From 41059330982cec39acb5b5840f97a90329e33562 Mon Sep 17 00:00:00 2001
From: Sergey Elpashev <elpashevs@bk.ru>
Date: Wed, 17 Jul 2024 23:46:33 +0300
Subject: [PATCH] feat: manhwa scroll and cache pages rework

---
 .../components/reader/lazyscroll.directive.ts |  19 --
 .../components/reader/reader.component.html   |  12 +-
 .../app/components/reader/reader.component.ts | 224 ++++++------------
 .../src/app/components/reader/reader.dto.ts   |   2 +-
 .../scale-image/scale-image.component.html    |   6 +-
 .../scale-image/scale-image.component.ts      |  26 +-
 6 files changed, 106 insertions(+), 183 deletions(-)
 delete mode 100644 apps/NwaifuAnime/src/app/components/reader/lazyscroll.directive.ts

diff --git a/apps/NwaifuAnime/src/app/components/reader/lazyscroll.directive.ts b/apps/NwaifuAnime/src/app/components/reader/lazyscroll.directive.ts
deleted file mode 100644
index 09fb31c..0000000
--- a/apps/NwaifuAnime/src/app/components/reader/lazyscroll.directive.ts
+++ /dev/null
@@ -1,19 +0,0 @@
-import { Directive, ElementRef } from "@angular/core";
-
-@Directive({
-  selector: "[appLazyLoad]",
-  standalone: true,
-})
-export class LazyLoadDirective {
-  constructor({ nativeElement }: ElementRef) {
-    const observer = new IntersectionObserver(
-      (entries) => {
-        console.log(entries);
-      },
-      {
-        rootMargin: "1000px",
-      },
-    );
-    observer.observe(nativeElement);
-  }
-}
diff --git a/apps/NwaifuAnime/src/app/components/reader/reader.component.html b/apps/NwaifuAnime/src/app/components/reader/reader.component.html
index 6ba6203..81dd75b 100644
--- a/apps/NwaifuAnime/src/app/components/reader/reader.component.html
+++ b/apps/NwaifuAnime/src/app/components/reader/reader.component.html
@@ -11,17 +11,21 @@
   <h3>{{ currentChapterInfo?.number }}. {{ currentChapterInfo?.name || "Нет названия" }}</h3>
 </div>
 <div class="flex flex-col items-center">
-  @if (pages.length > 0 && cachedPages.get(currentPageIndex)) {
+  @if (pages.length > 0 && currentPage) {
     <div [class]="imageContainerClass">
       @if (!isManhwa) {
-        <app-scale-image [imageSrc]="imageUrl"></app-scale-image>
+        <app-scale-image [imageSrc]="currentPage.imageUrl"></app-scale-image>
       } @else {
         @for (page of manhwaPages; track page.id) {
-          <app-scale-image [imageSrc]="page.imageUrl"></app-scale-image>
+          <app-scale-image
+            [imageSrc]="page.imageUrl"
+            [host]="host"
+            (view)="loadPage(page.index)"
+            [hostScrollable]="isHostScrollable()"
+          ></app-scale-image>
         }
       }
     </div>
-    <div #anchor></div>
     <div class="flex items-center justify-center space-x-4 my-10">
       <button (click)="prevPage()" class="p-3 text-white bg-slate-600 w-[100px] rounded-lg">
         ←
diff --git a/apps/NwaifuAnime/src/app/components/reader/reader.component.ts b/apps/NwaifuAnime/src/app/components/reader/reader.component.ts
index 3f44a65..bfcaa9b 100644
--- a/apps/NwaifuAnime/src/app/components/reader/reader.component.ts
+++ b/apps/NwaifuAnime/src/app/components/reader/reader.component.ts
@@ -3,19 +3,17 @@ import {
   AfterViewInit,
   Component,
   ElementRef,
+  HostListener,
   Inject,
   OnDestroy,
   PLATFORM_ID,
-  QueryList,
-  ViewChildren,
 } from "@angular/core";
 import { ActivatedRoute, Router, RouterLink } from "@angular/router";
-import { Observable, Subject, Subscription, fromEvent, map, takeUntil, throttleTime } from "rxjs";
+import { Subject, takeUntil } from "rxjs";
 import { Chapter, Page } from "../../services/parsers/rulib/rulib.chapter.dto";
 import { IRulibChapter } from "../../services/parsers/rulib/rulib.chapters.dto";
 import { SearchService } from "../../services/search.service";
 import { ScaleImageComponent } from "../scale-image/scale-image.component";
-import { LazyLoadDirective } from "./lazyscroll.directive";
 import { CachedPage, CachedPages } from "./reader.dto";
 
