ROI calculator

'use client';

import { useEffect, useId, useRef, useState } from 'react';
import { cn, round, useInView, useLocale, useTexts, type Locale } from '@/lib/kit';
import { Stagger, Magnetic } from '@/components/ui/motion';
import { Button } from '@/components/ui/button';
import { Icon } from '@/components/ui/icon';
import { NumberTicker } from '@/components/ui/number-ticker';
import { Reveal } from '@/components/ui/reveal';
import { Eyebrow, Section } from '@/components/ui/section';
import { Slider } from '@/components/ui/slider';

/*
 * What a product earns back, calculated by the visitor. All figures are plain
 * numbers in the props and formatted in the language of the page. The model
 * is deliberately simple and shown openly, so a buyer can repeat it:
 *
 *   value per year = people × hours saved per week × hourly cost × working weeks
 *   cost per year  = price × 12 (× people when the price is per seat) + setup
 *
 *   sliders    three sliders, the yearly value, return, payback and a cost bar
 *   payback    two sliders and a chart of 12 months, the break-even point moves
 *   scenarios  careful, expected or bold, plus team size, with the assumptions
 *   steps      one question at a time, then the result with its breakdown
 *   revenue    visitors, conversion, order value and uplift, as a funnel
 */

export type RoiCalculatorVariant = 'sliders' | 'payback' | 'scenarios' | 'steps' | 'revenue';

export interface RoiRange {
  label: string;
  min: number;
  max: number;
  step?: number;
  value: number;
  hint?: string;
}

export interface RoiPrice {
  amount: number;
  /** seat: per person and month. month: flat per month. */
  per: 'seat' | 'month';
  /** One-off setup cost, part of the first month */
  setup?: number;
  /** Product or plan name, e.g. Northwind Team */
  name: string;
}

export interface RoiCalculatorProps {
  variant?: RoiCalculatorVariant;
  eyebrow?: React.ReactNode;
  title: React.ReactNode;
  description?: React.ReactNode;
  /** sliders, payback, scenarios, steps: the time model */
  inputs?: { people: RoiRange; hours: RoiRange; rate: RoiRange };
  price?: RoiPrice;
  /** Working weeks per year, default 46 */
  weeks?: number;
  /** scenarios: hours saved per person and week in each case */
  scenarios?: { label: string; hours: number; note?: string }[];
  /** scenarios: the assumptions, shown openly */
  assumptions?: string[];
  /** steps: one question per input, same order as people, hours, rate */
  questions?: [string, string, string];
  /** revenue: the shop or lead model */
  revenue?: { visitors: RoiRange; conversion: RoiRange; order: RoiRange; uplift: RoiRange };
  /** ISO currency, default EUR */
  currency?: string;
  /** Unit after hours, e.g. h or Std. */
  hourUnit?: string;
  cta?: { label: string; href: string };
  /** Small print under the result, e.g. where the averages come from */
  note?: string;
  labels?: Partial<Texts>;
  className?: string;
}

const TEXTS = {
  en: {
    value: 'Value of the time saved',
    perYear: 'per year',
    perMonth: 'per month',
    net: 'Net gain',
    roi: 'Return',
    roiValue: '{x}×',
    roiNote: 'of what you pay',
    payback: 'Pays for itself after',
    days: '{n} days',
    daysShort: '{n} days',
    paybackShort: 'until it pays off',
    hoursBack: 'Hours back',
    cost: 'Cost of {n}',
    costYear: 'Your cost per year',
    breakeven: 'Break-even in month {n}',
    noBreakeven: 'No break-even within 12 months',
    month: 'Month',
    saved: 'Saved',
    paid: 'Paid',
    months: 'Months',
    scenario: 'Scenario',
    assumptions: 'Assumptions',
    next: 'Next',
    back: 'Back',
    restart: 'Start over',
    see: 'Show result',
    result: 'Your result',
    step: 'Question {n} of {t}',
    increase: 'More',
    decrease: 'Less',
    breakdown: 'How we got there',
    extra: 'Extra revenue',
    extraOrders: 'more orders a month',
    today: 'Today',
    after: 'With {n}',
    visitors: 'Visitors',
    ordersMonth: 'orders a month',
    chart: 'Saved and paid over 12 months',
  },
  de: {
    value: 'Wert der gesparten Zeit',
    perYear: 'pro Jahr',
    perMonth: 'pro Monat',
    net: 'Netto-Gewinn',
    roi: 'Rendite',
    roiValue: '{x}×',
    roiNote: 'von dem, was du zahlst',
    payback: 'Rechnet sich nach',
    days: '{n} Tagen',
    daysShort: '{n} Tage',
    paybackShort: 'bis es sich rechnet',
    hoursBack: 'Stunden zurück',
    cost: 'Kosten für {n}',
    costYear: 'Deine Kosten pro Jahr',
    breakeven: 'Gewinnschwelle im Monat {n}',
    noBreakeven: 'Keine Gewinnschwelle in 12 Monaten',
    month: 'Monat',
    saved: 'Gespart',
    paid: 'Bezahlt',
    months: 'Monate',
    scenario: 'Szenario',
    assumptions: 'Annahmen',
    next: 'Weiter',
    back: 'Zurück',
    restart: 'Neu starten',
    see: 'Ergebnis zeigen',
    result: 'Dein Ergebnis',
    step: 'Frage {n} von {t}',
    increase: 'Mehr',
    decrease: 'Weniger',
    breakdown: 'So haben wir gerechnet',
    extra: 'Mehr Umsatz',
    extraOrders: 'Bestellungen mehr im Monat',
    today: 'Heute',
    after: 'Mit {n}',
    visitors: 'Besucher',
    ordersMonth: 'Bestellungen im Monat',
    chart: 'Gespart und bezahlt über 12 Monate',
  },
};

