feat: implement API key resolution and live model listing for providers

entrypoints/background.ts

@@ -80,6 +80,18 @@ async function decryptApiKey(encKeyB64: string, apiKeyEncB64: string): Promise<s
   return new TextDecoder().decode(decrypted);
 }
 
+// Resolve the usable API key from stored config: prefer the encrypted path,
+// fall back to plaintext for backward compat. Returns null if none is set.
+async function resolveApiKey(config: LexAIConfig): Promise<string | null> {
+  let apiKey = config.apiKey;
+  if (config.apiKeyEnc && config.encKey) {
+    const decrypted = await decryptApiKey(config.encKey, config.apiKeyEnc);
+    if (decrypted) apiKey = decrypted;
+  }
+  if (!apiKey || apiKey.trim() === '') return null;
+  return apiKey.trim();
+}
+
 // ─── Provider implementations ─────────────────────────────────────────────────
 
 async function callOpenAI(payload: AnalyzePayload, config: LexAIConfig): Promise<LexAIResponse> {
@@ -353,26 +365,70 @@ async function callOpenRouterWithPrompt(payload: AnalyzePayload, config: LexAICo
   return { result: result.trim() };
 }
 
+// ─── Live model listing ───────────────────────────────────────────────────────
+
+const MODEL_LIST_ENDPOINTS: Record<string, string> = {
+  openai:     'https://api.openai.com/v1/models',
+  groq:       'https://api.groq.com/openai/v1/models',
+  openrouter: 'https://openrouter.ai/api/v1/models',
+  anthropic:  'https://api.anthropic.com/v1/models',
+};
+
+// Drop non-chat models (embeddings, audio, image, etc.) so the picker stays useful.
+const NON_CHAT_MODEL_RE = /embedding|whisper|tts|dall-e|audio|realtime|moderation|image|guard|transcribe|speech|rerank/i;
+
+async function listModels(provider: string, apiKey?: string): Promise<{ models?: string[]; error?: string }> {
+  const url = MODEL_LIST_ENDPOINTS[provider];
+  if (!url) return { error: `Unknown provider: "${provider}". Please check LexAI settings.` };
+
+  const headers: Record<string, string> = { 'Content-Type': 'application/json' };
+  if (provider === 'anthropic') {
+    if (!apiKey) return { error: 'Anthropic requires an API key to list models.' };
+    headers['x-api-key'] = apiKey;
+    headers['anthropic-version'] = '2023-06-01';
+    // Allow the extension origin to call Anthropic directly (avoids a CORS 403).
+    headers['anthropic-dangerous-direct-browser-access'] = 'true';
+  } else if (apiKey) {
+    // OpenRouter's list is public, so the key is optional there; OpenAI/Groq require it.
+    headers['Authorization'] = `Bearer ${apiKey}`;
+  }
+
+  let res: Response;
+  try {
+    res = await fetchWithTimeout(url, { method: 'GET', headers }, 15000);
+  } catch (err) {
+    return { error: `Network error reaching ${provider}: ${String(err)}` };
+  }
+
+  const data = await res.json().catch(() => null);
+  if (!res.ok) {
+    const msg = data?.error?.message ?? data?.error ?? `HTTP ${res.status}`;
+    return { error: `${provider} error: ${msg}` };
+  }
+
+  const raw = Array.isArray(data?.data) ? data.data : [];
+  const ids = raw
+    .map((m: any) => (typeof m === 'string' ? m : m?.id))
+    .filter((id: unknown): id is string => typeof id === 'string' && id.length > 0)
+    .filter((id: string) => !NON_CHAT_MODEL_RE.test(id))
+    .sort((a: string, b: string) => a.localeCompare(b));
+
+  if (ids.length === 0) return { error: `No models returned by ${provider}.` };
+  return { models: ids };
+}
+
 // ─── Main handler ─────────────────────────────────────────────────────────────
 
 async function handleAnalyzeText(payload: AnalyzePayload): Promise<LexAIResponse> {
   const stored = await chrome.storage.local.get(['provider', 'apiKey', 'apiKeyEnc', 'encKey', 'model']);
   const config = stored as LexAIConfig;
 
-  // Resolve API key — prefer encrypted path, fall back to plaintext for backward compat
-  let apiKey = config.apiKey;
-  if (config.apiKeyEnc && config.encKey) {
-    const decrypted = await decryptApiKey(config.encKey, config.apiKeyEnc);
-    if (decrypted) {
-      apiKey = decrypted;
-    }
-  }
-
-  if (!apiKey || apiKey.trim() === '') {
+  const apiKey = await resolveApiKey(config);
+  if (!apiKey) {
     return { error: 'No API key configured. Please open LexAI settings (click the extension icon).' };
   }
 
-  const resolvedConfig: LexAIConfig = { ...config, apiKey: apiKey.trim() };
+  const resolvedConfig: LexAIConfig = { ...config, apiKey };
   const provider = config.provider || 'openai';
 
   switch (provider) {
@@ -460,16 +516,12 @@ export default defineBackground(() => {
       chrome.storage.local.get(['provider', 'apiKey', 'apiKeyEnc', 'encKey', 'model'])
         .then(async (stored) => {
           const config = stored as LexAIConfig;
-          let apiKey = config.apiKey;
-          if (config.apiKeyEnc && config.encKey) {
-            const decrypted = await decryptApiKey(config.encKey, config.apiKeyEnc);
-            if (decrypted) apiKey = decrypted;
-          }
-          if (!apiKey || apiKey.trim() === '') {
+          const apiKey = await resolveApiKey(config);
+          if (!apiKey) {
             sendResponse({ error: 'No API key configured. Please open LexAI settings.' });
             return;
           }
-          const resolvedConfig: LexAIConfig = { ...config, apiKey: apiKey.trim() };
+          const resolvedConfig: LexAIConfig = { ...config, apiKey };
           const systemPrompt = `Reformat the following text as ${format}. Return only the reformatted result, no explanation.`;
           return callProvider(resolvedConfig, text, systemPrompt);
         })
@@ -477,5 +529,25 @@ export default defineBackground(() => {
         .catch((err) => sendResponse({ error: String(err) }));
       return true;
     }
+
+    if (message.type === 'LIST_MODELS') {
+      const provider = (message.provider as string) || 'openai';
+      // Prefer an inline key (freshly typed, not yet saved); else use the stored key.
+      const inlineKey = (message.apiKey as string | undefined)?.trim() || undefined;
+      (async () => {
+        let apiKey = inlineKey;
+        if (!apiKey) {
+          const stored = await chrome.storage.local.get(['apiKey', 'apiKeyEnc', 'encKey']);
+          apiKey = (await resolveApiKey(stored as LexAIConfig)) ?? undefined;
+        }
+        if (!apiKey && provider !== 'openrouter') {
+          return { error: 'No API key found. Enter your API key above, then click Load models.' };
+        }
+        return listModels(provider, apiKey);
+      })()
+        .then(sendResponse)
+        .catch((err) => sendResponse({ error: String(err) }));
+      return true;
+    }
   });
 });