wip(app): line selection

packages/ui/src/components/diff.tsx

@@ -7,7 +7,10 @@ import { getWorkerPool } from "../pierre/worker"
 
 export function Diff<T>(props: DiffProps<T>) {
   let container!: HTMLDivElement
-  const [local, others] = splitProps(props, ["before", "after", "class", "classList", "annotations"])
+  let observer: MutationObserver | undefined
+  let renderToken = 0
+
+  const [local, others] = splitProps(props, ["before", "after", "class", "classList", "annotations", "onRendered"])
 
   const mobile = createMediaQuery("(max-width: 640px)")
 
@@ -25,6 +28,95 @@ export function Diff<T>(props: DiffProps<T>) {
 
   let instance: FileDiff<T> | undefined
 
+  const getRoot = () => {
+    const host = container.querySelector("diffs-container")
+    if (!(host instanceof HTMLElement)) return
+
+    const root = host.shadowRoot
+    if (!root) return
+
+    return root
+  }
+
+  const notifyRendered = () => {
+    if (!local.onRendered) return
+
+    observer?.disconnect()
+    observer = undefined
+    renderToken++
+
+    const token = renderToken
+    let settle = 0
+
+    const isReady = (root: ShadowRoot) => root.querySelector("[data-line]") != null
+
+    const notify = () => {
+      if (token !== renderToken) return
+
+      observer?.disconnect()
+      observer = undefined
+      requestAnimationFrame(() => {
+        if (token !== renderToken) return
+        local.onRendered?.()
+      })
+    }
+
+    const schedule = () => {
+      settle++
+      const current = settle
+
+      requestAnimationFrame(() => {
+        if (token !== renderToken) return
+        if (current !== settle) return
+
+        requestAnimationFrame(() => {
+          if (token !== renderToken) return
+          if (current !== settle) return
+
+          notify()
+        })
+      })
+    }
+
+    const observeRoot = (root: ShadowRoot) => {
+      observer?.disconnect()
+      observer = new MutationObserver(() => {
+        if (token !== renderToken) return
+        if (!isReady(root)) return
+
+        schedule()
+      })
+
+      observer.observe(root, { childList: true, subtree: true })
+
+      if (!isReady(root)) return
+      schedule()
+    }
+
+    const root = getRoot()
+    if (typeof MutationObserver === "undefined") {
+      if (!root || !isReady(root)) return
+      local.onRendered()
+      return
+    }
+
+    if (root) {
+      observeRoot(root)
+      return
+    }
+
+    observer = new MutationObserver(() => {
+      if (token !== renderToken) return
+
+      const root = getRoot()
+      if (!root) return
+
+      observeRoot(root)
+    })
+
+    observer.observe(container, { childList: true, subtree: true })
+  }
+
   createEffect(() => {
     const opts = options()
     const workerPool = getWorkerPool(props.diffStyle)
@@ -50,9 +142,12 @@ export function Diff<T>(props: DiffProps<T>) {
       lineAnnotations: annotations,
       containerWrapper: container,
     })
+
+    notifyRendered()
   })
 
   onCleanup(() => {
+    observer?.disconnect()
     instance?.cleanUp()
   })