chore: app -> desktop

1 files changed, 846 insertions, 0 deletions

diff --git a/packages/desktop/src/components/code.tsx b/packages/desktop/src/components/code.tsx
new file mode 100644
index 000000000..40a40aa9a
--- /dev/null
+++ b/packages/desktop/src/components/code.tsx
@@ -0,0 +1,846 @@
+import { bundledLanguages, type BundledLanguage, type ShikiTransformer } from "shiki"
+import { splitProps, type ComponentProps, createEffect, onMount, onCleanup, createMemo, createResource } from "solid-js"
+import { useLocal, useShiki } from "@/context"
+import type { TextSelection } from "@/context/local"
+import { getFileExtension, getNodeOffsetInLine, getSelectionInContainer } from "@/utils"
+
+type DefinedSelection = Exclude<TextSelection, undefined>
+
+interface Props extends ComponentProps<"div"> {
+  code: string
+  path: string
+}
+
+export function Code(props: Props) {
+  const ctx = useLocal()
+  const highlighter = useShiki()
+  const [local, others] = splitProps(props, ["class", "classList", "code", "path"])
+  const lang = createMemo(() => {
+    const ext = getFileExtension(local.path)
+    if (ext in bundledLanguages) return ext
+    return "text"
+  })
+
+  let container: HTMLDivElement | undefined
+  let isProgrammaticSelection = false
+
+  const ranges = createMemo<DefinedSelection[]>(() => {
+    const items = ctx.context.all() as Array<{ type: "file"; path: string; selection?: DefinedSelection }>
+    const result: DefinedSelection[] = []
+    for (const item of items) {
+      if (item.path !== local.path) continue
+      const selection = item.selection
+      if (!selection) continue
+      result.push(selection)
+    }
+    return result
+  })
+
+  const createLineNumberTransformer = (selections: DefinedSelection[]): ShikiTransformer => {
+    const highlighted = new Set<number>()
+    for (const selection of selections) {
+      const startLine = selection.startLine
+      const endLine = selection.endLine
+      const start = Math.max(1, Math.min(startLine, endLine))
+      const end = Math.max(start, Math.max(startLine, endLine))
+      const count = end - start + 1
+      if (count <= 0) continue
+      const values = Array.from({ length: count }, (_, index) => start + index)
+      for (const value of values) highlighted.add(value)
+    }
+    return {
+      name: "line-number-highlight",
+      line(node, index) {
+        if (!highlighted.has(index)) return
+        this.addClassToHast(node, "line-number-highlight")
+        const children = node.children
+        if (!Array.isArray(children)) return
+        for (const child of children) {
+          if (!child || typeof child !== "object") continue
+          const element = child as { type?: string; properties?: { className?: string[] } }
+          if (element.type !== "element") continue
+          const className = element.properties?.className
+          if (!Array.isArray(className)) continue
+          const matches = className.includes("diff-oldln") || className.includes("diff-newln")
+          if (!matches) continue
+          if (className.includes("line-number-highlight")) continue
+          className.push("line-number-highlight")
+        }
+      },
+    }
+  }
+
+  const [html] = createResource(
+    () => ranges(),
+    async (activeRanges) => {
+      if (!highlighter.getLoadedLanguages().includes(lang())) {
+        await highlighter.loadLanguage(lang() as BundledLanguage)
+      }
+      return highlighter.codeToHtml(local.code || "", {
+        lang: lang() && lang() in bundledLanguages ? lang() : "text",
+        theme: "opencode",
+        transformers: [transformerUnifiedDiff(), transformerDiffGroups(), createLineNumberTransformer(activeRanges)],
+      }) as string
+    },
+  )
+
+  onMount(() => {
+    if (!container) return
+
+    let ticking = false
+    const onScroll = () => {
