feat: Add OpenAI Codex Provider & improve LaTeX rendering

deeptutor/services/llm/factory.py

@@ -258,9 +258,16 @@ async def _do_complete(
     ) -> str:
         try:
             if provider_mode == "oauth" and provider_name == "openai_codex":
-                raise LLMConfigError(
-                    "openai_codex requires OAuth login in CLI. "
-                    "Run `deeptutor provider login openai-codex` first."
+                from . import codex_provider
+
+                return await codex_provider.complete(
+                    prompt=prompt_value,
+                    system_prompt=system_prompt_value,
+                    model=model_value,
+                    api_key=api_key_value,
+                    messages=messages_value,
+                    reasoning_effort=reasoning_effort,
+                    **extra_kwargs,
                 )
             if provider_mode == "oauth":
                 raise LLMConfigError(
@@ -387,10 +394,20 @@ async def stream(
     for attempt in range(total_attempts):
         try:
             if provider_mode == "oauth" and provider_name == "openai_codex":
-                raise LLMConfigError(
-                    "openai_codex requires OAuth login in CLI. "
-                    "Run `deeptutor provider login openai-codex` first."
-                )
+                from . import codex_provider
+
+                async for chunk in codex_provider.stream(
+                    prompt=prompt,
+                    system_prompt=system_prompt,
+                    model=model,
+                    api_key=api_key,
+                    messages=messages,
+                    reasoning_effort=reasoning_effort,
+                    **extra_kwargs,
+                ):
+                    has_yielded = True
+                    yield chunk
+                return
             if provider_mode == "oauth":
                 raise LLMConfigError(
                     f"{provider_name} requires OAuth session. "

web/app/(utility)/memory/page.tsx

@@ -5,7 +5,7 @@ import { useCallback, useEffect, useRef, useState } from "react";
 import { Brain, Eraser, Loader2, RefreshCw, Save, BookOpen, User } from "lucide-react";
 import { useTranslation } from "react-i18next";
 import { useAppShell } from "@/context/AppShellContext";
-import { apiUrl } from "@/lib/api";
+import { API_BASE_URL, apiUrl } from "@/lib/api";
 
 const MarkdownRenderer = dynamic(() => import("@/components/common/MarkdownRenderer"), {
   ssr: false,
@@ -63,6 +63,7 @@ export default function MemoryPage() {
   const [activeView, setActiveView] = useState<"edit" | "preview">("edit");
   const [editors, setEditors] = useState<Record<MemoryFile, string>>({ summary: "", profile: "" });
   const [toast, setToast] = useState("");
+  const [loadError, setLoadError] = useState<string | null>(null);
   const textareaRef = useRef<HTMLTextAreaElement>(null);
 
   const tab = TABS.find((t) => t.key === activeTab)!;
@@ -79,10 +80,21 @@ export default function MemoryPage() {
   const loadMemory = useCallback(async () => {
     setLoading(true);
     try {
+      setLoadError(null);
       const res = await fetch(apiUrl("/api/v1/memory"));
+      if (!res.ok) {
+        throw new Error(`Memory request failed with ${res.status}`);
+      }
       const d: MemoryData = await res.json();
       setData(d);
       setEditors({ summary: d.summary || "", profile: d.profile || "" });
+    } catch (error) {
+      const message =
+        error instanceof Error
+          ? error.message
+          : `Could not reach backend at ${API_BASE_URL}`;
+      setLoadError(message);
+      setToast(`Backend unavailable. Start the API server on ${API_BASE_URL}.`);
     } finally {
       setLoading(false);
     }
@@ -155,6 +167,12 @@ export default function MemoryPage() {
   return (
     <div className="h-full overflow-y-auto [scrollbar-gutter:stable]">
       <div className="mx-auto max-w-[960px] px-6 py-8">
+        {loadError ? (
+          <div className="mb-6 rounded-xl border border-red-500/30 bg-red-500/8 px-4 py-3 text-[13px] text-red-500">
+            Could not reach the backend at <code className="rounded bg-black/10 px-1 py-0.5">{API_BASE_URL}</code>.
+            Start <code className="rounded bg-black/10 px-1 py-0.5">python -m deeptutor.api.run_server</code> and refresh.
+          </div>
+        ) : null}
 
         {/* Header */}
         <div className="mb-6 flex items-start justify-between">

web/app/(utility)/settings/page.tsx

@@ -24,8 +24,9 @@ import {
 import { useTranslation } from "react-i18next";
 
 import { writeStoredLanguage } from "@/context/AppShellContext";
-import { apiUrl } from "@/lib/api";
+import { API_BASE_URL, apiUrl } from "@/lib/api";
 import { setTheme as applyThemePreference } from "@/lib/theme";
+import { CodexSection } from "@/components/CodexSection";
 
 type ServiceName = "llm" | "embedding" | "search";
 