 @Component({
@@ -23,7 +21,7 @@ import { CachedPage, CachedPages } from "./reader.dto";
   templateUrl: "./reader.component.html",
   styleUrls: ["./reader.component.less"],
   standalone: true,
-  imports: [CommonModule, ScaleImageComponent, RouterLink, LazyLoadDirective],
+  imports: [CommonModule, ScaleImageComponent, RouterLink],
 })
 export class ReaderComponent implements AfterViewInit, OnDestroy {
   //FIXME: Scrolling to top when manhwa
@@ -39,21 +37,17 @@ export class ReaderComponent implements AfterViewInit, OnDestroy {
   private chapterVol: number = 0;
   private fromTowards = false;
   private destroy$ = new Subject<void>();
-  private scrollSubscription = new Subscription();
-  @ViewChildren("anchor") anchor: QueryList<ElementRef<HTMLDivElement>> = new QueryList();
-  private observer!: IntersectionObserver;
 
   constructor(
     private route: ActivatedRoute,
     private router: Router,
     private searchService: SearchService,
-    private host: ElementRef,
+    public host: ElementRef,
     @Inject(PLATFORM_ID) private platformId: object,
   ) {}
   ngOnDestroy(): void {
     this.destroy$.next();
     this.destroy$.complete();
-    if (this.observer) this.observer.disconnect();
   }
 
   get manhwaPages() {
@@ -72,7 +66,6 @@ export class ReaderComponent implements AfterViewInit, OnDestroy {
         this.chapterNum = +chapter;
         this.chapterVol = +volume;
         this.url = url;
-        this.loadChapter(url, chapter, volume);
         this.searchService
           .getChapters(url)
           .pipe(takeUntil(this.destroy$))
@@ -84,20 +77,7 @@ export class ReaderComponent implements AfterViewInit, OnDestroy {
           .pipe(takeUntil(this.destroy$))
           .subscribe((data) => {
             this.isManhwa = data;
-            if (this.isManhwa) {
-              //TODO: scroll offset
-              this.observer = new IntersectionObserver(
-                ([entry]) => entry.isIntersecting && this.testScrollEmitter(),
-                {
-                  root: this.isHostScrollable() ? this.host.nativeElement : null,
-                },
-              );
-              this.anchor.changes
-                .pipe(takeUntil(this.destroy$))
-                .subscribe((list: QueryList<ElementRef<HTMLDivElement>>) => {
-                  if (this.observer && list.first) this.observer.observe(list.first.nativeElement);
-                });
-            }
+            this.loadChapter(url, chapter, volume);
           });
       } else {
         this.router.navigate(["/"]);
@@ -105,10 +85,9 @@ export class ReaderComponent implements AfterViewInit, OnDestroy {
     });
   }
 
-  private isHostScrollable(): boolean {
+  public isHostScrollable(): boolean {
     if (isPlatformBrowser(this.platformId)) {
       const style = window.getComputedStyle(this.host.nativeElement);
-
       return (
         style.getPropertyValue("overflow") === "auto" ||
         style.getPropertyValue("overflow-y") === "scroll"
@@ -118,48 +97,6 @@ export class ReaderComponent implements AfterViewInit, OnDestroy {
     return false;
   }
 
