Kennzahlen-Banner

'use client';

import { useEffect, useState } from 'react';
import { cn, prefersReducedMotion, round, useInView, useLocale, useTexts } from '@/lib/kit';
import { NumberTicker } from '@/components/ui/number-ticker';
import { Eyebrow } from '@/components/ui/section';

/*
 * A band of figures between two sections, set large and counted up in the
 * format of the language. Four layouts:
 *
 *   band       a full-width band in the accent, dark or surface tone, figures between hairlines
 *   live       figures that keep rising while the page is open, each with a small trend line
 *   progress   figures against their goals, bars that fill when the band comes into view
 *   statement  one sentence with the figures inside it, each counting where it stands
 */

export type MetricsBandVariant = 'band' | 'live' | 'progress' | 'statement';

export interface Metric {
  value: number;
  prefix?: string;
  suffix?: string;
  /** Fixed decimals, e.g. 1 for 4.8 */
  decimals?: number;
  label: string;
  /** A short second line */
  detail?: string;
  /** progress: the goal the value is measured against */
  goal?: number;
  /** live: recent values for the trend line */
  trend?: number[];
  /** live: how much the value grows per minute while the page is open */
  perMinute?: number;
}

export interface MetricsBandProps {
  variant?: MetricsBandVariant;
  eyebrow?: React.ReactNode;
  title?: React.ReactNode;
  description?: React.ReactNode;
  metrics: Metric[];
  /** band: the tone of the band */
  tone?: 'accent' | 'dark' | 'surface';
  /** statement: the sentence, {0}, {1} … stand for the metrics in order */
  sentence?: string;
  /** A source line under the band */
  note?: string;
  labels?: Partial<Texts>;
  className?: string;
}

const TEXTS = {
  en: { live: 'Live', updated: 'Updated every few seconds', of: 'of {g}', reached: 'Goal reached' },
  de: { live: 'Live', updated: 'Alle paar Sekunden aktualisiert', of: 'von {g}', reached: 'Ziel erreicht' },
};

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

const fill = (s: string, v: Record<string, string | number>) => s.replace(/\{(\w+)\}/g, (_, k) => String(v[k] ?? ''));
const delay = (ms: number) => ({ '--kit-delay': `${ms}ms` }) as React.CSSProperties;

function useFormat() {
  const locale = useLocale();
  return (n: number, d = 0) => new Intl.NumberFormat(locale === 'de' ? 'de-DE' : 'en-US', { minimumFractionDigits: d, maximumFractionDigits: d }).format(n);
}

function Figure({ m, delay: ms = 0, className }: { m: Metric; delay?: number; className?: string }) {
  const d = m.decimals ?? 0;
  return (
    <span className={cn('tabular-nums', className)}>
      {m.prefix}
      <NumberTicker value={m.value} delay={ms} format={{ minimumFractionDigits: d, maximumFractionDigits: d }} />
      {m.suffix}
    </span>
  );
}

function Head({ eyebrow, title, description, center, className }: Pick<MetricsBandProps, 'eyebrow' | 'title' | 'description'> & { center?: boolean; className?: string }) {
  if (!title && !eyebrow) return null;
  return (
    <div className={cn('max-w-[46rem]', center && 'mx-auto max-w-[42rem] text-center', className)}>
      {eyebrow && <Eyebrow>{eyebrow}</Eyebrow>}
      {title && <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={delay(80)}>
          {description}
        </p>
      )}
    </div>
  );
}

/* ------------------------------------------------------------------ */
/* band                                                                */
/* ------------------------------------------------------------------ */