type Texts = (typeof TEXTS)['en'];
type ViewProps = RoiCalculatorProps & { t: Texts };

const nf = (l: Locale) => (l === 'de' ? 'de-DE' : 'en-US');
const money = (n: number, l: Locale, currency = 'EUR') => new Intl.NumberFormat(nf(l), { style: 'currency', currency, maximumFractionDigits: 0 }).format(Math.round(n));
const num = (n: number, l: Locale, digits = 0) => new Intl.NumberFormat(nf(l), { maximumFractionDigits: digits }).format(n);

const FALLBACK_RANGE: RoiRange = { label: '', min: 0, max: 10, value: 1 };
const FALLBACK_PRICE: RoiPrice = { amount: 0, per: 'month', name: '' };

function model(people: number, hours: number, rate: number, price: RoiPrice, weeks: number) {
  const value = people * hours * rate * weeks;
  const monthly = price.per === 'seat' ? price.amount * people : price.amount;
  const cost = monthly * 12 + (price.setup ?? 0);
  const roi = cost > 0 ? value / cost : 0;
  const payback = value > 0 ? Math.max(1, Math.ceil((cost / value) * 365)) : 0;
  return { value, cost, monthly, net: value - cost, roi, payback, hoursYear: people * hours * weeks };
}

/** A number that counts from its last value to the new one, for live results */
function Live({ value, format, className }: { value: number; format: Intl.NumberFormatOptions; className?: string }) {
  const last = useRef<number | null>(null);
  const from = last.current ?? 0;
  useEffect(() => {
    last.current = value;
  }, [value]);
  return <NumberTicker value={Math.round(value)} from={Math.round(from)} duration={last.current === null ? 1300 : 450} format={format} className={className} />;
}

function Head({ eyebrow, title, description, center, className }: Pick<RoiCalculatorProps, 'eyebrow' | 'title' | 'description'> & { center?: boolean; className?: string }) {
  return (
    <div className={cn('max-w-[46rem]', center && 'mx-auto max-w-[42rem] text-center', className)}>
      {eyebrow && <Eyebrow>{eyebrow}</Eyebrow>}
      <h2 className="kit-rise text-balance text-h2 font-semibold text-foreground">{title}</h2>
      {description && (
        <p className={cn('kit-rise mt-5 max-w-[36rem] text-pretty text-lead text-muted-foreground', center && 'mx-auto')} style={{ '--kit-delay': '80ms' } as React.CSSProperties}>
          {description}
        </p>
      )}
    </div>
  );
}

function Cta({ cta, note, className }: Pick<RoiCalculatorProps, 'cta' | 'note'> & { className?: string }) {
  if (!cta && !note) return null;
  return (
    <div className={className}>
      {cta && (
        <Button href={cta.href} size="lg" icon="arrow-right" className="w-full">
          {cta.label}
        </Button>
      )}
      {note && <p className="mt-3 text-pretty text-[12.5px] leading-relaxed text-muted-foreground">{note}</p>}
    </div>
  );
}

/** One input slider with the format of its kind */
function RangeField({ range, value, onChange, kind, locale, currency, hourUnit }: { range: RoiRange; value: number; onChange: (v: number) => void; kind: 'count' | 'hours' | 'money' | 'percent'; locale: Locale; currency: string; hourUnit?: string }) {
  const fmt = (v: number) => (kind === 'money' ? money(v, locale, currency) : kind === 'percent' ? `${num(v, locale, 1)}${locale === 'de' ? ' %' : '%'}` : kind === 'hours' ? `${num(v, locale, 1)}${hourUnit ? ` ${hourUnit}` : ''}` : num(v, locale));
  return (
    <div>
      <Slider label={range.label} min={range.min} max={range.max} step={range.step ?? 1} value={value} onValueChange={onChange} format={fmt} />
      {range.hint && <p className="mt-0.5 text-[12.5px] text-muted-foreground">{range.hint}</p>}
    </div>
  );
}

function useTimeInputs(p: RoiCalculatorProps) {
  const inputs = p.inputs ?? { people: FALLBACK_RANGE, hours: FALLBACK_RANGE, rate: FALLBACK_RANGE };
  const [people, setPeople] = useState(inputs.people.value);
  const [hours, setHours] = useState(inputs.hours.value);
  const [rate, setRate] = useState(inputs.rate.value);
  useEffect(() => setPeople(inputs.people.value), [inputs.people.value]);
  useEffect(() => setHours(inputs.hours.value), [inputs.hours.value]);
  useEffect(() => setRate(inputs.rate.value), [inputs.rate.value]);
  return { inputs, people, setPeople, hours, setHours, rate, setRate };
}

