Structure "reader" in sub-features

src/features/reader/viewer/hooks/useReaderConvertPagesForReadingMode.ts

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) Contributors to the Suwayomi project
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+import { useLayoutEffect, useState } from 'react';
+import { ReaderPageSpreadState, ReadingMode } from '@/features/reader/Reader.types.ts';
+import { getNextIndexFromPage, getPage } from '@/features/reader/overlay/progress-bar/ReaderProgressBar.utils.tsx';
+import { createPagesData } from '@/features/reader/viewer/pager/ReaderPager.utils.tsx';
+import { ReaderStatePages } from '@/features/reader/overlay/progress-bar/ReaderProgressBar.types.ts';
+import { ReaderControls } from '@/features/reader/services/ReaderControls.ts';
+
+export const useReaderConvertPagesForReadingMode = (
+    currentPageIndex: number,
+    actualPages: ReaderStatePages['pages'],
+    pageUrls: ReaderStatePages['pageUrls'],
+    setPages: ReaderStatePages['setPages'],
+    setPagesToSpreadState: (states: ReaderPageSpreadState[]) => void,
+    updateCurrentPageIndex: ReturnType<typeof ReaderControls.useUpdateCurrentPageIndex>,
+    readingMode: ReadingMode,
+) => {
+    const [wasDoublePageMode, setWasDoublePageMode] = useState(readingMode === ReadingMode.DOUBLE_PAGE);
+
+    useLayoutEffect(() => {
+        const convertPagesToNormalPageMode = wasDoublePageMode && readingMode !== ReadingMode.DOUBLE_PAGE;
+        if (convertPagesToNormalPageMode) {
+            setWasDoublePageMode(false);
+
+            const newPageData = createPagesData(pageUrls);
+            setPages(newPageData);
+            setPagesToSpreadState(newPageData.map(({ primary: { url } }) => ({ url, isSpread: false })));
+            return;
+        }
+
+        const convertPagesToDoublePageMode = readingMode === ReadingMode.DOUBLE_PAGE;
+        if (convertPagesToDoublePageMode) {
+            if (!wasDoublePageMode) {
+                updateCurrentPageIndex(getNextIndexFromPage(getPage(currentPageIndex, actualPages)));
+            }
+            setPages(actualPages);
+            setWasDoublePageMode(readingMode === ReadingMode.DOUBLE_PAGE);
+        }
+    }, [actualPages, readingMode]);
+};