from datetime import timedelta

from django.contrib.auth.decorators import login_required
from django.db.models import Count
from django.shortcuts import render
from django.utils import timezone

from analytics.models import Attribution, UTMVisit


def _bar_pct(rows, key="count"):
    max_count = max((row[key] for row in rows), default=1) or 1
    for row in rows:
        row["bar_pct"] = max(12, int(100 * row[key] / max_count))
    return rows


@login_required
def report(request):
    since_30d = timezone.now() - timedelta(days=30)
    visits_last_30_days = UTMVisit.objects.filter(created_at__gte=since_30d).count()

    visits_by_source = _bar_pct(
        list(
            UTMVisit.objects.values("utm_source")
            .annotate(count=Count("id"))
            .order_by("-count")[:20]
        )
    )
    visits_by_combo = list(
        UTMVisit.objects.values("utm_source", "utm_medium", "utm_campaign")
        .annotate(count=Count("id"))
        .order_by("-count")[:50]
    )
    top_visit = visits_by_source[0] if visits_by_source else None
    top_visit_campaign = (
        UTMVisit.objects.exclude(utm_campaign="")
        .values("utm_campaign")
        .annotate(count=Count("id"))
        .order_by("-count")
        .first()
    )

    leads_by_source = _bar_pct(
        list(
            Attribution.objects.values("utm_source")
            .annotate(count=Count("id"))
            .order_by("-count")[:20]
        )
    )
    leads_by_combo = list(
        Attribution.objects.values("utm_source", "utm_medium", "utm_campaign")
        .annotate(count=Count("id"))
        .order_by("-count")[:50]
    )

    recent_visits = UTMVisit.objects.all()[:25]

    return render(
        request,
        "analytics/report.html",
        {
            "visits_last_30_days": visits_last_30_days,
            "total_visits": UTMVisit.objects.count(),
            "total_attributed": Attribution.objects.count(),
            "top_source": (top_visit or {}).get("utm_source") or "(direct)",
            "top_campaign": (top_visit_campaign or {}).get("utm_campaign") or "—",
            "visits_by_source": visits_by_source,
            "visits_by_combo": visits_by_combo,
            "leads_by_source": leads_by_source,
            "leads_by_combo": leads_by_combo,
            "recent_visits": recent_visits,
        },
    )