Network graph

'use client';

import { useState } from 'react';
import { cn, round } from '@/lib/kit';
import { PlayToggle, SCENE_CSS, keyframes, rand, useSceneId, useScenePlay, type SceneMotionProps } from '@/components/ui/motion-scene';

/*
 * A connection graph: nodes on rings around a center, joined by hairlines.
 * On entry the lines draw outward ring by ring. Then a signal leaves the
 * center every few seconds as a ripple, and every node and line lights up
 * when the ripple reaches it, so the light always travels outward. Pointing
 * at a node or focusing it with Tab shows its name and its connections.
 */

export interface GraphNode {
  id: string;
  /** Shown on hover and focus, and read to screen readers */
  label: string;
  /** Avatar, icon or initials inside the node */
  content?: React.ReactNode;
  /** 0 center, 1 inner ring, 2 outer ring. Default: from the links, counted from the first node. */
  ring?: number;
  /** Explicit position in percent, overrides the ring layout */
  x?: number;
  y?: number;
}

export interface NetworkGraphProps extends SceneMotionProps {
  nodes: GraphNode[];
  /** Pairs of node ids */
  links: [string, string][];
  /** Scene ratio, width / height. Default "16 / 10". */
  aspect?: string;
  /** Seconds between two signals at speed 1. Default 3.6. */
  interval?: number;
  /** Seed for the small irregularities of the layout */
  seed?: number;
  /** Nodes take focus and show their links. Default true. */
  interactive?: boolean;
  /** Accessible description of the whole graph */
  label?: string;
  className?: string;
}

const VW = 1000;

export function NetworkGraph({ nodes, links, aspect = '16 / 10', interval = 3.6, seed = 2, interactive = true, speed = 1, autoPlay = 'in-view', controls = true, label, className }: NetworkGraphProps) {
  const sid = useSceneId('kvng');
  const play = useScenePlay<HTMLDivElement>(autoPlay);
  const [active, setActive] = useState<string | null>(null);
  const [aw, ah] = aspect.split('/').map((n) => Number(n.trim()) || 1);
  const VH = round((VW * ah) / aw);

  // rings from the links, breadth first from the first node
  const ring = new Map<string, number>();
  if (nodes[0]) ring.set(nodes[0].id, nodes[0].ring ?? 0);
  for (let pass = 0; pass < 4; pass++) {
    for (const [a, b] of links) {
      if (ring.has(a) && !ring.has(b)) ring.set(b, (ring.get(a) ?? 0) + 1);
      if (ring.has(b) && !ring.has(a)) ring.set(a, (ring.get(b) ?? 0) + 1);
    }
  }
  const ringOf = (n: GraphNode) => n.ring ?? ring.get(n.id) ?? 2;
  const groups = new Map<number, GraphNode[]>();
  nodes.forEach((n) => groups.set(ringOf(n), [...(groups.get(ringOf(n)) ?? []), n]));
  const pos = new Map<string, { x: number; y: number; r: number; dist: number }>();
  // Inner ring evenly around the center; outer nodes gather around the angle of their parent
  const angleOf = new Map<string, number>();
  const inner = groups.get(1) ?? [];
  inner.forEach((n, i) => angleOf.set(n.id, -90 + (360 / Math.max(1, inner.length)) * i + (rand(seed, i + 31) - 0.5) * 10));
  const outer = groups.get(2) ?? [];
  const parentOf = (n: GraphNode) => links.map(([a, b]) => (a === n.id ? b : b === n.id ? a : null)).find((p) => p && angleOf.has(p)) ?? null;
  const kids = new Map<string, GraphNode[]>();
  outer.forEach((n) => {
    const p = parentOf(n) ?? '';
    kids.set(p, [...(kids.get(p) ?? []), n]);
  });
  const spread = Math.min(26, 300 / Math.max(1, outer.length));
  let orphan = 0;
  for (const [p, list] of kids) {
    list.forEach((n, j) => {
      const baseAngle = angleOf.get(p) ?? -90 + (360 / Math.max(1, outer.length)) * orphan++;
      angleOf.set(n.id, baseAngle + (j - (list.length - 1) / 2) * spread + (rand(seed + 9, j) - 0.5) * 6);
    });
  }
  for (const [r, list] of groups) {
    list.forEach((n, i) => {
      if (n.x != null && n.y != null) {
        const x = (n.x / 100) * VW;
        const y = (n.y / 100) * VH;
        pos.set(n.id, { x, y, r, dist: Math.hypot(x - VW / 2, (y - VH / 2) * (VW / VH)) / (VW / 2) });
        return;
      }
      if (r === 0) {
        pos.set(n.id, { x: VW / 2, y: VH / 2, r, dist: 0 });
        return;
      }
      const a = ((angleOf.get(n.id) ?? -90 + (360 / list.length) * i) * Math.PI) / 180;
      const rx = (r === 1 ? 0.24 : 0.43) * VW * (1 + (rand(seed + 3, i + r * 17) - 0.5) * 0.08);
      const ry = (r === 1 ? 0.27 : 0.42) * VH * (1 + (rand(seed + 5, i + r * 13) - 0.5) * 0.08);
      const x = VW / 2 + Math.cos(a) * rx;
      const y = VH / 2 + Math.sin(a) * ry;
      pos.set(n.id, { x: round(x), y: round(y), r, dist: r === 1 ? 0.5 : 1 });
    });
  }

