fix(mobile): prevent server input focus loss and text modification while typing

overlay/src/app/pages/auth/ServerPicker.tsx

@@ -0,0 +1,149 @@
+import React, {
+  FocusEventHandler,
+  KeyboardEventHandler,
+  MouseEventHandler,
+  useEffect,
+  useRef,
+  useState,
+} from 'react';
+import {
+  Header,
+  Icon,
+  IconButton,
+  Icons,
+  Input,
+  Menu,
+  MenuItem,
+  PopOut,
+  RectCords,
+  Text,
+  config,
+} from 'folds';
+import FocusTrap from 'focus-trap-react';
+
+import { stopPropagation } from '../../utils/keyboard';
+
+export function ServerPicker({
+  server,
+  serverList,
+  allowCustomServer,
+  onServerChange,
+}: {
+  server: string;
+  serverList: string[];
+  allowCustomServer?: boolean;
+  onServerChange: (server: string) => void;
+}) {
+  const [serverMenuAnchor, setServerMenuAnchor] = useState<RectCords>();
+  const serverInputRef = useRef<HTMLInputElement>(null);
+
+  useEffect(() => {
+    // Only sync input when server changes externally (e.g., from menu selection)
+    // and input is not focused to avoid cursor jumping during typing
+    if (
+      serverInputRef.current &&
+      serverInputRef.current.value !== server &&
+      document.activeElement !== serverInputRef.current
+    ) {
+      serverInputRef.current.value = server;
+    }
+  }, [server]);
+
+  const handleBlur: FocusEventHandler<HTMLInputElement> = (evt) => {
+    const inputServer = evt.target.value.trim();
+    if (inputServer && inputServer !== server) {
+      onServerChange(inputServer);
+    }
+  };
+
+  const handleKeyDown: KeyboardEventHandler<HTMLInputElement> = (evt) => {
+    if (evt.key === 'ArrowDown') {
+      evt.preventDefault();
+      setServerMenuAnchor(undefined);
+    }
+    if (evt.key === 'Enter') {
+      evt.preventDefault();
+      const inputServer = evt.currentTarget.value.trim();
+      if (inputServer) onServerChange(inputServer);
+    }
+  };
+
+  const handleServerSelect: MouseEventHandler<HTMLButtonElement> = (evt) => {
+    const selectedServer = evt.currentTarget.getAttribute('data-server');
+    if (selectedServer) {
+      onServerChange(selectedServer);
+    }
+    setServerMenuAnchor(undefined);
+  };
+
+  const handleOpenServerMenu: MouseEventHandler<HTMLElement> = (evt) => {
+    const target = evt.currentTarget.parentElement ?? evt.currentTarget;
+    setServerMenuAnchor(target.getBoundingClientRect());
+  };
+
+  return (
+    <Input
+      ref={serverInputRef}
+      style={{ paddingRight: config.space.S200 }}
+      variant={allowCustomServer ? 'Background' : 'Surface'}
+      outlined
+      defaultValue={server}
+      onBlur={handleBlur}
+      onKeyDown={handleKeyDown}
+      size="500"
+      readOnly={!allowCustomServer}
+      onClick={allowCustomServer ? undefined : handleOpenServerMenu}
+      after={
+        serverList.length === 0 || (serverList.length === 1 && !allowCustomServer) ? undefined : (
+          <PopOut
+            anchor={serverMenuAnchor}
+            position="Bottom"
+            align="End"
+            offset={4}
+            content={
+              <FocusTrap
+                focusTrapOptions={{
+                  initialFocus: false,
+                  onDeactivate: () => setServerMenuAnchor(undefined),
+                  clickOutsideDeactivates: true,
+                  isKeyForward: (evt: KeyboardEvent) => evt.key === 'ArrowDown',
+                  isKeyBackward: (evt: KeyboardEvent) => evt.key === 'ArrowUp',
+                  escapeDeactivates: stopPropagation,
+                }}
+              >
+                <Menu>
+                  <Header size="300" style={{ padding: `0 ${config.space.S200}` }}>
+                    <Text size="L400">Homeserver List</Text>
+                  </Header>
+                  <div style={{ padding: config.space.S100, paddingTop: 0 }}>
+                    {serverList?.map((serverName) => (
+                      <MenuItem
+                        key={serverName}
+                        radii="300"
+                        aria-pressed={serverName === server}
+                        data-server={serverName}
+                        onClick={handleServerSelect}
+                      >
+                        <Text>{serverName}</Text>
+                      </MenuItem>
+                    ))}
+                  </div>
+                </Menu>
+              </FocusTrap>
+            }
+          >
+            <IconButton
+              onClick={handleOpenServerMenu}
+              variant={allowCustomServer ? 'Background' : 'Surface'}
+              size="300"
+              aria-pressed={!!serverMenuAnchor}
+              radii="300"
+            >
+              <Icon src={Icons.ChevronBottom} />
+            </IconButton>
+          </PopOut>
+        )
+      }
+    />
+  );
+}