From 0b57dc9c96fed24e6db440834f257aa4cf854f18 Mon Sep 17 00:00:00 2001
From: Gauthier Roebroeck <gauthier.roebroeck@gmail.com>
Date: Wed, 18 Jan 2023 17:36:55 +0800
Subject: [PATCH] perf(webui): readlist/collection expansion panels load data
 by page

Refs: #817
---
 .../components/CollectionsExpansionPanels.vue | 38 +++++++++++++------
 .../components/ReadListsExpansionPanels.vue   | 38 +++++++++++++------
 komga-webui/src/types/pageLoader.ts           | 15 ++++++--
 3 files changed, 63 insertions(+), 28 deletions(-)

diff --git a/komga-webui/src/components/CollectionsExpansionPanels.vue b/komga-webui/src/components/CollectionsExpansionPanels.vue
index e55d3e48b..1c9f18a5c 100644
--- a/komga-webui/src/components/CollectionsExpansionPanels.vue
+++ b/komga-webui/src/components/CollectionsExpansionPanels.vue
@@ -5,14 +5,18 @@
     >
       <v-expansion-panel-header>{{ $t('collections_expansion_panel.title', {name: c.name}) }}</v-expansion-panel-header>
       <v-expansion-panel-content>
-        <horizontal-scroller>
+        <horizontal-scroller
+          :tick="collectionsLoaders[index].tick"
+          @scroll-changed="(percent) => scrollChanged(collectionsLoaders[index], percent)"
+        >
           <template v-slot:prepend>
             <router-link class="text-overline"
                          :to="{name: 'browse-collection', params: {collectionId: c.id}}"
-            >{{ $t('collections_expansion_panel.manage_collection') }}</router-link>
+            >{{ $t('collections_expansion_panel.manage_collection') }}
+            </router-link>
           </template>
           <template v-slot:content>
-            <item-browser :items="collectionsContent[index]"
+            <item-browser :items="collectionsLoaders[index].items"
                           nowrap
                           :selectable="false"
                           :action-menu="false"
@@ -31,6 +35,7 @@ import ItemBrowser from '@/components/ItemBrowser.vue'
 import Vue from 'vue'
 import {ContextOrigin} from '@/types/context'
 import {SeriesDto} from '@/types/komga-series'
+import {PageLoader} from '@/types/pageLoader'
 
 export default Vue.extend({
   name: 'CollectionsExpansionPanels',
@@ -47,27 +52,36 @@ export default Vue.extend({
   data: () => {
     return {
       collectionPanel: undefined as number | undefined,
-      collectionsContent: [[]] as any[],
+      collectionsLoaders: [] as PageLoader<SeriesDto>[],
     }
   },
   watch: {
     collections: {
-      handler (val) {
+      handler(val: CollectionDto[]) {
         this.collectionPanel = undefined
-        this.collectionsContent = [...Array(val.length)].map(elem => new Array(0))
+        this.collectionsLoaders = val.map(coll => new PageLoader<SeriesDto>(
+          {},
+          (pageable: PageRequest) => this.$komgaCollections.getSeries(coll.id, pageable),
+          (x: SeriesDto) => {
+            x.context = {origin: ContextOrigin.COLLECTION, id: coll.id}
+            return x
+          },
+        ))
       },
       immediate: true,
     },
-    async collectionPanel (val) {
+    async collectionPanel(val) {
       if (val !== undefined) {
-        const collId = this.collections[val].id
-        if (this.$_.isEmpty(this.collectionsContent[val])) {
-          const content = (await this.$komgaCollections.getSeries(collId, { unpaged: true } as PageRequest)).content
-          content.forEach((x: SeriesDto) => x.context = { origin: ContextOrigin.COLLECTION, id: collId })
-          this.collectionsContent.splice(val, 1, content)
+        if (!this.collectionsLoaders[val].hasLoadedAny) {
+          this.collectionsLoaders[val].loadNext()
         }
       }
     },
   },
+  methods: {
+    async scrollChanged(loader: PageLoader<any>, percent: number) {
+      if (percent > 0.95) await loader.loadNext()
+    },
+  },
 })
 </script>
diff --git a/komga-webui/src/components/ReadListsExpansionPanels.vue b/komga-webui/src/components/ReadListsExpansionPanels.vue
index 21de8ab35..0df7c5712 100644
--- a/komga-webui/src/components/ReadListsExpansionPanels.vue
+++ b/komga-webui/src/components/ReadListsExpansionPanels.vue
@@ -5,14 +5,18 @@
     >
       <v-expansion-panel-header>{{ $t('readlists_expansion_panel.title', {name: r.name}) }}</v-expansion-panel-header>
       <v-expansion-panel-content>
-        <horizontal-scroller>
+        <horizontal-scroller
+          :tick="readListsLoaders[index].tick"
+          @scroll-changed="(percent) => scrollChanged(readListsLoaders[index], percent)"
+        >
           <template v-slot:prepend>
             <router-link class="text-overline"
                          :to="{name: 'browse-readlist', params: {readListId: r.id}}"
-            >{{ $t('readlists_expansion_panel.manage_readlist') }}</router-link>
+            >{{ $t('readlists_expansion_panel.manage_readlist') }}
+            </router-link>
           </template>
           <template v-slot:content>
-            <item-browser :items="readListsContent[index]"
+            <item-browser :items="readListsLoaders[index].items"
                           :item-context="[ItemContext.SHOW_SERIES]"
                           nowrap
                           :selectable="false"
@@ -33,6 +37,7 @@ import Vue from 'vue'
 import {BookDto} from '@/types/komga-books'
 import {ContextOrigin} from '@/types/context'
 import {ItemContext} from '@/types/items'
+import {PageLoader} from '@/types/pageLoader'
 
