refactor: replace useQuestionInputFocusSync with question-viewport-coordinator for improved list management

src/app/globals.css

@@ -253,31 +253,14 @@ body.dropdown-open .app-shell {
     margin 300ms ease-in-out;
 }
 
-body.question-keyboard-open .app-shell .question-snap-list {
-  padding-top: 0;
-  padding-bottom: 0;
-}
-
-body.question-keyboard-open .app-shell .question-snap-item[aria-current="step"] {
-  top: 0;
-  bottom: 0;
-}
-
-body.question-keyboard-open
-  .app-shell
-  .question-snap-item[aria-current="step"]
-  .question-snap-content {
-  /* Preserve the normal centered layout and only lift it by measured height. */
-  margin-top: auto;
-  margin-bottom: auto;
-  transform: translateY(calc(var(--question-keyboard-shift, 0px) * -1));
-}
-
-body.question-keyboard-open
-  .app-shell
-  .question-snap-item[aria-current="step"]
-  .question-snap-spacer {
-  display: none;
+.question-snap-content {
+  transform: translate3d(
+    0,
+    calc(var(--question-lift-y, 0px) * -1),
+    0
+  );
+  transition: transform 340ms cubic-bezier(0.22, 1, 0.36, 1);
+  will-change: transform;
 }
 
 .page-background-none,

src/components/Componentes/question-sheet.tsx

@@ -8,6 +8,7 @@ import { Button } from "./button";
 import { ExplanationUiFont } from "./explanation-ui-font";
 import { useQuestionAnswers } from "./question-answer-storage";
 import QuestionTitle from "./question-title";
+import { registerCompactQuestionSheet } from "./question-viewport-coordinator";
 import { useSheetScrollLock } from "./use-sheet-scroll-lock";
 
 const EXIT_ANIMATION_MS = 300;
@@ -38,6 +39,7 @@ export function QuestionSheet({ question, disabled }: QuestionSheetProps) {
   const [isClosing, setIsClosing] = useState(false);
   const [searchQuery, setSearchQuery] = useState("");
   const listRef = useRef<HTMLDivElement>(null);
+  const sheetRef = useRef<HTMLElement>(null);
   const closeSheet = useCallback(() => {
     setIsClosing(true);
     window.setTimeout(() => {
@@ -77,6 +79,22 @@ export function QuestionSheet({ question, disabled }: QuestionSheetProps) {
   })();
   const isCompact = options.length <= 5;
 
+  useEffect(() => {
+    if (!isOpen || isClosing || !isCompact) return;
+
+    let unregister: (() => void) | undefined;
+    const frame = window.requestAnimationFrame(() => {
+      if (sheetRef.current) {
+        unregister = registerCompactQuestionSheet(sheetRef.current);
+      }
+    });
+
+    return () => {
+      window.cancelAnimationFrame(frame);
+      unregister?.();
+    };
+  }, [isCompact, isClosing, isOpen]);
+
   const filteredOptions = options.filter((option) =>
     option.label.toLowerCase().includes(searchQuery.toLowerCase()),
   );
@@ -200,6 +218,7 @@ export function QuestionSheet({ question, disabled }: QuestionSheetProps) {
             }}
           >
             <section
+              ref={sheetRef}
               className={[
                 "flex w-full flex-col overflow-hidden rounded-t-[22px] bg-white pb-[env(safe-area-inset-bottom)] shadow-[0_-10px_32px_rgba(0,0,0,0.12)] transition-transform duration-[300ms] ease-out sm:max-w-[375px] animate-in slide-in-from-bottom",
                 isCompact ? "h-auto max-h-[82svh]" : "h-[82svh]",

src/components/Componentes/question-snap-list.test.tsx

@@ -6,6 +6,7 @@ import {
   waitFor,
 } from "@testing-library/react";
 import { afterEach, describe, expect, it, vi } from "vitest";
+import { updateQuestionKeyboardHeight } from "./question-viewport-coordinator";
 import { QuestionSnapList } from "./question-snap-list";
 
