init claude-code

services/rateLimitMocking.ts

@@ -0,0 +1,144 @@
+/**
+ * Facade for rate limit header processing
+ * This isolates mock logic from production code
+ */
+
+import { APIError } from '@anthropic-ai/sdk'
+import {
+  applyMockHeaders,
+  checkMockFastModeRateLimit,
+  getMockHeaderless429Message,
+  getMockHeaders,
+  isMockFastModeRateLimitScenario,
+  shouldProcessMockLimits,
+} from './mockRateLimits.js'
+
+/**
+ * Process headers, applying mocks if /mock-limits command is active
+ */
+export function processRateLimitHeaders(
+  headers: globalThis.Headers,
+): globalThis.Headers {
+  // Only apply mocks for Ant employees using /mock-limits command
+  if (shouldProcessMockLimits()) {
+    return applyMockHeaders(headers)
+  }
+  return headers
+}
+
+/**
+ * Check if we should process rate limits (either real subscriber or /mock-limits command)
+ */
+export function shouldProcessRateLimits(isSubscriber: boolean): boolean {
+  return isSubscriber || shouldProcessMockLimits()
+}
+
+/**
+ * Check if mock rate limits should throw a 429 error
+ * Returns the error to throw, or null if no error should be thrown
+ * @param currentModel The model being used for the current request
+ * @param isFastModeActive Whether fast mode is currently active (for fast-mode-only mocks)
+ */
+export function checkMockRateLimitError(
+  currentModel: string,
+  isFastModeActive?: boolean,
+): APIError | null {
+  if (!shouldProcessMockLimits()) {
+    return null
+  }
+
+  const headerlessMessage = getMockHeaderless429Message()
+  if (headerlessMessage) {
+    return new APIError(
+      429,
+      { error: { type: 'rate_limit_error', message: headerlessMessage } },
+      headerlessMessage,
+      // eslint-disable-next-line eslint-plugin-n/no-unsupported-features/node-builtins
+      new globalThis.Headers(),
+    )
+  }
+
+  const mockHeaders = getMockHeaders()
+  if (!mockHeaders) {
+    return null
+  }
+
+  // Check if we should throw a 429 error
+  // Only throw if:
+  // 1. Status is rejected AND
+  // 2. Either no overage headers OR overage is also rejected
+  // 3. For Opus-specific limits, only throw if actually using an Opus model
+  const status = mockHeaders['anthropic-ratelimit-unified-status']
+  const overageStatus =
+    mockHeaders['anthropic-ratelimit-unified-overage-status']
+  const rateLimitType =
+    mockHeaders['anthropic-ratelimit-unified-representative-claim']
+
+  // Check if this is an Opus-specific rate limit
+  const isOpusLimit = rateLimitType === 'seven_day_opus'
+
+  // Check if current model is an Opus model (handles all variants including aliases)
+  const isUsingOpus = currentModel.includes('opus')
+
+  // For Opus limits, only throw 429 if actually using Opus
+  // This simulates the real API behavior where fallback to Sonnet succeeds
+  if (isOpusLimit && !isUsingOpus) {
+    return null
+  }
+
+  // Check for mock fast mode rate limits (handles expiry, countdown, etc.)
+  if (isMockFastModeRateLimitScenario()) {
+    const fastModeHeaders = checkMockFastModeRateLimit(isFastModeActive)
+    if (fastModeHeaders === null) {
+      return null
+    }
+    // Create a mock 429 error with the fast mode headers
+    const error = new APIError(
+      429,
+      { error: { type: 'rate_limit_error', message: 'Rate limit exceeded' } },
+      'Rate limit exceeded',
+      // eslint-disable-next-line eslint-plugin-n/no-unsupported-features/node-builtins
+      new globalThis.Headers(
+        Object.entries(fastModeHeaders).filter(([_, v]) => v !== undefined) as [
+          string,
+          string,
+        ][],
+      ),
+    )
+    return error
+  }
+
+  const shouldThrow429 =
+    status === 'rejected' && (!overageStatus || overageStatus === 'rejected')
+
+  if (shouldThrow429) {
+    // Create a mock 429 error with the appropriate headers
+    const error = new APIError(
+      429,
+      { error: { type: 'rate_limit_error', message: 'Rate limit exceeded' } },
+      'Rate limit exceeded',
+      // eslint-disable-next-line eslint-plugin-n/no-unsupported-features/node-builtins
+      new globalThis.Headers(
+        Object.entries(mockHeaders).filter(([_, v]) => v !== undefined) as [
+          string,
+          string,
+        ][],
+      ),
+    )
+    return error
+  }
+
+  return null
+}
+
+/**
+ * Check if this is a mock 429 error that shouldn't be retried
+ */
+export function isMockRateLimitError(error: APIError): boolean {
+  return shouldProcessMockLimits() && error.status === 429
+}
+
+/**
+ * Check if /mock-limits command is currently active (for UI purposes)
+ */
+export { shouldProcessMockLimits }