feat: migrate runtime backend to node server

src/services/llmClient.ts

@@ -1,10 +1,66 @@
 import type {TextStreamOptions} from './aiTypes';
+import { fetchWithApiAuth } from './apiClient';
 
 const ENV: Partial<ImportMetaEnv> = import.meta.env ?? {};
 
-const API_BASE_URL = ENV.VITE_LLM_PROXY_BASE_URL || '/api/llm';
-const MODEL = ENV.VITE_LLM_MODEL || 'doubao-1-5-pro-32k-character-250715';
-const ENABLE_LLM_DEBUG_LOG = Boolean(ENV.DEV) || ENV.VITE_LLM_DEBUG_LOG === 'true';
+type NodeProcessLike = {
+  env?: Record<string, string | undefined>;
+};
+
+function getNodeEnv() {
+  if (typeof window !== 'undefined') {
+    return {};
+  }
+
+  return (
+    (globalThis as typeof globalThis & {process?: NodeProcessLike}).process?.env
+    ?? {}
+  );
+}
+
+function normalizeBaseUrl(value: string) {
+  return value.replace(/\/+$/u, '');
+}
+
+function coerceBoolean(value: string | undefined) {
+  return value?.trim().toLowerCase() === 'true';
+}
+
+function resolveHeaders(headers?: HeadersInit) {
+  const nextHeaders: Record<string, string> = {};
+
+  if (headers instanceof Headers) {
+    headers.forEach((value, key) => {
+      nextHeaders[key] = value;
+    });
+  } else if (Array.isArray(headers)) {
+    for (const [key, value] of headers) {
+      nextHeaders[key] = value;
+    }
+  } else if (headers) {
+    Object.assign(nextHeaders, headers);
+  }
+
+  return nextHeaders;
+}
+
+const NODE_ENV = getNodeEnv();
+const IS_SERVER_RUNTIME = typeof window === 'undefined';
+const SERVER_API_KEY =
+  NODE_ENV.LLM_API_KEY || NODE_ENV.ARK_API_KEY || NODE_ENV.VITE_LLM_API_KEY || '';
+const API_BASE_URL = IS_SERVER_RUNTIME
+  ? normalizeBaseUrl(
+      NODE_ENV.LLM_BASE_URL || 'https://ark.cn-beijing.volces.com/api/v3',
+    )
+  : (ENV.VITE_LLM_PROXY_BASE_URL || '/api/llm');
+const MODEL = IS_SERVER_RUNTIME
+  ? (NODE_ENV.LLM_MODEL
+    || NODE_ENV.VITE_LLM_MODEL
+    || 'doubao-1-5-pro-32k-character-250715')
+  : (ENV.VITE_LLM_MODEL || 'doubao-1-5-pro-32k-character-250715');
+const ENABLE_LLM_DEBUG_LOG = IS_SERVER_RUNTIME
+  ? coerceBoolean(NODE_ENV.LLM_DEBUG_LOG)
+  : (Boolean(ENV.DEV) || ENV.VITE_LLM_DEBUG_LOG === 'true');
 
 export interface PlainTextCompletionOptions {
   timeoutMs?: number;
@@ -31,9 +87,16 @@ export function resolveTimeoutMs(rawValue: string | undefined, fallback: number)
   return Number.isFinite(parsed) && parsed > 0 ? Math.round(parsed) : fallback;
 }
 
-export const REQUEST_TIMEOUT_MS = resolveTimeoutMs(ENV.VITE_LLM_REQUEST_TIMEOUT_MS, 15000);
+export const REQUEST_TIMEOUT_MS = resolveTimeoutMs(
+  IS_SERVER_RUNTIME
+    ? (NODE_ENV.LLM_REQUEST_TIMEOUT_MS || NODE_ENV.VITE_LLM_REQUEST_TIMEOUT_MS)
+    : ENV.VITE_LLM_REQUEST_TIMEOUT_MS,
+  15000,
+);
 export const CUSTOM_WORLD_REQUEST_TIMEOUT_MS = resolveTimeoutMs(
-  ENV.VITE_LLM_CUSTOM_WORLD_TIMEOUT_MS,
+  IS_SERVER_RUNTIME
+    ? (NODE_ENV.LLM_CUSTOM_WORLD_TIMEOUT_MS || NODE_ENV.VITE_LLM_CUSTOM_WORLD_TIMEOUT_MS)
+    : ENV.VITE_LLM_CUSTOM_WORLD_TIMEOUT_MS,
   Math.max(REQUEST_TIMEOUT_MS, 120000),
 );
 
@@ -57,6 +120,22 @@ function normalizeLlmError(error: unknown): never {
   throw error;
 }
 
+function requestLlmEndpoint(input: string, init: RequestInit = {}) {
+  const headers = resolveHeaders(init.headers);
+  if (IS_SERVER_RUNTIME && SERVER_API_KEY.trim()) {
+    headers.Authorization = `Bearer ${SERVER_API_KEY.trim()}`;
+  }
+
+  const nextInit = {
+    ...init,
+    headers,
+  } satisfies RequestInit;
+
+  return IS_SERVER_RUNTIME
+    ? fetch(input, nextInit)
+    : fetchWithApiAuth(input, nextInit);
+}
+
 export function isLlmConnectivityError(error: unknown): error is LlmConnectivityError {
   return error instanceof LlmConnectivityError;
 }
@@ -99,7 +178,7 @@ async function requestMessageContent(
   try {
     logLlmDebug(`[LLM:${debugLabel}] prompt text`, rawPromptText);
 
-    const response = await fetch(`${API_BASE_URL}/chat/completions`, {
+    const response = await requestLlmEndpoint(`${API_BASE_URL}/chat/completions`, {
       method: 'POST',
       headers: {'Content-Type': 'application/json'},
       body: JSON.stringify(requestBody),
@@ -175,7 +254,7 @@ export async function streamPlainTextCompletion(
   const timeout = setTimeout(() => controller.abort(), REQUEST_TIMEOUT_MS);
 
   try {
-    const response = await fetch(`${API_BASE_URL}/chat/completions`, {
+    const response = await requestLlmEndpoint(`${API_BASE_URL}/chat/completions`, {
       method: 'POST',
       headers: {'Content-Type': 'application/json'},
       body: JSON.stringify({