Radar chart

'use client';

import { useState } from 'react';
import { cn, round, useTexts } from '@/lib/kit';
import { ChartRoot, ChartSurface, ChartTable, ChartTooltip, Swatch, fill, niceTicks, numberFormatter, polar, textWidth, useEntrance, useIntlLocale, useShown, useWidth, type ChartA11y, type TooltipRow } from '@/components/ui/chart';
import { ChartFigure, HALO, PickLegend, type ChartFigureProps } from '@/components/ui/chart-figure';

/*
 * Several measures of one thing on spokes around a center.
 *   profile    one shape, every spoke readable
 *   compare    two shapes, the legend brings one forward
 *   with-list  the shape and a list of the spokes with bars, both linked
 *   multiples  one small shape per item on the same scale, a key in front
 *   target     the shape against a target outline, misses marked
 *
 * All spokes share one scale from zero, so shapes stay comparable. The
 * pointer picks the nearest spoke by angle, arrow keys step around.
 * Readable without the shape: every value is in the table and the list.
 */

export type RadarVariant = 'profile' | 'compare' | 'with-list' | 'multiples' | 'target';

export interface RadarSeries {
  label: string;
  /** One value per axis, in axis order */
  values: number[];
}

export interface RadarChartProps extends Omit<ChartA11y, 'label'>, ChartFigureProps {
  /** Accessible name of the chart. Default: the title. */
  label?: string;
  variant?: RadarVariant;
  /** Names of the spokes, clockwise from twelve o'clock. Five to eight work best. */
  axes: string[];
  /** profile, with-list, target: the first series. compare: two. multiples: one per small chart. */
  series: RadarSeries[];
  /** target: one target value per axis */
  target?: number[];
  /** Top of the scale. Default: a round value above the largest value. */
  max?: number;
  /** Value format, e.g. { maximumFractionDigits: 1 } */
  format?: Intl.NumberFormatOptions;
  /** Name of the target outline in legend and tooltip */
  targetLabel?: string;
  className?: string;
}

const TEXTS = {
  en: { avg: 'avg. {v}', target: 'Target', key: 'How to read', of: 'of {max}', axis: 'Axis', gap: '{n} of {total} below target' },
  de: { avg: 'Ø {v}', target: 'Ziel', key: 'So lesen', of: 'von {max}', axis: 'Achse', gap: '{n} von {total} unter Ziel' },
};

const shapePath = (cx: number, cy: number, r: number, values: number[], max: number) =>
  values.map((v, i) => polar(cx, cy, (Math.max(0, Math.min(v, max)) / max) * r, (360 * i) / values.length)).map(([x, y], i) => `${i ? 'L' : 'M'}${x} ${y}`).join('') + 'Z';

const ringPath = (cx: number, cy: number, r: number, n: number) =>
  Array.from({ length: n }, (_, i) => polar(cx, cy, r, (360 * i) / n)).map(([x, y], i) => `${i ? 'L' : 'M'}${x} ${y}`).join('') + 'Z';

const SERIES_COLOR = ['var(--kitch-1)', 'var(--kitch-2)'];

/** Breaks a spoke label into lines no wider than maxW */
function wrap(text: string, maxW: number, size: number) {
  // Breaks at spaces and after hyphens (Preis-Leistung)
  const words = text.split(/ |(?<=-)/);
  const lines: string[] = [];
  let cur = '';
  for (const w of words) {
    const next = cur ? (cur.endsWith('-') ? cur + w : `${cur} ${w}`) : w;
    if (cur && textWidth(next, size) > maxW) {
      lines.push(cur);
      cur = w;
    } else cur = next;
  }
  if (cur) lines.push(cur);
  return lines;
}

interface RadarGeometry {
  width: number;
  height: number;
  cx: number;
  cy: number;
  r: number;
  font: number;
  lines: string[][];
}

