PDF source adapter

1"use client";
2 
3import * as React from "react";
4 
5import type {
6  Source,
7  SourceAnchor,
8  SourceLocation,
9} from "@/lib/document-source";
10import {
11  PdfHighlight,
12  type PageOverlayProps,
13  type PdfViewerHandle,
14} from "@/components/ui/pdf-viewer";
15 
16export interface SourceTarget {
17  scrollTo?: (source: Source, options: { behavior: ScrollBehavior }) => void;
18}
19 
20/**
21 * Turn a source anchor into a PDF target, or `undefined` when the anchor isn't
22 * a page region (a spreadsheet cell, a text span, …). PDF/image bbox anchors are
23 * normalized [0, 1]; the viewer wants percentages, so scale by 100. An image
24 * lands on the single page 1.
25 */
26export function pdfAnchorToTarget(
27  anchor: SourceAnchor,
28): SourceLocation | undefined {
29  if (anchor.kind === "pdf_bbox") {
30    if (!isPositiveInteger(anchor.page) || !isValidNormalizedBox(anchor)) {
31      return undefined;
32    }
33    return {
34      page: anchor.page,
35      area: {
36        left: anchor.left * 100,
37        top: anchor.top * 100,
38        width: anchor.width * 100,
39        height: anchor.height * 100,
40      },
41    };
42  }
43  if (anchor.kind === "image_bbox") {
44    if (anchor.page != null && !isPositiveInteger(anchor.page)) {
45      return undefined;
46    }
47    if (!isValidNormalizedBox(anchor)) return undefined;
48    return {
49      page: 1,
50      area: {
51        left: anchor.left * 100,
52        top: anchor.top * 100,
53        width: anchor.width * 100,
54        height: anchor.height * 100,
55      },
56    };
57  }
58  return undefined;
59}
60 
61function isPositiveInteger(value: number): boolean {
62  return Number.isInteger(value) && value >= 1;
63}
64 
65function isValidNormalizedBox({
66  left,
67  top,
68  width,
69  height,
70}: {
71  left: number;
72  top: number;
73  width: number;
74  height: number;
75}): boolean {
76  return (
77    Number.isFinite(left) &&
78    Number.isFinite(top) &&
79    Number.isFinite(width) &&
80    Number.isFinite(height) &&
81    left >= 0 &&
82    top >= 0 &&
83    width > 0 &&
84    height > 0 &&
85    left + width <= 1 &&
86    top + height <= 1
87  );
88}
89 
90/**
91 * A stable source target over a `PdfViewer` ref. The ref is read lazily, so this
92 * is just the bridge from source anchors to the viewer's imperative handle.
93 */
94export function usePdfSourceTarget(
95  viewerRef: React.RefObject<PdfViewerHandle | null>,
96): SourceTarget {
97  return React.useMemo<SourceTarget>(
98    () => ({
99      scrollTo: (source: Source, options) => {
100        const target = pdfAnchorToTarget(source.anchor);
101        if (target) {
102// … truncated