"use client";

import { useEffect, useId, useRef, type CSSProperties, type ElementType, type PointerEvent, type ReactNode } from "react";
import { animate, motion, useMotionValue, useReducedMotion, useSpring, useTransform } from "motion/react";

export type DashboardHeroStat = {
  label: string;
  value: number;
  /** Goes before the number, such as $. */
  prefix?: string;
  /** Goes after the number, such as %. */
  suffix?: string;
  /** Small note under the number, such as +12%. */
  note?: string;
};

type DashboardHeroProps = {
  title: string;
  /** Tiles along the top of the screen. */
  stats: DashboardHeroStat[];
  /** The line chart, oldest first. Two values or more. */
  series: number[];
  /** Names the chart, for screen readers too. */
  seriesLabel?: string;
  /** The bar chart. Leave out for a wider line chart. */
  bars?: { label: string; value: number }[];
  /** Name in the window bar. */
  appName?: string;
  /** Small line above the title. */
  eyebrow?: string;
  subtitle?: string;
  /** Buttons or links under the text. */
  children?: ReactNode;
  /** Chart colour. */
  color?: string;
  /** Colour of the dashboard panel. */
  tile?: string;
  /** h1 by default. Use h2 if the page already has an h1. */
  headingAs?: ElementType;
  /** Set the background and text colour here. */
  className?: string;
};

const EASE = [0.16, 1, 0.3, 1] as const;
const SPRING = { stiffness: 110, damping: 18 };

const places = (value: number) => (String(value).split(".")[1] ?? "").length;
const format = (value: number, digits: number) => value.toLocaleString("en-US", { minimumFractionDigits: digits, maximumFractionDigits: digits });

function Count({ stat }: { stat: DashboardHeroStat }) {
  const number = useRef<HTMLSpanElement>(null);
  useEffect(() => {
    const el = number.current;
    if (!el || window.matchMedia("(prefers-reduced-motion: reduce)").matches) return;
    const digits = places(stat.value);
    const run = animate(0, stat.value, {
      duration: 1.5,
      delay: 0.35,
      ease: EASE,
      onUpdate: (now) => {
        el.textContent = format(now, digits);
      },
    });
    return () => run.stop();
  }, [stat.value]);
  return (
    <>
      {stat.prefix}
      <span ref={number}>{format(stat.value, places(stat.value))}</span>
      {stat.suffix}
    </>
  );
}

/* DashboardHero: a headline over a working dashboard. The screen tips up from a tilt, numbers count up, the chart draws itself, and it leans gently toward the pointer. */
export function DashboardHero({
  title,
  stats,
  series,
  seriesLabel = "Trend",
  bars,
  appName = "Overview",
  eyebrow,
  subtitle,
  children,
  color = "#a78bfa",
  tile = "#15122a",
  headingAs: Heading = "h1",
  className = "bg-[#0b0a14] text-white",
}: DashboardHeroProps) {
  const reduce = useReducedMotion();
  const id = useId();
  const panel = useRef<HTMLDivElement>(null);
  const x = useMotionValue(0);
  const y = useMotionValue(0);
  const rotateY = useSpring(useTransform(x, [-0.5, 0.5], [-4, 4]), SPRING);
  const rotateX = useSpring(useTransform(y, [-0.5, 0.5], [3, -3]), SPRING);

  const move = (e: PointerEvent) => {
    const box = panel.current?.getBoundingClientRect();
    if (reduce || e.pointerType !== "mouse" || !box) return;
    x.set(Math.max(-0.5, Math.min(0.5, (e.clientX - box.left) / box.width - 0.5)));
    y.set(Math.max(-0.5, Math.min(0.5, (e.clientY - box.top) / box.height - 0.5)));
  };
  const leave = () => {
    x.set(0);
    y.set(0);
  };

  const rise = (delay: number) =>
    reduce
      ? { initial: { opacity: 0 }, animate: { opacity: 1 }, transition: { duration: 0.4 } }
      : { initial: { opacity: 0, y: 22 }, animate: { opacity: 1, y: 0 }, transition: { duration: 0.7, delay, ease: EASE } };

  const low = Math.min(...series);
  const span = Math.max(...series) - low || 1;
  const points = series.map((value, i) => [(i / (series.length - 1)) * 100, 37 - ((value - low) / span) * 33] as const);
  const line = points.map(([px, py], i) => `${i ? "L" : "M"}${px.toFixed(2)} ${py.toFixed(2)}`).join(" ");
  const end = points[points.length - 1];
  const tallest = Math.max(...(bars ?? []).map((bar) => bar.value), 1);