/* ------------------------------------------------------------------ */
/* sliders                                                             */
/* ------------------------------------------------------------------ */

function Sliders(p: ViewProps) {
  const { t } = p;
  const locale = useLocale();
  const cur = p.currency ?? 'EUR';
  const price = p.price ?? FALLBACK_PRICE;
  const s = useTimeInputs(p);
  const m = model(s.people, s.hours, s.rate, price, p.weeks ?? 46);
  const [barRef, inView] = useInView<HTMLDivElement>();
  const scale = Math.max(m.value, m.cost, 1);
  const moneyFmt = { style: 'currency', currency: cur, maximumFractionDigits: 0 } as const;
  return (
    <Section className={p.className}>
      <Head {...p} />
      <Reveal effect="scale" className="mt-12 sm:mt-14">
        <div className="grid grid-cols-[minmax(0,1fr)] overflow-hidden rounded-[1.5rem] border border-border bg-card shadow-[var(--highlight),var(--shadow-lg)] lg:grid-cols-[minmax(0,1fr)_minmax(0,1.05fr)]">
          <div className="grid content-start gap-7 p-6 sm:p-8 lg:p-10">
            <RangeField range={s.inputs.people} value={s.people} onChange={s.setPeople} kind="count" locale={locale} currency={cur} />
            <RangeField range={s.inputs.hours} value={s.hours} onChange={s.setHours} kind="hours" locale={locale} currency={cur} hourUnit={p.hourUnit} />
            <RangeField range={s.inputs.rate} value={s.rate} onChange={s.setRate} kind="money" locale={locale} currency={cur} />
            <p className="flex items-center gap-2 rounded-xl bg-surface px-4 py-3 text-[13.5px] text-muted-foreground">
              <Icon name="receipt" size={16} className="shrink-0" />
              <span>
                {t.cost.replace('{n}', price.name)} <strong className="font-semibold text-foreground">{money(m.monthly, locale, cur)}</strong> {t.perMonth}
              </span>
            </p>
          </div>
          <div className="relative flex flex-col border-t border-border bg-surface p-6 sm:p-8 lg:border-l lg:border-t-0 lg:p-10" aria-live="polite">
            <p className="text-[14px] font-medium text-muted-foreground">
              {t.value} <span className="text-subtle-foreground">{t.perYear}</span>
            </p>
            <p className="mt-2">
              <Live value={m.value} format={moneyFmt} className="text-[clamp(2.5rem,1.9rem+2.6vw,4rem)] font-semibold leading-none tracking-[-0.04em] text-foreground" />
            </p>
            <dl className="mt-8 grid grid-cols-3 gap-px overflow-hidden rounded-xl border border-border bg-border">
              {[
                { label: t.roi, value: <span className="tabular-nums">{t.roiValue.replace('{x}', num(m.roi, locale, 1))}</span> },
                { label: t.paybackShort, value: <span className="tabular-nums">{t.daysShort.replace('{n}', num(m.payback, locale))}</span> },
                { label: t.hoursBack, value: <span className="tabular-nums">{num(m.hoursYear, locale)}</span> },
              ].map((x, i) => (
                <div key={i} className="flex flex-col-reverse justify-end gap-1 bg-card px-3 py-3.5 sm:px-4">
                  <dt className="text-[12px] leading-snug text-muted-foreground">{x.label}</dt>
                  <dd className="text-[clamp(1rem,0.9rem+0.5vw,1.25rem)] font-semibold tracking-[-0.015em] text-foreground">{x.value}</dd>
                </div>
              ))}
            </dl>
            <div ref={barRef} className="mt-7 space-y-2.5" aria-hidden>
              {[
                { label: t.saved, v: m.value, cls: 'bg-primary' },
                { label: t.costYear, v: m.cost, cls: 'bg-[color-mix(in_oklab,var(--foreground)_30%,var(--card))]' },
              ].map((b) => (
                <div key={b.label} className="grid grid-cols-[8.5rem_minmax(0,1fr)] items-center gap-3 text-[12.5px] leading-tight text-muted-foreground">
                  <span>{b.label}</span>
                  <span className="h-2.5 overflow-hidden rounded-full bg-track">
                    <span className={cn('block h-full w-full origin-left rounded-full transition-transform duration-500 ease-[var(--ease-kit)] motion-reduce:transition-none', b.cls)} style={{ transform: `scaleX(${inView ? round(Math.max(0.01, b.v / scale), 4) : 0})` }} />
                  </span>
                </div>
              ))}
            </div>
            <Cta cta={p.cta} note={p.note} className="mt-8 lg:mt-auto lg:pt-8" />
          </div>
        </div>
      </Reveal>
    </Section>
  );
}

