feat(app): better diff/code comments (#14621)

Co-authored-by: adamelmore <2363879+adamdottv@users.noreply.github.com>
Co-authored-by: David Hill <iamdavidhill@gmail.com>

packages/ui/src/components/session-review-search.ts

@@ -0,0 +1,59 @@
+export type SessionSearchHit = {
+  file: string
+  side: "additions" | "deletions"
+  line: number
+  col: number
+  len: number
+}
+
+type SessionSearchFile = {
+  file: string
+  before?: string
+  after?: string
+}
+
+function hitsForSide(args: { file: string; side: SessionSearchHit["side"]; text: string; needle: string }) {
+  return args.text.split("\n").flatMap((line, i) => {
+    if (!line) return []
+
+    const hay = line.toLowerCase()
+    let at = hay.indexOf(args.needle)
+    if (at < 0) return []
+
+    const out: SessionSearchHit[] = []
+    while (at >= 0) {
+      out.push({
+        file: args.file,
+        side: args.side,
+        line: i + 1,
+        col: at + 1,
+        len: args.needle.length,
+      })
+      at = hay.indexOf(args.needle, at + args.needle.length)
+    }
+
+    return out
+  })
+}
+
+export function buildSessionSearchHits(args: { query: string; files: SessionSearchFile[] }) {
+  const value = args.query.trim().toLowerCase()
+  if (!value) return []
+
+  return args.files.flatMap((file) => {
+    const out: SessionSearchHit[] = []
+    if (typeof file.before === "string") {
+      out.push(...hitsForSide({ file: file.file, side: "deletions", text: file.before, needle: value }))
+    }
+    if (typeof file.after === "string") {
+      out.push(...hitsForSide({ file: file.file, side: "additions", text: file.after, needle: value }))
+    }
+    return out
+  })
+}
+
+export function stepSessionSearchIndex(total: number, current: number, dir: 1 | -1) {
+  if (total <= 0) return 0
+  if (current < 0 || current >= total) return dir > 0 ? 0 : total - 1
+  return (current + dir + total) % total
+}