 vi.mock("@/translations/provider", () => ({
@@ -16,7 +17,7 @@ describe("QuestionSnapList keyboard interaction", () => {
   afterEach(() => {
     cleanup();
     document.body.classList.remove("question-keyboard-open");
-    document.documentElement.style.removeProperty("--question-keyboard-shift");
+    document.documentElement.style.removeProperty("--question-lift-y");
   });
 
   it("does not treat pointer contact as input focus", () => {
@@ -42,10 +43,27 @@ describe("QuestionSnapList keyboard interaction", () => {
     );
 
     const firstInput = screen.getByRole("textbox", { name: "Question one" });
-    const secondInput = screen.getByRole("textbox", { name: "Question two" });
+    const secondInput = document.querySelector<HTMLInputElement>(
+      'input[aria-label="Question two"]',
+    );
+    const content = firstInput.closest<HTMLElement>(".question-snap-content");
+    vi.spyOn(content as HTMLElement, "getBoundingClientRect").mockReturnValue({
+      top: 300,
+      bottom: 600,
+      left: 0,
+      right: 300,
+      width: 300,
+      height: 300,
+      x: 0,
+      y: 300,
+      toJSON: () => ({}),
+    });
 
-    fireEvent.focusIn(firstInput);
-    expect(document.body).toHaveClass("question-keyboard-open");
+    firstInput.focus();
+    updateQuestionKeyboardHeight(300);
+    await waitFor(() => {
+      expect(document.body).toHaveClass("question-keyboard-open");
+    });
 
     fireEvent.wheel(screen.getByRole("region", { name: "Questions" }), {
       deltaY: 100,
@@ -57,7 +75,7 @@ describe("QuestionSnapList keyboard interaction", () => {
       expect(secondInput).not.toHaveFocus();
       expect(
         document.documentElement.style.getPropertyValue(
-          "--question-keyboard-shift",
+          "--question-lift-y",
         ),
       ).toBe("0px");
     });
@@ -75,14 +93,72 @@ describe("QuestionSnapList keyboard interaction", () => {
       </>,
     );
 
-    fireEvent.focusIn(screen.getByRole("textbox", { name: "Question input" }));
-    expect(document.body).toHaveClass("question-keyboard-open");
+    const questionInput = screen.getByRole("textbox", {
+      name: "Question input",
+    });
+    const content = questionInput.closest<HTMLElement>(
+      ".question-snap-content",
+    );
+    vi.spyOn(content as HTMLElement, "getBoundingClientRect").mockReturnValue({
+      top: 300,
+      bottom: 600,
+      left: 0,
+      right: 300,
+      width: 300,
+      height: 300,
+      x: 0,
+      y: 300,
+      toJSON: () => ({}),
+    });
+
+    questionInput.focus();
+    updateQuestionKeyboardHeight(300);
+    await waitFor(() => {
+      expect(document.body).toHaveClass("question-keyboard-open");
+    });
+
+    screen.getByRole("textbox", { name: "Dialog search" }).focus();
+
+    await waitFor(() => {
+      expect(document.body).not.toHaveClass("question-keyboard-open");
+    });
+  });
+
+  it("raises again when Flutter reopens the keyboard without another focusin", async () => {
+    render(
+      <QuestionSnapList>
+        <input aria-label="Persistent input" type="text" />
+      </QuestionSnapList>,
+    );
+
+    const input = screen.getByRole("textbox", { name: "Persistent input" });
+    const content = input.closest<HTMLElement>(".question-snap-content");
+    vi.spyOn(content as HTMLElement, "getBoundingClientRect").mockReturnValue({
+      top: 300,
+      bottom: 600,
+      left: 0,
+      right: 300,
+      width: 300,
+      height: 300,
+      x: 0,
+      y: 300,
+      toJSON: () => ({}),
+    });
 
-    fireEvent.focusOut(screen.getByRole("textbox", { name: "Question input" }));
-    fireEvent.focusIn(screen.getByRole("textbox", { name: "Dialog search" }));
+    input.focus();
+    updateQuestionKeyboardHeight(300);
+    await waitFor(() => expect(document.body).toHaveClass("question-keyboard-open"));
 