+      if (!container) return
+      if (ctx.file.active()?.path !== local.path) return
+      if (ticking) return
+      ticking = true
+      requestAnimationFrame(() => {
+        ticking = false
+        ctx.file.scroll(local.path, container!.scrollTop)
+      })
+    }
+
+    const onSelectionChange = () => {
+      if (!container) return
+      if (isProgrammaticSelection) return
+      if (ctx.file.active()?.path !== local.path) return
+      const d = getSelectionInContainer(container)
+      if (!d) return
+      const p = ctx.file.node(local.path)?.selection
+      if (p && p.startLine === d.sl && p.endLine === d.el && p.startChar === d.sch && p.endChar === d.ech) return
+      ctx.file.select(local.path, { startLine: d.sl, startChar: d.sch, endLine: d.el, endChar: d.ech })
+    }
+
+    const MOD = typeof navigator === "object" && /(Mac|iPod|iPhone|iPad)/.test(navigator.platform) ? "Meta" : "Control"
+    const onKeyDown = (e: KeyboardEvent) => {
+      if (ctx.file.active()?.path !== local.path) return
+      const ae = document.activeElement as HTMLElement | undefined
+      const tag = (ae?.tagName || "").toLowerCase()
+      const inputFocused = !!ae && (tag === "input" || tag === "textarea" || ae.isContentEditable)
+      if (inputFocused) return
+      if (e.getModifierState(MOD) && e.key.toLowerCase() === "a") {
+        e.preventDefault()
+        if (!container) return
+        const element = container.querySelector("code") as HTMLElement | undefined
+        if (!element) return
+        const lines = Array.from(element.querySelectorAll(".line"))
+        if (!lines.length) return
+        const r = document.createRange()
+        const last = lines[lines.length - 1]
+        r.selectNodeContents(last)
+        const lastLen = r.toString().length
+        ctx.file.select(local.path, { startLine: 1, startChar: 0, endLine: lines.length, endChar: lastLen })
+      }
+    }
+
+    container.addEventListener("scroll", onScroll)
+    document.addEventListener("selectionchange", onSelectionChange)
+    document.addEventListener("keydown", onKeyDown)
+
+    onCleanup(() => {
+      container?.removeEventListener("scroll", onScroll)
+      document.removeEventListener("selectionchange", onSelectionChange)
+      document.removeEventListener("keydown", onKeyDown)
+    })
+  })
+
+  // Restore scroll position from store when content is ready
+  createEffect(() => {
+    const content = html()
+    if (!container || !content) return
+    const top = ctx.file.node(local.path)?.scrollTop
+    if (top !== undefined && container.scrollTop !== top) container.scrollTop = top
+  })
+
+  // Sync selection from store -> DOM
+  createEffect(() => {
+    const content = html()
+    if (!container || !content) return
+    if (ctx.file.active()?.path !== local.path) return
+    const codeEl = container.querySelector("code") as HTMLElement | undefined
+    if (!codeEl) return
+    const target = ctx.file.node(local.path)?.selection
+    const current = getSelectionInContainer(container)
+    const sel = window.getSelection()
+    if (!sel) return
+    if (!target) {
+      if (current) {
+        isProgrammaticSelection = true
+        sel.removeAllRanges()
+        queueMicrotask(() => {
+          isProgrammaticSelection = false
+        })
+      }
+      return
+    }
+    const matches = !!(
+      current &&
+      current.sl === target.startLine &&
+      current.sch === target.startChar &&
+      current.el === target.endLine &&
+      current.ech === target.endChar
+    )
+    if (matches) return
+    const lines = Array.from(codeEl.querySelectorAll(".line"))
+    if (lines.length === 0) return
+    let sIdx = Math.max(0, target.startLine - 1)
+    let eIdx = Math.max(0, target.endLine - 1)
+    let sChar = Math.max(0, target.startChar || 0)
+    let eChar = Math.max(0, target.endChar || 0)
