feat: add desktop/web app package (#2606)

Co-authored-by: adamdotdevin <[email protected]>
Co-authored-by: Adam <[email protected]>
Co-authored-by: GitHub Action <[email protected]>

1 files changed, 51 insertions, 0 deletions

diff --git a/packages/app/src/utils/dom.ts b/packages/app/src/utils/dom.ts
new file mode 100644
index 000000000..4f3724c7c
--- /dev/null
+++ b/packages/app/src/utils/dom.ts
@@ -0,0 +1,51 @@
+export function getCharacterOffsetInLine(lineElement: Element, targetNode: Node, offset: number): number {
+  const r = document.createRange()
+  r.selectNodeContents(lineElement)
+  r.setEnd(targetNode, offset)
+  return r.toString().length
+}
+
+export function getNodeOffsetInLine(lineElement: Element, charIndex: number): { node: Node; offset: number } | null {
+  const walker = document.createTreeWalker(lineElement, NodeFilter.SHOW_TEXT, null)
+  let remaining = Math.max(0, charIndex)
+  let lastText: Node | null = null
+  let lastLen = 0
+  let node: Node | null
+  while ((node = walker.nextNode())) {
+    const len = node.textContent?.length || 0
+    lastText = node
+    lastLen = len
+    if (remaining <= len) return { node, offset: remaining }
+    remaining -= len
+  }
+  if (lastText) return { node: lastText, offset: lastLen }
+  if (lineElement.firstChild) return { node: lineElement.firstChild, offset: 0 }
+  return null
+}
+
+export function getSelectionInContainer(
+  container: HTMLElement,
+): { sl: number; sch: number; el: number; ech: number } | null {
+  const s = window.getSelection()
+  if (!s || s.rangeCount === 0) return null
+  const r = s.getRangeAt(0)
+  const sc = r.startContainer
+  const ec = r.endContainer
+  const getLineElement = (n: Node) =>
+    (n.nodeType === Node.TEXT_NODE ? (n.parentElement as Element) : (n as Element))?.closest(".line")
+  const sle = getLineElement(sc)
+  const ele = getLineElement(ec)
+  if (!sle || !ele) return null
+  if (!container.contains(sle as Node) || !container.contains(ele as Node)) return null
+  const cc = container.querySelector("code") as HTMLElement | null
+  if (!cc) return null
+  const lines = Array.from(cc.querySelectorAll(".line"))
+  const sli = lines.indexOf(sle as Element)
+  const eli = lines.indexOf(ele as Element)
+  if (sli === -1 || eli === -1) return null
+  const sl = sli + 1
+  const el = eli + 1
+  const sch = getCharacterOffsetInLine(sle as Element, sc, r.startOffset)
+  const ech = getCharacterOffsetInLine(ele as Element, ec, r.endOffset)
+  return { sl, sch, el, ech }
+}