From 033e161455ba723243a3f705a09652b00279da91 Mon Sep 17 00:00:00 2001
From: Huang Xin <chrox.huang@gmail.com>
Date: Sun, 25 May 2025 15:32:00 +0800
Subject: [PATCH] layout: overlay the footer of the translator popup and less
 sensitive page flip with mouse wheel (#1238)

* layout: overlay the footer of the translator popup

* fix: less sensitive page flip with mouse wheel, addresses #1165
---
 .../components/annotator/TranslatorPopup.tsx  | 37 +++++++++---------
 .../src/app/reader/hooks/useIframeEvents.ts   | 16 +++-----
 apps/readest-app/src/utils/debounce.ts        | 38 +++++++++++++++++++
 apps/readest-app/src/utils/throttle.ts        |  2 +-
 4 files changed, 64 insertions(+), 29 deletions(-)
 create mode 100644 apps/readest-app/src/utils/debounce.ts

diff --git a/apps/readest-app/src/app/reader/components/annotator/TranslatorPopup.tsx b/apps/readest-app/src/app/reader/components/annotator/TranslatorPopup.tsx
index 866bd49e..8bb08149 100644
--- a/apps/readest-app/src/app/reader/components/annotator/TranslatorPopup.tsx
+++ b/apps/readest-app/src/app/reader/components/annotator/TranslatorPopup.tsx
@@ -170,7 +170,7 @@ const TranslatorPopup: React.FC<TranslatorPopupProps> = ({
 
         <div className='mx-4 flex-shrink-0 border-t border-gray-500/30'></div>
 
-        <div className='overflow-y-auto px-4 pt-4 font-sans'>
+        <div className='overflow-y-auto px-4 pb-8 pt-4 font-sans'>
           <div className='mb-2 flex items-center justify-between'>
             <h2 className='text-sm font-normal'>{_('Translated Text')}</h2>
             <Select
@@ -181,7 +181,6 @@ const TranslatorPopup: React.FC<TranslatorPopupProps> = ({
                 .map(([code, name]) => ({ value: code, label: name }))}
             />
           </div>
-
           {loading ? (
             <p className='text-base italic text-gray-500'>{_('Loading...')}</p>
           ) : (
@@ -193,25 +192,27 @@ const TranslatorPopup: React.FC<TranslatorPopupProps> = ({
                   {translation || _('No translation available.')}
                 </p>
               )}
-              <div className='flex h-10 items-center justify-between pt-4'>
-                {provider && (
-                  <div className='text-xs opacity-60'>
-                    {error
-                      ? ''
-                      : _('Translated by {{provider}}.', {
-                          provider: providers.find((p) => p.name === provider)?.label,
-                        })}
-                  </div>
-                )}
-                <Select
-                  value={provider}
-                  onChange={handleProviderChange}
-                  options={providers.map(({ name: value, label }) => ({ value, label }))}
-                />
-              </div>
             </div>
           )}
         </div>
+        <div className='absolute bottom-0 flex h-8 w-full items-center justify-between bg-gray-600 px-4'>
+          {provider && !loading && (
+            <div className='text-xs opacity-60'>
+              {error
+                ? ''
+                : _('Translated by {{provider}}.', {
+                    provider: providers.find((p) => p.name === provider)?.label,
+                  })}
+            </div>
+          )}
+          <div className='ml-auto'>
+            <Select
+              value={provider}
+              onChange={handleProviderChange}
+              options={providers.map(({ name: value, label }) => ({ value, label }))}
+            />
+          </div>
+        </div>
       </Popup>
     </div>
   );
diff --git a/apps/readest-app/src/app/reader/hooks/useIframeEvents.ts b/apps/readest-app/src/app/reader/hooks/useIframeEvents.ts
index 8c94d0e0..4a201aba 100644
--- a/apps/readest-app/src/app/reader/hooks/useIframeEvents.ts
+++ b/apps/readest-app/src/app/reader/hooks/useIframeEvents.ts
@@ -1,6 +1,6 @@
 import { useEffect } from 'react';
 import { useReaderStore } from '@/store/readerStore';
-import { throttle } from '@/utils/throttle';
+import { debounce } from '@/utils/debounce';
 import { ScrollSource } from './usePagination';
 
 export const useMouseEvent = (
@@ -9,27 +9,23 @@ export const useMouseEvent = (
   handleContinuousScroll: (source: ScrollSource, delta: number, threshold: number) => void,
 ) => {
   const { hoveredBookKey } = useReaderStore();
-  const throttledScroll = throttle(handleContinuousScroll, 500, {
-    emitLast: false,
-  });
-  const throttledFlip = throttle(handlePageFlip, 1000, {
-    emitLast: false,
-  });
+  const debounceScroll = debounce(handleContinuousScroll, 500);
+  const debounceFlip = debounce(handlePageFlip, 100);
   const handleMouseEvent = (msg: MessageEvent | React.MouseEvent<HTMLDivElement, MouseEvent>) => {
     if (msg instanceof MessageEvent) {
       if (msg.data && msg.data.bookKey === bookKey) {
         if (msg.data.type === 'iframe-wheel') {
-          throttledScroll('mouse', -msg.data.deltaY, 0);
+          debounceScroll('mouse', -msg.data.deltaY, 0);
         }
         if (msg.data.type === 'iframe-wheel') {
-          throttledFlip(msg);
+          debounceFlip(msg);
         } else {
           handlePageFlip(msg);
         }
       }
     } else if (msg.type === 'wheel') {
       const event = msg as React.WheelEvent<HTMLDivElement>;
-      throttledScroll('mouse', -event.deltaY, 0);
+      debounceScroll('mouse', -event.deltaY, 0);
     } else {
       handlePageFlip(msg);
     }
diff --git a/apps/readest-app/src/utils/debounce.ts b/apps/readest-app/src/utils/debounce.ts
new file mode 100644
index 00000000..c72dc81b
--- /dev/null
+++ b/apps/readest-app/src/utils/debounce.ts
@@ -0,0 +1,38 @@
+interface DebounceOptions {
+  emitLast?: boolean;
+}
+
+/**
+ * Debounces a function by waiting `delay` ms after the last call before executing it.
+ * If `emitLast` is false, it cancels the call instead of delaying it.
+ */
+export const debounce = <T extends (...args: Parameters<T>) => void | Promise<void>>(
+  func: T,
+  delay: number,
+  options: DebounceOptions = { emitLast: true },
+): ((...args: Parameters<T>) => void) => {
+  let timeout: ReturnType<typeof setTimeout> | null = null;
+  let lastArgs: Parameters<T> | null = null;
+
+  return (...args: Parameters<T>): void => {
+    if (timeout) {
+      clearTimeout(timeout);
+    }
+
+    if (options.emitLast) {
+      lastArgs = args;
+      timeout = setTimeout(() => {
+        if (lastArgs) {
+          func(...(lastArgs as Parameters<T>));
+          lastArgs = null;
+        }
+        timeout = null;
+      }, delay);
+    } else {
+      timeout = setTimeout(() => {
+        func(...args);
+        timeout = null;
+      }, delay);
+    }
+  };
+};
diff --git a/apps/readest-app/src/utils/throttle.ts b/apps/readest-app/src/utils/throttle.ts
index 8472dccf..0b39c0db 100644
--- a/apps/readest-app/src/utils/throttle.ts
+++ b/apps/readest-app/src/utils/throttle.ts
@@ -1,4 +1,4 @@
-export interface ThrottleOptions {
+interface ThrottleOptions {
   emitLast?: boolean;
 }