import React, { useMemo, useState } from "react";
import { Check, Package as PackageIcon, Loader2 } from "lucide-react";
import { Button } from "@/components/ui/button";
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
import { Badge } from "@/components/ui/badge";
import { useCheckoutWizard } from "../WizardContext";
import type { CheckoutPackage } from "../types";

const currencyFormatter = new Intl.NumberFormat("de-DE", {
  style: "currency",
  currency: "EUR",
  minimumFractionDigits: 2,
});

function PackageSummary({ pkg }: { pkg: CheckoutPackage }) {
  return (
    <Card className="shadow-sm">
      <CardHeader className="space-y-1">
        <CardTitle className="flex items-center gap-3 text-2xl">
          <PackageIcon className="h-6 w-6 text-primary" />
          {pkg.name}
        </CardTitle>
        <CardDescription className="text-base text-muted-foreground">
          {pkg.description}
        </CardDescription>
      </CardHeader>
      <CardContent className="space-y-6">
        <div className="flex items-baseline gap-2">
          <span className="text-3xl font-semibold">
            {pkg.price === 0 ? "Kostenlos" : currencyFormatter.format(pkg.price)}
          </span>
          <Badge variant="secondary" className="uppercase tracking-wider text-xs">
            {pkg.type === "reseller" ? "Reseller" : "Endkunde"}
          </Badge>
        </div>
        {Array.isArray(pkg.features) && pkg.features.length > 0 && (
          <ul className="space-y-3">
            {pkg.features.map((feature, index) => (
              <li key={index} className="flex items-start gap-3 text-sm text-muted-foreground">
                <Check className="mt-0.5 h-4 w-4 text-primary" />
                <span>{feature}</span>
              </li>
            ))}
          </ul>
        )}
      </CardContent>
    </Card>
  );
}

function PackageOption({ pkg, isActive, onSelect }: { pkg: CheckoutPackage; isActive: boolean; onSelect: () => void }) {
  return (
    <button
      type="button"
      onClick={onSelect}
      className={`w-full rounded-md border bg-background p-4 text-left transition focus:outline-none focus-visible:ring-2 focus-visible:ring-primary/40 ${
        isActive ? "border-primary shadow-sm" : "border-border hover:border-primary/40"
      }`}
    >
      <div className="flex items-center justify-between text-sm font-medium">
        <span>{pkg.name}</span>
        <span className="text-muted-foreground">
          {pkg.price === 0 ? "Kostenlos" : currencyFormatter.format(pkg.price)}
        </span>
      </div>
      <p className="mt-1 line-clamp-2 text-xs text-muted-foreground">{pkg.description}</p>
    </button>
  );
}

export const PackageStep: React.FC = () => {
  const { selectedPackage, packageOptions, setSelectedPackage, resetPaymentState, nextStep } = useCheckoutWizard();
  const [isLoading, setIsLoading] = useState(false);

  const comparablePackages = useMemo(() => {
    return packageOptions.filter((pkg) => pkg.type === selectedPackage.type);
  }, [packageOptions, selectedPackage.type]);

  const handlePackageChange = (pkg: CheckoutPackage) => {
    if (pkg.id === selectedPackage.id) {
      return;
    }
    setSelectedPackage(pkg);
    resetPaymentState();
  };

  const handleNextStep = async () => {
    setIsLoading(true);
    // Kleine Verzögerung für bessere UX
    setTimeout(() => {
      nextStep();
      setIsLoading(false);
    }, 300);
  };

  return (
    <div className="grid gap-8 lg:grid-cols-[2fr_1fr]">
      <div className="space-y-6">
        <PackageSummary pkg={selectedPackage} />
        <div className="flex justify-end">
          <Button size="lg" onClick={handleNextStep} disabled={isLoading}>
            {isLoading ? (
              <>
                <Loader2 className="mr-2 h-4 w-4 animate-spin" />
                Wird geladen...
              </>
            ) : (
              "Weiter zum Konto"
            )}
          </Button>
        </div>
      </div>
      <aside className="space-y-4">
        <h3 className="text-sm font-semibold uppercase tracking-wider text-muted-foreground">
          Alternative Pakete
        </h3>
        <div className="space-y-3">
          {comparablePackages.map((pkg) => (
            <PackageOption
              key={pkg.id}
              pkg={pkg}
              isActive={pkg.id === selectedPackage.id}
              onSelect={() => handlePackageChange(pkg)}
            />
          ))}
          {comparablePackages.length === 0 && (
            <p className="text-xs text-muted-foreground">
              Keine weiteren Pakete in dieser Kategorie verfuegbar.
            </p>
          )}
        </div>
      </aside>
    </div>
  );
};