-  private testScrollEmitter() {
-    this.nextPage();
-  }
-
-  private handleScrollManhwa(event: Event) {
-    if (event.currentTarget) {
-      if (
-        (event.currentTarget as HTMLElement).scrollHeight -
-          (event.currentTarget as HTMLElement).scrollTop <
-        3000
-      ) {
-        // this.loadPage(this.currentPageIndex + 1);
-        console.log("load");
-      }
-    }
-  }
-
-  private initManhwaScroll() {
-    const component = document.querySelector("app-reader");
-    if (component && this.isManhwa) {
-      this.scrollSubscription = fromEvent(component, "scroll")
-        .pipe(
-          throttleTime(300),
-          map((data) => {
-            console.log("throttle");
-            return data;
-          }),
-          takeUntil(this.destroy$),
-        )
-        .subscribe((event) => {
-          this.handleScrollManhwa(event);
-        });
-    }
-  }
-
-  private noManhwaScroll() {
-    const component = document.querySelector("app-reader");
-    if (component && !this.isManhwa) {
-      this.scrollSubscription.unsubscribe();
-    }
-  }
-
   backToTitle() {
     this.router.navigate(["/", "detail"], { queryParams: { url: this.url } });
   }
@@ -172,6 +109,15 @@ export class ReaderComponent implements AfterViewInit, OnDestroy {
         next: (data) => {
           this.currentChapterInfo = data.data;
           this.pages = data.data.pages;
+          this.pages.forEach((page, index) => {
+            this.cachedPages.set(index, {
+              ...page,
+              imageUrl: "",
+              isManhwa: this.isManhwa,
+              index,
+            });
+          });
+          this.loadPage(0);
           if (this.fromTowards) {
             this.currentPageIndex = this.pages.length - 1;
             this.loadPage(this.pages.length - 1); // Загрузить последнюю страницу при открытии главы
@@ -184,32 +130,52 @@ export class ReaderComponent implements AfterViewInit, OnDestroy {
       });
   }
 
+  public intersectionLoadPage(id: number) {
+    const data = Array.from(this.cachedPages.values()).find((page) => page.id === id)!;
+    this.fetchPage(data);
+  }
+
+  private loadPageByIndex(index: number) {
+    const data = this.cachedPages.get(index)!;
+    this.fetchPage(data);
+  }
+
+  get currentPage() {
+    return this.cachedPages.get(this.currentPageIndex);
+  }
+
+  private fetchPage(page: CachedPage) {
+    if (!page.imageUrl)
+      this.searchService
+        .getImageData(this.searchService.getImageServer() + page.url)
+        .pipe(takeUntil(this.destroy$))
+        .subscribe((data) => {
+          const url = this.getImageUrl(data);
+          this.cachedPages.set(page.index, {
+            ...page,
+            imageUrl: url,
+          });
+        });
+  }
+
+  private cachePage(index: number) {
+    for (let i = index; i < Math.min(index + 2, this.cachedPages.size); i++) {
+      this.loadPageByIndex(i);
+    }
+  }
+
+  private clearCache(index: number) {
+    for (let i = 0; i <= index; i++) {
+      this.cachedPages.get(i)!.imageUrl = "";
+    }
+  }
+
   loadPage(index: number) {
     if (index >= 0 && index < this.pages.length) {
       this.currentPageIndex = index;
-      this.cachePage(index); // Кэшируем текущую и соседние страницы
-      if (!this.isManhwa) this.unloadCachedPages(index); // Сгружаем ненужные страницы из кэша
-      if (!this.isManhwa) {
-        const container = document.querySelector("app-reader");
-        if (container) {
-          container.scrollTo({
-            top: 0,
-            behavior: "smooth",
-          });
-        }
-      }
-      if (!this.cachedPages.get(index)?.imageData) {
-        // Если страница не закэширована, загружаем её
-        this.fetchAndCachePage(index)
-          .pipe(takeUntil(this.destroy$))
-          .subscribe(() => {
-            this.updateImage();
-          });
-      } else {
-        // Если страница уже в кэше, просто обновляем изображение
-        this.updateImage();
-      }
-    } else if (index == this.pages.length && !this.isManhwa) {
+      this.cachePage(index);
+      this.clearCache(index - 2);
+    } else if (index == this.cachedPages.size) {
       const thisChapterIndex = this.chaptersInfo.findIndex((chapter) => {
         return +chapter.number === this.chapterNum && +chapter.volume === this.chapterVol;
       });
@@ -225,7 +191,7 @@ export class ReaderComponent implements AfterViewInit, OnDestroy {
           },
         });
       }
-    } else if (index == -1 && !this.isManhwa) {
+    } else if (index == -1) {
       const thisChapterIndex = this.chaptersInfo.findIndex((chapter) => {
         return +chapter.number === this.chapterNum && +chapter.volume === this.chapterVol;
       });
@@ -245,56 +211,16 @@ export class ReaderComponent implements AfterViewInit, OnDestroy {
     }
   }
 