+    if (sIdx > eIdx || (sIdx === eIdx && sChar > eChar)) {
+      const ti = sIdx
+      sIdx = eIdx
+      eIdx = ti
+      const tc = sChar
+      sChar = eChar
+      eChar = tc
+    }
+    if (eChar === 0 && eIdx > sIdx) {
+      eIdx = eIdx - 1
+      eChar = Number.POSITIVE_INFINITY
+    }
+    if (sIdx >= lines.length) return
+    if (eIdx >= lines.length) eIdx = lines.length - 1
+    const s = getNodeOffsetInLine(lines[sIdx], sChar) ?? { node: lines[sIdx], offset: 0 }
+    const e = getNodeOffsetInLine(lines[eIdx], eChar) ?? { node: lines[eIdx], offset: lines[eIdx].childNodes.length }
+    const range = document.createRange()
+    range.setStart(s.node, s.offset)
+    range.setEnd(e.node, e.offset)
+    isProgrammaticSelection = true
+    sel.removeAllRanges()
+    sel.addRange(range)
+    queueMicrotask(() => {
+      isProgrammaticSelection = false
+    })
+  })
+
+  // Build/toggle split layout and apply folding (both unified and split)
+  createEffect(() => {
+    const content = html()
+    if (!container || !content) return
+    const view = ctx.file.view(local.path)
+
+    const pres = Array.from(container.querySelectorAll<HTMLPreElement>("pre"))
+    if (pres.length === 0) return
+    const originalPre = pres[0]
+
+    const split = container.querySelector<HTMLElement>(".diff-split")
+    if (view === "diff-split") {
+      applySplitDiff(container)
+      const next = container.querySelector<HTMLElement>(".diff-split")
+      if (next) next.style.display = ""
+      originalPre.style.display = "none"
+    } else {
+      if (split) split.style.display = "none"
+      originalPre.style.display = ""
+    }
+
+    const expanded = ctx.file.folded(local.path)
+    if (view === "diff-split") {
+      const left = container.querySelector<HTMLElement>(".diff-split pre:nth-child(1) code")
+      const right = container.querySelector<HTMLElement>(".diff-split pre:nth-child(2) code")
+      if (left)
+        applyDiffFolding(left, 3, { expanded, onExpand: (key) => ctx.file.unfold(local.path, key), side: "left" })
+      if (right)
+        applyDiffFolding(right, 3, { expanded, onExpand: (key) => ctx.file.unfold(local.path, key), side: "right" })
+    } else {
+      const code = container.querySelector<HTMLElement>("pre code")
+      if (code)
+        applyDiffFolding(code, 3, {
+          expanded,
+          onExpand: (key) => ctx.file.unfold(local.path, key),
+        })
+    }
+  })
+
+  // Highlight groups + scroll coupling
+  const clearHighlights = () => {
+    if (!container) return
+    container.querySelectorAll<HTMLElement>(".diff-selected").forEach((el) => el.classList.remove("diff-selected"))
+  }
+
+  const applyHighlight = (idx: number, scroll?: boolean) => {
+    if (!container) return
+    const view = ctx.file.view(local.path)
+    if (view === "raw") return
+
+    clearHighlights()
+
+    const nodes: HTMLElement[] = []
+    if (view === "diff-split") {
+      const left = container.querySelector<HTMLElement>(".diff-split pre:nth-child(1) code")
+      const right = container.querySelector<HTMLElement>(".diff-split pre:nth-child(2) code")
+      if (left)
+        nodes.push(...Array.from(left.querySelectorAll<HTMLElement>(`[data-chgrp="${idx}"][data-diff="remove"]`)))
+      if (right)
+        nodes.push(...Array.from(right.querySelectorAll<HTMLElement>(`[data-chgrp="${idx}"][data-diff="add"]`)))
+    } else {
+      const code = container.querySelector<HTMLElement>("pre code")
+      if (code) nodes.push(...Array.from(code.querySelectorAll<HTMLElement>(`[data-chgrp="${idx}"]`)))
+    }
+
+    for (const n of nodes) n.classList.add("diff-selected")
+    if (scroll && nodes.length) nodes[0].scrollIntoView({ block: "center", behavior: "smooth" })
+  }
+
+  const countGroups = () => {
+    if (!container) return 0
+    const code = container.querySelector<HTMLElement>("pre code")
