"use client";

import { useRef, useState } from "react";
import { AnimatePresence, motion, useReducedMotion } from "motion/react";

type Notification = { id: string | number; title: string; description?: string; time?: string };

type NotificationStackProps = {
  /** Newest first. */
  items: Notification[];
  /** Called with the id when a notification is dismissed. Remove it from `items` there. */
  onDismiss: (id: Notification["id"]) => void;
  /** Heading on the toggle. */
  title?: string;
  /** Height of one card in pixels. Long text is cut to fit. */
  rowHeight?: number;
  /** Tallest the open list gets before it scrolls. */
  maxHeight?: number;
  /** Replaces the card look. */
  className?: string;
};

const GAP = 8;
const PEEK = 10;
const SHOWN = 3;

/* NotificationStack: notifications pile into a deck with the newest on top. Open it and the cards fan out into a list; dismiss one and the rest close the gap. */
export function NotificationStack({
  items,
  onDismiss,
  title = "Notifications",
  rowHeight = 68,
  maxHeight = 320,
  className = "rounded-2xl border border-white/10 bg-[#17151f] text-white shadow-lg",
}: NotificationStackProps) {
  const reduce = useReducedMotion();
  const toggle = useRef<HTMLButtonElement>(null);
  const [wantOpen, setWantOpen] = useState(false);
  const count = items.length;
  const open = wantOpen && count > 1;
  const spring = reduce ? { duration: 0 } : { type: "spring" as const, stiffness: 380, damping: 32 };
  const pile = Math.min(count, SHOWN);
  const height = open ? Math.min(count * (rowHeight + GAP) - GAP, maxHeight) : pile ? rowHeight + (pile - 1) * PEEK : 0;

  const dismiss = (id: Notification["id"]) => {
    onDismiss(id);
    toggle.current?.focus();
  };

  return (
    <section aria-label={title} className="w-full">
      <button
        ref={toggle}
        type="button"
        aria-expanded={open}
        onClick={() => setWantOpen(!open)}
        className="mb-2 flex w-full items-center gap-2 rounded-lg px-1 py-1.5 text-left text-sm font-medium text-white outline-none focus-visible:ring-2 focus-visible:ring-white/70"
      >
        {title}
        <motion.span
          key={count}
          aria-hidden
          className="grid h-5 min-w-5 place-items-center rounded-full bg-violet-400 px-1.5 text-xs font-semibold text-[#0b0a14] tabular-nums"
          initial={reduce ? false : { scale: 1.4 }}
          animate={{ scale: 1 }}
          transition={spring}
        >
          {count}
        </motion.span>
        {count > 1 && (
          <motion.svg aria-hidden viewBox="0 0 16 16" className="ml-auto size-4 text-white/60" animate={{ rotate: open ? 180 : 0 }} transition={spring}>
            <path d="M3 6l5 5 5-5" fill="none" stroke="currentColor" strokeWidth={1.75} strokeLinecap="round" strokeLinejoin="round" />
          </motion.svg>
        )}
        <span role="status" className="sr-only">{`${count} ${count === 1 ? "notification" : "notifications"}`}</span>
      </button>

      {count === 0 && <p className="px-1 py-3 text-sm text-white/50">All caught up.</p>}

      <motion.ul className={`relative ${open ? "overflow-x-hidden overflow-y-auto" : ""}`} initial={false} animate={{ height }} transition={spring}>
        <AnimatePresence initial={false}>
          {items.map((item, i) => {
            const depth = Math.min(i, SHOWN - 1);
            return (
              <motion.li
                key={item.id}
                inert={!open && i > 0}
                style={{ height: rowHeight, zIndex: count - i }}
                className="absolute inset-x-0 top-0 origin-bottom"
                onClick={open ? undefined : () => setWantOpen(true)}
                initial={{ y: -24, scale: 0.96, opacity: 0 }}
                animate={open ? { y: i * (rowHeight + GAP), scale: 1, opacity: 1 } : { y: depth * PEEK, scale: 1 - depth * 0.05, opacity: i < SHOWN ? 1 - depth * 0.2 : 0 }}
                exit={{ x: 48, opacity: 0 }}
                transition={spring}
              >
                <div className={`h-full pr-2 pl-4 ${className}`}>
                  <div className={`flex h-full items-center gap-3 transition-opacity duration-200 ${open || i === 0 ? "" : "opacity-0"}`}>
                    <div className="min-w-0 flex-1">
                      <p className="truncate text-sm font-medium">{item.title}</p>
                      {item.description && <p className="truncate text-[13px] text-white/60">{item.description}</p>}
                    </div>
                    {item.time && <span className="shrink-0 text-xs text-white/40">{item.time}</span>}
                    <button
                      type="button"
                      aria-label={`Dismiss ${item.title}`}
                      onClick={(e) => {
                        e.stopPropagation();
                        dismiss(item.id);
                      }}
                      className="grid size-8 shrink-0 place-items-center rounded-lg text-white/50 outline-none hover:bg-white/10 hover:text-white focus-visible:ring-2 focus-visible:ring-white/70"
                    >
                      <svg aria-hidden viewBox="0 0 16 16" className="size-3.5">
                        <path d="M4 4l8 8M12 4l-8 8" fill="none" stroke="currentColor" strokeWidth={1.75} strokeLinecap="round" />
                      </svg>
                    </button>
                  </div>
                </div>
              </motion.li>
            );
          })}
        </AnimatePresence>
      </motion.ul>
    </section>
  );
}