/** Lays the web into a box of the given width: labels wrap, the radius takes what is left */
function geometry(axes: string[], width: number, { font = 12, maxR = 170, extraLine = false, minR = 48 } = {}): RadarGeometry {
  const n = axes.length;
  const maxW = width < 420 ? 76 : 120;
  const lines = axes.map((a) => (a ? wrap(a, maxW, font) : []));
  const lh = font + 3;
  let side = 0;
  let topPad = 10;
  let bottomPad = 10;
  axes.forEach((_, i) => {
    if (!lines[i].length) return;
    const deg = (360 * i) / n;
    const h = (lines[i].length + (extraLine ? 1 : 0)) * lh;
    const w = Math.max(...lines[i].map((l) => textWidth(l, font)));
    if (deg === 0) topPad = Math.max(topPad, h + 14);
    else if (deg === 180) bottomPad = Math.max(bottomPad, h + 14);
    else {
      side = Math.max(side, w + 16);
      // Labels near the top and bottom also need vertical room
      const c = Math.cos((deg * Math.PI) / 180);
      if (Math.abs(c) > 0.5) {
        if (c > 0) topPad = Math.max(topPad, h / 2 + 8);
        else bottomPad = Math.max(bottomPad, h / 2 + 8);
      }
    }
  });
  const r = Math.max(minR, Math.min(maxR, (width - 2 * side) / 2));
  return { width, height: Math.round(topPad + 2 * r + bottomPad), cx: Math.round(width / 2), cy: Math.round(topPad + r), r: Math.round(r), font, lines };
}

interface PlotProps {
  g: RadarGeometry;
  axes: string[];
  series: RadarSeries[];
  target?: number[];
  max: number;
  rings: number[];
  labels: boolean;
  active: number | null;
  focus: number | null;
  anim: boolean;
  fmt: (n: number) => string;
  ringLabels?: boolean;
  /** Value of the first series under each spoke label */
  values?: boolean;
  /** Only the web with its labels (key of the multiples) */
  bare?: boolean;
}

/** The web, rings, spokes, shapes and labels as one SVG */
function RadarPlot({ g, axes, series, target, max, rings, labels, active, focus, anim, fmt, ringLabels, values, bare }: PlotProps) {
  const n = axes.length;
  const { cx, cy, r } = g;
  const delay = (ms: number) => (anim ? ({ '--kitch-d': `${ms}ms` } as React.CSSProperties) : undefined);
  const lh = g.font + 3;
  // Ring values sit between the first two spokes, where shapes cross least
  const ringDeg = 180 / n;
  return (
    <svg width="100%" height={g.height} viewBox={`0 0 ${g.width} ${g.height}`} aria-hidden className="block overflow-visible">
      <g className={anim ? 'kitch-fade' : undefined}>
        {rings.map((v) => (
          <path key={v} d={ringPath(cx, cy, (v / max) * r, n)} fill="none" stroke={v === max ? 'var(--kitch-axis)' : 'var(--kitch-grid)'} strokeWidth="1" />
        ))}
        {axes.map((_, i) => {
          const [x, y] = polar(cx, cy, r, (360 * i) / n);
          return <line key={i} x1={cx} y1={cy} x2={x} y2={y} stroke={active === i ? 'var(--kitch-axis)' : 'var(--kitch-grid)'} strokeWidth={active === i ? 1.5 : 1} className="transition-[stroke] duration-200" />;
        })}
      </g>
      {target && !bare && (
        <path d={shapePath(cx, cy, r, target, max)} fill="none" stroke="var(--foreground)" strokeOpacity="0.7" strokeWidth="1.5" strokeDasharray="4 4" strokeLinejoin="round" className={anim ? 'kitch-fade' : undefined} style={delay(500)} />
      )}
      {!bare &&
        [...series.keys()].reverse().map((si) => {
          const s = series[si];
          const color = SERIES_COLOR[Math.min(si, 1)];
          const dim = focus !== null && focus !== si;
          return (
            <g key={si} className="kitch-series" opacity={dim ? 0.18 : 1}>
              <g className={anim ? 'kitch-pop' : undefined} style={{ ...delay(140 + si * 180), transformOrigin: `${cx}px ${cy}px`, transformBox: 'view-box' }}>
                <path d={shapePath(cx, cy, r, s.values, max)} fill={color} fillOpacity={si === 0 ? 0.16 : 0.1} stroke={color} strokeWidth="2" strokeLinejoin="round" />
              </g>
              {s.values.map((v, i) => {
                const [x, y] = polar(cx, cy, (Math.max(0, Math.min(v, max)) / max) * r, (360 * i) / n);
                const miss = target && si === 0 && v < target[i];
                return (
                  <circle key={i} cx={x} cy={y} r={active === i ? 5.5 : 4} fill={miss ? 'var(--kitch-surface)' : color} stroke={miss ? color : 'var(--kitch-surface)'} strokeWidth="2" className={cn('transition-[r] duration-200', anim && 'kitch-pop')} style={delay(500 + i * 50)} />
                );
              })}
            </g>
          );
        })}
      {ringLabels &&
        r >= 90 &&
        rings.map((v) => {
          const [x, y] = polar(cx, cy, (v / max) * r, ringDeg);
          return (
            <text key={v} x={x + 4} y={y} dy="0.34em" className="text-[10px] tabular-nums" fill="var(--muted-foreground)" style={HALO}>
              {fmt(v)}
            </text>
          );
        })}
      {labels &&
        axes.map((_, i) => {
          const deg = (360 * i) / n;
          const [x, y] = polar(cx, cy, r + 10, deg);
          const anchor = deg === 0 || deg === 180 ? 'middle' : deg < 180 ? 'start' : 'end';
          const lines = g.lines[i];
          const count = lines.length + (values ? 1 : 0);
          // Block of lines: above the top spoke, below the bottom one, centered beside the others
          const y0 = deg === 0 ? y - (count - 1) * lh - 4 : deg === 180 ? y + lh - 2 : y - ((count - 1) * lh) / 2;
          return (
            <text key={i} x={x} y={y0} dy="0.34em" textAnchor={anchor} style={{ fontSize: g.font }} className={cn('transition-[fill] duration-200', active === i ? 'fill-foreground' : 'fill-muted-foreground')}>
              {lines.map((l, k) => (
                <tspan key={k} x={x} dy={k ? lh : 0}>
                  {l}
                </tspan>
              ))}
              {values && series[0] && (
                <tspan x={x} dy={lh} className="fill-foreground font-semibold tabular-nums">
                  {fmt(series[0].values[i] ?? 0)}
                </tspan>
              )}
            </text>
          );
        })}
    </svg>
  );
}