+    if (!code) return 0
+    const set = new Set<string>()
+    for (const el of Array.from(code.querySelectorAll<HTMLElement>(".diff-line[data-chgrp]"))) {
+      const v = el.getAttribute("data-chgrp")
+      if (v != undefined) set.add(v)
+    }
+    return set.size
+  }
+
+  let lastIdx: number | undefined = undefined
+  let lastView: string | undefined
+  let lastContent: string | undefined
+  let lastRawIdx: number | undefined = undefined
+  createEffect(() => {
+    const content = html()
+    if (!container || !content) return
+    const view = ctx.file.view(local.path)
+    const raw = ctx.file.changeIndex(local.path)
+    if (raw === undefined) return
+    const total = countGroups()
+    if (total <= 0) return
+    const next = ((raw % total) + total) % total
+
+    const navigated = lastRawIdx !== undefined && lastRawIdx !== raw
+
+    if (next !== raw) {
+      ctx.file.setChangeIndex(local.path, next)
+      applyHighlight(next, true)
+    } else {
+      if (lastView !== view || lastContent !== content) applyHighlight(next)
+      if ((lastIdx !== undefined && lastIdx !== next) || navigated) applyHighlight(next, true)
+    }
+
+    lastRawIdx = raw
+    lastIdx = next
+    lastView = view
+    lastContent = content
+  })
+
+  return (
+    <div
+      ref={(el) => {
+        container = el
+      }}
+      innerHTML={html()}
+      class="
+          font-mono text-xs tracking-wide overflow-y-auto h-full
+          [&]:[counter-reset:line]
+          [&_pre]:focus-visible:outline-none
+          [&_pre]:overflow-x-auto [&_pre]:no-scrollbar
+          [&_code]:min-w-full [&_code]:inline-block 
+          [&_.tab]:relative
+          [&_.tab::before]:content['⇥']
+          [&_.tab::before]:absolute
+          [&_.tab::before]:opacity-0
+          [&_.space]:relative
+          [&_.space::before]:content-['·']
+          [&_.space::before]:absolute
+          [&_.space::before]:opacity-0
+          [&_.line]:inline-block [&_.line]:w-full
+          [&_.line]:hover:bg-background-element
+          [&_.line::before]:sticky [&_.line::before]:left-0
+          [&_.line::before]:w-12 [&_.line::before]:pr-4
+          [&_.line::before]:z-10
+          [&_.line::before]:bg-background-panel
+          [&_.line::before]:text-text-muted/60
+          [&_.line::before]:text-right [&_.line::before]:inline-block
+          [&_.line::before]:select-none
+          [&_.line::before]:[counter-increment:line]
+          [&_.line::before]:content-[counter(line)]
+          [&_.line-number-highlight]:bg-accent/20
+          [&_.line-number-highlight::before]:bg-accent/40!
+          [&_.line-number-highlight::before]:text-background-panel!
+          [&_code.code-diff_.line::before]:content-['']
+          [&_code.code-diff_.line::before]:w-0
+          [&_code.code-diff_.line::before]:pr-0
+          [&_.diff-split_code.code-diff::before]:w-10
+          [&_.diff-split_.diff-newln]:left-0
+          [&_.diff-oldln]:sticky [&_.diff-oldln]:left-0
+          [&_.diff-oldln]:w-10 [&_.diff-oldln]:pr-2
+          [&_.diff-oldln]:z-40
+          [&_.diff-oldln]:text-text-muted/60
+          [&_.diff-oldln]:text-right [&_.diff-oldln]:inline-block
+          [&_.diff-oldln]:select-none
+          [&_.diff-oldln]:bg-background-panel
+          [&_.diff-newln]:sticky [&_.diff-newln]:left-10
+          [&_.diff-newln]:w-10 [&_.diff-newln]:pr-2
+          [&_.diff-newln]:z-40
+          [&_.diff-newln]:text-text-muted/60
+          [&_.diff-newln]:text-right [&_.diff-newln]:inline-block
+          [&_.diff-newln]:select-none
+          [&_.diff-newln]:bg-background-panel
+          [&_.diff-add]:bg-success/20!
+          [&_.diff-add.diff-selected]:bg-success/50!
+          [&_.diff-add_.diff-oldln]:bg-success!
+          [&_.diff-add_.diff-oldln]:text-background-panel!
