cid

        params = request.GET
        has_utm = any(params.get(k) for k in (
            "utm_source", "utm_medium", "utm_campaign", "utm_term", "utm_content"
        ))
        if has_utm or params.get("utm_source"):
            UTMVisit.objects.create(
                correlation_id=cid,
                path=request.path[:512],
                referrer=(request.META.get("HTTP_REFERER") or "")[:1024],
                utm_source=params.get("utm_source", "")[:128],
                utm_medium=params.get("utm_medium", "")[:128],
                utm_campaign=params.get("utm_campaign", "")[:128],
                utm_term=params.get("utm_term", "")[:128],
                utm_content=params.get("utm_content", "")[:128],
                user_agent=(request.META.get("HTTP_USER_AGENT") or "")[:512],
            )

        response = self.get_response(request)
        if CORRELATION_COOKIE not in request.COOKIES:
            response.set_cookie(
                CORRELATION_COOKIE,
                cid,
                max_age=60 * 60 * 24 * 30,
                samesite="Lax",
            )
        return response


def attribute_lead_from_request(request, lead) -> Attribution | None:
    cid = getattr(request, "utm_correlation_id", None) or request.COOKIES.get(
        CORRELATION_COOKIE
    )
    visit = None
    if cid:
        visit = (
            UTMVisit.objects.filter(correlation_id=cid).order_by("-created_at").first()
        )
    return Attribution.objects.create(
        lead=lead,
        visit=visit,
        utm_source=visit.utm_source if visit else "",
        utm_medium=visit.utm_medium if visit else "",
        utm_campaign=visit.utm_campaign if visit else "",
    )