@@ -378,6 +379,7 @@ function SettingsPageContent() {
   const [applying, setApplying] = useState(false);
   const [toast, setToast] = useState<string>("");
   const [diagnosticsOpen, setDiagnosticsOpen] = useState(false);
+  const [loadError, setLoadError] = useState<string | null>(null);
   const [providers, setProviders] = useState<Record<ServiceName, ProviderOption[]>>({ llm: [], embedding: [], search: [] });
   const eventSourceRef = useRef<EventSource | null>(null);
 
@@ -393,19 +395,42 @@ function SettingsPageContent() {
 
   useEffect(() => {
     const load = async () => {
-      const settingsResponse = await fetch(apiUrl("/api/v1/settings"));
-      const settingsPayload = (await settingsResponse.json()) as SettingsPayload;
-      setCatalog(settingsPayload.catalog);
-      setDraft(cloneCatalog(settingsPayload.catalog));
-      setTheme(settingsPayload.ui.theme);
-      setLanguage(settingsPayload.ui.language);
-      if (settingsPayload.providers) setProviders(settingsPayload.providers);
+      try {
+        setLoadError(null);
 
-      const statusResponse = await fetch(apiUrl("/api/v1/system/status"));
-      const statusPayload = (await statusResponse.json()) as SystemStatus;
-      setStatus(statusPayload);
+        const settingsResponse = await fetch(apiUrl("/api/v1/settings"));
+        if (!settingsResponse.ok) {
+          throw new Error(`Settings request failed with ${settingsResponse.status}`);
+        }
+        const settingsPayload = (await settingsResponse.json()) as SettingsPayload;
+        setCatalog(settingsPayload.catalog);
+        setDraft(cloneCatalog(settingsPayload.catalog));
+        setTheme(settingsPayload.ui.theme);
+        setLanguage(settingsPayload.ui.language);
+        if (settingsPayload.providers) setProviders(settingsPayload.providers);
+
+        const statusResponse = await fetch(apiUrl("/api/v1/system/status"));
+        if (!statusResponse.ok) {
+          throw new Error(`Status request failed with ${statusResponse.status}`);
+        }
+        const statusPayload = (await statusResponse.json()) as SystemStatus;
+        setStatus(statusPayload);
+      } catch (error) {
+        const message =
+          error instanceof Error
+            ? error.message
+            : `Could not reach backend at ${API_BASE_URL}`;
+        setLoadError(message);
+        setToast(`Backend unavailable. Start the API server on ${API_BASE_URL}.`);
+        setStatus({
+          backend: { status: "offline", timestamp: new Date().toISOString() },
+          llm: { status: "unknown", error: message },
+          embeddings: { status: "unknown", error: message },
+          search: { status: "unknown", error: message },
+        });
+      }
     };
-    load();
+    void load();
     return () => {
       if (eventSourceRef.current) eventSourceRef.current.close();
     };
@@ -775,6 +800,12 @@ function SettingsPageContent() {
   return (
     <div className="h-full overflow-y-auto [scrollbar-gutter:stable]">
       <div className="mx-auto max-w-[960px] px-6 py-8">
+        {loadError ? (
+          <div className="mb-6 rounded-xl border border-red-500/30 bg-red-500/8 px-4 py-3 text-[13px] text-red-500">
+            Could not reach the backend at <code className="rounded bg-black/10 px-1 py-0.5">{API_BASE_URL}</code>.
+            Start <code className="rounded bg-black/10 px-1 py-0.5">python -m deeptutor.api.run_server</code> and refresh.
+          </div>
+        ) : null}
 
         {/* ── Tour Banner ── */}
         {isTourMode && !tourCompleted && (
@@ -1224,6 +1255,9 @@ function SettingsPageContent() {
           )}
         </div>
 
+        {/* ── Codex Session ── */}
+        <CodexSection />
+
         {/* ── Footer ── */}
         <div className="flex items-center justify-between border-t border-[var(--border)]/30 pt-4 pb-2">
           {!isTourMode && (