+          [&_.diff-add_.diff-newln]:bg-success!
+          [&_.diff-add_.diff-newln]:text-background-panel!
+          [&_.diff-remove]:bg-error/20!
+          [&_.diff-remove.diff-selected]:bg-error/50!
+          [&_.diff-remove_.diff-newln]:bg-error!
+          [&_.diff-remove_.diff-newln]:text-background-panel!
+          [&_.diff-remove_.diff-oldln]:bg-error!
+          [&_.diff-remove_.diff-oldln]:text-background-panel!
+          [&_.diff-sign]:inline-block [&_.diff-sign]:px-2 [&_.diff-sign]:select-none
+          [&_.diff-blank]:bg-background-element
+          [&_.diff-blank_.diff-oldln]:bg-background-element
+          [&_.diff-blank_.diff-newln]:bg-background-element
+          [&_.diff-collapsed]:block! [&_.diff-collapsed]:w-full [&_.diff-collapsed]:relative
+          [&_.diff-collapsed]:cursor-pointer [&_.diff-collapsed]:select-none
+          [&_.diff-collapsed]:bg-info/20 [&_.diff-collapsed]:hover:bg-info/40!
+          [&_.diff-collapsed]:text-info/80 [&_.diff-collapsed]:hover:text-info
+          [&_.diff-collapsed]:text-xs
+          [&_.diff-collapsed_.diff-oldln]:bg-info!
+          [&_.diff-collapsed_.diff-newln]:bg-info!
+        "
+      classList={{
+        ...(local.classList || {}),
+        [local.class ?? ""]: !!local.class,
+      }}
+      {...others}
+    ></div>
+  )
+}
+
+function transformerUnifiedDiff(): ShikiTransformer {
+  const kinds = new Map<number, string>()
+  const meta = new Map<number, { old?: number; new?: number; sign?: string }>()
+  let isDiff = false
+
+  return {
+    name: "unified-diff",
+    preprocess(input) {
+      kinds.clear()
+      meta.clear()
+      isDiff = false
+
+      const ls = input.split(/\r?\n/)
+      const out: Array<string> = []
+      let oldNo = 0
+      let newNo = 0
+      let inHunk = false
+
+      for (let i = 0; i < ls.length; i++) {
+        const s = ls[i]
+
+        const m = s.match(/^@@\s*-(\d+)(?:,(\d+))?\s+\+(\d+)(?:,(\d+))?\s*@@/)
+        if (m) {
+          isDiff = true
+          inHunk = true
+          oldNo = parseInt(m[1], 10)
+          newNo = parseInt(m[3], 10)
+          continue
+        }
+
+        if (
+          /^diff --git /.test(s) ||
+          /^Index: /.test(s) ||
+          /^--- /.test(s) ||
+          /^\+\+\+ /.test(s) ||
+          /^[=]{3,}$/.test(s) ||
+          /^\*{3,}$/.test(s) ||
+          /^\\ No newline at end of file$/.test(s)
+        ) {
+          isDiff = true
+          continue
+        }
+
+        if (!inHunk) {
+          out.push(s)
+          continue
+        }
+
+        if (/^\+/.test(s)) {
+          out.push(s)
+          const ln = out.length
+          kinds.set(ln, "add")
+          meta.set(ln, { new: newNo, sign: "+" })
+          newNo++
+          continue
+        }
+
+        if (/^-/.test(s)) {
+          out.push(s)
+          const ln = out.length
+          kinds.set(ln, "remove")
+          meta.set(ln, { old: oldNo, sign: "-" })
+          oldNo++
+          continue
+        }
+
+        if (/^ /.test(s)) {
+          out.push(s)
+          const ln = out.length
+          kinds.set(ln, "context")
+          meta.set(ln, { old: oldNo, new: newNo })
+          oldNo++
+          newNo++
+          continue
+        }
+
+        // fallback in hunks
+        out.push(s)
+      }
+
+      return out.join("\n").trimEnd()
+    },
+    code(node) {
+      if (isDiff) this.addClassToHast(node, "code-diff")
+    },
+    pre(node) {
+      if (isDiff) this.addClassToHast(node, "code-diff")
+    },
+    line(node, line) {
+      if (!isDiff) return
+      const kind = kinds.get(line)
+      if (!kind) return
+
+      const m = meta.get(line) || {}
+
+      this.addClassToHast(node, "diff-line")
+      this.addClassToHast(node, `diff-${kind}`)
