zen: track session in usage

packages/console/core/src/subscription.ts

@@ -0,0 +1,75 @@
+import { z } from "zod"
+import { fn } from "./util/fn"
+import { centsToMicroCents } from "./util/price"
+import { getWeekBounds } from "./util/date"
+
+export namespace Subscription {
+  export const analyzeRollingUsage = fn(
+    z.object({
+      limit: z.number().int(),
+      window: z.number().int(),
+      usage: z.number().int(),
+      timeUpdated: z.date(),
+    }),
+    ({ limit, window, usage, timeUpdated }) => {
+      const now = new Date()
+      const rollingWindowMs = window * 3600 * 1000
+      const rollingLimitInMicroCents = centsToMicroCents(limit * 100)
+      const windowStart = new Date(now.getTime() - rollingWindowMs)
+      if (timeUpdated < windowStart) {
+        return {
+          status: "ok" as const,
+          resetInSec: window * 3600,
+          usagePercent: 0,
+        }
+      }
+
+      const windowEnd = new Date(timeUpdated.getTime() + rollingWindowMs)
+      if (usage < rollingLimitInMicroCents) {
+        return {
+          status: "ok" as const,
+          resetInSec: Math.ceil((windowEnd.getTime() - now.getTime()) / 1000),
+          usagePercent: Math.ceil(Math.min(100, (usage / rollingLimitInMicroCents) * 100)),
+        }
+      }
+      return {
+        status: "rate-limited" as const,
+        resetInSec: Math.ceil((windowEnd.getTime() - now.getTime()) / 1000),
+        usagePercent: 100,
+      }
+    },
+  )
+
+  export const analyzeWeeklyUsage = fn(
+    z.object({
+      limit: z.number().int(),
+      usage: z.number().int(),
+      timeUpdated: z.date(),
+    }),
+    ({ limit, usage, timeUpdated }) => {
+      const now = new Date()
+      const week = getWeekBounds(now)
+      const fixedLimitInMicroCents = centsToMicroCents(limit * 100)
+      if (timeUpdated < week.start) {
+        return {
+          status: "ok" as const,
+          resetInSec: Math.ceil((week.end.getTime() - now.getTime()) / 1000),
+          usagePercent: 0,
+        }
+      }
+      if (usage < fixedLimitInMicroCents) {
+        return {
+          status: "ok" as const,
+          resetInSec: Math.ceil((week.end.getTime() - now.getTime()) / 1000),
+          usagePercent: Math.ceil(Math.min(100, (usage / fixedLimitInMicroCents) * 100)),
+        }
+      }
+
+      return {
+        status: "rate-limited" as const,
+        resetInSec: Math.ceil((week.end.getTime() - now.getTime()) / 1000),
+        usagePercent: 100,
+      }
+    },
+  )
+}