From 3b299809e1d053f80b84ae16d803c3a1a790cde7 Mon Sep 17 00:00:00 2001
From: Steffen Becker <stffn.becker@gmail.com>
Date: Sun, 28 Jun 2026 00:05:37 +0200
Subject: [PATCH] feat: search and replace

---
 src/App.svelte                             |  45 ++++-
 src/lib/components/FindReplaceBar.svelte   | 180 ++++++++++++++++++
 src/lib/components/LinkDialog.svelte       |   3 +-
 src/lib/editor/extensions.ts               |   2 +
 src/lib/editor/extensions/searchReplace.ts | 210 +++++++++++++++++++++
 src/styles/editor.css                      |   9 +
 tests/unit/search-replace.test.ts          |  43 +++++
 7 files changed, 490 insertions(+), 2 deletions(-)
 create mode 100644 src/lib/components/FindReplaceBar.svelte
 create mode 100644 src/lib/editor/extensions/searchReplace.ts
 create mode 100644 tests/unit/search-replace.test.ts

diff --git a/src/App.svelte b/src/App.svelte
index 1f10e97..9d692d9 100644
--- a/src/App.svelte
+++ b/src/App.svelte
@@ -5,6 +5,7 @@
   import EditorComponent from './lib/components/Editor.svelte';
   import Toolbar from './lib/components/Toolbar.svelte';
   import ToolbarExpanded from './lib/components/ToolbarExpanded.svelte';
+  import FindReplaceBar from './lib/components/FindReplaceBar.svelte';
   import { buildOdt, deriveFilename } from './lib/export/odt';
   import { exportPdf, printPdf } from './lib/export/pdf';
   import { supportsFsAccess, saveOdt, saveAsOdt, openOdt } from './lib/export/saveFile';
@@ -40,6 +41,24 @@
   let activeEditor = $derived(hfActive ? hfEditor : editor);
   let activeTick = $derived(hfActive ? hfTick : tick);
 
+  // Find & Replace bar (searchReplace.ts). Targets the body editor; positioned just
+  // below the toolbar region (toolbarRegionH tracks its height, expanded or not).
+  let findOpen = $state(false);
+  let findMode: 'find' | 'replace' = $state('find');
+  let findNonce = $state(0);
+  let toolbarRegionH = $state(0);
+
+  function openFind(mode: 'find' | 'replace') {
+    findMode = mode;
+    findOpen = true;
+    findNonce++;
+  }
+
+  function closeFind() {
+    findOpen = false;
+    editor?.commands.clearSearch();
+  }
+
   // Word/character counts for the status-bar counter. Reading `tick` makes these
   // recompute on every body transaction (incl. selection changes), so they stay
   // live without subscribing to ProseMirror directly.
@@ -441,6 +460,17 @@
         e.preventDefault();
         handlePrintPdf();
       }
+      // Ctrl/Cmd+F → Find, Ctrl/Cmd+H → Find & Replace (suppress the browser's own find).
+      if ((e.ctrlKey || e.metaKey) && !e.shiftKey && (e.key === 'f' || e.key === 'F')) {
+        e.preventDefault();
+        openFind('find');
+      }
+      if ((e.ctrlKey || e.metaKey) && !e.shiftKey && (e.key === 'h' || e.key === 'H')) {
+        e.preventDefault();
+        openFind('replace');
+      }
+      // Escape closes the bar (when it isn't handled inside an input).