+    updateQuestionKeyboardHeight(0);
     await waitFor(() => {
       expect(document.body).not.toHaveClass("question-keyboard-open");
+      expect(input).toHaveFocus();
+    });
+
+    updateQuestionKeyboardHeight(300);
+    await waitFor(() => {
+      expect(document.body).toHaveClass("question-keyboard-open");
+      expect(input).toHaveFocus();
     });
   });
 });

src/components/Componentes/question-snap-list.tsx

@@ -11,8 +11,8 @@ import {
 } from "react";
 import {
   resetQuestionKeyboardState,
-  useQuestionInputFocusSync,
-} from "./use-sheet-scroll-lock";
+  useQuestionViewportCoordinator,
+} from "./question-viewport-coordinator";
 
 const WHEEL_GESTURE_IDLE_MS = 320;
 const TOUCH_MIN_DISTANCE = 8;
@@ -65,7 +65,7 @@ export function QuestionSnapList({
   onActiveIndexChange,
   alignTop,
 }: QuestionSnapListProps) {
-  useQuestionInputFocusSync();
+  useQuestionViewportCoordinator();
   const questions = Children.toArray(children);
   const wheelLockedRef = useRef(false);
   const wheelUnlockTimeoutRef = useRef<number | null>(null);

src/components/Componentes/question-viewport-coordinator.ts

@@ -0,0 +1,254 @@
+"use client";
+
+import { useEffect } from "react";
+import { viewPaddingsBridge } from "@/lib/view-paddings";
+
+const KEYBOARD_THRESHOLD = 80;
+const QUESTION_GAP = 16;
+const LIFT_VARIABLE = "--question-lift-y";
+
+let activeQuestionInput: HTMLElement | null = null;
+let keyboardVisible = false;
+let keyboardHeight = 0;
+let lastKeyboardHeight = 0;
+let compactSheetTop: number | null = null;
+let currentLift = 0;
+let geometryFrame: number | null = null;
+let closedViewportHeight = 0;
+
+const NON_KEYBOARD_INPUT_TYPES = new Set([
+  "button",
+  "checkbox",
+  "color",
+  "file",
+  "hidden",
+  "image",
+  "radio",
+  "range",
+  "reset",
+  "submit",
+]);
+
+export type QuestionLiftGeometry = {
+  baseTop: number;
+  baseBottom: number;
+  visibleTop: number;
+  visibleBottom: number;
+  gap?: number;
+};
+
+export function computeQuestionLift({
+  baseTop,
+  baseBottom,
+  visibleTop,
+  visibleBottom,
+  gap = QUESTION_GAP,
+}: QuestionLiftGeometry) {
+  const contentHeight = baseBottom - baseTop;
+  const availableTop = visibleTop + gap;
+  const availableBottom = visibleBottom - gap;
+  const availableCenter = (availableTop + availableBottom) / 2;
+  const contentCenter = baseTop + contentHeight / 2;
+  const centerShift = Math.max(0, contentCenter - availableCenter);
+  const overlapShift = Math.max(0, baseBottom - availableBottom);
+  const maxShift = Math.max(0, baseTop - availableTop);
+
+  return Math.min(Math.max(centerShift, overlapShift), maxShift);
+}
+
+function isKeyboardInputTarget(target: EventTarget | null): target is HTMLElement {
+  if (target instanceof HTMLTextAreaElement) {
+    return !target.disabled && !target.readOnly;
+  }
+  if (target instanceof HTMLInputElement) {
+    const type = (target.getAttribute("type") ?? "text").toLowerCase();
+    return (
+      !NON_KEYBOARD_INPUT_TYPES.has(type) &&
+      !target.disabled &&
+      !target.readOnly
+    );
+  }
+  return target instanceof HTMLElement && target.isContentEditable;
+}
+
+export function isActiveQuestionKeyboardInput(
+  target: EventTarget | null,
+): target is HTMLElement {
+  return (
+    isKeyboardInputTarget(target) &&
+    target.closest('.question-snap-item[aria-current="step"]') !== null
+  );
+}
+
+function setLift(nextLift: number) {
+  currentLift = Math.max(0, nextLift);
+  document.documentElement.style.setProperty(
+    LIFT_VARIABLE,
+    `${currentLift}px`,
+  );
+  document.body.classList.toggle(
+    "question-keyboard-open",
+    currentLift > 0 && keyboardVisible && activeQuestionInput !== null,
+  );
+}
+
+function getKeyboardTop() {
+  if (!keyboardVisible || !activeQuestionInput) return null;
+
+  const flutterTop = window.innerHeight - keyboardHeight;
+  const viewport = window.visualViewport;
+  const viewportBottom = viewport
+    ? viewport.offsetTop + viewport.height
+    : window.innerHeight;
+
+  return Math.min(flutterTop, viewportBottom);
+}
+
+function updateLift() {
+  const content = document.querySelector<HTMLElement>(
+    '.question-snap-item[aria-current="step"] .question-snap-content',
+  );
+  if (!content) {
+    setLift(0);
+    return;
+  }
+
+  const keyboardTop = getKeyboardTop();
+  const visibleBottomCandidates = [keyboardTop, compactSheetTop].filter(
+    (value): value is number => value !== null,
