readest/apps/readest-app/src/app/reader/components/FoliateViewer.tsx

import React, { useEffect, useRef, useState } from 'react';
import { BookDoc, getDirection } from '@/libs/document';
import { BookConfig } from '@/types/book';
import { FoliateView, wrappedFoliateView } from '@/types/view';
import { useEnv } from '@/context/EnvContext';
import { useThemeStore } from '@/store/themeStore';
import { useReaderStore } from '@/store/readerStore';
import { useParallelViewStore } from '@/store/parallelViewStore';
import { useMouseEvent, useTouchEvent } from '../hooks/useIframeEvents';
import { usePagination } from '../hooks/usePagination';
import { useFoliateEvents } from '../hooks/useFoliateEvents';
import { useProgressSync } from '../hooks/useProgressSync';
import { useProgressAutoSave } from '../hooks/useProgressAutoSave';
import { getStyles, mountAdditionalFonts, transformStylesheet } from '@/utils/style';
import { getBookDirFromLanguage, getBookDirFromWritingMode } from '@/utils/book';
import { useUICSS } from '@/hooks/useUICSS';
import {
  handleKeydown,
  handleMousedown,
  handleMouseup,
  handleClick,
  handleWheel,
  handleTouchStart,
  handleTouchMove,
  handleTouchEnd,
} from '../utils/iframeEventHandlers';
import { getMaxInlineSize } from '@/utils/config';
import { getDirFromUILanguage } from '@/utils/rtl';
import { transformContent } from '@/services/transformService';
import { lockScreenOrientation } from '@/utils/bridge';
import { useTextTranslation } from '../hooks/useTextTranslation';

const FoliateViewer: React.FC<{
  bookKey: string;
  bookDoc: BookDoc;
  config: BookConfig;
}> = ({ bookKey, bookDoc, config }) => {
  const { appService } = useEnv();
  const containerRef = useRef<HTMLDivElement>(null);
  const viewRef = useRef<FoliateView | null>(null);
  const isViewCreated = useRef(false);
  const { getView, setView: setFoliateView, setProgress } = useReaderStore();
  const { getViewSettings, setViewSettings } = useReaderStore();
  const { getParallels } = useParallelViewStore();
  const { themeCode, isDarkMode } = useThemeStore();

  const [toastMessage, setToastMessage] = useState('');
  useEffect(() => {
    const timer = setTimeout(() => setToastMessage(''), 2000);
    return () => clearTimeout(timer);
  }, [toastMessage]);

  useUICSS(bookKey);
  useProgressSync(bookKey);
  useProgressAutoSave(bookKey);
  useTextTranslation(bookKey, viewRef.current);

  const progressRelocateHandler = (event: Event) => {
    const detail = (event as CustomEvent).detail;
    setProgress(bookKey, detail.cfi, detail.tocItem, detail.section, detail.location, detail.range);
  };

  const getDocTransformHandler = ({ width, height }: { width: number; height: number }) => {
    return (event: Event) => {
      const { detail } = event as CustomEvent;
      detail.data = Promise.resolve(detail.data)
        .then((data) => {
          const viewSettings = getViewSettings(bookKey);
          if (viewSettings && detail.type === 'text/css')
            return transformStylesheet(viewSettings, width, height, data);
          if (viewSettings && detail.type === 'application/xhtml+xml') {
            const ctx = {
              bookKey,
              viewSettings,
              content: data,
              transformers: ['punctuation', 'footnote'],
            };
            return Promise.resolve(transformContent(ctx));
          }
          return data;
        })
        .catch((e) => {
          console.error(new Error(`Failed to load ${detail.name}`, { cause: e }));
          return '';
        });
    };
  };

  const docLoadHandler = (event: Event) => {
    const detail = (event as CustomEvent).detail;
    console.log('doc index loaded:', detail.index);
    if (detail.doc) {
      const writingDir = viewRef.current?.renderer.setStyles && getDirection(detail.doc);
      const viewSettings = getViewSettings(bookKey)!;
      viewSettings.vertical =
        writingDir?.vertical || viewSettings.writingMode.includes('vertical') || false;
      viewSettings.rtl =
        writingDir?.rtl ||
        getDirFromUILanguage() === 'rtl' ||
        viewSettings.writingMode.includes('rl') ||
        false;
      setViewSettings(bookKey, { ...viewSettings });

      mountAdditionalFonts(detail.doc);

      if (!detail.doc.isEventListenersAdded) {
        // listened events in iframes are posted to the main window
        // and then used by useMouseEvent and useTouchEvent
        // and more gesture events can be detected in the iframeEventHandlers
        detail.doc.isEventListenersAdded = true;
        detail.doc.addEventListener('keydown', handleKeydown.bind(null, bookKey));
        detail.doc.addEventListener('mousedown', handleMousedown.bind(null, bookKey));
        detail.doc.addEventListener('mouseup', handleMouseup.bind(null, bookKey));
        detail.doc.addEventListener('click', handleClick.bind(null, bookKey));
        detail.doc.addEventListener('wheel', handleWheel.bind(null, bookKey));
        detail.doc.addEventListener('touchstart', handleTouchStart.bind(null, bookKey));
        detail.doc.addEventListener('touchmove', handleTouchMove.bind(null, bookKey));
        detail.doc.addEventListener('touchend', handleTouchEnd.bind(null, bookKey));
      }
    }
  };