+      if (e.key === 'Escape' && findOpen) closeFind();
     }
     window.addEventListener('keydown', onKeydown);
     return () => window.removeEventListener('keydown', onKeydown);
@@ -471,7 +501,7 @@
 </script>
 
 <main>
-  <div class="toolbar-region">
+  <div class="toolbar-region" bind:clientHeight={toolbarRegionH}>
     <div class="toolbar-clip" id="primary-toolbar" bind:this={toolbarClipEl} onwheel={onToolbarWheel}>
       <div class="toolbar-stack" bind:this={toolbarStackEl} style="transform: translateX(-{tbScroll}px);">
   <header class:expanded={toolbarExpanded}>
@@ -706,6 +736,11 @@
     {pageMargins}
     orientation={pageOrientation}
   />
+  {#if findOpen && editor}
+    <div class="find-bar-anchor" style="top: {toolbarRegionH + 8}px;">
+      <FindReplaceBar {editor} {tick} mode={findMode} focusNonce={findNonce} onClose={closeFind} />
+    </div>
+  {/if}
   <footer class="statusbar">
     <div class="sb-left">
       <span>Page {currentPage} of {numPages}</span>
@@ -775,6 +810,14 @@
     height: 100%;
   }
 
+  /* Find & Replace bar: floats at the top-right of the editing area, just under the
+     toolbar (top is set inline from the toolbar height). Below the toolbar's z-index. */
+  .find-bar-anchor {
+    position: fixed;
+    right: 1.5rem;
+    z-index: 190;
+  }
+
   /* Toolbar scroll region. A stacking context (z-index) so the whole toolbar — incl.
      its dropdowns, which live inside the translated stack — paints above the editor
      and its overlays. */
diff --git a/src/lib/components/FindReplaceBar.svelte b/src/lib/components/FindReplaceBar.svelte
new file mode 100644
index 0000000..0e4629f
--- /dev/null
+++ b/src/lib/components/FindReplaceBar.svelte
@@ -0,0 +1,180 @@
+<script lang="ts">
+  import type { Editor } from '@tiptap/core';
+  import { onMount } from 'svelte';
+  import { getSearchState } from '../editor/extensions/searchReplace';
+
+  let { editor, tick, mode, focusNonce, onClose }:
+    { editor: Editor | null; tick: number; mode: 'find' | 'replace'; focusNonce: number; onClose: () => void } = $props();
+
+  let findText = $state('');
+  let replaceText = $state('');
+  let matchCase = $state(false);
+  let wholeWord = $state(false);
+  let showReplace = $state(false); // set from `mode` in the focusNonce effect below
+  let findInput = $state<HTMLInputElement | null>(null);
+
+  // Live match count / current index, recomputed on every editor transaction.
+  let results = $derived.by(() => {
+    void tick;
+    return editor ? getSearchState(editor.state) : { count: 0, current: -1, term: '' };
+  });
+
+  function applySearch() {
+    editor?.commands.setSearch({ term: findText, matchCase, wholeWord });
+    editor?.commands.scrollToCurrent();
+  }
+
+  function next() { editor?.commands.findNext(); }
+  function prev() { editor?.commands.findPrevious(); }
+  function replaceOne() { editor?.commands.replaceCurrent(replaceText); }
+  function replaceEvery() { editor?.commands.replaceAll(replaceText); }
+
+  function onFindKeydown(e: KeyboardEvent) {
+    if (e.key === 'Enter') { e.preventDefault(); e.shiftKey ? prev() : next(); }
+    else if (e.key === 'Escape') { e.preventDefault(); onClose(); }
+  }
+
+  function onReplaceKeydown(e: KeyboardEvent) {
+    if (e.key === 'Enter') { e.preventDefault(); replaceOne(); }
+    else if (e.key === 'Escape') { e.preventDefault(); onClose(); }
+  }
+
+  function toggleCase() { matchCase = !matchCase; applySearch(); }
+  function toggleWord() { wholeWord = !wholeWord; applySearch(); }
+
+  // Prefill from the current selection (single line) on first open.
+  onMount(() => {
+    if (editor) {
+      const { from, to } = editor.state.selection;
+      if (to > from) {
+        const sel = editor.state.doc.textBetween(from, to, '\n');
+        if (sel && !sel.includes('\n')) findText = sel;
+      }
+    }
+    applySearch();
+  });
+
+  // Each Ctrl+F / Ctrl+H bumps focusNonce → refocus and reveal the replace row as asked.
