"use client";

import { useId, useRef, useState, type CSSProperties, type ElementType, type PointerEvent } from "react";
import { AnimatePresence, motion, useMotionValue, useReducedMotion, useSpring } from "motion/react";

export type PortfolioGridItem = {
  title: string;
  /** Used for the filter chips. */
  tag: string;
  src: string;
  alt: string;
  href?: string;
  /** Small line after the tag, such as the year. */
  note?: string;
  /** Takes two columns on a wide screen. */
  wide?: boolean;
};

type PortfolioGridProps = {
  items: PortfolioGridItem[];
  title?: string;
  /** Small line above the title. */
  eyebrow?: string;
  subtitle?: string;
  /** Word for the chip that shows everything. */
  allLabel?: string;
  /** Word on the pill that follows the pointer over a link. */
  viewLabel?: string;
  /** Colour of the active chip and the pill. */
  color?: string;
  /** Text colour on that colour. */
  ink?: string;
  /** h2 by default. */
  headingAs?: ElementType;
  /** Set padding and colours here. */
  className?: string;
};

const SPRING = { stiffness: 320, damping: 30 };

/* PortfolioGrid: project tiles with filter chips. Tiles glide to their new places when the filter changes; on hover the picture grows, the caption rises and a small pill follows the pointer. */
export function PortfolioGrid({
  items,
  title,
  eyebrow,
  subtitle,
  allLabel = "All",
  viewLabel = "View",
  color = "#a78bfa",
  ink = "#0b0a14",
  headingAs: Heading = "h2",
  className = "bg-[#0b0a14] px-5 py-16 text-white",
}: PortfolioGridProps) {
  const reduce = useReducedMotion();
  const id = useId();
  const grid = useRef<HTMLUListElement>(null);
  const [tag, setTag] = useState(allLabel);
  const [pill, setPill] = useState(false);
  const x = useMotionValue(0);
  const y = useMotionValue(0);
  const pillX = useSpring(x, SPRING);
  const pillY = useSpring(y, SPRING);
  const tags = [allLabel, ...new Set(items.map((item) => item.tag))];
  const shown = items.filter((item) => tag === allLabel || item.tag === tag);

  const move = (e: PointerEvent) => {
    const box = grid.current?.getBoundingClientRect();
    if (e.pointerType !== "mouse" || !box) return;
    const over = Boolean((e.target as Element).closest("a"));
    x.set(e.clientX - box.left);
    y.set(e.clientY - box.top);
    if (over && !pill) {
      pillX.jump(e.clientX - box.left);
      pillY.jump(e.clientY - box.top);
    }
    setPill(over);
  };

  return (
    <section aria-labelledby={title ? id : undefined} className={`@container ${className}`} style={{ "--pg-color": color, "--pg-ink": ink } as CSSProperties}>
      {title && (
        <header className="mx-auto mb-6 max-w-2xl text-center">
          {eyebrow && <p className="mb-2 text-xs font-medium tracking-[0.2em] uppercase opacity-70">{eyebrow}</p>}
          <Heading id={id} className="text-[clamp(1.5rem,6cqw,2.5rem)] leading-tight font-semibold tracking-tight text-balance">
            {title}
          </Heading>
          {subtitle && <p className="mt-3 text-pretty opacity-70">{subtitle}</p>}
        </header>
      )}
      <div role="group" aria-label="Filter" className="mx-auto mb-6 flex max-w-6xl flex-wrap justify-center gap-2">
        {tags.map((name) => {
          const on = name === tag;
          return (
            <button
              key={name}
              type="button"
              aria-pressed={on}
              onClick={() => setTag(name)}
              className={`rounded-full border px-3.5 py-1.5 text-sm transition-colors ${on ? "border-[var(--pg-color)] bg-[var(--pg-color)] text-[var(--pg-ink)]" : "border-current/15 hover:border-current/40"}`}
            >
              {name}
            </button>
          );
        })}
      </div>
      <p role="status" className="sr-only">
        {shown.length} shown
      </p>
      <ul
        ref={grid}
        onPointerMove={reduce ? undefined : move}
        onPointerLeave={() => setPill(false)}
        className="relative mx-auto grid max-w-6xl grid-flow-dense grid-cols-1 gap-3 overflow-hidden @lg:grid-cols-2 @3xl:grid-cols-3 @3xl:gap-4"
      >
        <AnimatePresence mode="popLayout" initial={false}>
          {shown.map((item) => {
            const body = (
              <>
                <img
                  src={item.src}
                  alt={item.alt}
                  className="absolute inset-0 size-full object-cover transition-transform duration-700 ease-out group-hover/tile:scale-105 motion-reduce:transition-none motion-reduce:group-hover/tile:scale-100"
                />
                <span className="absolute inset-x-0 bottom-0 translate-y-1 bg-gradient-to-t from-black/80 to-transparent p-4 pt-12 text-white opacity-0 transition-[opacity,translate] duration-300 group-focus-within/tile:translate-y-0 group-focus-within/tile:opacity-100 group-hover/tile:translate-y-0 group-hover/tile:opacity-100 pointer-coarse:translate-y-0 pointer-coarse:opacity-100 motion-reduce:translate-y-0">
                  <span className="block font-semibold">{item.title}</span>
                  <span className="block text-sm opacity-80">
                    {item.tag}
                    {item.note && ` · ${item.note}`}
                  </span>
                </span>
              </>
            );
            return (
              <motion.li
                key={item.title}
                layout={!reduce}
                initial={{ opacity: 0, scale: reduce ? 1 : 0.94 }}
                animate={{ opacity: 1, scale: 1 }}
                exit={{ opacity: 0, scale: reduce ? 1 : 0.94 }}
                transition={{ duration: reduce ? 0 : 0.45, ease: [0.16, 1, 0.3, 1] }}
                className={`group/tile relative aspect-[4/3] place-self-stretch overflow-hidden rounded-2xl ${item.wide ? "@3xl:col-span-2 @3xl:aspect-[8/3]" : ""}`}
              >
                {item.href ? (
                  <a href={item.href} className="absolute inset-0 block outline-offset-[-3px]">
                    {body}
                  </a>
                ) : (
                  body
                )}
              </motion.li>
            );
          })}
        </AnimatePresence>
        <motion.span
          aria-hidden
          className="pointer-events-none absolute top-0 left-0 z-10 -mt-5 -ml-8 grid h-10 w-16 place-items-center rounded-full bg-[var(--pg-color)] text-sm font-medium text-[var(--pg-ink)]"
          style={{ x: pillX, y: pillY }}
          initial={false}
          animate={{ opacity: pill ? 1 : 0, scale: pill ? 1 : 0.6 }}
          transition={{ duration: 0.2 }}
        >
          {viewLabel}
        </motion.span>
      </ul>
    </section>
  );
}