Address review feedback on video upload telemetry

- Restore minimumFileSizeForCompress: 0 on the rnc call so
  unacceptable-format files still get force-transcoded regardless
  of size; the acceptable-format early-return above keeps the new
  metrics signal intact
- Extract the skip-reason union into VideoCompressSkipReason in
  video/types.ts so the analytics event type and the telemetry
  helper share one source of truth
- Rename the compressSkipped payload field reason -> skipReason
- Rename the skip reason 'below-threshold' -> 'below-byte-threshold'
  to leave room for future below-duration / below-bitrate skips
- Replace the hand-rolled uploadId generator with nanoid/non-secure,
  matching the rest of the codebase

src/analytics/metrics/types.ts

@@ -5,6 +5,7 @@
 import {type Platform} from 'react-native'
 
 import {type NotificationReason} from '#/lib/hooks/useNotificationHandler'
+import {type VideoCompressSkipReason} from '#/lib/media/video/types'
 import {type NotificationType} from '#/state/queries/notifications/types'
 import {type FeedDescriptor} from '#/state/queries/post-feed'
 import {type LiveEventFeedMetricContext} from '#/features/liveEvents/types'
@@ -1362,11 +1363,7 @@ export type Events = {
   'video:upload:compressSkipped': {
     uploadId: string
     engine: string
-    reason:
+    skipReason: VideoCompressSkipReason
-      | 'gif'
-      | 'below-threshold'
-      | 'no-webcodecs'
-      | 'compress-error-fallback'
     bytes: number
     mimeType: string
     elapsedMs: number

src/lib/media/video/compress.ts

@@ -43,7 +43,7 @@ export async function compressVideo(
       uri: file.uri,
       size: file.fileSize,
       mimeType: file.mimeType ?? 'video/mp4',
-      passthroughReason: 'below-threshold',
+      passthroughReason: 'below-byte-threshold',
     }
   }
 
@@ -53,6 +53,13 @@ export async function compressVideo(
       compressionMethod: 'manual',
       bitrate: 3_000_000, // 3mbps
       maxSize: 1920,
+      // Force a transcode for unacceptable-format files regardless of size.
+      // rnc's default minimumFileSizeForCompress would otherwise pass small
+      // unacceptable-format files through unchanged and the server would
+      // reject them. Acceptable formats are already short-circuited above so
+      // they never reach this call.
+      // WARNING: this ONE SPECIFIC ARG is in MB -sfn
+      minimumFileSizeForCompress: 0,
       getCancellationId: id => {
         if (signal) {
           signal.addEventListener('abort', () => {

src/lib/media/video/compress.web.ts

@@ -65,7 +65,7 @@ export async function compressVideo(
   } else if (!hasCodecs) {
     fallbackReason = 'no-webcodecs'
   } else if (blob.size < COMPRESSION_MIN_SIZE_BYTES) {
-    fallbackReason = 'below-threshold'
+    fallbackReason = 'below-byte-threshold'
   } else {
     try {
       return await doCompression(blob, asset.uri, {onProgress, signal})

src/lib/media/video/telemetry.ts

@@ -1,6 +1,8 @@
 import {Platform} from 'react-native'
 import {type ImagePickerAsset} from 'expo-image-picker'
+import {nanoid} from 'nanoid/non-secure'
 
+import {type VideoCompressSkipReason} from '#/lib/media/video/types'
 import {Sentry} from '#/logger/sentry/lib'
 import {type Metrics} from '#/analytics/metrics'
 
@@ -16,20 +18,6 @@ const COMPRESS_ENGINE =
 
 type Phase = 'compress' | 'upload' | 'processing'
 
-type SkipReason =
-  | 'gif'
-  | 'below-threshold'
-  | 'no-webcodecs'
-  | 'compress-error-fallback'
-
-function makeUploadId(): string {
-  const c = (globalThis as {crypto?: {randomUUID?: () => string}}).crypto
-  if (c?.randomUUID) return c.randomUUID()
-  return `up_${Date.now().toString(36)}_${Math.random()
-    .toString(36)
-    .slice(2, 10)}`
-}
-
 function errorClass(e: unknown): string {
   if (e instanceof Error) return e.name || 'Error'
   return 'Unknown'
@@ -43,7 +31,7 @@ export type VideoTelemetry = {
   compressSkipped: (video: {
     size: number
     mimeType: string
-    reason: SkipReason
+    skipReason: VideoCompressSkipReason
   }) => void
   compressCompleted: (video: {size: number; mimeType: string}) => void
   compressFailed: (e: unknown) => void
@@ -65,7 +53,7 @@ export function createVideoTelemetry({
   signal: AbortSignal
   metric: MetricFn
 }): VideoTelemetry {
-  const uploadId = makeUploadId()
+  const uploadId = nanoid()
   const engine = COMPRESS_ENGINE
   const startedAt = Date.now()
 
@@ -167,11 +155,11 @@ export function createVideoTelemetry({
       })
     },
 
-    compressSkipped({size, mimeType, reason}) {
+    compressSkipped({size, mimeType, skipReason}) {
       metric('video:upload:compressSkipped', {
         uploadId,
         engine,
-        reason,
+        skipReason,
         bytes: size,
         mimeType,
         elapsedMs: Date.now() - phaseStartedAt,

src/lib/media/video/types.ts

@@ -1,3 +1,13 @@
+// Why the compress engine returned the input unchanged. Used both as the
+// reason on `CompressedVideo.passthroughReason` and as the `skipReason` field
+// on the `video:upload:compressSkipped` analytics event, so the two stay in
+// sync.
+export type VideoCompressSkipReason =
+  | 'gif'
+  | 'below-byte-threshold'
+  | 'no-webcodecs'
+  | 'compress-error-fallback'
+
 export type CompressedVideo = {
   uri: string
   mimeType: string
@@ -5,11 +15,6 @@ export type CompressedVideo = {
   // web only, can fall back to uri if missing
   bytes?: ArrayBuffer
   // Set when the engine returned the input unchanged. Undefined means the
-  // bytes were actually re-encoded. Used by telemetry to split
+  // bytes were actually re-encoded.
-  // compressCompleted vs compressSkipped, and to label the skip reason.
+  passthroughReason?: VideoCompressSkipReason
-  passthroughReason?:
-    | 'gif'
-    | 'below-threshold'
-    | 'no-webcodecs'
-    | 'compress-error-fallback'
 }

src/view/com/composer/state/video.ts

@@ -305,7 +305,7 @@ export async function processVideo(
     telemetry.compressSkipped({
       size: video.size,
       mimeType: video.mimeType,
-      reason: video.passthroughReason,
+      skipReason: video.passthroughReason,
     })
   } else {
     telemetry.compressCompleted({size: video.size, mimeType: video.mimeType})