+  $effect(() => {
+    void focusNonce;
+    showReplace = showReplace || mode === 'replace';
+    queueMicrotask(() => { findInput?.focus(); findInput?.select(); });
+  });
+</script>
+
+<div class="find-bar" role="dialog" aria-label="Find and replace">
+  <button class="fb-expand" onclick={() => (showReplace = !showReplace)} title={showReplace ? 'Hide replace' : 'Show replace'} aria-label="Toggle replace">
+    <svg width="10" height="10" viewBox="0 0 10 10" fill="none" aria-hidden="true" style="transform: rotate({showReplace ? 90 : 0}deg)">
+      <path d="M3 1.5l3.5 3.5L3 8.5" stroke="currentColor" stroke-width="1.4" stroke-linecap="round" stroke-linejoin="round"/>
+    </svg>
+  </button>
+
+  <div class="fb-rows">
+    <div class="fb-row">
+      <input
+        bind:this={findInput}
+        bind:value={findText}
+        oninput={applySearch}
+        onkeydown={onFindKeydown}
+        type="text"
+        placeholder="Find"
+        spellcheck="false"
+        autocomplete="off"
+      />
+      <span class="fb-count">
+        {#if findText && results.count === 0}No results
+        {:else if results.count > 0}{results.current + 1}/{results.count}
+        {/if}
+      </span>
+      <button class="fb-opt" class:on={matchCase} onclick={toggleCase} title="Match case" aria-pressed={matchCase}>Aa</button>
+      <button class="fb-opt fb-word" class:on={wholeWord} onclick={toggleWord} title="Whole word" aria-pressed={wholeWord}>
+        <span>W</span>
+      </button>
+      <button class="fb-nav" onclick={prev} disabled={!results.count} title="Previous (Shift+Enter)" aria-label="Previous match">
+        <svg width="12" height="12" viewBox="0 0 12 12" fill="none" aria-hidden="true"><path d="M2.5 7.5L6 4l3.5 3.5" stroke="currentColor" stroke-width="1.4" stroke-linecap="round" stroke-linejoin="round"/></svg>
+      </button>
+      <button class="fb-nav" onclick={next} disabled={!results.count} title="Next (Enter)" aria-label="Next match">
+        <svg width="12" height="12" viewBox="0 0 12 12" fill="none" aria-hidden="true"><path d="M2.5 4.5L6 8l3.5-3.5" stroke="currentColor" stroke-width="1.4" stroke-linecap="round" stroke-linejoin="round"/></svg>
+      </button>
+      <button class="fb-close" onclick={onClose} title="Close (Esc)" aria-label="Close">
+        <svg width="12" height="12" viewBox="0 0 12 12" fill="none" aria-hidden="true"><path d="M2.5 2.5l7 7M9.5 2.5l-7 7" stroke="currentColor" stroke-width="1.4" stroke-linecap="round"/></svg>
+      </button>
+    </div>
+
+    {#if showReplace}
+      <div class="fb-row">
+        <input
+          bind:value={replaceText}
+          onkeydown={onReplaceKeydown}
+          type="text"
+          placeholder="Replace"
+          spellcheck="false"
+          autocomplete="off"
+        />
+        <button class="fb-text-btn" onclick={replaceOne} disabled={!results.count} title="Replace current match">Replace</button>
+        <button class="fb-text-btn" onclick={replaceEvery} disabled={!results.count} title="Replace all matches">All</button>
+      </div>
+    {/if}
+  </div>
+</div>
+
+<style>
+  .find-bar {
+    display: flex;
+    align-items: flex-start;
+    gap: 0.25rem;
+    padding: 0.4rem 0.5rem;
+    background: var(--color-toolbar-bg, #fff);
+    border: 1px solid var(--color-border);
+    border-radius: var(--radius);
+    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.18);
+    font-family: var(--font-sans);
+  }
+