  const docRelocateHandler = (event: Event) => {
    const detail = (event as CustomEvent).detail;
    if (detail.reason !== 'scroll' && detail.reason !== 'page') return;

    const parallelViews = getParallels(bookKey);
    if (parallelViews && parallelViews.size > 0) {
      parallelViews.forEach((key) => {
        if (key !== bookKey) {
          const target = getView(key)?.renderer;
          if (target) {
            target.goTo?.({ index: detail.index, anchor: detail.fraction });
          }
        }
      });
    }
  };

  const { handlePageFlip, handleContinuousScroll } = usePagination(bookKey, viewRef, containerRef);
  const mouseHandlers = useMouseEvent(bookKey, handlePageFlip, handleContinuousScroll);
  const touchHandlers = useTouchEvent(bookKey, handleContinuousScroll);

  useFoliateEvents(viewRef.current, {
    onLoad: docLoadHandler,
    onRelocate: progressRelocateHandler,
    onRendererRelocate: docRelocateHandler,
  });

  useEffect(() => {
    if (viewRef.current && viewRef.current.renderer) {
      const viewSettings = getViewSettings(bookKey)!;
      viewRef.current.renderer.setStyles?.(getStyles(viewSettings));
    }
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [themeCode, isDarkMode]);

  useEffect(() => {
    if (isViewCreated.current) return;
    isViewCreated.current = true;

    const openBook = async () => {
      console.log('Opening book', bookKey);
      await import('foliate-js/view.js');
      const view = wrappedFoliateView(document.createElement('foliate-view') as FoliateView);
      view.id = `foliate-view-${bookKey}`;
      document.body.append(view);
      containerRef.current?.appendChild(view);

      const containerRect = containerRef.current?.getBoundingClientRect();
      const width = containerRect?.width || window.innerWidth;
      const height = containerRect?.height || window.innerHeight;

      const viewSettings = getViewSettings(bookKey)!;
      const writingMode = viewSettings.writingMode;
      if (writingMode) {
        const settingsDir = getBookDirFromWritingMode(writingMode);
        const languageDir = getBookDirFromLanguage(bookDoc.metadata.language);
        if (settingsDir !== 'auto') {
          bookDoc.dir = settingsDir;
        } else if (languageDir !== 'auto') {
          bookDoc.dir = languageDir;
        }
      }

      await view.open(bookDoc);
      // make sure we can listen renderer events after opening book
      viewRef.current = view;
      setFoliateView(bookKey, view);

      const { book } = view;

      book.transformTarget?.addEventListener('data', getDocTransformHandler({ width, height }));
      view.renderer.setStyles?.(getStyles(viewSettings));

      const isScrolled = viewSettings.scrolled!;
      const showHeader = viewSettings.showHeader!;
      const showFooter = viewSettings.showFooter!;
      const isCompact = !showHeader && !showFooter;
      const marginPx = isCompact ? viewSettings.compactMarginPx : viewSettings.marginPx;
      const gapPercent = isCompact ? viewSettings.compactGapPercent : viewSettings.gapPercent;
      const animated = viewSettings.animated!;
      const maxColumnCount = viewSettings.maxColumnCount!;
      const maxInlineSize = getMaxInlineSize(viewSettings);
      const maxBlockSize = viewSettings.maxBlockSize!;
      const screenOrientation = viewSettings.screenOrientation!;
      if (appService?.isMobileApp) {
        await lockScreenOrientation({ orientation: screenOrientation });
      }
      if (animated) {
        view.renderer.setAttribute('animated', '');
      } else {
        view.renderer.removeAttribute('animated');
      }
      view.renderer.setAttribute('flow', isScrolled ? 'scrolled' : 'paginated');
      view.renderer.setAttribute('margin', `${marginPx}px`);
      view.renderer.setAttribute('gap', `${gapPercent}%`);
      view.renderer.setAttribute('max-column-count', maxColumnCount);
      view.renderer.setAttribute('max-inline-size', `${maxInlineSize}px`);
      view.renderer.setAttribute('max-block-size', `${maxBlockSize}px`);

      const lastLocation = config.location;
      if (lastLocation) {
        await view.init({ lastLocation });
      } else {
        await view.goToFraction(0);
      }
    };

    openBook();
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  return (
    <>
      <div
        ref={containerRef}
        className='foliate-viewer h-[100%] w-[100%]'
        {...mouseHandlers}
        {...touchHandlers}
      />
    </>
  );
};

export default FoliateViewer;