+  );
+  if (visibleBottomCandidates.length === 0) {
+    setLift(0);
+    return;
+  }
+
+  const rect = content.getBoundingClientRect();
+  const snapList = content.closest<HTMLElement>(".question-snap-list");
+  const baseTop = rect.top + currentLift;
+  const baseBottom = rect.bottom + currentLift;
+  const safeTop = Number.parseFloat(
+    getComputedStyle(document.documentElement).getPropertyValue("--safe-top"),
+  );
+
+  setLift(
+    computeQuestionLift({
+      baseTop,
+      baseBottom,
+      visibleTop: Math.max(
+        Number.isFinite(safeTop) ? safeTop : 0,
+        snapList?.getBoundingClientRect().top ?? 0,
+      ),
+      visibleBottom: Math.min(...visibleBottomCandidates),
+    }),
+  );
+}
+
+function scheduleLiftUpdate() {
+  if (geometryFrame !== null) window.cancelAnimationFrame(geometryFrame);
+  geometryFrame = window.requestAnimationFrame(() => {
+    geometryFrame = null;
+    updateLift();
+  });
+}
+
+export function updateQuestionKeyboardHeight(height: number) {
+  keyboardHeight = Math.max(0, height);
+  keyboardVisible = keyboardHeight > KEYBOARD_THRESHOLD;
+  if (keyboardVisible) {
+    lastKeyboardHeight = keyboardHeight;
+    if (isActiveQuestionKeyboardInput(document.activeElement)) {
+      activeQuestionInput = document.activeElement;
+    }
+  }
+  scheduleLiftUpdate();
+}
+
+export function registerCompactQuestionSheet(element: HTMLElement) {
+  compactSheetTop = element.getBoundingClientRect().top;
+  scheduleLiftUpdate();
+  return () => {
+    compactSheetTop = null;
+    scheduleLiftUpdate();
+  };
+}
+
+export function resetQuestionKeyboardState() {
+  if (geometryFrame !== null) {
+    window.cancelAnimationFrame(geometryFrame);
+    geometryFrame = null;
+  }
+  if (isActiveQuestionKeyboardInput(document.activeElement)) {
+    document.activeElement.blur();
+  }
+  activeQuestionInput = null;
+  keyboardVisible = false;
+  keyboardHeight = 0;
+  compactSheetTop = null;
+  setLift(0);
+}
+
+export function useQuestionViewportCoordinator() {
+  useEffect(() => {
+    closedViewportHeight = window.visualViewport?.height ?? window.innerHeight;
+
+    const handleFocusIn = (event: FocusEvent) => {
+      if (!isActiveQuestionKeyboardInput(event.target)) return;
+      activeQuestionInput = event.target;
+
+      // Start with the last known keyboard geometry so lifting begins in the
+      // same frame as focus; Flutter then replaces it with the exact height.
+      if (!keyboardVisible && lastKeyboardHeight > KEYBOARD_THRESHOLD) {
+        keyboardHeight = lastKeyboardHeight;
+        keyboardVisible = true;
+      }
+      scheduleLiftUpdate();
+    };
+
+    const handleFocusOut = () => {
+      window.setTimeout(() => {
+        activeQuestionInput = isActiveQuestionKeyboardInput(
+          document.activeElement,
+        )
+          ? document.activeElement
+          : null;
+        if (!activeQuestionInput) scheduleLiftUpdate();
+      }, 0);
+    };
+
+    const unsubscribeConfig = viewPaddingsBridge.subscribeConfig((config) => {
+      updateQuestionKeyboardHeight(config.keyboardHeight);
+    });
+
+    const handleViewportResize = () => {
+      const viewportHeight = window.visualViewport?.height ?? window.innerHeight;
+      const reduction = closedViewportHeight - viewportHeight;
+
+      if (reduction > KEYBOARD_THRESHOLD) {
+        if (isActiveQuestionKeyboardInput(document.activeElement)) {
+          activeQuestionInput = document.activeElement;
+          keyboardVisible = true;
+          keyboardHeight = Math.max(keyboardHeight, reduction);
+          lastKeyboardHeight = keyboardHeight;
+          scheduleLiftUpdate();
+        }
+      } else if (keyboardHeight <= KEYBOARD_THRESHOLD) {
+        keyboardVisible = false;
+        keyboardHeight = 0;
+        closedViewportHeight = viewportHeight;
+        scheduleLiftUpdate();
+      }
+    };
+
+    document.addEventListener("focusin", handleFocusIn);
+    document.addEventListener("focusout", handleFocusOut);
+    window.visualViewport?.addEventListener("resize", handleViewportResize);
+
+    return () => {
+      document.removeEventListener("focusin", handleFocusIn);
+      document.removeEventListener("focusout", handleFocusOut);
+      window.visualViewport?.removeEventListener("resize", handleViewportResize);
+      unsubscribeConfig();
+      resetQuestionKeyboardState();
+    };
+  }, []);
+}