  const T = round(interval / Math.max(0.1, speed), 2);
  const wave = 1.5; // seconds the ripple needs from center to the edge
  const css = `${SCENE_CSS}
${keyframes(`${sid}-ripple`, [[0, 'opacity:.5;transform:translate(-50%,-50%) scale(.05)'], [(wave / interval) * 100, 'opacity:0;transform:translate(-50%,-50%) scale(1)'], [100, 'opacity:0;transform:translate(-50%,-50%) scale(1)']])}
${keyframes(`${sid}-lit`, [[0, 'opacity:0'], [6, 'opacity:1'], [34, 'opacity:0'], [100, 'opacity:0']])}
${keyframes(`${sid}-glow`, [[0, 'opacity:0;transform:scale(.8)'], [5, 'opacity:.9;transform:scale(1)'], [32, 'opacity:0;transform:scale(1.5)'], [100, 'opacity:0;transform:scale(1.5)']])}
${keyframes(`${sid}-draw`, [[0, 'stroke-dashoffset:1'], [100, 'stroke-dashoffset:0']])}
${keyframes(`${sid}-pop`, [[0, 'opacity:0;transform:translate(-50%,-50%) scale(.6)'], [100, 'opacity:1;transform:translate(-50%,-50%) scale(1)']])}
.${sid}:not([data-kv="off"]) .${sid}-ripple { animation: ${sid}-ripple ${T}s cubic-bezier(.2,.6,.3,1) 1.2s infinite both; }
.${sid}:not([data-kv="off"]) .${sid}-lit { animation: ${sid}-lit ${T}s ease-out var(--d) infinite both; }
.${sid}:not([data-kv="off"]) .${sid}-glow { animation: ${sid}-glow ${T}s ease-out var(--d) infinite both; }
.${sid}:not([data-kv="off"]) .${sid}-line { stroke-dasharray: 1 1; animation: ${sid}-draw .9s var(--ease-kit) var(--e) 1 both; }
.${sid}:not([data-kv="off"]) .${sid}-pop { animation: ${sid}-pop .6s var(--ease-kit) var(--e) 1 both; }`;

  const linked = (id: string) => new Set(links.filter(([a, b]) => a === id || b === id).flatMap(([a, b]) => [a, b]));
  const near = active ? linked(active) : null;
  const delayOf = (dist: number) => round(1.2 + (wave * Math.min(1, dist)) * (1 / Math.max(0.1, speed)), 2);

