"use client";

import { useId, type ReactNode } from "react";
import { motion, useReducedMotion } from "motion/react";

type LiquidCanvasProps = {
  children?: ReactNode;
  className?: string;
  /** Blobs alternate between these two colours. */
  colors?: [string, string];
  background?: string;
  /** 1 is the default pace; 2 is twice as fast. */
  speed?: number;
};

// Position (%), size (px), path (px) and seconds per loop of each blob.
const BLOBS = [
  { left: 15, top: 25, size: 130, x: [0, 90, 30, 0], y: [0, 40, -30, 0], d: 13 },
  { left: 55, top: 15, size: 110, x: [0, -70, 20, 0], y: [0, 60, 90, 0], d: 11 },
  { left: 35, top: 55, size: 150, x: [0, 60, -50, 0], y: [0, -50, 10, 0], d: 15 },
  { left: 70, top: 55, size: 100, x: [0, -90, -30, 0], y: [0, -30, 40, 0], d: 12 },
  { left: 5, top: 65, size: 90, x: [0, 70, 120, 0], y: [0, -60, 10, 0], d: 14 },
  { left: 80, top: 20, size: 80, x: [0, -40, -110, 0], y: [0, 70, 20, 0], d: 10 },
];

/* LiquidCanvas: colour blobs drift and melt into each other like liquid, using an SVG goo filter. */
export function LiquidCanvas({
  children,
  className = "",
  colors = ["#a78bfa", "#f472b6"],
  background = "#08070f",
  speed = 1,
}: LiquidCanvasProps) {
  const reduce = useReducedMotion();
  const filterId = `goo-${useId().replace(/[^a-zA-Z0-9-]/g, "")}`;

  return (
    <div className={`relative overflow-hidden ${className}`} style={{ background }}>
      <svg aria-hidden className="absolute h-0 w-0">
        <filter id={filterId}>
          <feGaussianBlur in="SourceGraphic" stdDeviation="16" result="blur" />
          <feColorMatrix in="blur" mode="matrix" values="1 0 0 0 0  0 1 0 0 0  0 0 1 0 0  0 0 0 24 -10" />
        </filter>
      </svg>
      <div aria-hidden className="absolute inset-0 opacity-90" style={{ filter: `url(#${filterId})` }}>
        {BLOBS.map((b, i) => (
          <motion.div
            key={i}
            className="absolute rounded-full"
            style={{ left: `${b.left}%`, top: `${b.top}%`, width: b.size, height: b.size, background: colors[i % 2] }}
            animate={reduce ? undefined : { x: b.x, y: b.y }}
            transition={{ duration: b.d / speed, repeat: Infinity, ease: "easeInOut" }}
          />
        ))}
      </div>
      <div className="relative h-full">{children}</div>
    </div>
  );
}