+      node.properties = node.properties || {}
+      ;(node.properties as any)["data-diff"] = kind
+      if (m.old != undefined) (node.properties as any)["data-old"] = String(m.old)
+      if (m.new != undefined) (node.properties as any)["data-new"] = String(m.new)
+
+      const oldSpan = {
+        type: "element",
+        tagName: "span",
+        properties: { className: ["diff-oldln"] },
+        children: [{ type: "text", value: m.old != undefined ? String(m.old) : " " }],
+      }
+      const newSpan = {
+        type: "element",
+        tagName: "span",
+        properties: { className: ["diff-newln"] },
+        children: [{ type: "text", value: m.new != undefined ? String(m.new) : " " }],
+      }
+
+      if (kind === "add" || kind === "remove" || kind === "context") {
+        const first = (node.children && (node.children as any[])[0]) as any
+        if (first && first.type === "element" && first.children && first.children.length > 0) {
+          const t = first.children[0]
+          if (t && t.type === "text" && typeof t.value === "string" && t.value.length > 0) {
+            const ch = t.value[0]
+            if (ch === "+" || ch === "-" || ch === " ") t.value = t.value.slice(1)
+          }
+        }
+      }
+
+      const signSpan = {
+        type: "element",
+        tagName: "span",
+        properties: { className: ["diff-sign"] },
+        children: [{ type: "text", value: (m as any).sign || " " }],
+      }
+
+      // @ts-expect-error hast typing across versions
+      node.children = [oldSpan, newSpan, signSpan, ...(node.children || [])]
+    },
+  }
+}
+
+function transformerDiffGroups(): ShikiTransformer {
+  let group = -1
+  let inGroup = false
+  return {
+    name: "diff-groups",
+    pre() {
+      group = -1
+      inGroup = false
+    },
+    line(node) {
+      const props = (node.properties || {}) as any
+      const kind = props["data-diff"] as string | undefined
+      if (kind === "add" || kind === "remove") {
+        if (!inGroup) {
+          group += 1
+          inGroup = true
+        }
+        ;(node.properties as any)["data-chgrp"] = String(group)
+      } else {
+        inGroup = false
+      }
+    },
+  }
+}
+
+function applyDiffFolding(
+  root: HTMLElement,
+  context = 3,
+  options?: { expanded?: string[]; onExpand?: (key: string) => void; side?: "left" | "right" },
+) {
+  if (!root.classList.contains("code-diff")) return
+
+  // Cleanup: unwrap previous collapsed blocks and remove toggles
+  const blocks = Array.from(root.querySelectorAll<HTMLElement>(".diff-collapsed-block"))
+  for (const block of blocks) {
+    const p = block.parentNode
+    if (!p) {
+      block.remove()
+      continue
+    }
+    while (block.firstChild) p.insertBefore(block.firstChild, block)
+    block.remove()
+  }
+  const toggles = Array.from(root.querySelectorAll<HTMLElement>(".diff-collapsed"))
+  for (const t of toggles) t.remove()
+
+  const lines = Array.from(root.querySelectorAll<HTMLElement>(".diff-line"))
+  if (lines.length === 0) return
+
+  const n = lines.length
+  const isChange = lines.map((l) => l.dataset["diff"] === "add" || l.dataset["diff"] === "remove")
+  const isContext = lines.map((l) => l.dataset["diff"] === "context")
+  if (!isChange.some(Boolean)) return
+
+  const visible = new Array(n).fill(false) as boolean[]
+  for (let i = 0; i < n; i++) if (isChange[i]) visible[i] = true
+  for (let i = 0; i < n; i++) {
+    if (isChange[i]) {
+      const s = Math.max(0, i - context)
+      const e = Math.min(n - 1, i + context)
+      for (let j = s; j <= e; j++) if (isContext[j]) visible[j] = true
+    }
+  }
+
+  type Range = { start: number; end: number }
+  const ranges: Range[] = []
+  let i = 0
+  while (i < n) {
+    if (!visible[i] && isContext[i]) {
