import React, { useMemo } from "react";
import { useTranslation } from 'react-i18next';
import type { TFunction } from 'i18next';
import { Check, Package as PackageIcon } from "lucide-react";
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
import { Badge } from "@/components/ui/badge";
import { cn } from "@/lib/utils";
import { useCheckoutWizard } from "../WizardContext";
import type { CheckoutPackage } from "../types";

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

function translateFeature(feature: string, t: TFunction<'marketing'>) {
  const fallback = feature.replace(/_/g, ' ');
  return t(`packages.feature_${feature}`, { defaultValue: fallback });
}

const DETAIL_LABEL_MAP: Record<string, string> = {
  fotos: 'photos',
  photos: 'photos',
  gaeste: 'guests',
  gäste: 'guests',
  guests: 'guests',
  aufgaben: 'tasks',
  challenges: 'tasks',
  galerie: 'gallery',
  gallery: 'gallery',
  branding: 'branding',
  'events_jahr': 'events_per_year',
  eventsjahr: 'events_per_year',
};

function translateDetailLabel(label: string | undefined, t: TFunction<'marketing'>): string | undefined {
  if (!label) {
    return label;
  }

  const normalised = label
    .normalize('NFD')
    .replace(/\p{Diacritic}/gu, '')
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, '_')
    .replace(/^_|_$/g, '') || label.toLowerCase();

  const key = DETAIL_LABEL_MAP[normalised] ?? normalised;
  return t(`packages.detail_labels.${key}`, { defaultValue: label });
}

function PackageSummary({ pkg, t }: { pkg: CheckoutPackage; t: TFunction<'marketing'> }) {
  const isFree = pkg.price === 0;
  const accentGradient = pkg.type === 'reseller'
    ? 'border-amber-100 bg-gradient-to-br from-amber-50/80 via-white to-amber-100/70 shadow-lg shadow-amber-100/60'
    : 'border-rose-100 bg-gradient-to-br from-rose-50/80 via-white to-rose-100/70 shadow-lg shadow-rose-100/60';

  return (
    <Card className={cn('shadow-sm transition', isFree ? 'opacity-75' : accentGradient)}>
      <CardHeader className="space-y-1">
        <CardTitle className={`flex items-center gap-3 text-2xl ${isFree ? 'text-muted-foreground' : ''}`}>
          <PackageIcon className={`h-6 w-6 ${isFree ? 'text-muted-foreground' : '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 ${isFree ? 'text-muted-foreground' : ''}`}>
            {pkg.price === 0 ? t('packages.free') : currencyFormatter.format(pkg.price)}
          </span>
          <Badge variant={isFree ? 'outline' : 'secondary'} className="uppercase tracking-wider text-xs">
            {pkg.type === 'reseller' ? t('packages.subscription') : t('packages.one_time')}
          </Badge>
        </div>
        {pkg.gallery_duration_label && (
          <div className="rounded-md border border-dashed border-muted px-3 py-2 text-sm text-muted-foreground">
            {t('packages.gallery_days_label')}: {pkg.gallery_duration_label}
          </div>
        )}
        {Array.isArray(pkg.description_breakdown) && pkg.description_breakdown.length > 0 && (
          <div className="space-y-3">
            <h4 className="text-sm font-semibold uppercase tracking-wide text-muted-foreground">
              {t('packages.breakdown_label')}
            </h4>
            <div className="grid gap-3 md:grid-cols-2">
              {pkg.description_breakdown.map((row, index) => (
                <div key={index} className="rounded-lg border border-muted/40 bg-muted/20 px-3 py-2">
                  {row.title && (
                    <p className="text-xs font-semibold uppercase tracking-wide text-muted-foreground">
                      {translateDetailLabel(row.title, t)}
                    </p>
                  )}
                  <p className="text-sm text-muted-foreground">{row.value}</p>
                </div>
              ))}
            </div>
          </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 ${isFree ? 'text-muted-foreground' : 'text-primary'}`} />
                <span>{translateFeature(feature, t)}</span>
              </li>
            ))}
          </ul>
        )}
      </CardContent>
    </Card>
  );
}

function PackageOption({ pkg, isActive, onSelect, t }: { pkg: CheckoutPackage; isActive: boolean; onSelect: () => void; t: TFunction<'marketing'> }) {
  const isFree = pkg.price === 0;
  const accentGradient = pkg.type === 'reseller'
    ? 'border-amber-100 bg-gradient-to-r from-amber-50/70 via-white to-amber-100/60 shadow-md shadow-amber-100/60'
    : 'border-rose-100 bg-gradient-to-r from-rose-50/70 via-white to-rose-100/60 shadow-md shadow-rose-100/60';

  return (
    <button
      type="button"
      onClick={onSelect}
      className={cn(
        '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
          ? accentGradient
          : isFree
            ? 'border-border hover:border-primary/40 opacity-75 hover:opacity-100'
            : 'border-border hover:border-primary/40',
      )}
    >
      <div className="flex items-center justify-between text-sm font-medium">
        <span className={isFree ? "text-muted-foreground" : ""}>{pkg.name}</span>
        <span className={isFree ? "text-muted-foreground font-normal" : "text-muted-foreground"}>
          {pkg.price === 0 ? t('packages.free') : 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 { t } = useTranslation('marketing');
  const { selectedPackage, packageOptions, setSelectedPackage, resetPaymentState } = useCheckoutWizard();


  // Early return if no package is selected
  if (!selectedPackage) {
    return (
      <div className="text-center py-8">
        <p className="text-muted-foreground">{t('checkout.package_step.no_package_selected')}</p>
      </div>
    );
  }

  const comparablePackages = useMemo(() => {
    // Filter by type and sort: free packages first, then by price ascending
    return packageOptions
      .filter((pkg: CheckoutPackage) => pkg.type === selectedPackage.type)
      .sort((a: CheckoutPackage, b: CheckoutPackage) => {
        // Free packages first
        if (a.price === 0 && b.price > 0) return -1;
        if (a.price > 0 && b.price === 0) return 1;
        // Then sort by price ascending
        return a.price - b.price;
      });
  }, [packageOptions, selectedPackage]);

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

  return (
    <div className="grid gap-8 lg:grid-cols-[2fr_1fr]">
      <div className="space-y-6">
        <PackageSummary pkg={selectedPackage} t={t} />
      </div>
      <aside className="space-y-4">
        <h3 className="text-sm font-semibold uppercase tracking-wider text-muted-foreground">
          {t('checkout.package_step.alternatives_title')}
        </h3>
        <div className="space-y-3">
          {comparablePackages.map((pkg) => (
            <PackageOption
              key={pkg.id}
              pkg={pkg}
              isActive={pkg.id === selectedPackage.id}
              onSelect={() => handlePackageChange(pkg)}
              t={t}
            />
          ))}
          {comparablePackages.length === 0 && (
            <p className="text-xs text-muted-foreground">
              {t('checkout.package_step.no_alternatives')}
            </p>
          )}
        </div>
      </aside>
    </div>
  );
};
