import { useCallback, useEffect, useRef, useState } from 'react' import PDFJSWrapper from '../util/pdf-js-wrapper' import { sendMB } from '@/infrastructure/event-tracking' type StoredPDFState = { scrollMode?: number spreadMode?: number currentScaleValue?: string } export default function usePresentationMode( pdfJsWrapper: PDFJSWrapper | null | undefined, page: number | null, handlePageChange: (page: number) => void, scale: string, setScale: (scale: string) => void ): () => void { const storedState = useRef({}) const [presentationMode, setPresentationMode] = useState(false) const nextPage = useCallback(() => { if (page !== null) { handlePageChange(page + 1) } }, [handlePageChange, page]) const previousPage = useCallback(() => { if (page !== null) { handlePageChange(page - 1) } }, [handlePageChange, page]) const clickListener = useCallback( event => { if (event.target.tagName === 'A') { return } if (event.shiftKey) { previousPage() } else { nextPage() } }, [nextPage, previousPage] ) const arrowKeyListener = useCallback( event => { switch (event.key) { case 'ArrowLeft': case 'ArrowUp': case 'PageUp': case 'Backspace': previousPage() break case 'ArrowRight': case 'ArrowDown': case 'PageDown': nextPage() break case ' ': if (event.shiftKey) { previousPage() } else { nextPage() } break } }, [nextPage, previousPage] ) useEffect(() => { if (presentationMode) { window.addEventListener('keydown', arrowKeyListener) window.addEventListener('click', clickListener) return () => { window.removeEventListener('keydown', arrowKeyListener) window.removeEventListener('click', clickListener) } } }, [presentationMode, arrowKeyListener, clickListener]) const requestPresentationMode = useCallback(() => { sendMB('pdf-viewer-enter-presentation-mode') if (pdfJsWrapper) { pdfJsWrapper.container.parentNode.requestFullscreen() } }, [pdfJsWrapper]) const handleEnterFullscreen = useCallback(() => { if (pdfJsWrapper) { storedState.current.scrollMode = pdfJsWrapper.viewer.scrollMode storedState.current.spreadMode = pdfJsWrapper.viewer.spreadMode storedState.current.currentScaleValue = scale setScale('page-fit') pdfJsWrapper.viewer.scrollMode = 3 // page pdfJsWrapper.viewer.spreadMode = 0 // none setPresentationMode(true) } }, [pdfJsWrapper, setScale, scale]) const handleExitFullscreen = useCallback(() => { if (pdfJsWrapper) { pdfJsWrapper.viewer.scrollMode = storedState.current.scrollMode pdfJsWrapper.viewer.spreadMode = storedState.current.spreadMode if (storedState.current.currentScaleValue !== undefined) { setScale(storedState.current.currentScaleValue) } setPresentationMode(false) } }, [pdfJsWrapper, setScale]) const handleFullscreenChange = useCallback(() => { if (pdfJsWrapper) { const fullscreen = document.fullscreenElement === pdfJsWrapper.container.parentNode if (fullscreen) { handleEnterFullscreen() } else { handleExitFullscreen() } } }, [pdfJsWrapper, handleEnterFullscreen, handleExitFullscreen]) useEffect(() => { window.addEventListener('fullscreenchange', handleFullscreenChange) return () => { window.removeEventListener('fullscreenchange', handleFullscreenChange) } }, [handleFullscreenChange]) return requestPresentationMode }