Frontend updates: caching basic data (json) from CDragon

Implement caching in the patch_detector, consume the cache from API routes in frontend

frontend/server/utils/cdragon-cache.ts

@@ -0,0 +1,205 @@
+import { readFile, existsSync } from 'fs'
+import { join } from 'path'
+import { promisify } from 'util'
+
+const readFileAsync = promisify(readFile)
+
+// CDragon base URL for fallback
+const CDRAGON_BASE = 'https://raw.communitydragon.org/'
+
+// Cache directory - can be configured via environment variable
+// Default to dev/cdragon for development
+const getCacheDir = () => {
+  if (process.env.CDRAGON_CACHE_DIR) {
+    return process.env.CDRAGON_CACHE_DIR
+  }
+  // Default to dev/cdragon relative to project root
+  return join(process.cwd(), '..', 'dev', 'data', 'cdragon')
+}
+
+/**
+ * Get the current patch from the patch.txt file or fallback to 'latest'
+ * Converts patch format for CDragon: "16.4.1" -> "16.4"
+ */
+async function getCurrentPatch(): Promise<string> {
+  const cacheDir = getCacheDir()
+  const patchFile = join(cacheDir, 'latest', 'patch.txt')
+
+  if (existsSync(patchFile)) {
+    const patch = await readFileAsync(patchFile, 'utf-8')
+    const trimmedPatch = patch.trim()
+    // Convert patch format for CDragon: "16.4.1" -> "16.4"
+    return trimmedPatch.split('.').slice(0, 2).join('.')
+  }
+
+  // Fallback to 'latest' if no patch file exists
+  return 'latest'
+}
+
+/**
+ * Cached CDragon data types
+ */
+interface CDragonCacheOptions {
+  patch?: string
+}
+
+/**
+ * Fetch data from local cache with CDragon fallback
+ */
+async function fetchFromCache<T>(
+  assetName: string,
+  cdragonPath: string,
+  options?: CDragonCacheOptions
+): Promise<T> {
+  const cacheDir = getCacheDir()
+  const patch = options?.patch || (await getCurrentPatch())
+  const cachePath = join(cacheDir, patch, assetName)
+
+  // Try to read from cache first
+  if (existsSync(cachePath)) {
+    try {
+      const data = await readFileAsync(cachePath, 'utf-8')
+      return JSON.parse(data) as T
+    } catch (error) {
+      console.error(`Error reading cache file ${cachePath}:`, error)
+    }
+  }
+
+  // Fallback to CDragon
+  console.log(`Cache miss for ${assetName}, fetching from CDragon...`)
+  const url = `${CDRAGON_BASE}${patch}/${cdragonPath}`
+  const response = await fetch(url)
+
+  if (!response.ok) {
+    throw new Error(`Failed to fetch ${assetName} from CDragon: ${response.status}`)
+  }
+
+  return (await response.json()) as T
+}
+
+/**
+ * Get items data from cache
+ */
+async function getItems(patch?: string): Promise<CDragonItem[]> {
+  return fetchFromCache<CDragonItem[]>(
+    'items.json',
+    'plugins/rcp-be-lol-game-data/global/default/v1/items.json',
+    { patch }
+  )
+}
+
+/**
+ * Get perks (runes) data from cache
+ */
+async function getPerks(patch?: string): Promise<CDragonPerk[]> {
+  return fetchFromCache<CDragonPerk[]>(
+    'perks.json',
+    'plugins/rcp-be-lol-game-data/global/default/v1/perks.json',
+    { patch }
+  )
+}
+
+/**
+ * Get perk styles data from cache
+ */
+async function getPerkStyles(patch?: string): Promise<CDragonPerkStyles> {
+  return fetchFromCache<CDragonPerkStyles>(
+    'perkstyles.json',
+    'plugins/rcp-be-lol-game-data/global/default/v1/perkstyles.json',
+    { patch }
+  )
+}
+
+/**
+ * Get summoner spells data from cache
+ */
+async function getSummonerSpells(patch?: string): Promise<CDragonSummonerSpell[]> {
+  return fetchFromCache<CDragonSummonerSpell[]>(
+    'summoner-spells.json',
+    'plugins/rcp-be-lol-game-data/global/default/v1/summoner-spells.json',
+    { patch }
+  )
+}
+
+/**
+ * Get champion summary data from cache
+ */
+async function getChampionSummary(patch?: string): Promise<CDragonChampionSummary[]> {
+  return fetchFromCache<CDragonChampionSummary[]>(
+    'champion-summary.json',
+    'plugins/rcp-be-lol-game-data/global/default/v1/champion-summary.json',
+    { patch }
+  )
+}
+
+// Type definitions for CDragon data
+interface CDragonItem {
+  id: number
+  name: string
+  iconPath: string
+  description?: string
+  plaintext?: string
+  into?: number[]
+  from?: number[]
+  gold?: {
+    base: number
+    total: number
+    sell: number
+  }
+}
+
+interface CDragonPerk {
+  id: number
+  name: string
+  iconPath: string
+  shortDesc?: string
+  longDesc?: string
+}
+
+interface CDragonPerkStyle {
+  id: number
+  name: string
+  iconPath: string
+  slots: Array<{
+    type: string
+    perks: number[]
+  }>
+}
+
+interface CDragonPerkStyles {
+  styles: CDragonPerkStyle[]
+}
+
+interface CDragonSummonerSpell {
+  id: number
+  name: string
+  iconPath: string
+  description?: string
+}
+
+interface CDragonChampionSummary {
+  id: number
+  name: string
+  alias: string
+  squarePortraitPath: string
+  roles?: string[]
+}
+
+export {
+  getItems,
+  getPerks,
+  getPerkStyles,
+  getSummonerSpells,
+  getChampionSummary,
+  getCurrentPatch,
+  CDRAGON_BASE
+}
+
+export type {
+  CDragonItem,
+  CDragonPerk,
+  CDragonPerkStyle,
+  CDragonPerkStyles,
+  CDragonSummonerSpell,
+  CDragonChampionSummary
+}