 export default Vue.extend({
   name: 'ReadListsExpansionPanels',
@@ -50,27 +55,36 @@ export default Vue.extend({
     return {
       ItemContext,
       readListPanel: undefined as number | undefined,
-      readListsContent: [[]] as any[],
+      readListsLoaders: [] as PageLoader<BookDto>[],
     }
   },
   watch: {
     readLists: {
-      handler (val) {
+      handler(val: ReadListDto[]) {
         this.readListPanel = undefined
-        this.readListsContent = [...Array(val.length)].map(elem => new Array(0))
+        this.readListsLoaders = val.map(rl => new PageLoader<BookDto>(
+          {},
+          (pageable: PageRequest) => this.$komgaReadLists.getBooks(rl.id, pageable),
+          (x: BookDto) => {
+            x.context = {origin: ContextOrigin.READLIST, id: rl.id}
+            return x
+          },
+        ))
       },
       immediate: true,
     },
-    async readListPanel (val) {
+    async readListPanel(val) {
       if (val !== undefined) {
-        const rlId = this.readLists[val].id
-        if (this.$_.isEmpty(this.readListsContent[val])) {
-          const content = (await this.$komgaReadLists.getBooks(rlId, { unpaged: true } as PageRequest)).content
-          content.forEach((x: BookDto) => x.context = { origin: ContextOrigin.READLIST, id: rlId })
-          this.readListsContent.splice(val, 1, content)
+        if (!this.readListsLoaders[val].hasLoadedAny) {
+          this.readListsLoaders[val].loadNext()
         }
       }
     },
   },
+  methods: {
+    async scrollChanged(loader: PageLoader<any>, percent: number) {
+      if (percent > 0.95) await loader.loadNext()
+    },
+  },
 })
 </script>
diff --git a/komga-webui/src/types/pageLoader.ts b/komga-webui/src/types/pageLoader.ts
index 9f0dd3809..8bf03a23e 100644
--- a/komga-webui/src/types/pageLoader.ts
+++ b/komga-webui/src/types/pageLoader.ts
@@ -1,6 +1,7 @@
 export class PageLoader<T> {
   private readonly pageable: PageRequest
   private readonly loader: (pageRequest: PageRequest) => Promise<Page<T>>
+  private readonly postProcessor: (item: T) => T
 
   private currentPage = undefined as unknown as Page<T>
   private loadedPages: number[] = []
@@ -15,9 +16,15 @@ export class PageLoader<T> {
     return this._tick
   }
 
-  constructor(pageable: PageRequest, loader: (pageRequest: PageRequest) => Promise<Page<T>>) {
+  // whether anything has been loaded yet
+  get hasLoadedAny() {
+    return this.currentPage
+  }
+
+  constructor(pageable: PageRequest, loader: (pageRequest: PageRequest) => Promise<Page<T>>, postProcessor: (item: T) => T = (item) => item) {
     this.pageable = pageable
     this.loader = loader
+    this.postProcessor = postProcessor
   }
 
   async reload() {
@@ -29,7 +36,7 @@ export class PageLoader<T> {
         page: 0,
       })
     const page = await this.loader(pageable)
-    this.items.splice(0, this.items.length, ...page.content)
+    this.items.splice(0, this.items.length, ...page.content.map(this.postProcessor))
     this._tick++
   }
 
@@ -38,7 +45,7 @@ export class PageLoader<T> {
     if (!this.currentPage) {
       this.loadedPages.push(this.pageable.page || 0)
       this.currentPage = await this.loader(this.pageable)
-      this.items.push(...this.currentPage.content)
+      this.items.push(...this.currentPage.content.map(this.postProcessor))
       this._tick++
       return true
     }
@@ -50,7 +57,7 @@ export class PageLoader<T> {
         this.loadedPages.push(nextPage)
         const pageable = Object.assign({}, this.pageable, {page: nextPage})
         this.currentPage = await this.loader(pageable)
-        this.items.push(...this.currentPage.content)
+        this.items.push(...this.currentPage.content.map(this.postProcessor))
         this._tick++
         return true
       }