/**
 * Spokes around a center: one profile, a comparison, a list beside it, small multiples or against a target.
 *   <RadarChart variant="profile" axes={['Cleanliness', 'Location', …]} series={[{ label: 'Guests', values: [9.1, 8.4, …] }]} max={10} />
 */
export function RadarChart(props: RadarChartProps) {
  const { variant = 'profile', axes, series, target, format, targetLabel, label, summary, labels, animate = true, title, value, delta, meta, source, framed, className } = props;
  const t = useTexts(TEXTS, undefined);
  const intl = useIntlLocale();
  const fmt = numberFormatter(intl, format);
  const [wrapRef, width] = useWidth<HTMLDivElement>(560);
  const [rootRef, anim] = useEntrance<HTMLDivElement>(animate);
  const [active, setActive] = useState<number | null>(null);
  const { shown, open, jump } = useShown(active);
  const [focus, setFocus] = useState<number | null>(null);

  const n = axes.length;
  const all = series.flatMap((s) => s.values).concat(target ?? []);
  const nice = niceTicks(0, props.max ?? Math.max(1, ...all), 5);
  const max = props.max ?? nice.max;
  const rings = props.max ? niceTicks(0, props.max, 5).ticks.filter((v) => v > 0 && v <= props.max!) : nice.ticks.filter((v) => v > 0);
  const name = label ?? title ?? axes.join(', ');
  const shownSeries = variant === 'compare' ? series.slice(0, 2) : series.slice(0, 1);

  const listBeside = variant === 'with-list' && width >= 620;
  const avail = Math.round(listBeside ? (width - 32) * 0.52 : width);
  const showValues = variant === 'profile' || variant === 'target';
  const g = geometry(axes, avail, { font: avail < 420 ? 11 : 12, extraLine: showValues });

  const rows = (i: number): TooltipRow[] => {
    const out: TooltipRow[] = shownSeries.map((s, si) => ({ key: s.label, label: s.label, value: fmt(s.values[i] ?? 0), color: SERIES_COLOR[Math.min(si, 1)], shape: 'line' }));
    if (target) out.push({ key: '__target', label: targetLabel ?? t.target, value: fmt(target[i] ?? 0), color: 'var(--foreground)', shape: 'line', dashed: true });
    return out;
  };

  const pick = (clientX: number, clientY: number, el: HTMLElement) => {
    const svg = el.querySelector('svg');
    if (!svg) return;
    const b = svg.getBoundingClientRect();
    const k = g.width / (b.width || g.width);
    const dx = (clientX - b.left) * k - g.cx;
    const dy = (clientY - b.top) * k - g.cy;
    if (Math.hypot(dx, dy) < 6) return;
    const deg = ((Math.atan2(dy, dx) * 180) / Math.PI + 90 + 360) % 360;
    setActive(Math.round(deg / (360 / n)) % n);
  };
  const onKeyDown = (e: React.KeyboardEvent) => {
    const cur = active ?? -1;
    let next: number | null = cur;
    if (e.key === 'ArrowRight' || e.key === 'ArrowDown') next = (cur + 1) % n;
    else if (e.key === 'ArrowLeft' || e.key === 'ArrowUp') next = cur < 0 ? n - 1 : (cur - 1 + n) % n;
    else if (e.key === 'Home') next = 0;
    else if (e.key === 'End') next = n - 1;
    else if (e.key === 'Escape') next = null;
    else return;
    e.preventDefault();
    setActive(next);
  };

