feat: widgets and ai chat

packages/ai-assistant/src/providers/index.ts

@@ -0,0 +1,67 @@
+import { createOpenAI } from '@ai-sdk/openai';
+import { createAnthropic } from '@ai-sdk/anthropic';
+import { createGoogleGenerativeAI } from '@ai-sdk/google';
+import { AIProvider, type AIProviderConfig } from '../types';
+
+const DEFAULT_MODELS: Record<AIProvider, string> = {
+  [AIProvider.OPENAI]: 'gpt-4o',
+  [AIProvider.ANTHROPIC]: 'claude-sonnet-4-20250514',
+  [AIProvider.GOOGLE]: 'gemini-2.5-flash'
+};
+
+const PROVIDER_API_KEY_ENV: Record<AIProvider, string> = {
+  [AIProvider.OPENAI]: 'OPENAI_API_KEY',
+  [AIProvider.ANTHROPIC]: 'ANTHROPIC_API_KEY',
+  [AIProvider.GOOGLE]: 'GOOGLE_API_KEY'
+};
+
+/**
+ * Creates an AI SDK LanguageModel from provider configuration.
+ * Normalizes OpenAI, Anthropic, and Google into a single interface for streamText().
+ */
+export function createModel(config: AIProviderConfig) {
+  const modelName = config.model || DEFAULT_MODELS[config.provider];
+
+  switch (config.provider) {
+    case AIProvider.OPENAI: {
+      const openai = createOpenAI({ apiKey: config.apiKey });
+      return openai(modelName);
+    }
+    case AIProvider.ANTHROPIC: {
+      const anthropic = createAnthropic({ apiKey: config.apiKey });
+      return anthropic(modelName);
+    }
+    case AIProvider.GOOGLE: {
+      const google = createGoogleGenerativeAI({ apiKey: config.apiKey });
+      return google(modelName);
+    }
+    default:
+      throw new Error(`Unsupported AI provider: ${config.provider}`);
+  }
+}
+
+/**
+ * Reads the API key for a specific provider from its dedicated env var.
+ * Returns null when the key is unset, so callers can decide whether to 503.
+ */
+export function getProviderConfigForProvider(provider: AIProvider): AIProviderConfig | null {
+  const apiKey = process.env[PROVIDER_API_KEY_ENV[provider]];
+  if (!apiKey) return null;
+
+  return { provider, apiKey };
+}
+
+/**
+ * Returns the first provider that has a key configured, in preference order.
+ * Used by routes that don't take an explicit model (status check, title generation).
+ */
+export function pickAnyConfiguredProvider(): AIProviderConfig | null {
+  const order: AIProvider[] = [AIProvider.GOOGLE, AIProvider.OPENAI, AIProvider.ANTHROPIC];
+
+  for (const provider of order) {
+    const config = getProviderConfigForProvider(provider);
+    if (config) return config;
+  }
+
+  return null;
+}