/* ------------------------------------------------------------------ */
/* payback                                                             */
/* ------------------------------------------------------------------ */

function Payback(p: ViewProps) {
  const { t } = p;
  const locale = useLocale();
  const cur = p.currency ?? 'EUR';
  const price = p.price ?? FALLBACK_PRICE;
  const s = useTimeInputs(p);
  const m = model(s.people, s.hours, s.rate, price, p.weeks ?? 46);
  const [ref, inView] = useInView<HTMLDivElement>('0px 0px -15% 0px');
  const W = 640;
  const H = 280;
  const pad = { l: 8, r: 8, t: 16, b: 28 };
  const months = Array.from({ length: 13 }, (_, i) => i);
  const saved = months.map((i) => (m.value / 12) * i);
  const paid = months.map((i) => (i === 0 ? 0 : m.monthly * i + (price.setup ?? 0)));
  const top = Math.max(saved[12], paid[12], 1) * 1.08;
  const x = (i: number) => round(pad.l + (i / 12) * (W - pad.l - pad.r));
  const y = (v: number) => round(H - pad.b - (v / top) * (H - pad.t - pad.b));
  const line = (vals: number[]) => vals.map((v, i) => `${i ? 'L' : 'M'}${x(i)} ${y(v)}`).join(' ');
  const area = `${line(saved)} L${x(12)} ${y(0)} L${x(0)} ${y(0)} Z`;
  // First month in which the savings pass what was paid
  const be = months.find((i) => i > 0 && saved[i] >= paid[i]);
  const id = useId().replace(/:/g, '');
  return (
    <Section className={p.className}>
      <div className="grid grid-cols-[minmax(0,1fr)] gap-12 lg:grid-cols-[minmax(0,22rem)_minmax(0,1fr)] lg:gap-16">
        <div>
          <Head {...p} />
          <div className="mt-8 grid gap-6">
            <RangeField range={s.inputs.people} value={s.people} onChange={s.setPeople} kind="count" locale={locale} currency={cur} />
            <RangeField range={s.inputs.hours} value={s.hours} onChange={s.setHours} kind="hours" locale={locale} currency={cur} hourUnit={p.hourUnit} />
          </div>
          <Cta cta={p.cta} note={p.note} className="mt-8 hidden max-w-[22rem] lg:block" />
        </div>
        <Reveal effect="scale" className="min-w-0">
          <div ref={ref} className="rounded-[1.5rem] border border-border bg-card p-5 shadow-[var(--highlight),var(--shadow-lg)] sm:p-7">
            <div className="flex flex-wrap items-start justify-between gap-x-6 gap-y-4">
              <div aria-live="polite">
                <p className="text-[13.5px] font-medium text-muted-foreground">{t.net}</p>
                <p className="mt-1.5">
                  <Live value={m.net} format={{ style: 'currency', currency: cur, maximumFractionDigits: 0 }} className="text-[clamp(2rem,1.6rem+1.8vw,3rem)] font-semibold leading-none tracking-[-0.035em] text-foreground" />
                  <span className="ml-2 text-[14px] text-muted-foreground">{t.perYear}</span>
                </p>
              </div>
              <p className={cn('inline-flex items-center gap-2 rounded-full px-3 py-1.5 text-[13px] font-medium', be ? 'bg-[color-mix(in_oklab,var(--success)_14%,var(--card))] text-success-foreground' : 'bg-muted text-muted-foreground')}>
                <Icon name={be ? 'flag' : 'clock'} size={14} />
                <span key={be ?? 0} className="kit-rise">
                  {be ? t.breakeven.replace('{n}', String(be)) : t.noBreakeven}
                </span>
              </p>
            </div>
            <figure className="mt-6">
              <div className="relative">
                <svg viewBox={`0 0 ${W} ${H}`} preserveAspectRatio="none" className="block h-[13.5rem] w-full overflow-visible sm:h-[17.5rem]" role="img" aria-label={t.chart}>