  const auto = shownSeries.map((s) => `${s.label}: ${axes.map((a, i) => `${a} ${fmt(s.values[i] ?? 0)}`).join(', ')}`).join('. ');
  const live = active !== null ? `${axes[active]}. ${rows(active).map((r) => `${r.label} ${r.value}`).join(', ')}` : '';
  const table = <ChartTable caption={name} head={[t.axis, ...shownSeries.map((s) => s.label), ...(target ? [targetLabel ?? t.target] : [])]} rows={axes.map((a, i) => [a, ...shownSeries.map((s) => fmt(s.values[i] ?? 0)), ...(target ? [fmt(target[i] ?? 0)] : [])])} />;

  // Tooltip anchored at the outer end of the active spoke
  const tip = shown !== null ? polar(g.cx, g.cy, g.r, (360 * shown) / n) : ([0, 0] as [number, number]);

  const misses = target ? axes.filter((_, i) => (series[0]?.values[i] ?? 0) < target[i]).length : 0;

  /* ---------- multiples: a key and one small web per series ---------- */
  if (variant === 'multiples') {
    // The key spans two cells, so key plus series fill whole rows more often
    const cols = width >= 900 ? 6 : width >= 480 ? 3 : 2;
    const cell = Math.floor((width - (cols - 1) * 12) / cols) - 26;
    const keyG = geometry(axes, Math.min(2 * cell + 36, 420), { font: 11, maxR: 64, minR: 34 });
    const smallBase = geometry(axes.map(() => ''), cell, { maxR: 72, minR: 36 });
    const smallG = { ...smallBase, width: cell, height: Math.round(2 * smallBase.r + 16), cy: Math.round(smallBase.r + 8) };
    return (
      <ChartFigure title={title} value={value} delta={delta} meta={meta} source={source} framed={framed} className={className}>
        <ChartRoot anim={anim} rootRef={rootRef}>
          <div ref={wrapRef}>
            <ul role="list" aria-label={name} className="grid gap-3" style={{ gridTemplateColumns: `repeat(${cols}, minmax(0, 1fr))` }}>
              <li className="col-span-2 flex flex-col rounded-lg border border-dashed border-border-strong px-3 pb-3 pt-2.5">
                <p className="text-[11px] font-medium uppercase tracking-[0.08em] text-muted-foreground">{t.key}</p>
                <div className="flex flex-1 items-center justify-center">
                  <div className="w-full" style={{ maxWidth: keyG.width }}>
                    <RadarPlot g={keyG} axes={axes} series={[]} max={max} rings={rings} labels active={null} focus={null} anim={false} fmt={fmt} bare />
                  </div>
                </div>
              </li>
              {series.map((s, si) => {
                const avg = s.values.reduce((a, v) => a + v, 0) / Math.max(1, s.values.length);
                return (
                  <li key={s.label} className={cn('group flex flex-col rounded-lg border border-border bg-card px-3 pb-3 pt-2.5 transition-[border-color,box-shadow] duration-300 hover:border-border-strong hover:shadow-[var(--shadow-sm)]', anim && 'kitch-rise')} style={anim ? ({ '--kitch-d': `${120 + si * 90}ms` } as React.CSSProperties) : undefined}>
                    {/* Two columns on phones: name and average stacked, so no name gets cut */}
                    <p className={cn('flex w-full text-[13px]', cols === 2 ? 'flex-col gap-0.5' : 'items-baseline justify-between gap-2')}>
                      <span className="min-w-0 truncate font-medium text-foreground">{s.label}</span>
                      <span className="whitespace-nowrap tabular-nums text-muted-foreground">{fill(t.avg, { v: fmt(round(avg, 1)) })}</span>
                    </p>
                    <div className="mt-2 transition-transform duration-500 ease-[var(--ease-kit)] group-hover:scale-[1.04] motion-reduce:transition-none">
                      <RadarPlot g={smallG} axes={axes} series={[s]} max={max} rings={rings} labels={false} active={null} focus={null} anim={!!anim} fmt={fmt} />
                    </div>
                    <span className="sr-only">{axes.map((a, i) => `${a} ${fmt(s.values[i] ?? 0)}`).join(', ')}</span>
                  </li>
                );
              })}
            </ul>
          </div>
          <ChartTable caption={name} head={[t.axis, ...series.map((s) => s.label)]} rows={axes.map((a, i) => [a, ...series.map((s) => fmt(s.values[i] ?? 0))])} />
        </ChartRoot>
      </ChartFigure>
    );
  }

