insights-correlations (#22)

Reviewed-on: #22

spa/src/features/insights.ts

@@ -0,0 +1,69 @@
+import { useQuery } from "@tanstack/react-query"
+import { get } from "@/lib/api/client"
+
+export type RatingLiftInsight = {
+  kind: "rating_lift"
+  genre: string
+  genre_avg: number
+  user_avg: number
+  delta: number
+  sample_count: number
+}
+
+export type SeasonalityInsight = {
+  kind: "seasonality"
+  genre: string
+  month: number
+  multiplier: number
+  sample_count: number
+}
+
+export type MediumTimingInsight = {
+  kind: "medium_timing"
+  medium: string
+  multiplier: number
+  weekend_share: number
+  baseline_share: number
+  sample_count: number
+}
+
+export type RhythmInsight = {
+  kind: "rhythm"
+  peak_hour_start: number
+  peak_hour_end: number
+  top_days: number[]
+  sample_count: number
+}
+
+export type Insight =
+  | RatingLiftInsight
+  | SeasonalityInsight
+  | MediumTimingInsight
+  | RhythmInsight
+
+export type InsightsResponse = {
+  insights: Insight[]
+}
+
+export const insightsKeys = {
+  all: ["insights"] as const,
+  forZone: (tz: string) => [...insightsKeys.all, tz] as const,
+}
+
+// Months, weekdays and hours are bucketed server-side in this zone, so the
+// rhythm card's hours read as the viewer's local time.
+function browserTimeZone(): string {
+  return Intl.DateTimeFormat().resolvedOptions().timeZone
+}
+
+function getInsights(tz: string) {
+  return get<InsightsResponse>("/insights", { tz })
+}
+
+export function useInsights() {
+  const tz = browserTimeZone()
+  return useQuery({
+    queryKey: insightsKeys.forZone(tz),
+    queryFn: () => getInsights(tz),
+  })
+}