+  .fb-rows { display: flex; flex-direction: column; gap: 0.3rem; }
+  .fb-row { display: flex; align-items: center; gap: 0.25rem; }
+
+  input {
+    width: 14rem;
+    box-sizing: border-box;
+    padding: 0.3rem 0.45rem;
+    border: 1px solid var(--color-border);
+    border-radius: var(--radius);
+    /* --color-surface (not page-bg): page-bg stays white in dark mode, surface follows the theme. */
+    background: var(--color-surface);
+    color: var(--color-text);
+    font-size: 0.82rem;
+  }
+
+  .fb-count {
+    min-width: 4.2rem;
+    text-align: center;
+    font-size: 0.72rem;
+    color: var(--color-text-muted, #6b7280);
+    white-space: nowrap;
+  }
+
+  button {
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    min-width: 1.7rem;
+    height: 1.7rem;
+    padding: 0 0.4rem;
+    border: 1px solid transparent;
+    border-radius: var(--radius);
+    background: transparent;
+    color: var(--color-text);
+    font-size: 0.74rem;
+    cursor: pointer;
+    transition: background 0.15s, border-color 0.15s;
+  }
+
+  button:hover:not(:disabled) { background: var(--color-btn-hover, rgba(0, 0, 0, 0.06)); }
+  button:disabled { opacity: 0.4; cursor: default; }
+  .fb-opt.on { background: var(--color-primary); color: #fff; }
+  .fb-opt { font-weight: 600; }
+  .fb-word span { text-decoration: underline; }
+  .fb-text-btn { min-width: auto; padding: 0 0.6rem; border-color: var(--color-border); }
+  .fb-expand { min-width: 1.2rem; width: 1.2rem; align-self: center; }
+</style>
diff --git a/src/lib/components/LinkDialog.svelte b/src/lib/components/LinkDialog.svelte
index 54b40c8..71eafd5 100644
--- a/src/lib/components/LinkDialog.svelte
+++ b/src/lib/components/LinkDialog.svelte
@@ -84,7 +84,8 @@
     padding: 0.4rem 0.5rem;
     border: 1px solid var(--color-border);
     border-radius: var(--radius);
-    background: var(--color-page-bg, #fff);
+    /* --color-surface (not page-bg): page-bg stays white in dark mode, surface follows the theme. */
+    background: var(--color-surface);
     color: var(--color-text);
     font-size: 0.85rem;
   }
diff --git a/src/lib/editor/extensions.ts b/src/lib/editor/extensions.ts
index c016612..e9ff0ef 100644
--- a/src/lib/editor/extensions.ts
+++ b/src/lib/editor/extensions.ts
@@ -29,6 +29,7 @@ import { PageBreak } from './extensions/pageBreak';
 import { Indent } from './extensions/indent';
 import { FormattingMarks } from './extensions/formattingMarks';
 import { SpellCheck } from './extensions/spellCheck';
+import { SearchReplace } from './extensions/searchReplace';
 import { TableView } from './extensions/tableView';
 import { TableColumnResize } from './extensions/tableColumnResize';
 import { TableRowResize } from './extensions/tableRowResize';
@@ -91,4 +92,5 @@ export const extensions = [
   PageBreaks,
   FormattingMarks,
   SpellCheck,
+  SearchReplace,
 ];
diff --git a/src/lib/editor/extensions/searchReplace.ts b/src/lib/editor/extensions/searchReplace.ts
new file mode 100644
index 0000000..18f7e88
--- /dev/null
+++ b/src/lib/editor/extensions/searchReplace.ts
@@ -0,0 +1,210 @@
+import { Extension } from '@tiptap/core';
+import { Plugin, PluginKey, TextSelection } from '@tiptap/pm/state';
+import { Decoration, DecorationSet } from '@tiptap/pm/view';
+import type { EditorState, Transaction } from '@tiptap/pm/state';
+import type { Node as PmNode } from '@tiptap/pm/model';
+
+// Find & Replace: highlights all matches via decorations, navigates/replaces via commands.