                  <defs>
                    <linearGradient id={`${id}-fill`} x1="0" y1="0" x2="0" y2="1">
                      <stop offset="0%" stopColor="var(--primary)" stopOpacity="0.22" />
                      <stop offset="100%" stopColor="var(--primary)" stopOpacity="0" />
                    </linearGradient>
                  </defs>
                  {[0.25, 0.5, 0.75, 1].map((f) => (
                    <line key={f} vectorEffect="non-scaling-stroke" x1={pad.l} x2={W - pad.r} y1={round(pad.t + (H - pad.t - pad.b) * (1 - f))} y2={round(pad.t + (H - pad.t - pad.b) * (1 - f))} className="stroke-border" strokeDasharray="2 4" />
                  ))}
                  <line vectorEffect="non-scaling-stroke" x1={pad.l} x2={W - pad.r} y1={y(0)} y2={y(0)} className="stroke-border-strong" />
                  <path d={area} fill={`url(#${id}-fill)`} className={cn('transition-opacity delay-300 duration-700', inView ? 'opacity-100' : 'opacity-0')} />
                  <path d={line(paid)} vectorEffect="non-scaling-stroke" fill="none" strokeWidth="2" strokeDasharray="5 5" className="stroke-[color-mix(in_oklab,var(--foreground)_45%,var(--card))]" />
                  <path d={line(saved)} vectorEffect="non-scaling-stroke" fill="none" strokeWidth="2.75" strokeLinecap="round" className="stroke-primary transition-[clip-path] duration-[1100ms] ease-[var(--ease-kit)] motion-reduce:transition-none" style={{ clipPath: inView ? 'inset(-8px -8px -8px -8px)' : 'inset(-8px 100% -8px -8px)' }} />
                </svg>
                {be !== undefined && (
                  <span aria-hidden className="absolute grid size-5 -translate-x-1/2 -translate-y-1/2 place-items-center transition-[left,top] duration-500 ease-[var(--ease-kit)] motion-reduce:transition-none" style={{ left: `${round((x(be) / W) * 100, 3)}%`, top: `${round((y(saved[be]) / H) * 100, 3)}%` }}>
                    <span className="absolute inset-0 rounded-full bg-primary opacity-25 motion-safe:animate-kit-pulse" />
                    <span className="relative size-2.5 rounded-full bg-primary ring-2 ring-card" />
                  </span>
                )}
                <div aria-hidden className="absolute inset-x-0 bottom-0 h-5">
                  {months
                    .filter((i) => i % 3 === 0)
                    .map((i) => (
                      <span key={i} className={cn('absolute bottom-0 text-[12px] tabular-nums text-subtle-foreground', i === 0 ? '' : i === 12 ? '-translate-x-full' : '-translate-x-1/2')} style={{ left: `${round((x(i) / W) * 100, 3)}%` }}>
                        {i}
                      </span>
                    ))}
                </div>
              </div>
              <figcaption className="mt-4 flex flex-wrap items-center gap-x-5 gap-y-2 text-[12.5px] text-muted-foreground">
                <span className="flex items-center gap-2">
                  <span className="h-0.5 w-5 rounded-full bg-primary" />
                  {t.saved}
                </span>
                <span className="flex items-center gap-2">
                  <span className="h-0 w-5 border-t-2 border-dashed border-[color-mix(in_oklab,var(--foreground)_45%,var(--card))]" />
                  {t.paid}
                </span>
                <span className="ml-auto">{t.months}</span>
              </figcaption>
            </figure>
          </div>
        </Reveal>
        <Cta cta={p.cta} note={p.note} className="-mt-4 sm:max-w-[22rem] lg:hidden" />
      </div>
    </Section>
  );
}