src/components/Componentes/use-sheet-scroll-lock.ts

@@ -1,18 +1,14 @@
 "use client";
 
 import { useEffect, useRef } from "react";
-import { viewPaddingsBridge } from "@/lib/view-paddings";
 
 let activeSheetCount = 0;
-let hasFocusedKeyboardInput = false;
-let keyboardHeight = 0;
 let bodyHadDropdownClass = false;
 let initialBodyOverflow = "";
 let initialHtmlOverflow = "";
 let initialAppShellOverflow = "";
 let initialAppShellTouchAction = "";
 let lockedAppShell: HTMLElement | null = null;
-let keyboardShiftFrame: number | null = null;
 const SHEET_HISTORY_KEY = "__habibQuestionSheet";
 
 type SheetScrollLockOptions = {
@@ -93,154 +89,3 @@ export function useSheetScrollLock(
     };
   }, [isOpen]);
 }
-
-const NON_KEYBOARD_INPUT_TYPES = new Set([
-  "button",
-  "checkbox",
-  "color",
-  "file",
-  "hidden",
-  "image",
-  "radio",
-  "range",
-  "reset",
-  "submit",
-]);
-
-function isKeyboardInputTarget(target: EventTarget | null): boolean {
-  if (target instanceof HTMLTextAreaElement) {
-    return !target.disabled && !target.readOnly;
-  }
-  if (target instanceof HTMLInputElement) {
-    const type = (target.getAttribute("type") ?? "text").toLowerCase();
-    return (
-      !NON_KEYBOARD_INPUT_TYPES.has(type) &&
-      !target.disabled &&
-      !target.readOnly
-    );
-  }
-  if (target instanceof HTMLElement) {
-    return target.isContentEditable;
-  }
-  return false;
-}
-
-function syncQuestionInputOpenClass() {
-  if (hasFocusedKeyboardInput) {
-    document.body.classList.add("question-keyboard-open");
-  } else {
-    document.body.classList.remove("question-keyboard-open");
-  }
-}
-
-function syncKeyboardShift(isOpen: boolean) {
-  const root = document.documentElement;
-  if (!isOpen) {
-    root.style.setProperty("--question-keyboard-shift", "0px");
-    return;
-  }
-
-  const activeContent = document.querySelector<HTMLElement>(
-    '.question-snap-item[aria-current="step"] .question-snap-content',
-  );
-  const snapList = document.querySelector<HTMLElement>(".question-snap-list");
-  if (!activeContent || !snapList) return;
-
-  const contentTop = activeContent.getBoundingClientRect().top;
-  const targetTop = snapList.getBoundingClientRect().top + 8;
-  const requiredShift = Math.max(0, contentTop - targetTop);
-  root.style.setProperty("--question-keyboard-shift", `${requiredShift}px`);
-}
-
-function isActiveQuestionKeyboardInput(
-  target: EventTarget | null,
-): target is HTMLElement {
-  return (
-    isKeyboardInputTarget(target) &&
-    target instanceof HTMLElement &&
-    target.closest('.question-snap-item[aria-current="step"]') !== null
-  );
-}
-
-export function resetQuestionKeyboardState() {
-  if (keyboardShiftFrame !== null) {