+// Pure editor feature — never touches the document model beyond the actual replacements.
+
+export interface SearchOptions { term: string; matchCase: boolean; wholeWord: boolean; }
+interface Match { from: number; to: number; }
+interface SearchState extends SearchOptions {
+  matches: Match[];
+  current: number; // index into matches, or -1
+  deco: DecorationSet;
+}
+
+export const searchKey = new PluginKey<SearchState>('searchReplace');
+const SET_SEARCH = 'searchReplace/setSearch';
+const SET_CURRENT = 'searchReplace/setCurrent';
+
+function escapeRegExp(s: string): string {
+  return s.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+}
+
+export function buildSearchRegex(term: string, matchCase: boolean, wholeWord: boolean): RegExp | null {
+  if (!term) return null;
+  let pat = escapeRegExp(term);
+  if (wholeWord) pat = `\\b${pat}\\b`;
+  try { return new RegExp(pat, matchCase ? 'g' : 'gi'); }
+  catch { return null; }
+}
+
+// All [start, end) char ranges of a global regex in `text` (skips zero-width matches).
+export function regexRanges(text: string, re: RegExp): [number, number][] {
+  const out: [number, number][] = [];
+  re.lastIndex = 0;
+  let m: RegExpExecArray | null;
+  while ((m = re.exec(text)) !== null) {
+    if (m[0].length === 0) { re.lastIndex++; continue; }
+    out.push([m.index, m.index + m[0].length]);
+  }
+  return out;
+}
+
+// Matches within each textblock, mapped to doc positions. Matches span runs/marks but
+// never block boundaries (each textblock is searched on its own concatenated text).
+function findMatches(doc: PmNode, re: RegExp | null): Match[] {
+  if (!re) return [];
+  const matches: Match[] = [];
+  doc.descendants((node, pos) => {
+    if (!node.isTextblock) return true;
+    let text = '';
+    const map: number[] = []; // map[i] = doc position of char i
+    node.forEach((child, offset) => {
+      if (child.isText) {
+        const t = child.text ?? '';
+        for (let k = 0; k < t.length; k++) { text += t[k]; map.push(pos + 1 + offset + k); }
+      } else {
+        text += '￿'; // inline atom (image/hardBreak): one non-matching slot
+        map.push(pos + 1 + offset);
+      }
+    });
+    for (const [s, e] of regexRanges(text, re)) matches.push({ from: map[s], to: map[e - 1] + 1 });
+    return false;
+  });
+  return matches;
+}
+
+function buildDeco(doc: PmNode, matches: Match[], current: number): DecorationSet {
+  if (!matches.length) return DecorationSet.empty;
+  return DecorationSet.create(doc, matches.map((m, i) =>
+    Decoration.inline(m.from, m.to, { class: i === current ? 'search-match search-match-current' : 'search-match' }),
+  ));
+}
+
+// First match at/after the cursor (wraps to the first match), or -1 when none.
+function pickCurrent(matches: Match[], selFrom: number): number {
+  if (!matches.length) return -1;
+  const i = matches.findIndex(m => m.from >= selFrom);
+  return i === -1 ? 0 : i;
+}
+
+const EMPTY: SearchState = { term: '', matchCase: false, wholeWord: false, matches: [], current: -1, deco: DecorationSet.empty };
+
+// Match count + current index for the toolbar UI (FindReplaceBar.svelte).
