"use client";
import { CompareIcon } from "../ui/icons.tsx";
import { useId, useRef, useState } from "react";
const whenBroken = (fail: () => void) => (img: HTMLImageElement | null) => {
  if (img?.complete && !img.naturalWidth) img.decode?.().catch(fail);
};
export function ImageCompare({
  before,
  after,
  value,
  onValueChange,
  label = "Image comparison",
  beforeLabel = "Before",
  afterLabel = "After",
  className = "",
}: {
  before: { src: string; alt: string };
  after: { src: string; alt: string };
  value: number;
  onValueChange: (value: number) => void;
  label?: string;
  beforeLabel?: string;
  afterLabel?: string;
  className?: string;
}) {
  const ref = useRef<HTMLDivElement>(null),
    id = useId(),
    [failed, setFailed] = useState<string>(),
    current = Math.max(0, Math.min(100, Number.isFinite(value) ? value : 50)),
    broken = failed === before.src || failed === after.src;
  const update = (x: number) => {
    const r = ref.current!.getBoundingClientRect();
    if (r.width)
      onValueChange(
        Math.round(Math.max(0, Math.min(100, ((x - r.left) / r.width) * 100))),
      );
  };
  return (
    <figure className={`mizu-image-compare ${className}`}>
      <figcaption>{label}</figcaption>
      <div
        ref={ref}
        className="mizu-image-compare-stage"
        onPointerDown={(e) => {
          if (e.button === 0 && !broken) {
            e.currentTarget.setPointerCapture(e.pointerId);
            update(e.clientX);
          }
        }}
        onPointerMove={(e) => {
          if (e.currentTarget.hasPointerCapture(e.pointerId)) update(e.clientX);
        }}
        onPointerUp={(e) => {
          if (e.currentTarget.hasPointerCapture(e.pointerId))
            e.currentTarget.releasePointerCapture(e.pointerId);
        }}
      >
        {broken ? (
          <p role="status">Comparison image unavailable.</p>
        ) : (
          <>
            <img
              ref={whenBroken(() => setFailed(before.src))}
              src={before.src}
              alt={before.alt}
              onError={() => setFailed(before.src)}
            />
            <img
              ref={whenBroken(() => setFailed(after.src))}
              className="mizu-image-compare-after"
              src={after.src}
              alt={after.alt}
              style={{ clipPath: `inset(0 ${100 - current}% 0 0)` }}
              onError={() => setFailed(after.src)}
            />
            <span
              className="mizu-image-compare-line"
              style={{ left: `${current}%` }}
              aria-hidden="true"
            >
              <span>
                <CompareIcon />
              </span>
            </span>
            <span className="mizu-image-compare-before" aria-hidden="true">
              {beforeLabel}
            </span>
            <span className="mizu-image-compare-label-after" aria-hidden="true">
              {afterLabel}
            </span>
          </>
        )}
      </div>
      <label htmlFor={id} className="mizu-sr-only">
        {label} reveal
      </label>
      <input
        id={id}
        type="range"
        min={0}
        max={100}
        value={current}
        disabled={broken}
        aria-valuetext={`${current}% ${afterLabel.toLowerCase()}`}
        onChange={(e) => onValueChange(Number(e.target.value))}
      />
      <div className="mizu-compare-legend">
        <span>{beforeLabel}</span>
        <output>
          {current}% {afterLabel.toLowerCase()}
        </output>
        <span>{afterLabel}</span>
      </div>
    </figure>
  );
}