Copy button

'use client';

import { useEffect, useRef, useState } from 'react';
import { cn, prefersReducedMotion, useTexts } from '@/lib/kit';
import { Icon } from '@/components/ui/icon';
import { iconButtonClass, iconPress, type IconButtonSize, type IconButtonVariant } from '@/components/ui/icon-button';

const TEXTS = {
  en: { copy: 'Copy', copied: 'Copied', failed: 'Copy failed', copyValue: 'Copy to clipboard' },
  de: { copy: 'Kopieren', copied: 'Kopiert', failed: 'Kopieren fehlgeschlagen', copyValue: 'In die Zwischenablage kopieren' },
};
type Texts = (typeof TEXTS)['en'];

async function writeClipboard(text: string) {
  try {
    await navigator.clipboard.writeText(text);
    return true;
  } catch {
    // Older browsers and insecure origins
    const ta = document.createElement('textarea');
    ta.value = text;
    ta.setAttribute('readonly', '');
    ta.style.cssText = 'position:fixed;opacity:0;pointer-events:none';
    document.body.append(ta);
    ta.select();
    const ok = document.execCommand('copy');
    ta.remove();
    return ok;
  }
}

/** Copies a text and reports back. state: idle, copied, failed. */
export function useCopy(timeout = 1800) {
  const [state, setState] = useState<'idle' | 'copied' | 'failed'>('idle');
  const timer = useRef<number | undefined>(undefined);
  useEffect(() => () => window.clearTimeout(timer.current), []);
  const copy = async (text: string) => {
    const ok = await writeClipboard(text);
    setState(ok ? 'copied' : 'failed');
    window.clearTimeout(timer.current);
    timer.current = window.setTimeout(() => setState('idle'), timeout);
  };
  return [state, copy] as const;
}

/**
 * Copy and check on top of each other. The copy icon turns away and shrinks,
 * the check draws itself (stroke-dashoffset), the pair settles with a small pop.
 */
function SwapIcon({ done, size }: { done: boolean; size: number }) {
  const ref = useRef<HTMLSpanElement>(null);
  const was = useRef(done);
  useEffect(() => {
    if (was.current === done) return;
    was.current = done;
    const el = ref.current;
    if (!done || !el || prefersReducedMotion() || typeof el.animate !== 'function') return;
    el.animate([{ transform: 'scale(1)' }, { transform: 'scale(0.82)', offset: 0.3 }, { transform: 'scale(1.1)', offset: 0.7 }, { transform: 'scale(1)' }], { duration: 460, easing: 'cubic-bezier(0.2,0.7,0.2,1)' });
  }, [done]);
  return (
    <span ref={ref} className="relative grid shrink-0 place-items-center" style={{ width: size, height: size }}>
      <Icon
        name="copy"
        size={size}
        className={cn('absolute transition-[opacity,scale,rotate] duration-200 ease-[var(--ease-kit)] motion-reduce:transition-none', done && '-rotate-12 scale-50 opacity-0')}
      />
      <svg viewBox="0 0 24 24" width={size} height={size} fill="none" aria-hidden className={cn('absolute text-success transition-opacity duration-200', !done && 'opacity-0')}>
        <path
          d="m5 12.5 4.5 4.5L19 7.5"
          pathLength={1}
          strokeDasharray="1 1"
          stroke="currentColor"
          strokeWidth="2"
          strokeLinecap="round"
          strokeLinejoin="round"
          className={cn('transition-[stroke-dashoffset] ease-[var(--ease-kit)] motion-reduce:transition-none', done ? 'duration-[420ms] delay-75 [stroke-dashoffset:0]' : 'duration-150 [stroke-dashoffset:1]')}
        />
      </svg>
    </span>
  );
}

/** Two words on one spot: the old one leaves upward, the new one comes up from below, the width of both stays reserved */
function SwapText({ done, idle, active, invisible }: { done: boolean; idle: string; active: string; invisible?: boolean }) {
  const base = 'col-start-1 row-start-1 transition-[opacity,translate] duration-300 ease-[var(--ease-kit)] motion-reduce:transition-none';
  return (
    <span className="grid overflow-hidden">
      <span className={cn(base, done && '-translate-y-2 opacity-0', invisible && done && 'invisible')}>{idle}</span>
      <span aria-hidden className={cn(base, !done && 'translate-y-2 opacity-0', invisible && !done && 'invisible')}>
        {active}
      </span>
    </span>
  );
}

export interface CopyButtonProps {
  /** The text that lands in the clipboard */
  value: string;
  /** icon: square icon button. label: icon and text ("Copy" turns into "Copied"). */
  display?: 'icon' | 'label';
  variant?: IconButtonVariant;
  size?: IconButtonSize;
  labels?: Partial<Texts>;
  onCopy?: () => void;
  className?: string;
}