+export function getSearchState(state: EditorState): { count: number; current: number; term: string } {
+  const s = searchKey.getState(state);
+  return { count: s?.matches.length ?? 0, current: s?.current ?? -1, term: s?.term ?? '' };
+}
+
+function moveCurrent(state: EditorState, dispatch: ((tr: Transaction) => void) | undefined, dir: 1 | -1): boolean {
+  const s = searchKey.getState(state);
+  if (!s || !s.matches.length) return false;
+  const n = s.matches.length;
+  const idx = s.current < 0 ? (dir > 0 ? 0 : n - 1) : (s.current + dir + n) % n;
+  const m = s.matches[idx];
+  if (dispatch) {
+    const tr = state.tr.setMeta(SET_CURRENT, idx);
+    tr.setSelection(TextSelection.create(tr.doc, m.from, m.to));
+    tr.scrollIntoView();
+    dispatch(tr);
+  }
+  return true;
+}
+
+declare module '@tiptap/core' {
+  interface Commands<ReturnType> {
+    searchReplace: {
+      setSearch: (opts: SearchOptions) => ReturnType;
+      findNext: () => ReturnType;
+      findPrevious: () => ReturnType;
+      scrollToCurrent: () => ReturnType;
+      replaceCurrent: (text: string) => ReturnType;
+      replaceAll: (text: string) => ReturnType;
+      clearSearch: () => ReturnType;
+    };
+  }
+}
+
+export const SearchReplace = Extension.create({
+  name: 'searchReplace',
+
+  addProseMirrorPlugins() {
+    return [
+      new Plugin<SearchState>({
+        key: searchKey,
+        state: {
+          init: () => EMPTY,
+          apply(tr: Transaction, old: SearchState, _oldState: EditorState, newState: EditorState): SearchState {
+            const set = tr.getMeta(SET_SEARCH) as SearchOptions | undefined;
+            if (set) {
+              const matches = findMatches(newState.doc, buildSearchRegex(set.term, set.matchCase, set.wholeWord));
+              const current = pickCurrent(matches, newState.selection.from);
+              return { ...set, matches, current, deco: buildDeco(newState.doc, matches, current) };
+            }
+            const cur = tr.getMeta(SET_CURRENT) as number | undefined;
+            if (cur !== undefined) return { ...old, current: cur, deco: buildDeco(newState.doc, old.matches, cur) };
+            if (tr.docChanged && old.term) {
+              const matches = findMatches(newState.doc, buildSearchRegex(old.term, old.matchCase, old.wholeWord));
+              const current = pickCurrent(matches, newState.selection.from);
+              return { ...old, matches, current, deco: buildDeco(newState.doc, matches, current) };
+            }
+            return old;
+          },
+        },
+        props: {
+          decorations(state) { return searchKey.getState(state)?.deco; },
+        },
+      }),
+    ];
+  },
+
+  addCommands() {
+    return {
+      setSearch: (opts: SearchOptions) => ({ state, dispatch }) => {
+        if (dispatch) dispatch(state.tr.setMeta(SET_SEARCH, opts));
+        return true;
+      },
+      findNext: () => ({ state, dispatch }) => moveCurrent(state, dispatch, 1),
+      findPrevious: () => ({ state, dispatch }) => moveCurrent(state, dispatch, -1),
+      scrollToCurrent: () => ({ state, dispatch }) => {
+        const s = searchKey.getState(state);
+        if (!s || s.current < 0) return false;
+        const m = s.matches[s.current];
+        if (dispatch) dispatch(state.tr.setSelection(TextSelection.create(state.doc, m.from, m.to)).scrollIntoView());
+        return true;
+      },
+      replaceCurrent: (text: string) => ({ state, dispatch }) => {
+        const s = searchKey.getState(state);
+        if (!s || s.current < 0 || !s.matches.length) return false;
+        const m = s.matches[s.current];
+        if (dispatch) {
+          // Marks of the first matched char (resolving at m.from would read the
+          // boundary before the match, i.e. the preceding run's formatting).
+          const marks = state.doc.resolve(m.from + 1).marks();
+          const tr = state.tr;
+          if (text) tr.replaceWith(m.from, m.to, state.schema.text(text, marks));
+          else tr.delete(m.from, m.to);
+          // Land the cursor after the replacement so the recompute picks the next match.
