Reader core parity

src/lib/core/reader/navigation.ts

@@ -0,0 +1,104 @@
+import {getAdapter} from '$lib/request-manager';
+import {loadChapterPages, updateProgress} from '$lib/request-manager/chapters';
+import {readerState} from '$lib/state/reader.svelte';
+import type {Chapter} from '$lib/types';
+
+export function sortChapters(chapters: Chapter[]): Chapter[] {
+    return [...chapters].sort((a, b) => a.sourceOrder - b.sourceOrder);
+}
+
+function currentChapterIndex(): number {
+    if (!readerState.chapter) return -1;
+    return sortChapters(readerState.chapters).findIndex(
+        (ch) => String(ch.id) === String(readerState.chapter?.id),
+    );
+}
+
+function clampPageIndex(index: number): number {
+    if (readerState.pages.length === 0) return 0;
+    return Math.min(Math.max(index, 0), readerState.pages.length - 1);
+}
+
+export function getAdjacentChapters(): {
+    previous: Chapter | null;
+    next: Chapter | null;
+} {
+    const chapters = sortChapters(readerState.chapters);
+    const index = currentChapterIndex();
+    return {
+        previous: index > 0 ? (chapters[index - 1] ?? null) : null,
+        next: index >= 0 && index < chapters.length - 1 ? (chapters[index + 1] ?? null) : null,
+    };
+}
+
+export async function setCurrentReaderPage(index: number): Promise<void> {
+    const nextIndex = clampPageIndex(index);
+    readerState.currentPage = nextIndex;
+
+    if (!readerState.chapter || readerState.pages.length === 0) return;
+
+    const lastPageRead = nextIndex + 1;
+    const completed = lastPageRead >= readerState.pages.length;
+
+    if (
+        readerState.chapter.lastPageRead === lastPageRead &&
+        readerState.chapter.read === completed
+    ) {
+        return;
+    }
+
+    try {
+        await updateProgress(String(readerState.chapter.id), lastPageRead, completed);
+    } catch (error) {
+        readerState.pagesError = error instanceof Error ? error.message : String(error);
+    }
+}
+
+export async function goToNextReaderPage(): Promise<boolean> {
+    if (readerState.currentPage >= readerState.pages.length - 1) return false;
+    await setCurrentReaderPage(readerState.currentPage + 1);
+    return true;
+}
+
+export async function goToPreviousReaderPage(): Promise<boolean> {
+    if (readerState.currentPage <= 0) return false;
+    await setCurrentReaderPage(readerState.currentPage - 1);
+    return true;
+}
+
+export async function ensureReaderSession(
+    mangaId: string,
+    chapterId: string,
+): Promise<void> {
+    const adapter = getAdapter();
+
+    const mangaPromise =
+        readerState.manga && String(readerState.manga.id) === mangaId
+            ? Promise.resolve(readerState.manga)
+            : adapter.getManga(mangaId);
+
+    const chaptersPromise =
+        readerState.chapters.length > 0 &&
+            String(readerState.chapters[0]?.mangaId) === mangaId
+            ? Promise.resolve(readerState.chapters)
+            : adapter.getChapters(mangaId);
+
+    const [manga, chapters] = await Promise.all([mangaPromise, chaptersPromise]);
+    const chapter =
+        chapters.find((ch) => String(ch.id) === chapterId) ??
+        (String(readerState.chapter?.id) === chapterId ? readerState.chapter : null) ??
+        (await adapter.getChapter(chapterId));
+
+    readerState.manga = manga;
+    readerState.chapters = chapters;
+    readerState.chapter = chapter;
+    readerState.pages = [];
+    readerState.currentPage = 0;
+    readerState.pagesError = null;
+
+    await loadChapterPages(chapterId);
+
+    if (readerState.pages.length > 0) {
+        readerState.currentPage = clampPageIndex((chapter.lastPageRead ?? 1) - 1);
+    }
+}