import json

from django.conf import settings
from django.core.mail import send_mail
from rest_framework import permissions, status, viewsets
from rest_framework.decorators import action
from rest_framework.request import Request
from rest_framework.response import Response

from api.models import Job, Rating, Reply, SystemConfig, Ticket, User
from api.serializers import (
    AdminUserDetailSerializer,
    AdminUserListSerializer,
    JobSerializer,
    SystemConfigSerializer,
)

JOB_TASK_MAP = {
    "sync_flavors": "api.sync_flavors",
    "cleanup_duplicates": "api.cleanup_duplicates",
    "backup_db": "api.backup_db",
    "seed_legacy": "api.seed_legacy",
    "seed_banners": "api.seed_banners",
}


def _sync_periodic_task(job: Job) -> None:
    """Create/update a django_celery_beat PeriodicTask for this Job.

    Called when the admin changes interval_hours. interval_hours == 0 disables
    the schedule (PeriodicTask.enabled=False).
    """
    from django_celery_beat.models import IntervalSchedule, PeriodicTask

    task_name = JOB_TASK_MAP.get(job.name)
    if not task_name:
        return

    periodic_name = f"job:{job.name}"

    if job.interval_hours <= 0:
        PeriodicTask.objects.filter(name=periodic_name).update(enabled=False)
        return

    schedule, _ = IntervalSchedule.objects.get_or_create(
        every=job.interval_hours,
        period=IntervalSchedule.HOURS,
    )
    PeriodicTask.objects.update_or_create(
        name=periodic_name,
        defaults={
            "interval": schedule,
            "task": task_name,
            "enabled": True,
            "kwargs": json.dumps({}),
        },
    )


class AdminViewSet(viewsets.ViewSet):
    permission_classes = [permissions.IsAdminUser]

    @action(detail=False, methods=["get"])
    def stats(self, request: Request) -> Response:
        return Response(
            {
                "total_users": User.objects.count(),
                "total_ratings": Rating.objects.count(),
                "total_replies": Reply.objects.count(),
                "open_tickets": Ticket.objects.filter(status="open").count(),
                "email_config": {
                    "host": getattr(settings, "EMAIL_HOST", "None"),
                    "port": getattr(settings, "EMAIL_PORT", "None"),
                    "use_tls": getattr(settings, "EMAIL_USE_TLS", False),
                    "use_ssl": getattr(settings, "EMAIL_USE_SSL", False),
                    "skip_verify": getattr(settings, "EMAIL_SKIP_CERT_VERIFICATION", False),
                },
                "server_info": {
                    "debug": settings.DEBUG,
                    "allowed_hosts": settings.ALLOWED_HOSTS,
                    "frontend_url": getattr(settings, "FRONTEND_URL", "Not set"),
                    "media_root": str(settings.MEDIA_ROOT),
                    "static_root": str(settings.STATIC_ROOT),
                },
            }
        )

    @action(detail=False, methods=["get", "patch"])
    def config(self, request: Request) -> Response:
        config = SystemConfig.get_solo()
        if request.method == "PATCH":
            serializer = SystemConfigSerializer(config, data=request.data, partial=True)
            serializer.is_valid(raise_exception=True)
            serializer.save()
            return Response(serializer.data)

        return Response(SystemConfigSerializer(config).data)

    @action(detail=False, methods=["get"])
    def jobs(self, request: Request) -> Response:
        for job_type, _ in Job.JOB_TYPES:
            Job.objects.get_or_create(name=job_type)

        jobs = Job.objects.all().order_by("name")
        return Response(JobSerializer(jobs, many=True).data)

    @action(detail=True, methods=["post"])
    def trigger_job(self, request: Request, pk=None) -> Response:
        from celery import current_app

        try:
            job = Job.objects.get(pk=pk)
        except Job.DoesNotExist:
            return Response(status=status.HTTP_404_NOT_FOUND)

        task_name = JOB_TASK_MAP.get(job.name)
        if not task_name:
            return Response(
                {"error": f"No celery task registered for {job.name}"},
                status=status.HTTP_400_BAD_REQUEST,
            )

        job.status = "pending"
        job.error_message = ""
        job.save(update_fields=["status", "error_message"])

        current_app.send_task(task_name)
        return Response({"status": "Job queued", "task": task_name})

    @action(detail=True, methods=["patch"])
    def update_job_schedule(self, request: Request, pk=None) -> Response:
        try:
            job = Job.objects.get(pk=pk)
        except Job.DoesNotExist:
            return Response(status=status.HTTP_404_NOT_FOUND)

        interval = request.data.get("interval_hours")
        if interval is not None:
            job.interval_hours = int(interval)
            job.save(update_fields=["interval_hours"])

        _sync_periodic_task(job)
        return Response(JobSerializer(job).data)

    @action(detail=False, methods=["post"])
    def send_test_email(self, request: Request) -> Response:
        try:
            send_mail(
                "Holy Flavors Admin Test Email",
                (
                    f"This is a test email sent to {request.user.email} from the "
                    f"Holy Flavors Admin Interface."
                ),
                settings.DEFAULT_FROM_EMAIL,
                [request.user.email],
                fail_silently=False,
            )
            return Response({"status": "Test email sent!"})
        except Exception as e:
            return Response({"error": str(e)}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)

    @action(detail=False, methods=["get"])
    def users(self, request: Request) -> Response:
        users = User.objects.all().prefetch_related("ips").order_by("-date_joined")
        return Response(AdminUserListSerializer(users, many=True).data)

    @action(detail=True, methods=["get", "patch", "delete"])
    def user_detail(self, request: Request, pk=None) -> Response:
        try:
            user = User.objects.get(pk=pk)
        except User.DoesNotExist:
            return Response(status=status.HTTP_404_NOT_FOUND)

        if request.method == "GET":
            return Response(AdminUserDetailSerializer(user, context={"request": request}).data)
        elif request.method == "PATCH":
            is_active = request.data.get("is_active")
            if is_active is not None:
                user.is_active = is_active
                user.save()
            return Response(AdminUserDetailSerializer(user, context={"request": request}).data)
        elif request.method == "DELETE":
            user.delete()
            return Response(status=status.HTTP_204_NO_CONTENT)