/* ------------------------------------------------------------------ */
/* scenarios                                                           */
/* ------------------------------------------------------------------ */

function Scenarios(p: ViewProps) {
  const { t } = p;
  const locale = useLocale();
  const cur = p.currency ?? 'EUR';
  const price = p.price ?? FALLBACK_PRICE;
  const s = useTimeInputs(p);
  const list = p.scenarios ?? [];
  const [pick, setPick] = useState(Math.min(1, Math.max(0, list.length - 1)));
  const sc = list[pick];
  const m = model(s.people, sc?.hours ?? s.hours, s.rate, price, p.weeks ?? 46);
  const id = useId();
  const moneyFmt = { style: 'currency', currency: cur, maximumFractionDigits: 0 } as const;
  return (
    <Section className={p.className}>
      <Head {...p} center />
      <Reveal effect="scale" className="mx-auto mt-12 max-w-[58rem] sm:mt-14">
        <div className="rounded-[1.5rem] border border-border bg-card p-5 shadow-[var(--highlight),var(--shadow-lg)] sm:p-8">
          <div className="grid grid-cols-[minmax(0,1fr)] gap-6 md:grid-cols-[minmax(0,1fr)_minmax(0,1fr)] md:items-end">
            <div>
              <p id={`${id}-sc`} className="mb-2 text-sm font-medium text-foreground">
                {t.scenario}
              </p>
              <div
                role="radiogroup"
                aria-labelledby={`${id}-sc`}
                onKeyDown={(e) => {
                  const d = e.key === 'ArrowRight' ? 1 : e.key === 'ArrowLeft' ? -1 : 0;
                  if (!d || !list.length) return;
                  e.preventDefault();
                  const next = (pick + d + list.length) % list.length;
                  setPick(next);
                  (e.currentTarget.querySelectorAll('[role="radio"]')[next] as HTMLElement | undefined)?.focus();
                }}
                className="relative grid h-[3.375rem] rounded-xl border border-border bg-surface p-1 sm:h-12"
                style={{ gridTemplateColumns: `repeat(${Math.max(1, list.length)}, minmax(0, 1fr))` }}
              >
                <span aria-hidden className="absolute inset-y-1 left-1 rounded-lg bg-card shadow-[var(--highlight),var(--shadow-sm)] transition-transform duration-500 ease-[var(--ease-kit)] motion-reduce:transition-none" style={{ width: `calc((100% - 8px) / ${Math.max(1, list.length)})`, transform: `translateX(${pick * 100}%)` }} />
                {list.map((x, i) => (
                  <button key={i} type="button" role="radio" aria-checked={pick === i} tabIndex={pick === i ? 0 : -1} onClick={() => setPick(i)} className={cn('relative z-10 truncate rounded-lg px-2 text-[14px] font-medium transition-colors duration-300', pick === i ? 'text-foreground' : 'text-muted-foreground hover:text-foreground')}>
                    {x.label}
                  </button>
                ))}
              </div>
            </div>
            <RangeField range={s.inputs.people} value={s.people} onChange={s.setPeople} kind="count" locale={locale} currency={cur} />
          </div>
          <Stagger step={80} className="mt-8 grid grid-cols-2 gap-px overflow-hidden rounded-xl border border-border bg-border md:grid-cols-4" aria-live="polite">
            {[
              { label: `${t.value} ${t.perYear}`, node: <Live value={m.value} format={moneyFmt} /> },
              { label: `${t.net} ${t.perYear}`, node: <Live value={m.net} format={moneyFmt} /> },
              { label: `${t.roi}, ${t.roiNote}`, node: <span className="tabular-nums">{t.roiValue.replace('{x}', num(m.roi, locale, 1))}</span> },
              { label: t.paybackShort, node: <span className="tabular-nums">{t.daysShort.replace('{n}', num(m.payback, locale))}</span> },
            ].map((x, i) => (
              <div key={i} className="bg-card">
                <div className="flex h-full flex-col-reverse justify-end gap-1.5 p-4 sm:p-5">
                  <p className="text-pretty text-[12.5px] leading-snug text-muted-foreground">{x.label}</p>
                  <p className={cn('font-semibold tracking-[-0.025em] text-foreground', i < 2 ? 'text-[clamp(1.375rem,1.1rem+1vw,1.875rem)]' : 'text-[clamp(1.25rem,1.05rem+0.8vw,1.625rem)]')}>{x.node}</p>
                </div>
              </div>
            ))}
          </Stagger>
          <div className="mt-6 grid grid-cols-[minmax(0,1fr)] gap-6 md:grid-cols-[minmax(0,1fr)_auto] md:items-end">
            <div>
              {sc?.note && (
                <p key={pick} className="kit-rise mb-4 flex gap-2 text-pretty text-[14px] leading-relaxed text-foreground">
                  <Icon name="info" size={16} className="mt-0.5 shrink-0 text-primary" />
                  {sc.note}
                </p>
              )}
              {p.assumptions && p.assumptions.length > 0 && (
                <div>
                  <p className="text-[12.5px] font-medium text-muted-foreground">{t.assumptions}</p>
                  <ul className="mt-2 flex flex-wrap gap-2">
                    {p.assumptions.map((a, i) => (
                      <li key={i} className="rounded-full border border-border bg-surface px-3 py-1 text-[12.5px] text-muted-foreground">
                        {a}
                      </li>
                    ))}
                  </ul>
                </div>
              )}
            </div>
            {p.cta && (
              <Magnetic className="max-md:flex max-md:w-full">
                <Button href={p.cta.href} size="lg" icon="arrow-right" className="max-md:w-full">
                  {p.cta.label}
                </Button>
              </Magnetic>
            )}
          </div>
          {p.note && <p className="mt-5 border-t border-border pt-4 text-[12.5px] text-muted-foreground">{p.note}</p>}
        </div>
      </Reveal>
    </Section>
  );
}

