import { CacheEntry, CacheConfig, DEFAULT_CACHE_CONFIG } from "../types/index.js";
import { randomBytes } from "crypto";
export interface CacheStats {
entryCount: number;
totalSizeBytes: number;
typeBreakdown: Record<string, number>;
config: CacheConfig;
}
export class CacheManager {
private cache = new Map<string, CacheEntry>();
private accessOrder: string[] = [];
private config: CacheConfig;
constructor(config: Partial<CacheConfig> = {}) {
this.config = { ...DEFAULT_CACHE_CONFIG, ...config };
}
generateId(type: string): string {
const hash = randomBytes(4).toString("hex");
const timestamp = Date.now();
return `${type}-${hash}-${timestamp}`;
}
set<T>(id: string, data: T, type: string, ttlMs?: number): void {
const now = Date.now();
const sizeBytes = JSON.stringify(data).length;
// LRU eviction
while (this.cache.size >= this.config.maxEntries) {
const oldest = this.accessOrder.shift();
if (oldest) {
this.cache.delete(oldest);
}
}
const entry: CacheEntry<T> = {
data,
expiresAt: now + (ttlMs ?? this.config.defaultTtlMs),
metadata: {
createdAt: now,
type,
sizeBytes,
},
};
this.cache.set(id, entry);
this.accessOrder.push(id);
}
get<T>(id: string): CacheEntry<T> | undefined {
const entry = this.cache.get(id) as CacheEntry<T> | undefined;
if (!entry) {
return undefined;
}
// Check expiration
if (Date.now() > entry.expiresAt) {
this.cache.delete(id);
this.accessOrder = this.accessOrder.filter((k) => k !== id);
return undefined;
}
// Update access order for LRU
this.accessOrder = this.accessOrder.filter((k) => k !== id);
this.accessOrder.push(id);
return entry;
}
clear(id: string): void {
this.cache.delete(id);
this.accessOrder = this.accessOrder.filter((k) => k !== id);
}
clearAll(): void {
this.cache.clear();
this.accessOrder = [];
}
invalidateByType(type: string): void {
for (const [id, entry] of this.cache.entries()) {
if (entry.metadata.type === type) {
this.cache.delete(id);
}
}
this.accessOrder = this.accessOrder.filter((id) => this.cache.has(id));
}
getStats(): CacheStats {
const typeBreakdown: Record<string, number> = {};
let totalSizeBytes = 0;
for (const entry of this.cache.values()) {
const type = entry.metadata.type;
typeBreakdown[type] = (typeBreakdown[type] ?? 0) + 1;
totalSizeBytes += entry.metadata.sizeBytes ?? 0;
}
return {
entryCount: this.cache.size,
totalSizeBytes,
typeBreakdown,
config: this.config,
};
}
getConfig(): CacheConfig {
return { ...this.config };
}
setConfig(config: Partial<CacheConfig>): void {
this.config = { ...this.config, ...config };
}
}