function Band(p: ViewProps) {
  const tone = p.tone ?? 'accent';
  const on = tone === 'accent';
  const n = p.metrics.length;
  return (
    <section className={cn('relative overflow-hidden py-14 sm:py-16', tone === 'accent' && 'bg-primary text-primary-foreground', tone === 'dark' && 'dark bg-bezel text-foreground', tone === 'surface' && 'bg-surface text-foreground', p.className)}>
      {/* a slow light across the band */}
      <div aria-hidden className={cn('pointer-events-none absolute inset-0 opacity-60', on ? 'bg-[radial-gradient(40%_120%_at_15%_0%,color-mix(in_oklch,var(--primary-foreground)_16%,transparent),transparent_70%)]' : 'bg-[radial-gradient(40%_120%_at_15%_0%,var(--glow),transparent_70%)]')} />
      <div className="kit-container relative">
        {(p.title || p.eyebrow) && (
          <div className="mb-10 max-w-[40rem]">
            {p.eyebrow && <p className={cn('mb-3 text-sm font-medium', on ? 'text-[color-mix(in_oklch,var(--primary-foreground)_75%,transparent)]' : 'text-muted-foreground')}>{p.eyebrow}</p>}
            {p.title && <h2 className="kit-rise text-balance text-[clamp(1.5rem,1.2rem+1vw,2rem)] font-semibold leading-tight tracking-[-0.02em]">{p.title}</h2>}
          </div>
        )}
        <dl className={cn('grid grid-cols-2 gap-y-10', n >= 4 ? 'lg:grid-cols-4' : n === 3 ? 'lg:grid-cols-3' : '')}>
          {p.metrics.map((m, i) => (
            <div
              key={i}
              className={cn(
                'kit-rise flex min-w-0 flex-col pr-4 sm:pr-6',
                on ? 'border-[color-mix(in_oklch,var(--primary-foreground)_22%,transparent)]' : 'border-border',
                i % 2 === 1 && 'border-l pl-4 sm:pl-6',
                n >= 3 && i > 0 && 'lg:border-l lg:pl-8',
              )}
              style={delay(i * 90)}
            >
              <dt className={cn('order-2 mt-2 text-pretty text-[14px] font-medium', on ? 'text-[color-mix(in_oklch,var(--primary-foreground)_85%,transparent)]' : 'text-foreground')}>{m.label}</dt>
              <dd className="order-1 text-[clamp(2.25rem,1.7rem+2.2vw,3.5rem)] font-semibold leading-none tracking-[-0.045em]">
                <Figure m={m} delay={i * 120} />
              </dd>
              {m.detail && <dd className={cn('order-3 mt-1 text-pretty text-[13px]', on ? 'text-[color-mix(in_oklch,var(--primary-foreground)_65%,transparent)]' : 'text-muted-foreground')}>{m.detail}</dd>}
            </div>
          ))}
        </dl>
        {p.note && <p className={cn('mt-10 text-[12.5px]', on ? 'text-[color-mix(in_oklch,var(--primary-foreground)_65%,transparent)]' : 'text-subtle-foreground')}>{p.note}</p>}
      </div>
    </section>
  );
}

/* ------------------------------------------------------------------ */
/* live                                                                */
/* ------------------------------------------------------------------ */

function Spark({ values, className }: { values: number[]; className?: string }) {
  if (values.length < 2) return null;
  const min = Math.min(...values);
  const max = Math.max(...values);
  const W = 120;
  const H = 32;
  const pts = values.map((v, i) => [round((i / (values.length - 1)) * W), round(H - 3 - ((v - min) / Math.max(1e-9, max - min)) * (H - 6))]);
  const d = pts.map(([x, y], i) => `${i ? 'L' : 'M'}${x} ${y}`).join(' ');
  return (
    <svg viewBox={`0 0 ${W} ${H}`} aria-hidden className={cn('h-8 w-full overflow-visible', className)} preserveAspectRatio="none">
      <path d={`${d} L${W} ${H} L0 ${H} Z`} fill="color-mix(in oklab, var(--primary) 14%, transparent)" />
      <path d={d} fill="none" stroke="var(--primary)" strokeWidth="1.8" strokeLinejoin="round" strokeLinecap="round" vectorEffect="non-scaling-stroke" />
      <circle cx={pts[pts.length - 1][0]} cy={pts[pts.length - 1][1]} r="3" fill="var(--primary)" className="animate-kit-pulse motion-reduce:animate-none" />
    </svg>
  );
}