-  // Кэширование текущей страницы и несколько соседних для ускорения процесса навигации по страницам
-  private cachePage(index: number) {
-    const startIndex = Math.max(0, index - 2);
-    const endIndex = Math.min(this.pages.length - 1, index + 2);
-
-    for (let i = startIndex; i <= endIndex; i++) {
-      if (!this.isPageCached(i)) {
-        this.fetchAndCachePage(i)
-          .pipe(takeUntil(this.destroy$))
-          .subscribe(() => {
-            if (i === this.currentPageIndex) {
-              this.updateImage();
-            }
-          });
-      }
+  @HostListener("window:keydown", ["$event"])
+  onKeydown(event: KeyboardEvent) {
+    if (event.key === "ArrowRight") {
+      this.nextPage();
+    } else if (event.key === "ArrowLeft") {
+      this.prevPage();
     }
   }
 
-  private isPageCached(index: number): boolean {
-    return !!this.cachedPages.get(index)?.imageData;
-  }
-
-  // Загрузка и сохранение изображения в кэш
-  private fetchAndCachePage(index: number): Observable<void> {
-    return this.searchService
-      .getImageData(this.searchService.getImageServer() + this.pages[index].url)
-      .pipe(
-        map((imageData) => {
-          const url = this.getImageUrl(imageData);
-          this.cachedPages.set(index, {
-            ...this.pages[index],
-            imageData,
-            imageUrl: url,
-            isManhwa: +this.pages[index].ratio < 0.5,
-          });
-        }),
-      );
-  }
-
-  // Выгрузка из кэша старых страниц
-  private unloadCachedPages(index: number) {
-    for (const key in this.cachedPages) {
-      const pageIndex = +key;
-      if (index - pageIndex > 2) {
-        this.cachedPages.delete(pageIndex);
-      }
-    }
-  }
-
-  getImageUrl(imageData?: Uint8Array): string {
+  private getImageUrl(imageData?: Uint8Array): string {
     if (!imageData) {
       return "";
     }
@@ -303,22 +229,6 @@ export class ReaderComponent implements AfterViewInit, OnDestroy {
     return urlCreator.createObjectURL(blob);
   }
 
-  // Обновляем изображение на странице
-  private updateImage() {
-    const currentPage = this.cachedPages.get(this.currentPageIndex);
-    if (currentPage && currentPage.imageData && !this.isManhwa) {
-      const blob = new Blob([currentPage.imageData], { type: "image/jpeg" });
-      const urlCreator = window.URL || window.webkitURL;
-      this.imageUrl = urlCreator.createObjectURL(blob);
-      const imageUrl = this.imageUrl;
-      const image = new Image();
-      image.onload = () => {
-        URL.revokeObjectURL(imageUrl);
-      };
-      image.src = imageUrl;
-    }
-  }
-
   nextPage() {
     this.loadPage(this.currentPageIndex + 1);
   }
@@ -328,6 +238,6 @@ export class ReaderComponent implements AfterViewInit, OnDestroy {
   }
 
