import random
from datetime import timedelta

from django.core.management.base import BaseCommand, CommandError
from django.db import transaction
from django.db.models import Max
from django.utils import timezone

from inventory.models import ChoiceValue, Device, Employee, NumberSequence
from inventory.device_types import bulk_create_specifications, clear_inapplicable


MODELS = ["Lenovo ThinkPad T480", "Dell Latitude 7490", "HP EliteBook 840 G5", "Lenovo ThinkCentre M720", "Dell OptiPlex 7060", "HP ProDesk 600 G4", "Lenovo ThinkPad P50"]
CPUS = ["Intel Core i5-8250U", "Intel Core i5-8350U", "Intel Core i7-8650U", "Intel Core i5-6500", "Intel Core i7-6700", "AMD Ryzen 5 3500U"]


class Command(BaseCommand):
    help = "Erzeugt realistische Testgeräte, z. B. generate_test_devices 5000."

    def add_arguments(self, parser):
        parser.add_argument("count", type=int)

    @transaction.atomic
    def handle(self, *args, **options):
        count = options["count"]
        if count < 1 or count > 100000:
            raise CommandError("Anzahl muss zwischen 1 und 100000 liegen.")
        statuses = list(ChoiceValue.objects.filter(kind=ChoiceValue.Kind.STATUS, active=True))
        types = list(ChoiceValue.objects.filter(kind=ChoiceValue.Kind.DEVICE_TYPE, active=True))
        employees = list(Employee.objects.filter(active=True))
        if not statuses:
            raise CommandError("Bitte zuerst seed_initial_data ausführen.")
        start = (Device.objects.aggregate(value=Max("number"))["value"] or 0) + 1
        today = timezone.localdate()
        devices = []
        for offset in range(count):
            model = random.choice(MODELS)
            device = Device(
                number=start + offset, shelf=f"{random.choice('ABCDEFGH')}{random.randint(1, 30)}",
                status=random.choice(statuses), device_type=random.choice(types) if types else None,
                date=today - timedelta(days=random.randint(0, 1500)), model=model, cpu=random.choice(CPUS),
                ram_gb=random.choice([4, 8, 8, 16, 32]), ssd_gb=random.choice([0, 128, 256, 512, 1000]),
                hdd_gb=random.choice([0, 0, 500, 1000, 2000]), employee=random.choice(employees) if employees else None,
                wifi=random.choice(Device.TriState.values), lan=random.choice(Device.TriState.values),
            )
            clear_inapplicable(device)
            device.custom_values = {}
            devices.append(device)
        for index in range(0, count, 1000):
            saved = Device.objects.bulk_create(devices[index:index + 1000], batch_size=1000)
            bulk_create_specifications(saved)
        NumberSequence.ensure_at_least(start + count - 1)
        self.stdout.write(self.style.SUCCESS(f"{count} Testgeräte angelegt."))