function LiveValue({ m, running }: { m: Metric; running: boolean }) {
  const format = useFormat();
  const [extra, setExtra] = useState(0);
  useEffect(() => {
    if (!running || !m.perMinute || prefersReducedMotion()) return;
    const step = m.perMinute / 20;
    const id = window.setInterval(() => setExtra((x) => x + step * (0.6 + Math.random() * 0.8)), 3000);
    return () => window.clearInterval(id);
  }, [running, m.perMinute]);
  const d = m.decimals ?? 0;
  if (!extra) return <Figure m={m} />;
  return (
    <span className="tabular-nums">
      {m.prefix}
      <span key={Math.floor(extra * 10 ** d)} className="inline-block animate-[mb-tick_.5s_var(--ease-kit)] motion-reduce:animate-none">
        {format(m.value + extra, d)}
      </span>
      {m.suffix}
    </span>
  );
}

function Live(p: ViewProps) {
  const { t } = p;
  const [ref, inView] = useInView<HTMLDivElement>();
  return (
    <section className={cn('dark relative overflow-hidden bg-bezel py-16 text-foreground sm:py-20', p.className)}>
      <div aria-hidden className="kit-grid pointer-events-none absolute inset-0 opacity-40 [mask-image:radial-gradient(70%_80%_at_50%_50%,black,transparent)]" />
      <div className="kit-container relative">
        <div className="flex flex-col gap-4 sm:flex-row sm:items-end sm:justify-between">
          <Head {...p} />
          <p className="flex shrink-0 items-center gap-2 text-[13px] text-muted-foreground">
            <span className="relative flex size-2">
              <span className="absolute inset-0 animate-ping rounded-full bg-success opacity-70 motion-reduce:animate-none" />
              <span className="relative size-2 rounded-full bg-success" />
            </span>
            <span className="font-semibold text-foreground">{t.live}</span> · {t.updated}
          </p>
        </div>
        <div ref={ref} className={cn('grid grid-cols-2 gap-px overflow-hidden rounded-2xl border border-border bg-border', p.metrics.length >= 4 ? 'lg:grid-cols-4' : 'lg:grid-cols-3', (p.title || p.eyebrow) && 'mt-10')}>
          {p.metrics.map((m, i) => (
            <div key={i} className="min-w-0 bg-card p-4 sm:p-6">
              <div className="kit-rise" style={delay(i * 80)}>
                <p className="min-h-[2lh] text-[13px] font-medium leading-snug text-muted-foreground sm:min-h-0">{m.label}</p>
                <p aria-live="off" className="mt-3 text-[clamp(2rem,1.6rem+1.4vw,2.75rem)] font-semibold leading-none tracking-[-0.04em] text-foreground">
                  <LiveValue m={m} running={inView} />
                </p>
                {m.trend && <Spark values={m.trend} className="mt-5" />}
                {m.detail && <p className="mt-3 text-[12.5px] text-subtle-foreground">{m.detail}</p>}
              </div>
            </div>
          ))}
        </div>
        {p.note && <p className="mt-6 text-[12.5px] text-subtle-foreground">{p.note}</p>}
      </div>
      <style>{'@keyframes mb-tick{from{opacity:.35;transform:translateY(-30%)}}'}</style>
    </section>
  );
}

/* ------------------------------------------------------------------ */
/* progress                                                            */
/* ------------------------------------------------------------------ */

