import uuid
from urllib.parse import urlparse
from django.utils import timezone
from .models import Visit


class VisitTrackingMiddleware:
    """Middleware très léger pour enregistrer des statistiques de visites.

    - Assigne un cookie visiteur persistant (vid) si absent
    - Enregistre/Met à jour une ligne Visit par visiteur et par jour
    - Capture la source (UTM/referrer) et le pays si disponible via headers
    """

    COOKIE_NAME = 'vid'
    COOKIE_MAX_AGE = 60 * 60 * 24 * 365 * 2  # 2 ans

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

    def __call__(self, request):
        vid = request.COOKIES.get(self.COOKIE_NAME)
        if not vid:
            vid = uuid.uuid4().hex

        request.visitor_id = vid

        # Enregistrer la visite (agrégée par jour)
        try:
            self._track(request, vid)
        except Exception:
            # On ne casse jamais la requête pour des stats
            pass

        response = self.get_response(request)
        # S'assurer que le cookie est posé
        if request.COOKIES.get(self.COOKIE_NAME) != vid:
            response.set_cookie(
                self.COOKIE_NAME,
                vid,
                max_age=self.COOKIE_MAX_AGE,
                httponly=True,
                samesite='Lax',
            )
        return response

    def _track(self, request, vid):
        # On ignore l'admin et les assets statiques
        path = request.path
        if path.startswith('/admin') or path.startswith('/static') or path.startswith('/staticfiles'):
            return

        now = timezone.now()
        date = now.date()

        ref = request.META.get('HTTP_REFERER', '')[:512]
        utm_source = request.GET.get('utm_source', '')[:100]
        utm_medium = request.GET.get('utm_medium', '')[:100]
        utm_campaign = request.GET.get('utm_campaign', '')[:150]

        # Déterminer source
        source = ''
        if utm_source:
            source = utm_source
        elif ref:
            try:
                netloc = urlparse(ref).netloc
                source = netloc
            except Exception:
                source = ref[:150]

        # Déterminer pays via en-têtes si fournis par proxy/CDN
        country = (
            request.META.get('HTTP_CF_IPCOUNTRY')
            or request.META.get('HTTP_X_APPENGINE_COUNTRY')
            or request.META.get('HTTP_X_COUNTRY')
            or ''
        )[:64]

        became_user_at = now if request.user.is_authenticated else None
        visit, created = Visit.objects.get_or_create(
            visitor_id=vid,
            date=date,
            defaults={
                'path': path[:512],
                'referrer': ref,
                'utm_source': utm_source,
                'utm_medium': utm_medium,
                'utm_campaign': utm_campaign,
                'source': source,
                'country': country,
                'first_seen': now,
                'last_seen': now,
                'user': request.user if request.user.is_authenticated else None,
                'became_user_at': became_user_at,
            }
        )

        if not created:
            # Mise à jour basique
            dirty = False
            if not visit.source and source:
                visit.source = source
                dirty = True
            if not visit.country and country:
                visit.country = country
                dirty = True
            if request.user.is_authenticated and visit.user_id is None:
                visit.user = request.user
                dirty = True
                # Marquer la conversion si pas encore définie
                if visit.became_user_at is None:
                    visit.became_user_at = now
            visit.last_seen = now
            dirty = True
            if dirty:
                visit.save(update_fields=['source', 'country', 'user', 'became_user_at', 'last_seen'])