Create a full-stack web application using Next.js App Router, React, Tailwind CSS, and Drizzle ORM with PostgreSQL. The application should allow users to upload images and generate 3D models using an AI model optimized for Apple Silicon (like TRELLIS.2). The app should feature a multi-page structure, including a landing page, a user dashboard, an image upload page, and a 3D model generation/viewing page. Implement a robust backend with API routes for image handling, AI model interaction, and database operations.
**Key Features:**
1. **User Authentication:** Implement secure user signup, login, and session management (e.g., using NextAuth.js or Clerk).
2. **Image Upload:** Allow users to upload images via a drag-and-drop interface. Store uploaded images temporarily and link them to user projects.
3. **AI Model Integration:** Integrate the image-to-3D generation model. Since direct AI model execution on the frontend is not feasible for complex models, the backend should handle the AI processing. For MVP, simulate the AI process with a placeholder that returns a dummy 3D model file after a specified delay (e.g., 3.5 minutes) to mimic the TRELLIS.2 generation time on M4 Pro. The actual integration would involve a Python backend service or a dedicated AI inference server that the Next.js API routes communicate with.
4. **3D Model Generation & Viewing:** After image processing, generate a 3D model. Provide a viewer (e.g., using `react-three-fiber` or `three.js`) to display the generated model within the application. Allow users to download the generated model in common formats (e.g., .obj, .glb).
5. **Database Schema (Drizzle ORM with PostgreSQL):**
* `users` table: id, name, email, password_hash, created_at, updated_at
* `projects` table: id, user_id (fk to users), name, description, created_at, updated_at
* `images` table: id, project_id (fk to projects), file_url, original_filename, uploaded_at
* `generated_models` table: id, project_id (fk to projects), image_id (fk to images), model_file_url, generation_time, created_at
6. **API Routes (Next.js App Router):**
* `/api/auth/*`: For authentication endpoints (if using NextAuth.js).
* `/api/upload`: Handle image uploads, save to temporary storage, and create an entry in the `images` table.
* `/api/generate-3d`: Trigger the 3D model generation process (backend simulation or actual AI call), update project status, and link the generated model.
* `/api/models/:modelId`: Fetch details of a generated model and provide a download URL.
* CRUD operations for projects and images.
7. **Frontend (React, Next.js App Router, Tailwind CSS):**
* Implement responsive UI components for all features.
* `app/page.tsx`: Landing page with app description and call to action.
* `app/(dashboard)/layout.tsx`: Dashboard layout with navigation.
* `app/(dashboard)/dashboard/page.tsx`: User's project overview.
* `app/(dashboard)/projects/[projectId]/page.tsx`: View a specific project, upload images, and trigger generation.
* `app/(dashboard)/projects/[projectId]/models/[modelId]/page.tsx`: View and download a generated 3D model.
8. **Error Handling & Feedback:** Implement clear error messages and loading states for all asynchronous operations.
9. **Deployment Considerations:** Structure the project for easy deployment on platforms like Vercel. Ensure backend processing can be scaled if needed (e.g., using serverless functions or dedicated inference servers).