  return (
    <div className={cn('relative w-full', className)}>
      <div
        ref={play.ref}
        data-kv={play.state}
        role="group"
        aria-label={label}
        className={cn(sid, '@container relative w-full')}
        style={{ aspectRatio: aspect }}
      >
        <style dangerouslySetInnerHTML={{ __html: css }} />
        <span
          aria-hidden
          className={`${sid}-ripple pointer-events-none absolute left-1/2 top-1/2 aspect-square w-[96%] rounded-full border border-[color-mix(in_oklab,var(--primary)_55%,transparent)] bg-[radial-gradient(closest-side,transparent_70%,color-mix(in_oklab,var(--primary)_12%,transparent))] opacity-0`}
        />
        <svg key={play.cycle} viewBox={`0 0 ${VW} ${VH}`} className="absolute inset-0 size-full overflow-visible" aria-hidden>
          {links.map(([a, b], i) => {
            const p = pos.get(a);
            const q = pos.get(b);
            if (!p || !q) return null;
            const on = near ? near.has(a) && near.has(b) && (a === active || b === active) : false;
            const mid = (p.dist + q.dist) / 2;
            const d = `M${p.x} ${p.y} L${q.x} ${q.y}`;
            return (
              <g key={i} style={{ '--e': `${round(0.1 + Math.min(p.r, q.r) * 0.25, 2)}s`, '--d': `${delayOf(mid)}s` } as React.CSSProperties}>
                <path
                  className={`${sid}-line transition-[stroke,opacity] duration-300`}
                  pathLength={1}
                  d={d}
                  fill="none"
                  stroke={on ? 'var(--primary)' : 'color-mix(in oklab, var(--foreground) 15%, transparent)'}
                  strokeWidth={on ? 2 : 1.2}
                  opacity={near && !on ? 0.35 : 1}
                  vectorEffect="non-scaling-stroke"
                />
                <path className={`${sid}-lit`} d={d} fill="none" stroke="var(--primary)" strokeWidth="1.8" opacity="0" vectorEffect="non-scaling-stroke" />
              </g>
            );
          })}
        </svg>
        {nodes.map((n) => {
          const p = pos.get(n.id);
          if (!p) return null;
          const center = p.r === 0;
          const dim = near && !near.has(n.id);
          const Tag = interactive ? 'button' : 'div';
          return (
            <Tag
              key={n.id}
              {...(interactive ? { type: 'button' as const, onFocus: () => setActive(n.id), onBlur: () => setActive(null), onPointerEnter: () => setActive(n.id), onPointerLeave: () => setActive(null), 'aria-label': n.label } : { 'aria-hidden': true })}
              className={cn(`${sid}-pop group/node absolute z-10 rounded-full outline-none transition-opacity duration-300`, dim && 'opacity-40')}
              style={{ left: `${round((p.x / VW) * 100, 2)}%`, top: `${round((p.y / VH) * 100, 2)}%`, transform: 'translate(-50%,-50%)', '--e': `${round(0.05 + p.r * 0.22 + rand(seed, p.x) * 0.1, 2)}s` } as React.CSSProperties}
            >
              <span aria-hidden className={`${sid}-glow pointer-events-none absolute -inset-1.5 rounded-full bg-[color-mix(in_oklab,var(--primary)_28%,transparent)] opacity-0 blur-[3px]`} style={{ '--d': `${delayOf(p.dist)}s` } as React.CSSProperties} />
              <span
                className={cn(
                  'relative grid place-items-center overflow-hidden rounded-full border shadow-[var(--highlight),var(--shadow-md)] transition-[transform,box-shadow,border-color] duration-300 ease-[var(--ease-kit)] group-hover/node:scale-110 group-focus-visible/node:scale-110 group-focus-visible/node:shadow-[0_0_0_3px_var(--ring)] [&_svg]:size-[46%]',
                  center ? 'size-16 border-[color-mix(in_oklab,var(--primary)_50%,var(--border))] bg-primary text-primary-foreground @max-[34rem]:size-12' : p.r === 1 ? 'size-12 border-border bg-card text-foreground @max-[34rem]:size-9' : 'size-9 border-border bg-card text-muted-foreground @max-[34rem]:size-7',
                  active === n.id && 'border-[var(--primary)]',
                )}
              >
                {n.content ?? <span className="size-2 rounded-full bg-current" />}
              </span>
              {interactive && (
                <span
                  aria-hidden
                  className="pointer-events-none absolute left-1/2 top-full z-20 mt-2 -translate-x-1/2 translate-y-1 whitespace-nowrap rounded-md border border-border bg-popover px-2 py-1 text-[11.5px] font-medium text-foreground opacity-0 shadow-[var(--shadow-md)] transition-[opacity,transform] duration-200 group-hover/node:translate-y-0 group-hover/node:opacity-100 group-focus-visible/node:translate-y-0 group-focus-visible/node:opacity-100"
                >
                  {n.label}
                </span>
              )}
            </Tag>
          );
        })}
      </div>
      {controls && (
        <div className="mt-2 flex justify-end">
          <PlayToggle inline state={play.state} reduced={play.reduced} onToggle={play.toggle} />
        </div>
      )}
    </div>
  );
}