+      let j = i
+      while (j + 1 < n && !visible[j + 1] && isContext[j + 1]) j++
+      ranges.push({ start: i, end: j })
+      i = j + 1
+    } else {
+      i++
+    }
+  }
+
+  for (const r of ranges) {
+    const start = lines[r.start]
+    const end = lines[r.end]
+    const count = r.end - r.start + 1
+    const minCollapse = 20
+    if (count < minCollapse) {
+      continue
+    }
+
+    // Wrap the entire collapsed chunk (including trailing newline) so it takes no space
+    const block = document.createElement("span")
+    block.className = "diff-collapsed-block"
+    start.parentElement?.insertBefore(block, start)
+
+    let cur: Node | undefined = start
+    while (cur) {
+      const next: Node | undefined = cur.nextSibling || undefined
+      block.appendChild(cur)
+      if (cur === end) {
+        // Also move the newline after the last line into the block
+        if (next && next.nodeType === Node.TEXT_NODE && (next.textContent || "").startsWith("\n")) {
+          block.appendChild(next)
+        }
+        break
+      }
+      cur = next
+    }
+
+    block.style.display = "none"
+    const row = document.createElement("span")
+    row.className = "line diff-collapsed"
+    row.setAttribute("data-kind", "collapsed")
+    row.setAttribute("data-count", String(count))
+    row.setAttribute("tabindex", "0")
+    row.setAttribute("role", "button")
+
+    const oldln = document.createElement("span")
+    oldln.className = "diff-oldln"
+    oldln.textContent = " "
+
+    const newln = document.createElement("span")
+    newln.className = "diff-newln"
+    newln.textContent = " "
+
+    const sign = document.createElement("span")
+    sign.className = "diff-sign"
+    sign.textContent = "…"
+
+    const label = document.createElement("span")
+    label.textContent = `show ${count} unchanged line${count > 1 ? "s" : ""}`
+
+    const key = `o${start.dataset["old"] || ""}-${end.dataset["old"] || ""}:n${start.dataset["new"] || ""}-${end.dataset["new"] || ""}`
+
+    const show = (record = true) => {
+      if (record) options?.onExpand?.(key)
+      const p = block.parentNode
+      if (p) {
+        while (block.firstChild) p.insertBefore(block.firstChild, block)
+        block.remove()
+      }
+      row.remove()
+    }
+
+    row.addEventListener("click", () => show(true))
+    row.addEventListener("keydown", (ev) => {
+      if (ev.key === "Enter" || ev.key === " ") {
+        ev.preventDefault()
+        show(true)
+      }
+    })
+
+    block.parentElement?.insertBefore(row, block)
+    if (!options?.side || options.side === "left") row.appendChild(oldln)
+    if (!options?.side || options.side === "right") row.appendChild(newln)
+    row.appendChild(sign)
+    row.appendChild(label)
+
+    if (options?.expanded && options.expanded.includes(key)) {
+      show(false)
+    }
+  }
+}
+
+function applySplitDiff(container: HTMLElement) {
+  const pres = Array.from(container.querySelectorAll<HTMLPreElement>("pre"))
+  if (pres.length === 0) return
+  const originalPre = pres[0]
+  const originalCode = originalPre.querySelector("code") as HTMLElement | undefined
+  if (!originalCode || !originalCode.classList.contains("code-diff")) return
+
+  // Rebuild split each time to match current content
+  const existing = container.querySelector<HTMLElement>(".diff-split")
+  if (existing) existing.remove()
+
+  const grid = document.createElement("div")
+  grid.className = "diff-split grid grid-cols-2 gap-x-6"
+
+  const makeColumn = () => {
+    const pre = document.createElement("pre")
+    pre.className = originalPre.className
+    const code = document.createElement("code")
+    code.className = originalCode.className
+    pre.appendChild(code)
+    return { pre, code }
+  }
+