/* ------------------------------------------------------------------ */
/* steps                                                               */
/* ------------------------------------------------------------------ */

function Steps(p: ViewProps) {
  const { t } = p;
  const locale = useLocale();
  const cur = p.currency ?? 'EUR';
  const price = p.price ?? FALLBACK_PRICE;
  const s = useTimeInputs(p);
  const [step, setStep] = useState(0);
  const [moved, setMoved] = useState(false);
  const m = model(s.people, s.hours, s.rate, price, p.weeks ?? 46);
  const fields = [
    { range: s.inputs.people, value: s.people, set: s.setPeople, kind: 'count' as const },
    { range: s.inputs.hours, value: s.hours, set: s.setHours, kind: 'hours' as const },
    { range: s.inputs.rate, value: s.rate, set: s.setRate, kind: 'money' as const },
  ];
  const total = fields.length;
  const done = step >= total;
  const f = fields[Math.min(step, total - 1)];
  const fmt = (v: number, kind: (typeof fields)[number]['kind']) => (kind === 'money' ? money(v, locale, cur) : kind === 'hours' ? `${num(v, locale, 1)}${p.hourUnit ? ` ${p.hourUnit}` : ''}` : num(v, locale));
  const go = (n: number) => {
    setMoved(true);
    setStep(n);
  };
  const nudge = (d: number) => {
    const st = f.range.step ?? 1;
    f.set(Math.min(f.range.max, Math.max(f.range.min, round(f.value + d * st, 2))));
  };
  const progress = done ? 1 : (step + 1) / (total + 1);
  const headingRef = useRef<HTMLHeadingElement>(null);
  useEffect(() => {
    if (moved) headingRef.current?.focus();
  }, [step, moved]);
  return (
    <Section className={p.className}>
      <Head {...p} center />
      <Reveal effect="scale" className="mx-auto mt-12 max-w-[40rem] sm:mt-14">
        <div className="overflow-hidden rounded-[1.5rem] border border-border bg-card shadow-[var(--highlight),var(--shadow-lg)]">
          <div className="h-1 bg-track" aria-hidden>
            <div className="h-full origin-left bg-primary transition-transform duration-700 ease-[var(--ease-kit)] motion-reduce:transition-none" style={{ transform: `scaleX(${round(Math.max(0.04, progress), 3)})` }} />
          </div>
          <div className="p-6 sm:p-9">
            {!done ? (
              <div key={step} className={cn(moved && 'kit-rise')}>
                <p className="text-[13px] font-medium text-muted-foreground">{t.step.replace('{n}', String(step + 1)).replace('{t}', String(total))}</p>
                <h3 ref={headingRef} tabIndex={-1} className="mt-2 text-pretty text-[clamp(1.25rem,1.1rem+0.6vw,1.5rem)] font-semibold leading-snug tracking-[-0.015em] text-foreground focus:outline-none">
                  {p.questions?.[step] ?? f.range.label}
                </h3>
                <div className="mt-7 flex items-center justify-between gap-3">
                  <button type="button" onClick={() => nudge(-1)} disabled={f.value <= f.range.min} aria-label={`${t.decrease}, ${f.range.label}`} className="grid size-12 shrink-0 place-items-center rounded-full border border-border bg-background text-foreground transition-[background-color,transform] hover:bg-accent active:scale-95 disabled:opacity-40">
                    <Icon name="minus" size={18} />
                  </button>
                  <output className="min-w-0 text-center text-[clamp(2.25rem,1.7rem+2.4vw,3.5rem)] font-semibold leading-none tracking-[-0.035em] tabular-nums text-foreground" aria-live="polite">
                    {fmt(f.value, f.kind)}
                  </output>
                  <button type="button" onClick={() => nudge(1)} disabled={f.value >= f.range.max} aria-label={`${t.increase}, ${f.range.label}`} className="grid size-12 shrink-0 place-items-center rounded-full border border-border bg-background text-foreground transition-[background-color,transform] hover:bg-accent active:scale-95 disabled:opacity-40">
                    <Icon name="plus" size={18} />
                  </button>
                </div>
                <div className="mt-6 [&_label]:sr-only [&_output]:sr-only">
                  <RangeField range={{ ...f.range, label: f.range.label }} value={f.value} onChange={f.set} kind={f.kind} locale={locale} currency={cur} hourUnit={p.hourUnit} />
                </div>
                <div className="mt-8 flex items-center justify-between gap-3 border-t border-border pt-6">
                  <Button variant="ghost" iconLeft="arrow-left" onClick={() => go(step - 1)} disabled={step === 0}>
                    {t.back}
                  </Button>
                  <Button icon="arrow-right" onClick={() => go(step + 1)}>
                    {step === total - 1 ? t.see : t.next}
                  </Button>
                </div>
              </div>
            ) : (
              <div key="result" className="kit-rise" aria-live="polite">
                <p className="text-[13px] font-medium text-muted-foreground">{t.result}</p>
                <h3 ref={headingRef} tabIndex={-1} className="mt-3 focus:outline-none">
                  <span className="block text-[14px] font-medium text-muted-foreground">
                    {t.net} {t.perYear}
                  </span>
                  <NumberTicker value={Math.round(m.net)} trigger="load" duration={1300} format={{ style: 'currency', currency: cur, maximumFractionDigits: 0 }} className="mt-1 text-[clamp(2.5rem,1.9rem+2.6vw,3.75rem)] font-semibold leading-none tracking-[-0.04em] text-foreground" />
                </h3>
                <p className="mt-6 text-[12.5px] font-medium text-muted-foreground">{t.breakdown}</p>
                <dl className="mt-2 divide-y divide-border rounded-xl border border-border">
                  {[
                    [`${num(s.people, locale)} × ${num(s.hours, locale, 1)}${p.hourUnit ? ` ${p.hourUnit}` : ''} × ${num(p.weeks ?? 46, locale)} × ${money(s.rate, locale, cur)}`, money(m.value, locale, cur)],
                    [t.costYear, `− ${money(m.cost, locale, cur)}`],
                    [t.payback, t.days.replace('{n}', num(m.payback, locale))],
                  ].map(([a, b], i) => (
                    <div key={i} className="flex items-baseline justify-between gap-4 px-4 py-3 text-[14px]">
                      <dt className="min-w-0 text-pretty text-muted-foreground">{a}</dt>
                      <dd className="shrink-0 font-semibold tabular-nums text-foreground">{b}</dd>
                    </div>
                  ))}
                </dl>
                <div className="mt-8 flex flex-col-reverse gap-3 sm:flex-row sm:items-center sm:justify-between">
                  <Button variant="ghost" iconLeft="rotate-ccw" onClick={() => go(0)}>
                    {t.restart}
                  </Button>
                  {p.cta && (
                    <Magnetic className="max-sm:flex max-sm:w-full">
                      <Button href={p.cta.href} icon="arrow-right" className="max-sm:w-full">
                        {p.cta.label}
                      </Button>
                    </Magnetic>
                  )}
                </div>
              </div>
            )}
          </div>
        </div>
        {p.note && <p className="mt-4 text-center text-[12.5px] text-muted-foreground">{p.note}</p>}
      </Reveal>
    </Section>
  );
}