/**
 * Copies a value with one click. The icon turns into a check, a polite live region announces it.
 *   <CopyButton value="npm i @northwind/sdk" />
 */
export function CopyButton({ value, display = 'icon', variant = 'ghost', size = 'sm', labels, onCopy, className }: CopyButtonProps) {
  const t = useTexts(TEXTS, labels);
  const [state, copy] = useCopy();
  const done = state === 'copied';
  const iconSize = size === 'xs' ? 14 : size === 'sm' ? 16 : 18;
  const status = <span aria-live="polite" className="sr-only">{state === 'copied' ? t.copied : state === 'failed' ? t.failed : ''}</span>;
  const click = () => {
    copy(value);
    onCopy?.();
  };

  if (display === 'label') {
    return (
      <button
        type="button"
        onClick={click}
        onPointerDown={iconPress}
        className={cn(
          iconButtonClass({ variant, size }),
          'inline-flex w-auto gap-1.5 font-medium',
          size === 'xs' ? 'h-7 px-2 text-xs' : size === 'sm' ? 'h-9 px-3 text-[13px]' : 'h-11 px-4 text-sm',
          className,
        )}
      >
        <SwapIcon done={done} size={iconSize} />
        {/* Both words reserve their width, so the button never jumps */}
        <SwapText done={done} idle={t.copy} active={t.copied} />
        {status}
      </button>
    );
  }
  return (
    <button type="button" onClick={click} onPointerDown={iconPress} aria-label={done ? t.copied : t.copyValue} title={t.copy} className={iconButtonClass({ variant, size, className })}>
      <SwapIcon done={done} size={iconSize} />
      {status}
    </button>
  );
}

export interface CopyFieldProps {
  value: string;
  /** Visible label above the field */
  label?: string;
  /** Shown before the value, e.g. "$" for a command */
  prompt?: string;
  /** Masks the value until revealed, e.g. for API keys */
  secret?: boolean;
  labels?: Partial<Texts>;
  className?: string;
}

/** A read-only value with a copy button: invite links, API keys, install commands. */
export function CopyField({ value, label, prompt, secret, labels, className }: CopyFieldProps) {
  const t = useTexts(TEXTS, labels);
  const [state, copy] = useCopy();
  const done = state === 'copied';
  const valueRef = useRef<HTMLSpanElement>(null);
  // A light passes over the value, so you see what went to the clipboard
  const sweep = () => {
    const el = valueRef.current;
    if (!el || prefersReducedMotion() || typeof el.animate !== 'function') return;
    const band = document.createElement('span');
    band.setAttribute('aria-hidden', 'true');
    band.style.cssText = 'position:absolute;inset:0;pointer-events:none;background:linear-gradient(100deg,transparent 20%,color-mix(in oklab, var(--success) 22%, transparent) 50%,transparent 80%);';
    el.append(band);
    const a = band.animate([{ transform: 'translateX(-100%)', opacity: 1 }, { transform: 'translateX(100%)', opacity: 0.6 }], { duration: 640, easing: 'cubic-bezier(0.2,0.7,0.2,1)' });
    a.onfinish = a.oncancel = () => band.remove();
  };
  const shown = secret ? value.slice(0, 7) + '•'.repeat(Math.max(8, Math.min(20, value.length - 11))) + value.slice(-4) : value;
  return (
    <div className={cn('grid w-full min-w-0 gap-2', className)}>
      {label && <p className="text-sm font-medium text-foreground">{label}</p>}
      {/* The row measures itself: in a narrow spot (phone, popover) the button folds to its icon and the value keeps the room */}
      <div
        data-done={done || undefined}
        className="@container/copy flex h-11 min-w-[12rem] items-center rounded-lg border border-border bg-surface ps-3.5 pe-1.5 shadow-[var(--highlight)] transition-[border-color,box-shadow] duration-300 data-done:border-[color-mix(in_oklab,var(--success)_45%,var(--border))] data-done:shadow-[0_0_0_3px_color-mix(in_oklab,var(--success)_12%,transparent),var(--highlight)]"
      >
        {prompt && <span className="me-2 select-none text-subtle-foreground">{prompt}</span>}
        <span ref={valueRef} className="relative min-w-0 flex-1 truncate text-sm tabular-nums text-foreground" aria-label={secret ? label : undefined}>
          {shown}
        </span>
        <button
          type="button"
          onClick={() => {
            copy(value);
            sweep();
          }}
          onPointerDown={iconPress}
          aria-label={done ? t.copied : label ? `${t.copy}: ${label}` : t.copy}
          className={cn(
            'relative isolate ms-2 inline-flex h-8 shrink-0 items-center justify-center gap-1.5 rounded-md border border-border bg-background px-2.5 text-xs font-medium text-foreground shadow-[var(--shadow-sm)] transition-[background-color,scale] duration-200 hover:bg-accent active:scale-95 active:duration-100 motion-reduce:active:scale-100 @max-[22rem]/copy:w-8 @max-[22rem]/copy:px-0',
            'after:absolute after:-inset-1.5 after:content-[""]',
          )}
        >
          <SwapIcon done={done} size={14} />
          <span aria-hidden className="@max-[22rem]/copy:hidden">
            <SwapText done={done} idle={t.copy} active={t.copied} invisible />
          </span>
          <span aria-live="polite" className="sr-only">
            {done ? t.copied : ''}
          </span>
        </button>
      </div>
    </div>
  );
}