feat(api): 支持电池分页和安全预测

src/server/prediction/client.ts

@@ -1,3 +1,4 @@
+import { LRUCache } from 'lru-cache'
 import { z } from 'zod'
 import type { BatteryInfo, BatteryPrediction } from '@/domain/battery'
 import { env } from '@/env'
@@ -60,13 +61,12 @@ const predictionResponseSchema = z.object({
   updated_at: z.string().nullable().optional(),
 })
 
-type CacheEntry = {
-  expiresAt: number
-  value: SohPrediction
-}
-
 const logger = getLogger(['prediction'])
-const cache = new Map<string, CacheEntry>()
+const cache = new LRUCache<string, SohPrediction>({
+  max: 5_000,
+  ttl: env.SOH_PREDICTION_CACHE_TTL_SECONDS * 1000,
+})
+const inFlightRequests = new Map<string, Promise<SohPrediction | null>>()
 
 const round2 = (value: number) => Math.round(value * 100) / 100
 
@@ -155,7 +155,22 @@ export async function predictSoh(battery: BatteryInfo, history: BatteryInfo[]):
 
   const cacheKey = createCacheKey(battery, history)
   const cached = cache.get(cacheKey)
-  if (cached && cached.expiresAt > Date.now()) return cached.value
+  if (cached) return cached
+  const pendingRequest = inFlightRequests.get(cacheKey)
+  if (pendingRequest) return pendingRequest
+
+  const requestPromise = requestPrediction(cacheKey, battery, request)
+  inFlightRequests.set(cacheKey, requestPromise)
+
+  return requestPromise
+}
+
+async function requestPrediction(
+  cacheKey: string,
+  battery: BatteryInfo,
+  request: PredictionRequest,
+): Promise<SohPrediction | null> {
+  if (!env.SOH_PREDICTION_API_BASE_URL) return null
 
   const controller = new AbortController()
   const timeout = setTimeout(() => controller.abort(), env.SOH_PREDICTION_TIMEOUT_MS)
@@ -179,10 +194,7 @@ export async function predictSoh(battery: BatteryInfo, history: BatteryInfo[]):
 
     const json = await response.json()
     const prediction = normalizePrediction(predictionResponseSchema.parse(json))
-    cache.set(cacheKey, {
-      expiresAt: Date.now() + env.SOH_PREDICTION_CACHE_TTL_SECONDS * 1000,
-      value: prediction,
-    })
+    cache.set(cacheKey, prediction)
 
     return prediction
   } catch (error) {
@@ -190,9 +202,11 @@ export async function predictSoh(battery: BatteryInfo, history: BatteryInfo[]):
     return null
   } finally {
     clearTimeout(timeout)
+    inFlightRequests.delete(cacheKey)
   }
 }
 
 export function clearPredictionCache() {
   cache.clear()
+  inFlightRequests.clear()
 }