NOTICE

Paper Burner X - License Notice
================================

## Licensing Structure

This project uses a clear licensing approach:

**Primary License**: GNU Affero General Public License v3.0 (AGPL-3.0)
- Applies to all new code written by Feather-2 and contributors (~98% of current codebase)
- Copyright (C) 2024-2025 Feather-2 and contributors

**Historical Attribution**: GNU General Public License v2.0 (GPL-2.0)
- Original Paper Burner code (pre-refactoring commits in git history)
- See git history for the original app.js and index.html before major refactoring
- Copyright (C) 2024 Baoyu (baoyudu)

**Note**: The entire current codebase must be used under AGPL-3.0 terms. GPL-2.0 applies only to
historical snapshots preserved in commit history before the major refactoring.

---

## Code Attribution and Licensing Details

### Original Paper Burner (GPL-2.0)

The foundational concepts and early code came from the original Paper Burner project:

**Original Project Attribution:**
- Author: Baoyu (baoyudu)
- Repository: https://github.com/baoyudu/paper-burner
- License: GPL-2.0
- Scope: Basic PDF OCR and translation tool (~6 files, ~2,000 lines)

**Historical Code Under GPL-2.0:**
- Original code related to Mistral translation and partial UI (see git history before May 16, 2025)
- Specific files: Original `app.js` and `index.html` before major refactoring
- Basic PDF processing workflow concepts
- Initial OCR integration approach
- Basic translation pipeline structure

**Important**: We deeply respect the original author's contribution. The GPL-2.0 portions
remain available in the git history for anyone who wishes to use them under GPL-2.0 terms.

### Paper Burner X - New Development (AGPL-3.0)

All code in the current version has been rewritten, refactored, or newly created by Feather-2:

**Complete Backend System (NEW - ~40,000 lines):**
- Node.js + Express server architecture
- PostgreSQL database integration
- Prisma ORM implementation
- RESTful API design
- Authentication & authorization system (JWT, bcrypt)
- Multi-tenant user management
- Admin panel and management interface

**Docker Deployment Architecture (NEW):**
- Multi-stage Dockerfile
- Docker Compose orchestration
- Database migration system
- Health check implementation
- Production-ready configuration

**Advanced Features (NEW):**
- Dual-mode deployment (frontend-only vs. full-stack)
- Storage adapter pattern for mode switching
- Multiple OCR engine support (MinerU, Doc2X)
- Enhanced translation workflows
- Batch processing system
- History management with IndexedDB
- Annotation and highlighting system
- AI chatbot integration
- Mind map and flowchart generation
- Advanced document analysis tools

**UI/UX Enhancements (NEW):**
- Complete UI refactoring
- Enhanced markdown rendering
- Split-view comparison
- Table of contents navigation
- Immersive reading mode
- Glossary management system
- Key management interface
- Settings and configuration panels

---

## Why AGPL-3.0 for New Code?

### 1. Copyright and Legal Right

**As the author of ~98% of this codebase, I (Feather-2) hold the copyright and have the legal right
to choose the license for my work.**

The new code is my original creation, and I choose AGPL-3.0 to protect the open-source nature
of this project while respecting the original GPL-2.0 contributions (which remain in git history).

### 2. Preventing the "Cloud Service Loophole"
The primary motivation for AGPL-3.0 is **closing the cloud service loophole**:

**GPL-2.0 Limitation**: If someone deploys your GPL-2.0 software as a web service
(SaaS), they are NOT required to share their modifications because users don't
"receive" the software - they only access it remotely.

**AGPL-3.0 Solution**: Section 13 explicitly requires that users interacting with
the software over a network must be offered access to the source code.

**Real-World Scenario**:
```
Without AGPL-3.0:
Company X takes Paper Burner X → Modifies it → Deploys as paid SaaS
→ Keeps modifications private → Legal under GPL-2.0 (cloud loophole)

With AGPL-3.0:
Company X takes Paper Burner X → Modifies it → Deploys as paid SaaS
→ MUST provide source code link → Users can see modifications → Fair!
```

### 3. Protecting Open Source Values
This is NOT about preventing commercial use - it's about ensuring:
- **Transparency**: Users know what code is running
- **Freedom**: Users can run their own instances
- **Fairness**: Improvements benefit the community
- **Sustainability**: Prevents proprietary forks that don't contribute back