  return (
    <section aria-labelledby={id} onPointerMove={move} onPointerLeave={leave} className={`@container overflow-hidden ${className}`}>
      <div className="mx-auto max-w-6xl px-5 pt-8 @3xl:pt-20">
        <div className="mx-auto max-w-3xl text-center">
          {eyebrow && (
            <motion.p {...rise(0)} className="mb-3 text-xs font-medium tracking-[0.2em] uppercase opacity-70 @2xl:text-sm">
              {eyebrow}
            </motion.p>
          )}
          <motion.div {...rise(0.08)}>
            <Heading id={id} className="text-[clamp(1.6rem,8cqw,2.5rem)] leading-[1.06] font-semibold tracking-tight text-balance @2xl:text-[clamp(2rem,5.5cqw,4rem)]">
              {title}
            </Heading>
          </motion.div>
          {subtitle && (
            <motion.p {...rise(0.16)} className="mx-auto mt-3 max-w-xl text-sm text-pretty opacity-70 @2xl:mt-5 @2xl:text-lg">
              {subtitle}
            </motion.p>
          )}
          {children && (
            <motion.div {...rise(0.24)} className="mt-5 flex flex-wrap justify-center gap-3 @2xl:mt-8">
              {children}
            </motion.div>
          )}
        </div>
        <div ref={panel} className="mt-8 [perspective:1400px] @3xl:mt-14">
          <motion.div style={{ rotateX, rotateY }}>
            <motion.div
              className="origin-bottom overflow-hidden rounded-t-2xl border border-b-0 border-current/15 shadow-[0_-20px_80px_-30px_var(--dh-color)]"
              style={{ backgroundColor: tile, "--dh-color": color } as CSSProperties}
              initial={reduce ? { opacity: 0 } : { opacity: 0, rotateX: 24, y: 50 }}
              animate={reduce ? { opacity: 1 } : { opacity: 1, rotateX: 0, y: 0 }}
              transition={{ duration: reduce ? 0.4 : 1.2, delay: reduce ? 0 : 0.2, ease: EASE }}
            >
              <div className="flex items-center gap-1.5 border-b border-current/10 px-4 py-2.5">
                {[0, 1, 2].map((dot) => (
                  <span key={dot} aria-hidden className="size-2 rounded-full bg-current opacity-20" />
                ))}
                <span className="ml-2 text-xs opacity-60">{appName}</span>
              </div>
              <div className="grid gap-3 p-3 @3xl:p-4">
                <dl className="grid grid-cols-[repeat(auto-fit,minmax(8rem,1fr))] gap-3">
                  {stats.map((stat) => (
                    <div key={stat.label} className="rounded-xl border border-current/10 p-3">
                      <dt className="text-xs opacity-60">{stat.label}</dt>
                      <dd className="mt-1 text-xl font-semibold tracking-tight tabular-nums @3xl:text-2xl">
                        <Count stat={stat} />
                      </dd>
                      {stat.note && (
                        <dd className="mt-0.5 text-xs" style={{ color }}>
                          {stat.note}
                        </dd>
                      )}
                    </div>
                  ))}
                </dl>
                <div className={`grid gap-3 ${bars ? "@3xl:grid-cols-[minmax(0,2fr)_minmax(0,1fr)]" : ""}`}>
                  <figure className="rounded-xl border border-current/10 p-3">
                    <figcaption className="mb-2 text-xs opacity-60">{seriesLabel}</figcaption>
                    <div className="relative h-32 @3xl:h-44">
                      <motion.div
                        className="size-full"
                        initial={{ clipPath: "inset(-5% 100% -5% 0%)" }}
                        animate={{ clipPath: "inset(-5% 0% -5% 0%)" }}
                        transition={{ duration: reduce ? 0 : 1.6, delay: reduce ? 0 : 0.5, ease: "easeInOut" }}
                      >
                        <svg role="img" aria-label={`${seriesLabel}: from ${series[0]} to ${series[series.length - 1]}`} viewBox="0 0 100 40" preserveAspectRatio="none" className="size-full overflow-visible">
                          <defs>
                            <linearGradient id={`${id}-fill`} x1="0" y1="0" x2="0" y2="1">
                              <stop offset="0" stopColor={color} stopOpacity="0.35" />
                              <stop offset="1" stopColor={color} stopOpacity="0" />
                            </linearGradient>
                          </defs>
                          <path d={`${line} L100 40 L0 40 Z`} fill={`url(#${id}-fill)`} />
                          <path d={line} fill="none" stroke={color} strokeWidth="2" strokeLinejoin="round" vectorEffect="non-scaling-stroke" />
                        </svg>
                      </motion.div>
                      <motion.span
                        aria-hidden
                        className="absolute -mt-1 -ml-1 size-2 rounded-full"
                        style={{ left: `${end[0]}%`, top: `${(end[1] / 40) * 100}%`, backgroundColor: color }}
                        initial={{ opacity: 0 }}
                        animate={{ opacity: 1 }}
                        transition={{ delay: reduce ? 0 : 2 }}
                      >
                        <span className="absolute inset-0 animate-ping rounded-full motion-reduce:hidden" style={{ backgroundColor: color }} />
                      </motion.span>
                    </div>
                  </figure>
                  {bars && (
                    <ul className="flex items-stretch gap-2 rounded-xl border border-current/10 p-3">
                      {bars.map((bar, i) => (
                        <li key={bar.label} className="flex min-h-32 min-w-0 flex-1 flex-col gap-1 text-center text-[11px] @3xl:min-h-44">
                          <div className="flex min-h-0 flex-1 items-end">
                            <motion.span
                              className="block w-full origin-bottom rounded-t"
                              style={{ height: `${(bar.value / tallest) * 100}%`, backgroundColor: color }}
                              initial={{ scaleY: reduce ? 1 : 0 }}
                              animate={{ scaleY: 1 }}
                              transition={{ duration: reduce ? 0 : 0.8, delay: reduce ? 0 : 0.7 + i * 0.07, ease: EASE }}
                            />
                          </div>
                          <span className="truncate opacity-60">
                            <span className="sr-only">{bar.value} </span>
                            {bar.label}
                          </span>
                        </li>
                      ))}
                    </ul>
                  )}
                </div>
              </div>
            </motion.div>
          </motion.div>
        </div>
      </div>
    </section>
  );
}