from django.core.management.base import BaseCommand, CommandError

from apps.licensing.models import SoftwarePlan
from apps.licensing.services import LicensingError, grant_plan_to_existing_users


class Command(BaseCommand):
    help = "Preview or grant one active software plan to existing active non-staff users."

    def add_arguments(self, parser):
        parser.add_argument("--plan-id", type=int, required=True, help="Exact SoftwarePlan ID.")
        parser.add_argument(
            "--reason",
            required=True,
            help="Non-empty audit reason written to every grant event.",
        )
        parser.add_argument(
            "--execute",
            action="store_true",
            help="Apply grants. Without this flag the command is read-only.",
        )
        parser.add_argument(
            "--expected-grant-count",
            type=int,
            help="Required with --execute and must match the current preview count.",
        )

    def handle(self, *args, **options):
        execute = options["execute"]
        expected_grant_count = options["expected_grant_count"]
        if execute and expected_grant_count is None:
            raise CommandError("--execute 必须同时提供 --expected-grant-count")
        if not execute and expected_grant_count is not None:
            raise CommandError("预演模式不能提供 --expected-grant-count")

        try:
            plan = SoftwarePlan.objects.get(pk=options["plan_id"])
        except SoftwarePlan.DoesNotExist as exc:
            raise CommandError("指定套餐不存在") from exc

        try:
            result = grant_plan_to_existing_users(
                plan=plan,
                reason=options["reason"],
                execute=execute,
                expected_grant_count=expected_grant_count,
            )
        except LicensingError as exc:
            raise CommandError(exc.message) from exc

        mode = "EXECUTED" if result.executed else "DRY-RUN"
        summary = (
            f"mode={mode} plan_id={plan.pk} product={plan.product_code} "
            f"eligible={result.eligible_count} "
            f"skipped_existing={result.skipped_existing_count} "
            f"grant_count={result.grant_count}"
        )
        style = self.style.SUCCESS if result.executed else self.style.WARNING
        self.stdout.write(style(summary))