feat: refine codex live chat context flows

src/utils/clipboard.ts

@@ -0,0 +1,117 @@
+type SelectionSnapshot = {
+  activeElement: Element | null;
+  ranges: Range[];
+};
+
+function captureSelectionSnapshot(): SelectionSnapshot | null {
+  if (typeof window === 'undefined' || typeof document === 'undefined') {
+    return null;
+  }
+
+  const selection = window.getSelection();
+  const ranges: Range[] = [];
+
+  if (selection) {
+    for (let index = 0; index < selection.rangeCount; index += 1) {
+      ranges.push(selection.getRangeAt(index).cloneRange());
+    }
+  }
+
+  return {
+    activeElement: document.activeElement,
+    ranges,
+  };
+}
+
+function restoreSelectionSnapshot(snapshot: SelectionSnapshot | null) {
+  if (!snapshot || typeof window === 'undefined') {
+    return;
+  }
+
+  const selection = window.getSelection();
+  selection?.removeAllRanges();
+  snapshot.ranges.forEach((range) => selection?.addRange(range));
+
+  const target = snapshot.activeElement;
+
+  if (target instanceof HTMLElement || target instanceof SVGElement) {
+    try {
+      target.focus({ preventScroll: true });
+    } catch {
+      target.focus();
+    }
+  }
+}
+
+function copyUsingTextareaFallback(text: string) {
+  if (
+    typeof window === 'undefined' ||
+    typeof document === 'undefined' ||
+    typeof document.execCommand !== 'function' ||
+    !document.body
+  ) {
+    return false;
+  }
+
+  const snapshot = captureSelectionSnapshot();
+  const textarea = document.createElement('textarea');
+  textarea.value = text;
+  textarea.tabIndex = -1;
+  textarea.readOnly = true;
+  textarea.setAttribute('readonly', '');
+  textarea.setAttribute('aria-hidden', 'true');
+  textarea.style.position = 'fixed';
+  textarea.style.top = '0';
+  textarea.style.left = '0';
+  textarea.style.width = '1px';
+  textarea.style.height = '1px';
+  textarea.style.padding = '0';
+  textarea.style.border = '0';
+  textarea.style.outline = '0';
+  textarea.style.boxShadow = 'none';
+  textarea.style.background = 'transparent';
+  textarea.style.opacity = '0';
+  textarea.style.pointerEvents = 'none';
+  textarea.style.fontSize = '16px';
+  textarea.style.whiteSpace = 'pre';
+  textarea.style.userSelect = 'text';
+  textarea.style.webkitUserSelect = 'text';
+
+  document.body.appendChild(textarea);
+
+  try {
+    try {
+      textarea.focus({ preventScroll: true });
+    } catch {
+      textarea.focus();
+    }
+
+    textarea.select();
+    textarea.selectionStart = 0;
+    textarea.selectionEnd = text.length;
+    textarea.setSelectionRange(0, text.length);
+    return document.execCommand('copy');
+  } catch {
+    return false;
+  } finally {
+    textarea.remove();
+    restoreSelectionSnapshot(snapshot);
+  }
+}
+
+export async function copyTextToClipboard(text: string): Promise<void> {
+  if (typeof navigator !== 'undefined' && navigator.clipboard?.writeText) {
+    try {
+      await navigator.clipboard.writeText(text);
+      return;
+    } catch {
+      // Fall back when the browser exposes the API but rejects the write.
+    }
+  }
+
+  if (copyUsingTextareaFallback(text)) {
+    return;
+  }
+
+  throw new Error('브라우저가 클립보드 복사를 차단했습니다.');
+}