07Mention and hashtag highlight input

<main class="stage">
  <div class="mh is-demo" id="wrap">
    <label class="mh__label" for="mh-input">Message</label>
    <div class="mh__field">
      <div class="mh__backdrop" id="backdrop" aria-hidden="true"></div>
      <textarea class="mh__input" id="mh-input" rows="3" aria-describedby="mh-hint"></textarea>
    </div>
    <p class="mh__hint" id="mh-hint">Try typing @name or #tag</p>
  </div>
</main>

@use "../../../../site/static/demo-tokens" as *;

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-quick;    // 포커스 테두리 전환 시간
$easing: $ease-out;
$color: $subject-sky;     // 포커스 테두리 · 강조 텍스트 색

// ── 데모 무대 ──────────────────────────────────────────
@include stage($stage-orange);

.mh {
  box-sizing: border-box;
  width: min(280px, 86vw);
  background: $subject-cream;
  border-radius: $r-card;
  padding: $sp-5 $sp-5 $sp-4;
  box-shadow: $shadow-raised;

  &__label {
    display: block;
    margin: 0 0 $sp-2;
    font-weight: 700;
    font-size: 13px;
    line-height: 1;
    font-family: inherit;
    color: $stage-ink;
  }

  &__field {
    position: relative;
    width: 100%;
  }

  &__backdrop,
  &__input {
    box-sizing: border-box;
    width: 100%;
    min-height: 96px;
    max-height: 160px;
    padding: $sp-3 $sp-4;
    border: 2px solid transparent;
    border-radius: $r-control;
    font-weight: 500;
    font-size: clamp(13px, 3.8vw, 15px);
    line-height: 1.5;
    font-family: inherit;
    white-space: pre-wrap;
    word-wrap: break-word;
    overflow-wrap: break-word;
  }

  &__backdrop {
    position: absolute;
    inset: 0;
    overflow: hidden;
    pointer-events: none;
    color: $stage-ink;
    background: #fff;

    mark {
      background: none;
      color: $color;
      font-weight: 700;
      font-family: inherit;
    }
  }

  &__input {
    position: relative;
    display: block;
    resize: none;
    overflow-y: auto;
    color: transparent;
    caret-color: $stage-ink;
    background: transparent;
    transition: border-color $duration $easing;

    &:focus { outline: none; border-color: $color; }
  }

  &__hint {
    margin: $sp-2 0 0;
    font-size: 11px;
    line-height: 1.4;
    font-family: inherit;
    color: rgba($stage-ink, .72);
  }
}

// 320px 세로(무대 174px)에 맞춘다 — 입력칸을 96px 로 두면 카드가 2px 넘친다 (BD9 실측)
@media (max-width: 340px) {
  .mh__backdrop,
  .mh__input { min-height: 88px; }
}

@media (prefers-reduced-motion: reduce) {
  .mh__input { transition: none; }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.mh {
  box-sizing: border-box;
  width: min(280px, 86vw);
  background: #fff7e6;
  border-radius: 16px;
  padding: 20px 20px 16px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}
.mh__label {
  display: block;
  margin: 0 0 8px;
  font-weight: 700;
  font-size: 13px;
  line-height: 1;
  font-family: inherit;
  color: #17141a;
}
.mh__field {
  position: relative;
  width: 100%;
}
.mh__backdrop, .mh__input {
  box-sizing: border-box;
  width: 100%;
  min-height: 96px;
  max-height: 160px;
  padding: 12px 16px;
  border: 2px solid transparent;
  border-radius: 12px;
  font-weight: 500;
  font-size: clamp(13px, 3.8vw, 15px);
  line-height: 1.5;
  font-family: inherit;
  white-space: pre-wrap;
  word-wrap: break-word;
  overflow-wrap: break-word;
}
.mh__backdrop {
  position: absolute;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
  color: #17141a;
  background: #fff;
}
.mh__backdrop mark {
  background: none;
  color: #6ec8ff;
  font-weight: 700;
  font-family: inherit;
}
.mh__input {
  position: relative;
  display: block;
  resize: none;
  overflow-y: auto;
  color: transparent;
  caret-color: #17141a;
  background: transparent;
  transition: border-color 220ms ease-out;
}
.mh__input:focus {
  outline: none;
  border-color: #6ec8ff;
}
.mh__hint {
  margin: 8px 0 0;
  font-size: 11px;
  line-height: 1.4;
  font-family: inherit;
  color: rgba(23, 20, 26, 0.72);
}