+          tr.setSelection(TextSelection.create(tr.doc, m.from + text.length));
+          tr.scrollIntoView();
+          dispatch(tr);
+        }
+        return true;
+      },
+      replaceAll: (text: string) => ({ state, dispatch }) => {
+        const s = searchKey.getState(state);
+        if (!s || !s.matches.length) return false;
+        if (dispatch) {
+          const tr = state.tr;
+          // Reverse order so earlier positions stay valid as we splice.
+          for (let i = s.matches.length - 1; i >= 0; i--) {
+            const m = s.matches[i];
+            const marks = state.doc.resolve(m.from + 1).marks();
+            if (text) tr.replaceWith(m.from, m.to, state.schema.text(text, marks));
+            else tr.delete(m.from, m.to);
+          }
+          dispatch(tr);
+        }
+        return true;
+      },
+      clearSearch: () => ({ state, dispatch }) => {
+        const s = searchKey.getState(state);
+        if (dispatch) dispatch(state.tr.setMeta(SET_SEARCH, { term: '', matchCase: s?.matchCase ?? false, wholeWord: s?.wholeWord ?? false }));
+        return true;
+      },
+    };
+  },
+});
diff --git a/src/styles/editor.css b/src/styles/editor.css
index f62a72e..e17fdf4 100644
--- a/src/styles/editor.css
+++ b/src/styles/editor.css
@@ -154,6 +154,15 @@
   cursor: text;
 }
 
+/* Find & Replace match highlights (searchReplace.ts); current match is stronger. */
+.paper .tiptap .search-match {
+  background: rgba(255, 213, 0, 0.45);
+  border-radius: 2px;
+}
+.paper .tiptap .search-match-current {
+  background: rgba(255, 145, 0, 0.8);
+}
+
 /* Inline, as-character images (image.ts). The wrapper reserves the rotated bounding
    box; the rotor holds the <img>, resize handles and rotate grip, rotating together. */
 .paper .tiptap .image-node {
diff --git a/tests/unit/search-replace.test.ts b/tests/unit/search-replace.test.ts
new file mode 100644
index 0000000..f9c981e
--- /dev/null
+++ b/tests/unit/search-replace.test.ts
@@ -0,0 +1,43 @@
+import { describe, it, expect } from 'vitest';
+import { buildSearchRegex, regexRanges } from '../../src/lib/editor/extensions/searchReplace';
+
+function ranges(text: string, term: string, matchCase = false, wholeWord = false): [number, number][] {
+  const re = buildSearchRegex(term, matchCase, wholeWord);
+  return re ? regexRanges(text, re) : [];
+}
+
+describe('buildSearchRegex', () => {
+  it('returns null for an empty term', () => {
+    expect(buildSearchRegex('', false, false)).toBeNull();
+  });
+
+  it('escapes regex metacharacters (literal match)', () => {
+    expect(ranges('a.b a_b', 'a.b')).toEqual([[0, 3]]); // the dot is literal, not "any char"
+  });
+
+  it('is case-insensitive by default, case-sensitive when asked', () => {
+    expect(ranges('Foo foo FOO', 'foo')).toEqual([[0, 3], [4, 7], [8, 11]]);
+    expect(ranges('Foo foo FOO', 'foo', true)).toEqual([[4, 7]]);
+  });
+
+  it('honours whole-word boundaries', () => {
+    expect(ranges('cat category scat', 'cat')).toEqual([[0, 3], [4, 7], [14, 17]]);
+    expect(ranges('cat category scat', 'cat', false, true)).toEqual([[0, 3]]);
+  });
+});
+
+describe('regexRanges', () => {
+  it('finds all non-overlapping matches', () => {
+    expect(ranges('abab', 'ab')).toEqual([[0, 2], [2, 4]]);
+  });
+
+  it('returns nothing when there is no match', () => {
+    expect(ranges('hello', 'xyz')).toEqual([]);
+  });
+
+  it('does not loop on zero-width patterns', () => {
+    // term is escaped so this can't actually be zero-width, but guard the helper directly
+    const re = new RegExp('', 'g');
+    expect(regexRanges('abc', re)).toEqual([]);
+  });
+});