   get imageContainerClass() {
-    return `${this.isManhwa ? "h-auto" : "h-[70vh]"} w-[95vw] md:w-[700px] md:h-auto flex flex-col`;
+    return `${this.isManhwa ? "h-auto" : "h-[70vh]"} w-[95vw] md:w-[450px] flex flex-col`;
   }
 }
diff --git a/apps/NwaifuAnime/src/app/components/reader/reader.dto.ts b/apps/NwaifuAnime/src/app/components/reader/reader.dto.ts
index 3609113..b399b31 100644
--- a/apps/NwaifuAnime/src/app/components/reader/reader.dto.ts
+++ b/apps/NwaifuAnime/src/app/components/reader/reader.dto.ts
@@ -3,7 +3,7 @@ import { Page } from "../../services/parsers/rulib/rulib.chapter.dto";
 export interface CachedPage extends Page {
   imageData?: Uint8Array;
   imageUrl: string;
-
+  index: number;
   isManhwa: boolean;
 }
 
diff --git a/apps/NwaifuAnime/src/app/components/scale-image/scale-image.component.html b/apps/NwaifuAnime/src/app/components/scale-image/scale-image.component.html
index 0384096..0c1a7c2 100644
--- a/apps/NwaifuAnime/src/app/components/scale-image/scale-image.component.html
+++ b/apps/NwaifuAnime/src/app/components/scale-image/scale-image.component.html
@@ -1,3 +1,7 @@
 <div class="image-container" #container>
-  <img #image [src]="imageSrc" (load)="onImageLoad()" alt="Manga page" />
+  @if (imageSrc) {
+    <img #image [src]="imageSrc" (load)="onImageLoad()" alt="Manga page" />
+  } @else {
+    <div class="h-screen flex flex-col items-center justify-center"><h1>Loading...</h1></div>
+  }
 </div>
diff --git a/apps/NwaifuAnime/src/app/components/scale-image/scale-image.component.ts b/apps/NwaifuAnime/src/app/components/scale-image/scale-image.component.ts
index a28b4fd..53b5315 100644
--- a/apps/NwaifuAnime/src/app/components/scale-image/scale-image.component.ts
+++ b/apps/NwaifuAnime/src/app/components/scale-image/scale-image.component.ts
@@ -1,4 +1,13 @@
-import { AfterViewInit, Component, ElementRef, Input, OnDestroy, ViewChild } from "@angular/core";
+import {
+  AfterViewInit,
+  Component,
+  ElementRef,
+  EventEmitter,
+  Input,
+  OnDestroy,
+  Output,
+  ViewChild,
+} from "@angular/core";
 import { Subscription, debounceTime, fromEvent } from "rxjs";
 
 @Component({
@@ -11,15 +20,30 @@ export class ScaleImageComponent implements AfterViewInit, OnDestroy {
   @Input({ required: true }) imageSrc: string = "";
   @ViewChild("container", { static: true }) containerRef: ElementRef | null = null;
   @ViewChild("image", { static: true }) imageRef: ElementRef | null = null;
+  @Output() view = new EventEmitter<void>();
+  @Input() host: ElementRef | null = null;
+  @Input() hostScrollable: boolean = false;
 
   private resizeSubscription: Subscription = new Subscription();
+  private observer!: IntersectionObserver;
 
   ngAfterViewInit(): void {
     this.setupResizeListener();
+    if (this.host) {
+      this.observer = new IntersectionObserver(
+        ([entry]) => entry.isIntersecting && this.view.emit(),
+        {
+          root: this.hostScrollable ? this.host.nativeElement : null,
+          rootMargin: "1000px",
+        },
+      );
+      if (this.containerRef) this.observer.observe(this.containerRef.nativeElement);
+    }
   }
 
   ngOnDestroy(): void {
     if (this.resizeSubscription) this.resizeSubscription.unsubscribe();
+    if (this.observer) this.observer.disconnect();
   }
 
   onImageLoad() {