web/app/api/codex/apply/route.ts

@@ -0,0 +1,195 @@
+export const runtime = 'nodejs';
+
+import { NextRequest, NextResponse } from 'next/server';
+
+const BACKEND_URL = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:8001';
+
+/**
+ * POST /api/codex/apply
+ *
+ * Accepts { apiKey, model } and writes an openai_codex binding profile
+ * into the backend catalog, then applies it to .env.
+ *
+ * This bridges the frontend-only OAuth credential into the backend LLM pipeline.
+ */
+export async function POST(req: NextRequest) {
+  try {
+    const { apiKey, model } = (await req.json()) as {
+      apiKey?: string;
+      model?: string;
+    };
+
+    if (!apiKey?.trim()) {
+      return NextResponse.json({ error: 'apiKey is required' }, { status: 400 });
+    }
+
+    const effectiveModel = model?.trim() || 'gpt-5.3-codex';
+
+    // 1. Fetch current settings from backend
+    const settingsRes = await fetch(`${BACKEND_URL}/api/v1/settings`);
+    if (!settingsRes.ok) {
+      return NextResponse.json(
+        { error: 'Could not read current settings from backend' },
+        { status: 502 },
+      );
+    }
+    const settings = (await settingsRes.json()) as {
+      catalog: {
+        version: number;
+        services: {
+          llm: {
+            active_profile_id: string | null;
+            active_model_id?: string | null;
+            profiles: Array<{
+              id: string;
+              name: string;
+              binding?: string;
+              base_url: string;
+              api_key: string;
+              api_version: string;
+              models: Array<{ id: string; name: string; model: string }>;
+            }>;
+          };
+          embedding: unknown;
+          search: unknown;
+        };
+      };
+    };
+
+    const catalog = settings.catalog;
+    const llmService = catalog.services.llm;
+
+    // 2. Find or create the Codex profile
+    const CODEX_PROFILE_ID = 'codex-session';
+    const CODEX_MODEL_ID = 'codex-model';
+
+    let codexProfile = llmService.profiles.find((p) => p.id === CODEX_PROFILE_ID);
+
+    if (codexProfile) {
+      // Update existing
+      codexProfile.api_key = apiKey;
+      codexProfile.binding = 'openai_codex';
+      codexProfile.base_url = 'https://chatgpt.com/backend-api';
+      const existingModel = codexProfile.models.find((m) => m.id === CODEX_MODEL_ID);
+      if (existingModel) {
+        existingModel.model = effectiveModel;
+        existingModel.name = effectiveModel;
+      } else {
+        codexProfile.models = [
+          { id: CODEX_MODEL_ID, name: effectiveModel, model: effectiveModel },
+        ];
+      }
+    } else {
+      // Create new
+      codexProfile = {
+        id: CODEX_PROFILE_ID,
+        name: 'Codex Session',
+        binding: 'openai_codex',
+        base_url: 'https://chatgpt.com/backend-api',
+        api_key: apiKey,
+        api_version: '',
+        models: [
+          { id: CODEX_MODEL_ID, name: effectiveModel, model: effectiveModel },
+        ],
+      };
+      llmService.profiles.push(codexProfile);
+    }
+
+    // 3. Set as active
+    llmService.active_profile_id = CODEX_PROFILE_ID;
+    llmService.active_model_id = CODEX_MODEL_ID;
+
+    // 4. Apply to backend (.env + runtime)
+    const applyRes = await fetch(`${BACKEND_URL}/api/v1/settings/apply`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ catalog }),
+    });
+
+    if (!applyRes.ok) {
+      const errorText = await applyRes.text();
+      return NextResponse.json(
+        { error: `Backend apply failed: ${errorText}` },
+        { status: 502 },
+      );
+    }
+
+    const applied = await applyRes.json();
+    return NextResponse.json({
+      ok: true,
+      catalog: applied.catalog,
+      model: effectiveModel,
+    });
+  } catch (err) {
+    const message = err instanceof Error ? err.message : 'Could not apply Codex config';
+    return NextResponse.json({ error: message }, { status: 500 });
+  }
+}
+
+/**
+ * DELETE /api/codex/apply
+ *
+ * Remove the Codex profile and fall back to the first available profile.
+ */
+export async function DELETE() {
+  try {
+    const settingsRes = await fetch(`${BACKEND_URL}/api/v1/settings`);
+    if (!settingsRes.ok) {
+      return NextResponse.json(
+        { error: 'Could not read current settings' },
+        { status: 502 },
+      );
+    }
+    const settings = (await settingsRes.json()) as {
+      catalog: {
+        version: number;
+        services: {
+          llm: {
+            active_profile_id: string | null;
+            active_model_id?: string | null;
+            profiles: Array<{
+              id: string;
+              models: Array<{ id: string }>;
+            }>;
+          };
+          embedding: unknown;
+          search: unknown;
+        };
+      };
+    };
+
+    const catalog = settings.catalog;
+    const llmService = catalog.services.llm;
+
+    // Remove the codex profile
+    llmService.profiles = llmService.profiles.filter(
+      (p) => p.id !== 'codex-session',
+    );
+
+    // Fall back to first remaining profile
+    if (llmService.active_profile_id === 'codex-session') {
+      const fallback = llmService.profiles[0];
+      llmService.active_profile_id = fallback?.id ?? null;
+      llmService.active_model_id = fallback?.models?.[0]?.id ?? null;
+    }
+
+    const applyRes = await fetch(`${BACKEND_URL}/api/v1/settings/apply`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ catalog }),
+    });
+
+    if (!applyRes.ok) {
+      const errorText = await applyRes.text();
+      return NextResponse.json(
+        { error: `Backend apply failed: ${errorText}` },
+        { status: 502 },
+      );
+    }
+
+    return NextResponse.json({ ok: true });
+  } catch (err) {
+    const message = err instanceof Error ? err.message : 'Could not remove Codex config';
+    return NextResponse.json({ error: message }, { status: 500 });
+  }
+}