---

## AGPL-3.0 Requirements for Network Deployment

Under AGPL-3.0, Section 13, if you deploy this software as a network service:

### You MUST:
1. **Prominently display** a "Source Code" or "View Source" link in your UI
2. **Provide free access** to the complete source code (including your modifications)
3. **Use standard methods** for distributing the source (e.g., Git, download link)

### Example Implementation:

**Minimal Compliance (Footer Link):**
```html
<!-- In your footer or about section -->
<footer>
  <p>
    Powered by <a href="https://github.com/Feather-2/paper-burner-x">Paper Burner X</a> (AGPL-3.0)
    • <a href="https://github.com/your-org/your-fork" style="font-weight: bold;">
      📥 Download Source Code
    </a>
  </p>
</footer>
```

**Recommended Compliance (About/Settings Page):**
```html
<!-- In settings or about page -->
<div class="license-notice">
  <h3>Open Source License</h3>
  <p>
    This service is based on
    <a href="https://github.com/Feather-2/paper-burner-x">Paper Burner X</a>,
    licensed under AGPL-3.0.
  </p>
  <p>
    <strong>Source Code Access:</strong> You can download the complete source code,
    including any modifications we made:
  </p>
  <a href="https://github.com/your-org/your-fork" class="btn-primary">
    View/Download Source Code
  </a>
  <p style="margin-top: 1rem; font-size: 0.9em;">
    Under AGPL-3.0, you have the right to:
    • Use the software freely
    • Modify and redistribute it
    • Access the source code at any time
  </p>
</div>
```

**Best Practice (In-App Notice):**
```javascript
// Show on first visit or in help menu
function showLicenseNotice() {
  const notice = `
    This application uses Paper Burner X (AGPL-3.0).

    You have the right to:
    ✓ View and download the source code
    ✓ Run your own instance
    ✓ Modify and redistribute the software

    Access source code at: https://github.com/your-org/your-fork
  `;

  // Display in modal, notification, or about dialog
  showNotification(notice, { persistent: true, link: sourceCodeUrl });
}
```

### This applies to:
- ✅ Public web services
- ✅ SaaS platforms
- ✅ Internal corporate deployments (if accessed over network)
- ✅ University/institution deployments
- ❌ Personal use on your own computer (no network access)

---

## For Downstream Users and Deployers

### If you're deploying Paper Burner X:

**Pure Frontend Mode (Vercel/Static):**
- Uses only GPL-2.0 and AGPL-3.0 frontend code
- No backend deployment = Simpler compliance
- Recommend: Add source code link in your footer

**Full Docker Mode (with Backend):**
- Uses both GPL-2.0 and AGPL-3.0 code
- MUST provide source code access per AGPL-3.0 Section 13
- Required: Prominent source code link in UI

### If you're modifying Paper Burner X:

**GPL-2.0 Components**: Can modify, but must remain GPL-2.0 compatible
**AGPL-3.0 Components**: Can modify, but must share modifications if deployed
**New Components**: You can add under AGPL-3.0 or compatible license

### Compatibility Guide:
- ✅ GPL-3.0 code → Can integrate (AGPL-3.0 is GPL-3.0 + network clause)
- ✅ MIT/BSD/Apache 2.0 → Can integrate
- ✅ Commercial use → Allowed (with source disclosure)
- ❌ Proprietary license → Cannot integrate
- ❌ GPL-3.0-incompatible licenses → Cannot integrate

---

## Third-Party Components

This project uses the following open-source libraries and services:

### Frontend Libraries
- TailwindCSS (MIT License)
- Turndown (MIT License)
- Mammoth.js (BSD-2-Clause License)
- Iconify (MIT License)

### Backend Libraries (Docker mode only)
- Express.js (MIT License)
- Prisma (Apache 2.0 License)
- bcryptjs (MIT License)
- jsonwebtoken (MIT License)
- PostgreSQL (PostgreSQL License)

### OCR Services (API-based)
- MinerU (Apache 2.0 License)
- Doc2X (Commercial Service)

### AI Models (API-based)
- Various AI translation services (user-configured)

## Contact

- GitHub: https://github.com/Feather-2/paper-burner-x
- Issues: https://github.com/Feather-2/paper-burner-x/issues

## Full License Text

See the LICENSE file in the root directory for the full text of the
GNU Affero General Public License v3.0.

Online version: https://www.gnu.org/licenses/agpl-3.0.html