✨ add menu pdf & pdf lib

src/components/pdf-menu.tsx

@@ -0,0 +1,191 @@
+import { useEffect, useRef, useState } from 'react'
+import type { PDFDocumentProxy, RenderTask } from 'pdfjs-dist'
+
+type Props = {
+  src: string
+}
+
+// pdfjs-dist touches the DOM/Canvas at import time, so it's loaded lazily inside
+// the effect below instead of at module scope — this file also runs during SSR.
+export function PdfMenu({ src }: Props) {
+  const containerRef = useRef<HTMLDivElement>(null)
+  const canvasRef = useRef<HTMLCanvasElement>(null)
+  const pdfRef = useRef<PDFDocumentProxy | null>(null)
+  const directionRef = useRef(1)
+  const hasRenderedOnceRef = useRef(false)
+  const [error, setError] = useState(false)
+  const [numPages, setNumPages] = useState(0)
+  const [pageNumber, setPageNumber] = useState(1)
+  const [isBusy, setIsBusy] = useState(false)
+
+  function goToPage(next: number) {
+    directionRef.current = next > pageNumber ? 1 : -1
+    setPageNumber(next)
+  }
+
+  useEffect(() => {
+    let cancelled = false
+    setError(false)
+    setNumPages(0)
+    setPageNumber(1)
+    pdfRef.current = null
+    hasRenderedOnceRef.current = false
+
+    async function load() {
+      const pdfjsLib = await import('pdfjs-dist')
+      pdfjsLib.GlobalWorkerOptions.workerSrc = new URL(
+        'pdfjs-dist/build/pdf.worker.min.mjs',
+        import.meta.url,
+      ).href
+
+      try {
+        const pdf = await pdfjsLib.getDocument({ url: src }).promise
+        if (cancelled) return
+        pdfRef.current = pdf
+        setNumPages(pdf.numPages)
+      } catch (err) {
+        console.error('PdfMenu failed to load', err)
+        if (!cancelled) setError(true)
+      }
+    }
+
+    load()
+
+    return () => {
+      cancelled = true
+    }
+  }, [src])
+
+  useEffect(() => {
+    const pdf = pdfRef.current
+    const canvas = canvasRef.current
+    const container = containerRef.current
+    if (!pdf || !canvas || !container || numPages === 0) return
+
+    let cancelled = false
+    let renderTask: RenderTask | undefined
+    let exitTimeout: ReturnType<typeof setTimeout> | undefined
+
+    function wait(ms: number) {
+      return new Promise<void>((resolve) => {
+        exitTimeout = setTimeout(resolve, ms)
+      })
+    }
+
+    async function render(pdf: PDFDocumentProxy, canvas: HTMLCanvasElement, container: HTMLDivElement) {
+      const direction = directionRef.current
+      setIsBusy(true)
+
+      if (hasRenderedOnceRef.current) {
+        canvas.style.transition = 'opacity 0.18s ease, transform 0.18s ease'
+        canvas.style.opacity = '0'
+        canvas.style.transform = `translateX(${direction * -2}rem)`
+        await wait(180)
+        if (cancelled) return
+      }
+
+      try {
+        const page = await pdf.getPage(pageNumber)
+        if (cancelled) return
+        const unscaledViewport = page.getViewport({ scale: 1 })
+        const scale = container.clientWidth / unscaledViewport.width
+        const viewport = page.getViewport({ scale })
+
+        const pixelRatio = window.devicePixelRatio || 1
+        canvas.width = viewport.width * pixelRatio
+        canvas.height = viewport.height * pixelRatio
+        canvas.style.width = `${viewport.width}px`
+        canvas.style.height = `${viewport.height}px`
+
+        const context = canvas.getContext('2d')
+        if (!context) return
+        context.scale(pixelRatio, pixelRatio)
+
+        renderTask = page.render({ canvasContext: context, viewport, canvas })
+        await renderTask.promise
+        if (cancelled) return
+
+        // Jump to the entry offset with transitions off, then force the browser to
+        // commit that position before re-enabling them — otherwise the two style
+        // writes land in the same frame and the entry animation never paints.
+        canvas.style.transition = 'none'
+        canvas.style.transform = `translateX(${direction * 2}rem)`
+        canvas.offsetHeight
+        canvas.style.transition = 'opacity 0.22s ease, transform 0.22s ease'
+        canvas.style.opacity = '1'
+        canvas.style.transform = 'translateX(0)'
+        hasRenderedOnceRef.current = true
+      } catch (err) {
+        if (!cancelled) {
+          console.error('PdfMenu failed to render page', err)
+          setError(true)
+        }
+      } finally {
+        if (!cancelled) setIsBusy(false)
+      }
+    }
+
+    render(pdf, canvas, container)
+
+    return () => {
+      cancelled = true
+      clearTimeout(exitTimeout)
+      renderTask?.cancel()
+    }
+  }, [numPages, pageNumber])
+
+  if (error) {
+    return (
+      <p className="field-hint">
+        Die Speisekarte konnte nicht geladen werden.{' '}
+        <a href={src} target="_blank" rel="noopener noreferrer">
+          Als PDF öffnen
+        </a>
+        .
+      </p>
+    )
+  }
+
+  return (
+    <div className="pdf-menu" ref={containerRef}>
+      <div className="pdf-menu-viewport">
+        <canvas className="pdf-menu-page" ref={canvasRef} />
+        {numPages === 0 && (
+          <div className="pdf-menu-loading" role="status">
+            <div className="pdf-menu-spinner" aria-hidden="true" />
+            <p>Die Speisekarte wird aufgetischt …</p>
+          </div>
+        )}
+      </div>
+      {numPages > 1 && (
+        <div className="pdf-menu-pagination">
+          <button
+            type="button"
+            className="btn btn-secondary"
+            onClick={() => goToPage(pageNumber - 1)}
+            disabled={isBusy || pageNumber <= 1}
+          >
+            Zurück
+          </button>
+          <span>
+            Seite {pageNumber} von {numPages}
+          </span>
+          <button
+            type="button"
+            className="btn btn-secondary"
+            onClick={() => goToPage(pageNumber + 1)}
+            disabled={isBusy || pageNumber >= numPages}
+          >
+            Weiter
+          </button>
+        </div>
+      )}
+      <p className="field-hint">
+        Speisekarte nicht geladen?{' '}
+        <a href={src} target="_blank" rel="noopener noreferrer">
+          Klick hier
+        </a>
+      </p>
+    </div>
+  )
+}