1 files changed, 70 insertions, 6 deletions

diff --git a/frontend/src/lib/reader/Reader.svelte b/frontend/src/lib/reader/Reader.svelte
index 9bc7a82..b5cc725 100644
--- a/frontend/src/lib/reader/Reader.svelte
+++ b/frontend/src/lib/reader/Reader.svelte
@@ -1,32 +1,96 @@
+<script lang="ts" module>
+	import { Layout, type PageFragment } from '$gql/graphql';
+	import { getContext, setContext } from 'svelte';
+
+	export interface Chunk {
+		main: PageFragment;
+		secondary?: PageFragment;
+		index: number;
+	}
+
+	class ReaderContext {
+		visible = $state(false);
+		sidebar = $state(false);
+		pages: PageFragment[] = $state([]);
+		page = $state(0);
+
+		open = (page: number) => {
+			this.page = page;
+			this.visible = true;
+		};
+	}
+
+	export function initReaderContext() {
+		return setContext<ReaderContext>('reader', new ReaderContext());
+	}
+
+	export function getReaderContext() {
+		return getContext<ReaderContext>('reader');
+	}
+
+	export function partition(pages: PageFragment[], layout: Layout): [Chunk[], number[]] {
+		const single = layout === Layout.Single;
+		const offset = layout === Layout.DoubleOffset;
+
+		const chunks: Chunk[] = [];
+		const lookup: number[] = Array<number>(pages.length);
+
+		for (let chunkIndex = 0, pageIndex = 0; pageIndex < pages.length; chunkIndex++) {
+			const wide = () => pages[pageIndex].image.aspectRatio > 1;
+
+			const nextPage = () => {
+				lookup[pageIndex] = chunkIndex;
+				return pages[pageIndex++];
+			};
+
+			const offsetFirst = pageIndex === 0 && offset;
+			const full = single || wide() || offsetFirst;
+
+			const chunk: Chunk = { index: pageIndex, main: nextPage() };
+
+			if (!full && pageIndex < pages.length) {
+				if (!wide()) {
+					chunk.secondary = nextPage();
+				}
+			}
+
+			chunks.push(chunk);
+		}
+		return [chunks, lookup];
+	}
+</script>
+
 <script lang="ts">
 	import { trapFocus } from '$lib/Actions';
-	import { getReaderContext } from '$lib/Reader';
 	import { fadeDefault, slideXDefault } from '$lib/Transitions';
+	import type { Snippet } from 'svelte';
 	import { fade, slide } from 'svelte/transition';
 	import CloseReaderButton from './components/CloseReaderButton.svelte';
 	import PageIndicator from './components/PageIndicator.svelte';
 	import ReaderMenuButton from './components/ReaderMenuButton.svelte';
 
+	let { sidebar, children }: { sidebar?: Snippet; children?: Snippet } = $props();
+
 	const reader = getReaderContext();
 </script>
 
-{#if $reader.visible}
+{#if reader.visible}
 	<div
 		role="dialog"
 		class="fixed bottom-0 left-0 right-0 top-0 z-10 flex h-full w-full bg-black"
 		transition:fade={fadeDefault}
 		use:trapFocus
 	>
-		{#if $$slots.sidebar && $reader.sidebar}
+		{#if sidebar && reader.sidebar}
 			<aside class="w-[36rem] shrink-0 bg-slate-800" transition:slide={slideXDefault}>
 				<div class="flex h-full min-w-[36rem] flex-col gap-4 overflow-auto p-4">
-					<slot name="sidebar" />
+					{@render sidebar?.()}
 				</div>
 			</aside>
 		{/if}
 		<main class="relative flex grow">
 			<div class="absolute flex w-full p-1 text-lg [&>*:last-child]:ml-auto">
-				{#if $$slots.sidebar}
+				{#if sidebar}
 					<ReaderMenuButton />
 				{/if}
 				<CloseReaderButton />
@@ -36,7 +100,7 @@
 			</div>
 
 			<div class="flex grow">
-				<slot />
+				{@render children?.()}
 			</div>
 		</main>
 	</div>