"use client";

import { useCallback, useEffect, useRef, useState, type CSSProperties } from "react";
import { animate, AnimatePresence, motion, useMotionValue, useReducedMotion, useTransform } from "motion/react";

export type ToastWaveItem = {
  id: number;
  title: string;
  description?: string;
  tone?: "info" | "success" | "error";
};

type ToastWaveProps = {
  /** From useToastWave. */
  toasts: ToastWaveItem[];
  /** From useToastWave. */
  dismiss: (id: number) => void;
  /** Milliseconds a toast stays. Hover or focus pauses it. */
  duration?: number;
  /** Keep the toasts inside the nearest positioned parent instead of the screen. */
  contained?: boolean;
  /** Replaces the default toast look. */
  className?: string;
};

const TONES = { info: "#a78bfa", success: "#34d399", error: "#f87171" };

/* Holds the toast list. Give max to change how many show at once. */
export function useToastWave(max = 3) {
  const nextId = useRef(0);
  const [toasts, setToasts] = useState<ToastWaveItem[]>([]);

  const show = useCallback(
    (toast: Omit<ToastWaveItem, "id">) => {
      const id = ++nextId.current;
      setToasts((list) => [...list, { ...toast, id }].slice(-max));
    },
    [max],
  );
  const dismiss = useCallback((id: number) => setToasts((list) => list.filter((t) => t.id !== id)), []);

  return { toasts, show, dismiss };
}

function ToastCard({
  toast,
  dismiss,
  duration,
  className,
}: { toast: ToastWaveItem } & Pick<ToastWaveProps, "dismiss"> & { duration: number; className: string }) {
  const reduce = useReducedMotion();
  const [paused, setPaused] = useState(false);
  const left = useMotionValue(1);
  const clip = useTransform(left, (share) => `inset(0 ${(1 - share) * 100}% 0 0)`);

  // The wave line is the timer: it drains, and dismisses when empty. Pausing just stops it.
  useEffect(() => {
    if (paused) return;
    const run = animate(left, 0, {
      duration: (left.get() * duration) / 1000,
      ease: "linear",
      onComplete: () => dismiss(toast.id),
    });
    return () => run.stop();
  }, [paused, left, duration, dismiss, toast.id]);

  return (
    <div
      style={{ "--tw": TONES[toast.tone ?? "info"] } as CSSProperties}
      onPointerEnter={() => setPaused(true)}
      onPointerLeave={() => setPaused(false)}
      onFocus={() => setPaused(true)}
      onBlur={() => setPaused(false)}
      className={`relative overflow-hidden ${className}`}
    >
      {!reduce && (
        <motion.span
          aria-hidden
          className="pointer-events-none absolute inset-y-0 left-0 w-1/2 bg-linear-to-r from-transparent via-(--tw)/30 to-transparent"
          initial={{ x: "-100%", opacity: 1 }}
          animate={{ x: "200%", opacity: 0 }}
          transition={{ duration: 0.9, ease: "easeOut" }}
        />
      )}
      <div className="relative flex items-start gap-2.5 pr-6">
        <span aria-hidden className="mt-1.5 h-2 w-2 shrink-0 rounded-full bg-(--tw)" />
        <div className="min-w-0">
          <p className="text-sm font-medium">{toast.title}</p>
          {toast.description && <p className="mt-0.5 text-[13px] text-white/55">{toast.description}</p>}
        </div>
      </div>
      <button
        type="button"
        aria-label="Dismiss"
        onClick={() => dismiss(toast.id)}
        className="absolute top-2.5 right-2.5 grid h-6 w-6 place-items-center rounded-md 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 12 12" className="h-3 w-3" fill="none" stroke="currentColor" strokeWidth="1.6" strokeLinecap="round">
          <path d="M2 2l8 8M10 2l-8 8" />
        </svg>
      </button>
      <motion.div aria-hidden style={{ clipPath: clip }} className="absolute inset-x-0 bottom-0 h-1.5 overflow-hidden">
        <motion.svg
          viewBox="0 0 160 6"
          preserveAspectRatio="none"
          className="h-full w-[200%] text-(--tw)"
          animate={reduce ? undefined : { x: ["0%", "-50%"] }}
          transition={{ duration: 2.4, ease: "linear", repeat: Infinity }}
        >
          <path d="M0 3q10-5 20 0t20 0t20 0t20 0t20 0t20 0t20 0t20 0" fill="none" stroke="currentColor" strokeWidth="1.5" vectorEffect="non-scaling-stroke" />
        </motion.svg>
      </motion.div>
    </div>
  );
}

/* ToastWave: toasts ride in from the side on a band of colour, and a little wave along the bottom drains as the time runs out. Hover or focus holds it still. */
export function ToastWave({
  toasts,
  dismiss,
  duration = 4000,
  contained = false,
  className = "rounded-2xl border border-white/10 bg-[#141026]/95 p-3.5 pb-4 text-white shadow-xl shadow-black/50 backdrop-blur-xl",
}: ToastWaveProps) {
  const reduce = useReducedMotion();
  const hidden = reduce ? { opacity: 0 } : { opacity: 0, x: 48, scale: 0.96 };

  return (
    <ol
      aria-live="polite"
      aria-label="Notifications"
      className={`${contained ? "absolute" : "fixed"} right-4 bottom-4 z-50 flex w-[min(22rem,calc(100%-2rem))] flex-col gap-2`}
    >
      <AnimatePresence initial={false} mode="popLayout">
        {toasts.map((toast) => (
          <motion.li
            key={toast.id}
            layout={!reduce}
            initial={hidden}
            animate={{ opacity: 1, x: 0, scale: 1 }}
            exit={hidden}
            transition={reduce ? { duration: 0.15 } : { type: "spring", stiffness: 420, damping: 32 }}
          >
            <ToastCard toast={toast} dismiss={dismiss} duration={duration} className={className} />
          </motion.li>
        ))}
      </AnimatePresence>
    </ol>
  );
}