function Progress(p: ViewProps) {
  const { t } = p;
  const format = useFormat();
  const [ref, inView] = useInView<HTMLDivElement>();
  return (
    <section className={cn('py-20 sm:py-24', p.className)}>
      <div className="kit-container">
        <div className="grid grid-cols-[minmax(0,1fr)] gap-12 lg:grid-cols-[minmax(0,22rem)_minmax(0,1fr)] lg:gap-20">
          <Head {...p} />
          <div ref={ref} className={cn('grid gap-8', !p.title && 'lg:col-span-2')}>
            {p.metrics.map((m, i) => {
              const share = m.goal ? Math.min(1, m.value / m.goal) : 1;
              const done = m.goal !== undefined && m.value >= m.goal;
              return (
                <div key={i} className="kit-rise" style={delay(i * 90)}>
                  <div className="flex flex-wrap items-baseline justify-between gap-x-4 gap-y-1">
                    <p className="text-[15px] font-medium text-foreground">{m.label}</p>
                    <p className="flex items-baseline gap-2">
                      <span className="text-[28px] font-semibold leading-none tracking-[-0.03em] text-foreground">
                        <Figure m={m} delay={i * 120} />
                      </span>
                      {m.goal !== undefined && (
                        <span className="text-[13px] tabular-nums text-muted-foreground">
                          {fill(t.of, { g: `${m.prefix ?? ''}${format(m.goal, m.decimals ?? 0)}${m.suffix ?? ''}` })}
                        </span>
                      )}
                    </p>
                  </div>
                  <div className="relative mt-3 h-2.5 overflow-hidden rounded-full bg-track">
                    <span
                      className={cn('absolute inset-y-0 left-0 rounded-full transition-[width] duration-[1400ms] ease-[var(--ease-kit)] motion-reduce:transition-none', done ? 'bg-success' : 'bg-primary')}
                      style={{ width: `${inView ? round(share * 100, 2) : 0}%`, transitionDelay: `${i * 120}ms` }}
                    />
                  </div>
                  {(m.detail || done) && (
                    <p className={cn('mt-2 flex items-center gap-1.5 text-[13px]', done ? 'text-success-foreground' : 'text-muted-foreground')}>
                      {done && <span aria-hidden className="size-1.5 rounded-full bg-success" />}
                      {done ? t.reached : m.detail}
                      {done && m.detail && <span className="text-muted-foreground"> · {m.detail}</span>}
                    </p>
                  )}
                </div>
              );
            })}
            {p.note && <p className="text-[12.5px] text-subtle-foreground">{p.note}</p>}
          </div>
        </div>
      </div>
    </section>
  );
}

/* ------------------------------------------------------------------ */
/* statement                                                           */
/* ------------------------------------------------------------------ */

function Statement(p: ViewProps) {
  const [ref, inView] = useInView<HTMLParagraphElement>('0px 0px -20% 0px');
  const parts = (p.sentence ?? '').split(/\{(\d+)\}/g);
  return (
    <section className={cn('kit-glow relative overflow-hidden py-24 sm:py-32', p.className)}>
      <div className="kit-container">
        {p.eyebrow && <Eyebrow>{p.eyebrow}</Eyebrow>}
        <p ref={ref} className="max-w-[60rem] text-balance text-[clamp(1.75rem,1.2rem+2.4vw,3.25rem)] font-semibold leading-[1.18] tracking-[-0.03em] text-muted-foreground">
          {parts.map((s, i) => {
            if (i % 2 === 0) return <span key={i}>{s}</span>;
            const m = p.metrics[Number(s)];
            if (!m) return null;
            return (
              <span key={i} className="relative inline-block whitespace-nowrap text-foreground">
                <Figure m={m} delay={Number(s) * 200} />
                {/* a stroke under each figure that draws itself */}
                <span aria-hidden className="absolute inset-x-0 -bottom-0.5 h-[0.08em] origin-left rounded-full bg-primary transition-transform duration-1000 ease-[var(--ease-kit)] motion-reduce:transition-none" style={{ transform: `scaleX(${inView ? 1 : 0})`, transitionDelay: `${300 + Number(s) * 200}ms` }} />
              </span>
            );
          })}
        </p>
        <dl className="mt-14 grid grid-cols-2 gap-x-6 gap-y-6 border-t border-border pt-8 sm:grid-cols-[repeat(auto-fit,minmax(10rem,1fr))]">
          {p.metrics.map((m, i) => (
            <div key={i} className="kit-rise" style={delay(i * 80)}>
              <dt className="text-[13px] text-muted-foreground">{m.label}</dt>
              {m.detail && <dd className="mt-1 text-pretty text-[14px] font-medium text-foreground">{m.detail}</dd>}
            </div>
          ))}
        </dl>
        {p.note && <p className="mt-8 text-[12.5px] text-subtle-foreground">{p.note}</p>}
      </div>
    </section>
  );
}

/* ------------------------------------------------------------------ */

const VIEWS: Record<MetricsBandVariant, (p: ViewProps) => React.ReactNode> = {
  band: Band,
  live: Live,
  progress: Progress,
  statement: Statement,
};

export function MetricsBand({ variant = 'band', labels, ...rest }: MetricsBandProps) {
  const t = useTexts(TEXTS, labels);
  const View = VIEWS[variant] ?? Band;
  return <View {...rest} variant={variant} t={t} />;
}