+  const left = makeColumn()
+  const right = makeColumn()
+
+  // Helpers
+  const cloneSide = (line: HTMLElement, side: "old" | "new"): HTMLElement => {
+    const clone = line.cloneNode(true) as HTMLElement
+    const oldln = clone.querySelector(".diff-oldln")
+    const newln = clone.querySelector(".diff-newln")
+    if (side === "old") {
+      if (newln) newln.remove()
+    } else {
+      if (oldln) oldln.remove()
+    }
+    return clone
+  }
+
+  const blankLine = (side: "old" | "new", kind: "add" | "remove"): HTMLElement => {
+    const span = document.createElement("span")
+    span.className = "line diff-line diff-blank"
+    span.setAttribute("data-diff", kind)
+    const ln = document.createElement("span")
+    ln.className = side === "old" ? "diff-oldln" : "diff-newln"
+    ln.textContent = " "
+    span.appendChild(ln)
+    return span
+  }
+
+  const lines = Array.from(originalCode.querySelectorAll<HTMLElement>(".diff-line"))
+  let i = 0
+  while (i < lines.length) {
+    const cur = lines[i]
+    const kind = cur.dataset["diff"]
+
+    if (kind === "context") {
+      left.code.appendChild(cloneSide(cur, "old"))
+      left.code.appendChild(document.createTextNode("\n"))
+      right.code.appendChild(cloneSide(cur, "new"))
+      right.code.appendChild(document.createTextNode("\n"))
+      i++
+      continue
+    }
+
+    if (kind === "remove") {
+      // Batch consecutive removes and following adds, then pair
+      const removes: HTMLElement[] = []
+      const adds: HTMLElement[] = []
+      let j = i
+      while (j < lines.length && lines[j].dataset["diff"] === "remove") {
+        removes.push(lines[j])
+        j++
+      }
+      let k = j
+      while (k < lines.length && lines[k].dataset["diff"] === "add") {
+        adds.push(lines[k])
+        k++
+      }
+
+      const pairs = Math.min(removes.length, adds.length)
+      for (let p = 0; p < pairs; p++) {
+        left.code.appendChild(cloneSide(removes[p], "old"))
+        left.code.appendChild(document.createTextNode("\n"))
+        right.code.appendChild(cloneSide(adds[p], "new"))
+        right.code.appendChild(document.createTextNode("\n"))
+      }
+      for (let p = pairs; p < removes.length; p++) {
+        left.code.appendChild(cloneSide(removes[p], "old"))
+        left.code.appendChild(document.createTextNode("\n"))
+        right.code.appendChild(blankLine("new", "remove"))
+        right.code.appendChild(document.createTextNode("\n"))
+      }
+      for (let p = pairs; p < adds.length; p++) {
+        left.code.appendChild(blankLine("old", "add"))
+        left.code.appendChild(document.createTextNode("\n"))
+        right.code.appendChild(cloneSide(adds[p], "new"))
+        right.code.appendChild(document.createTextNode("\n"))
+      }
+
+      i = k
+      continue
+    }
+
+    if (kind === "add") {
+      // Run of adds not preceded by removes
+      const adds: HTMLElement[] = []
+      let j = i
+      while (j < lines.length && lines[j].dataset["diff"] === "add") {
+        adds.push(lines[j])
+        j++
+      }
+      for (let p = 0; p < adds.length; p++) {
+        left.code.appendChild(blankLine("old", "add"))
+        left.code.appendChild(document.createTextNode("\n"))
+        right.code.appendChild(cloneSide(adds[p], "new"))
+        right.code.appendChild(document.createTextNode("\n"))
+      }
+      i = j
+      continue
+    }
+
+    // Any other kind: mirror as context
+    left.code.appendChild(cloneSide(cur, "old"))
+    left.code.appendChild(document.createTextNode("\n"))
+    right.code.appendChild(cloneSide(cur, "new"))
+    right.code.appendChild(document.createTextNode("\n"))
+    i++
+  }
+
+  grid.appendChild(left.pre)
+  grid.appendChild(right.pre)
+  container.appendChild(grid)
+}