type TierName = "free" | "pro" | "enterprise";
interface TierDefinition {
name: TierName;
maxRequests: number;
windowMs: number;
description: string;
}
interface TierStatus {
tier: TierName;
maxRequests: number;
windowMs: number;
currentUsage: number;
remaining: number;
resetsAt: Date;
}
interface UserUsage {
count: number;
windowStart: number;
}
const tiers: Record<TierName, TierDefinition> = {
free: {
name: "free",
maxRequests: 30,
windowMs: 15 * 60 * 1000,
description: "Free tier: 30 requests per 15 minutes",
},
pro: {
name: "pro",
maxRequests: 300,
windowMs: 15 * 60 * 1000,
description: "Pro tier: 300 requests per 15 minutes",
},
enterprise: {
name: "enterprise",
maxRequests: 3000,
windowMs: 15 * 60 * 1000,
description: "Enterprise tier: 3000 requests per 15 minutes",
},
};
const userTiers = new Map<string, TierName>();
const userUsage = new Map<string, UserUsage>();
export function getTierForUser(userId: string): TierDefinition {
const tierName = userTiers.get(userId) || "free";
return tiers[tierName];
}
export function getAllTiers(): TierDefinition[] {
return Object.values(tiers);
}
export function setUserTier(userId: string, tier: TierName): void {
if (!tiers[tier]) {
throw new Error(`Invalid tier: ${tier}. Valid tiers: ${Object.keys(tiers).join(", ")}`);
}
userTiers.set(userId, tier);
}
export function getCurrentTierStatus(userId: string): TierStatus {
const tierDef = getTierForUser(userId);
const now = Date.now();
const usage = userUsage.get(userId);
let currentUsage = 0;
let windowStart = now;
if (usage) {
if (now - usage.windowStart < tierDef.windowMs) {
currentUsage = usage.count;
windowStart = usage.windowStart;
}
}
return {
tier: tierDef.name,
maxRequests: tierDef.maxRequests,
windowMs: tierDef.windowMs,
currentUsage,
remaining: Math.max(0, tierDef.maxRequests - currentUsage),
resetsAt: new Date(windowStart + tierDef.windowMs),
};
}
export function checkRateLimit(userId: string): { allowed: boolean; status: TierStatus } {
const tierDef = getTierForUser(userId);
const now = Date.now();
let usage = userUsage.get(userId);
if (!usage || now - usage.windowStart >= tierDef.windowMs) {
usage = { count: 0, windowStart: now };
userUsage.set(userId, usage);
}
usage.count++;
const allowed = usage.count <= tierDef.maxRequests;
const status = getCurrentTierStatus(userId);
return { allowed, status };
}
