from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework.permissions import IsAuthenticated, IsAdminUser
from django.utils import timezone
from datetime import timedelta
from django.db.models import Count
from django.db.models.functions import TruncDate
from rest_framework.authentication import TokenAuthentication

from apps.account.models import User, LoginHistory
from apps.api.models import AppVersion, SupportMessage


class AdminDashboardStatsView(APIView):
    authentication_classes = [TokenAuthentication]
    permission_classes = [IsAuthenticated, IsAdminUser]

    def get(self, request):
        now = timezone.now()
        thirty_days_ago = now - timedelta(days=30)
        seven_days_ago = now - timedelta(days=7)

        # 1. User metrics
        total_users = User.objects.count()
        active_users = User.objects.filter(is_active=True).count()
        new_users_30d = User.objects.filter(date_joined__gte=thirty_days_ago).count()
        staff_users = User.objects.filter(is_staff=True).count()

        # 2. Login activity
        logins_7d = LoginHistory.objects.filter(at_time__gte=seven_days_ago).count()
        login_chart_qs = (
            LoginHistory.objects.filter(at_time__gte=seven_days_ago)
            .annotate(date=TruncDate('at_time'))
            .values('date')
            .annotate(count=Count('id'))
            .order_by('date')
        )
        login_chart = [
            {"date": entry['date'].strftime('%Y-%m-%d'), "count": entry['count']}
            for entry in login_chart_qs
        ]

        # 3. System info
        latest_version = AppVersion.get_latest_active()
        unresolved_support = SupportMessage.objects.filter(is_resolved=False).count()

        data = {
            "summary": {
                "total_users": total_users,
                "active_users": active_users,
                "new_users_30d": new_users_30d,
                "staff_users": staff_users,
                "logins_7d": logins_7d,
                "unresolved_support": unresolved_support,
                "latest_app_version": latest_version.version if latest_version else None,
            },
            "charts": {
                "logins_by_day": login_chart,
            }
        }
        return Response(data)