@media (max-width: 340px) {
  .mh__backdrop,
  .mh__input {
    min-height: 88px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .mh__input {
    transition: none;
  }
}

(function () {
  var wrap = document.getElementById('wrap');
  var input = document.getElementById('mh-input');
  var backdrop = document.getElementById('backdrop');

  function escapeHtml(s) {
    return s
      .replace(/&/g, '&')
      .replace(/</g, '&lt;')
      .replace(/>/g, '&gt;')
      .replace(/"/g, '&quot;')
      .replace(/'/g, '&#39;');
  }

  function highlight(s) {
    return s.replace(/([@#])([\w가-힣]+)/g, function (m) {
      return '<mark>' + m + '</mark>';
    });
  }

  function rebuild() {
    var v = input.value;
    var html = highlight(escapeHtml(v));
    backdrop.innerHTML = html + (v.slice(-1) === '\n' ? ' ' : '');
  }
  input.addEventListener('input', rebuild);
  input.addEventListener('scroll', function () {
    backdrop.scrollTop = input.scrollTop;
  });

  function stopDemo() {
    if (!wrap.classList.contains('is-demo')) return;
    wrap.classList.remove('is-demo');
    clearInterval(timer);
  }
  input.addEventListener('pointerdown', stopDemo);
  input.addEventListener('keydown', stopDemo);

  var full = '@designteam how\'s this new #button style';
  var i = 0, paused = false;
  var timer = setInterval(function () {
    if (paused) return;
    if (i > full.length) {
      paused = true;
      setTimeout(function () { input.value = ''; rebuild(); i = 0; paused = false; }, 900);
      return;
    }
    input.value = full.slice(0, i);
    rebuild();
    i++;
  }, 110);
})();

import { useRef, useState, type ChangeEvent } from "react";
import styles from "./MentionHighlightInput.module.scss";

export type MentionHighlightInputProps = {
  label?: string;
};

function escapeHtml(s: string): string {
  return s
    .replace(/&/g, "&")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;")
    .replace(/"/g, "&quot;")
    .replace(/'/g, "&#39;");
}

function highlight(s: string): string {
  const escaped = escapeHtml(s);
  return escaped.replace(/([@#])([\w가-힣]+)/g, (m) => `<mark>${m}</mark>`);
}

export default function MentionHighlightInput({ label = "메시지" }: MentionHighlightInputProps) {
  const [value, setValue] = useState("");
  const backdropRef = useRef<HTMLDivElement>(null);
  const inputRef = useRef<HTMLTextAreaElement>(null);

  const onChange = (e: ChangeEvent<HTMLTextAreaElement>) => setValue(e.target.value);

  const onScroll = () => {
    if (backdropRef.current && inputRef.current) {
      backdropRef.current.scrollTop = inputRef.current.scrollTop;
    }
  };

  const html = highlight(value) + (value.slice(-1) === "\n" ? " " : "");

  return (
    <div className={styles.mh}>
      <label className={styles.label} htmlFor="mh-input-react">
        {label}
      </label>
      <div className={styles.field}>
        <div
          className={styles.backdrop}
          aria-hidden="true"
          ref={backdropRef}
          dangerouslySetInnerHTML={{ __html: html }}
        />
        <textarea
          id="mh-input-react"
          className={styles.input}
          ref={inputRef}
          rows={3}
          value={value}
          onChange={onChange}
          onScroll={onScroll}
          aria-describedby="mh-hint-react"
        />
      </div>
      <p className={styles.hint} id="mh-hint-react">
        @이름 #태그를 입력해 보세요
      </p>
    </div>
  );
}