feat: add enhanced file type support for attachment system #69
Description
📄 Enhanced File Support for Attachment System
📋 Overview
Expand the file attachment system beyond images to support documents, videos, and other file types for comprehensive file sharing between Discord and Unthread.
🎯 Scope
File Types: Documents (PDF, TXT, DOC, etc.), Videos (MP4, MOV, etc.), Audio files
Direction: Both Discord ↔ Unthread flows
Architecture: Extend existing buffer-based attachment system
🔧 Technical Requirements
Prerequisites
- Requires completion of image attachment flows (both directions)
- Existing AttachmentHandler and validation infrastructure
File Type Categories
1. Document Support
- PDF files
- Text documents (TXT, DOC, DOCX)
- Spreadsheets (XLS, XLSX, CSV)
- Presentations (PPT, PPTX)
2. Media Support
- Video files (MP4, MOV, AVI, WebM)
- Audio files (MP3, WAV, OGG)
- Advanced image formats (TIFF, SVG)
3. Archive Support
- Compressed files (ZIP, RAR, 7Z)
- Code archives and repositories
Configuration Updates
- Extend
DISCORD_ATTACHMENT_CONFIGwith new file types - Update size limits per file type category
- Add MIME type validation for each category
Validation Enhancements
- File signature validation (magic bytes)
- Content-type verification
- Security scanning for malicious files
- File corruption detection
✅ Acceptance Criteria
- Support major document formats (PDF, DOC, TXT)
- Handle video files within size constraints
- Process audio file attachments
- Validate file signatures and content types
- Maintain security through file scanning
- Update user feedback for new file types
- Extend error handling for format-specific issues
- Performance optimization for larger files
- Documentation for supported file types
🔄 Dependencies
- Prerequisite: Complete image attachment system (both directions)
- Infrastructure: Existing AttachmentHandler class
- Security: File validation and scanning capabilities
📚 Technical Considerations
- Discord file size limits vary by user type (Nitro vs free)
- Different file types may require different processing approaches
- Security implications of supporting executable file types
- Performance impact of processing large media files