-    window.cancelAnimationFrame(keyboardShiftFrame);
-    keyboardShiftFrame = null;
-  }
-
-  if (isActiveQuestionKeyboardInput(document.activeElement)) {
-    document.activeElement.blur();
-  }
-
-  hasFocusedKeyboardInput = false;
-  keyboardHeight = 0;
-  syncQuestionInputOpenClass();
-  syncKeyboardShift(false);
-}
-
-/**
- * Moves the active question up (same animation the dropdown sheet uses) while
- * a keyboard input is focused, so the mobile keyboard cannot cover it.
- */
-export function useQuestionInputFocusSync() {
-  useEffect(() => {
-    const handleFocusIn = (event: FocusEvent) => {
-      if (!isActiveQuestionKeyboardInput(event.target)) return;
-      hasFocusedKeyboardInput = true;
-      syncQuestionInputOpenClass();
-      if (keyboardShiftFrame !== null) {
-        window.cancelAnimationFrame(keyboardShiftFrame);
-      }
-      keyboardShiftFrame = window.requestAnimationFrame(() => {
-        keyboardShiftFrame = null;
-        syncKeyboardShift(true);
-      });
-    };
-    const handleFocusOut = (event: FocusEvent) => {
-      if (!isKeyboardInputTarget(event.target)) return;
-      window.setTimeout(() => {
-        hasFocusedKeyboardInput = isActiveQuestionKeyboardInput(
-          document.activeElement,
-        );
-        syncQuestionInputOpenClass();
-        if (!hasFocusedKeyboardInput) syncKeyboardShift(false);
-      }, 0);
-    };
-
-    const unsubscribeConfig = viewPaddingsBridge.subscribeConfig((config) => {
-      keyboardHeight = config.keyboardHeight;
-      if (keyboardHeight === 0) {
-        // Android Back can hide Flutter's keyboard without dispatching blur.
-        hasFocusedKeyboardInput = false;
-      }
-      syncQuestionInputOpenClass();
-      if (keyboardHeight === 0) syncKeyboardShift(false);
-    });
-
-    const initialViewportHeight = window.visualViewport?.height ?? 0;
-    const handleViewportResize = () => {
-      const viewportHeight = window.visualViewport?.height ?? 0;
-      if (
-        initialViewportHeight > 0 &&
-        viewportHeight >= initialViewportHeight - 40
-      ) {
-        hasFocusedKeyboardInput = false;
-        syncQuestionInputOpenClass();
-      }
-    };
-
-    document.addEventListener("focusin", handleFocusIn);
-    document.addEventListener("focusout", handleFocusOut);
-    window.visualViewport?.addEventListener("resize", handleViewportResize);
-    return () => {
-      document.removeEventListener("focusin", handleFocusIn);
-      document.removeEventListener("focusout", handleFocusOut);
-      window.visualViewport?.removeEventListener(
-        "resize",
-        handleViewportResize,
-      );
-      unsubscribeConfig();
-      resetQuestionKeyboardState();
-    };
-  }, []);
-}