  const legendItems =
    variant === 'compare'
      ? shownSeries.map((s, i) => ({ label: s.label, key: <Swatch shape="line" color={SERIES_COLOR[i]} /> }))
      : variant === 'target'
        ? [
            { label: series[0]?.label ?? '', key: <Swatch shape="line" color={SERIES_COLOR[0]} /> },
            { label: targetLabel ?? t.target, key: <Swatch shape="line" color="var(--foreground)" dashed /> },
          ]
        : [];

  return (
    <ChartFigure title={title} value={value} delta={delta} meta={meta} source={source} framed={framed} className={className}>
      <ChartRoot anim={anim} rootRef={rootRef}>
        {legendItems.length > 0 && (
          <div className="mb-3 flex flex-wrap items-center justify-between gap-x-4 gap-y-2">
            <PickLegend active={variant === 'compare' ? focus : null} onActive={variant === 'compare' ? setFocus : () => {}} items={legendItems} />
            {variant === 'target' && <span className="text-[12px] text-muted-foreground">{fill(t.gap, { n: String(misses), total: String(n) })}</span>}
          </div>
        )}
        <div ref={wrapRef} className={cn(listBeside && 'grid grid-cols-[minmax(0,1.1fr)_minmax(0,1fr)] items-center gap-8')}>
          <div>
            <ChartSurface
              label={name}
              summary={summary ?? auto}
              labels={labels}
              live={live}
              table={table}
              onKeyDown={onKeyDown}
              onFocus={(e) => e.target === e.currentTarget && active === null && e.currentTarget.matches(':focus-visible') && setActive(0)}
              onBlur={() => setActive(null)}
              onPointerMove={(e) => pick(e.clientX, e.clientY, e.currentTarget)}
              onPointerDown={(e) => pick(e.clientX, e.clientY, e.currentTarget)}
              onPointerLeave={(e) => e.pointerType === 'mouse' && setActive(null)}
              className="mx-auto"
              style={{ maxWidth: g.width }}
            >
              <RadarPlot g={g} axes={axes} series={shownSeries} target={variant === 'target' ? target : undefined} max={max} rings={rings} labels active={active} focus={focus} anim={!!anim} fmt={fmt} ringLabels values={showValues} />
              <ChartTooltip open={open} jump={jump} x={tip[0]} y={Math.max(0, tip[1] - 30)} width={g.width} offset={14} title={shown !== null ? axes[shown] : ''} rows={shown !== null ? rows(shown) : []} />
            </ChartSurface>
          </div>
          {variant === 'with-list' && (
            <ul className={cn('grid gap-1', !listBeside && 'mt-6')}>
              {axes.map((a, i) => {
                const v = series[0]?.values[i] ?? 0;
                return (
                  <li key={a}>
                    <button
                      type="button"
                      aria-pressed={active === i}
                      onPointerEnter={(e) => e.pointerType === 'mouse' && setActive(i)}
                      onPointerLeave={(e) => e.pointerType === 'mouse' && setActive(null)}
                      onFocus={() => setActive(i)}
                      onBlur={() => setActive(null)}
                      onClick={() => setActive(active === i ? null : i)}
                      className={cn('grid min-h-11 w-full grid-cols-[minmax(0,1fr)_auto] items-center gap-x-3 gap-y-1.5 rounded-md px-2 py-1.5 text-left text-[13px] transition-colors duration-200', active === i ? 'bg-accent' : 'hover:bg-accent/60')}
                    >
                      <span className={cn('truncate', active === i ? 'text-foreground' : 'text-muted-foreground')}>{a}</span>
                      <span className="font-medium tabular-nums text-foreground">
                        {fmt(v)} <span className="font-normal text-muted-foreground">{fill(t.of, { max: fmt(max) })}</span>
                      </span>
                      <span aria-hidden className="col-span-2 block h-1.5 overflow-hidden rounded-full bg-track">
                        <span className={cn('block h-full origin-left rounded-full bg-primary', anim && 'kitch-grow-x')} style={{ width: `${round((Math.min(v, max) / max) * 100, 1)}%`, ...(anim ? ({ '--kitch-d': `${200 + i * 70}ms` } as React.CSSProperties) : {}) }} />
                      </span>
                    </button>
                  </li>
                );
              })}
            </ul>
          )}
        </div>
      </ChartRoot>
    </ChartFigure>
  );
}