/* ------------------------------------------------------------------ */
/* revenue                                                             */
/* ------------------------------------------------------------------ */

function Revenue(p: ViewProps) {
  const { t } = p;
  const locale = useLocale();
  const cur = p.currency ?? 'EUR';
  const r = p.revenue ?? { visitors: FALLBACK_RANGE, conversion: FALLBACK_RANGE, order: FALLBACK_RANGE, uplift: FALLBACK_RANGE };
  const [visitors, setVisitors] = useState(r.visitors.value);
  const [conv, setConv] = useState(r.conversion.value);
  const [order, setOrder] = useState(r.order.value);
  const [uplift, setUplift] = useState(r.uplift.value);
  useEffect(() => setVisitors(r.visitors.value), [r.visitors.value]);
  useEffect(() => setConv(r.conversion.value), [r.conversion.value]);
  useEffect(() => setOrder(r.order.value), [r.order.value]);
  useEffect(() => setUplift(r.uplift.value), [r.uplift.value]);
  const ordersNow = (visitors * conv) / 100;
  const ordersNew = ordersNow * (1 + uplift / 100);
  const extraMonth = (ordersNew - ordersNow) * order;
  const extraYear = extraMonth * 12;
  const [ref, inView] = useInView<HTMLDivElement>();
  const scale = Math.max(ordersNew, 1);
  const name = p.price?.name ?? '';
  return (
    <Section className={p.className}>
      <Head {...p} />
      <div className="mt-12 grid grid-cols-[minmax(0,1fr)] gap-4 sm:mt-14 lg:grid-cols-[minmax(0,1fr)_minmax(0,1fr)] lg:gap-6">
        <Reveal className="grid content-start gap-6 rounded-[1.5rem] border border-border bg-card p-6 shadow-[var(--highlight),var(--shadow-md)] sm:p-8">
          <RangeField range={r.visitors} value={visitors} onChange={setVisitors} kind="count" locale={locale} currency={cur} />
          <RangeField range={r.conversion} value={conv} onChange={setConv} kind="percent" locale={locale} currency={cur} />
          <RangeField range={r.order} value={order} onChange={setOrder} kind="money" locale={locale} currency={cur} />
          <div className="rounded-xl border border-[color-mix(in_oklab,var(--primary)_30%,var(--border))] bg-[color-mix(in_oklab,var(--primary)_6%,var(--card))] px-4 pb-2 pt-4">
            <RangeField range={r.uplift} value={uplift} onChange={setUplift} kind="percent" locale={locale} currency={cur} />
          </div>
        </Reveal>
        <Reveal effect="scale" delay={100} className="flex flex-col rounded-[1.5rem] border border-border bg-surface p-6 shadow-[var(--highlight),var(--shadow-lg)] sm:p-8">
          <div aria-live="polite">
            <p className="text-[14px] font-medium text-muted-foreground">
              {t.extra} <span className="text-subtle-foreground">{t.perYear}</span>
            </p>
            <p className="mt-2">
              <Live value={extraYear} format={{ style: 'currency', currency: cur, maximumFractionDigits: 0 }} className="text-[clamp(2.5rem,1.9rem+2.6vw,4rem)] font-semibold leading-none tracking-[-0.04em] text-foreground" />
            </p>
            <p className="mt-3 text-[14px] text-muted-foreground">
              <span className="font-semibold tabular-nums text-success-foreground">+{num(ordersNew - ordersNow, locale)}</span> {t.extraOrders}, {money(extraMonth, locale, cur)} {t.perMonth}
            </p>
          </div>
          <div ref={ref} className="mt-8 grid gap-4" aria-hidden>
            {[
              { label: t.today, v: ordersNow, cls: 'bg-[color-mix(in_oklab,var(--foreground)_30%,var(--card))]' },
              { label: t.after.replace('{n}', name), v: ordersNew, cls: 'bg-primary' },
            ].map((b, i) => (
              <div key={i}>
                <div className="mb-1.5 flex items-baseline justify-between gap-3 text-[13px]">
                  <span className="truncate text-muted-foreground">{b.label}</span>
                  <span className="shrink-0 font-semibold tabular-nums text-foreground">
                    {num(b.v, locale)} <span className="font-normal text-muted-foreground">{t.ordersMonth}</span>
                  </span>
                </div>
                <div className="h-3 overflow-hidden rounded-full bg-track">
                  <div className={cn('h-full w-full origin-left rounded-full transition-transform duration-700 ease-[var(--ease-kit)] motion-reduce:transition-none', b.cls)} style={{ transform: `scaleX(${inView ? round(Math.max(0.01, b.v / scale), 4) : 0})`, transitionDelay: inView ? `${i * 120}ms` : '0ms' }} />
                </div>
              </div>
            ))}
          </div>
          <Cta cta={p.cta} note={p.note} className="mt-8 lg:mt-auto lg:pt-8" />
        </Reveal>
      </div>
    </Section>
  );
}

/* ------------------------------------------------------------------ */
/* RoiCalculator                                                       */
/* ------------------------------------------------------------------ */

const VARIANTS: Record<RoiCalculatorVariant, (p: ViewProps) => React.ReactNode> = {
  sliders: Sliders,
  payback: Payback,
  scenarios: Scenarios,
  steps: Steps,
  revenue: Revenue,
};

/**
 * What a product earns back, calculated by the visitor.
 *   <RoiCalculator variant="sliders" title="…" inputs={{ people, hours, rate }} price={{ amount: 12, per: 'seat', name: 'Northwind' }} cta={{ label, href }} />
 */
export function RoiCalculator({ variant = 'sliders', labels, ...props }: RoiCalculatorProps) {
  const t = useTexts(TEXTS, labels);
  const View = VARIANTS[variant] ?? Sliders;
  return <View {...props} t={t} />;
}