Story 3.1: Basic Group Creation and Selection

[bhowiebkr]

Summary

Complete implementation of Story 3.1 - Basic Group Creation and Selection, introducing core node grouping functionality to PyFlowGraph. This establishes the foundation for Epic 3 - Core Node Grouping System.

Story Implementation

Story 3.1: Basic Group Creation and Selection
Epic: 3 - Core Node Grouping System
Dependencies: Complete undo/redo system (Epic 2) ✅

Acceptance Criteria ✅

• AC1: ✅ Multi-select nodes using Ctrl+Click and drag-rectangle selection
• AC2: ✅ Right-click context menu "Group Selected" option on valid selections
• AC3: ✅ Keyboard shortcut Ctrl+G for grouping selected nodes
• AC4: ✅ Group creation validation preventing invalid selections
• AC5: ✅ Automatic group naming with user override option in creation dialog

Key Features Implemented

Core Group System

• Group Class (src/core/group.py): Complete QGraphicsRectItem-based visual representation
• Member Management: UUID-based node tracking with serialization/deserialization
• Visual Styling: Professional appearance with title bars, borders, and selection highlighting
• Auto-sizing: Dynamic bounds calculation based on member node positions

User Interface Integration

• Context Menu: "Group Selected" option appears when 2+ nodes selected
• Keyboard Shortcut: Ctrl+G triggers group creation workflow
• Validation: Real-time enabling/disabling based on selection validity
• Error Handling: User-friendly error messages for invalid selections

Group Creation Dialog

• Automatic Naming: Intelligent name generation from selected node titles
• User Customization: Name, description, padding, and auto-sizing options
• Live Preview: Shows selected nodes and counts in real-time
• Input Validation: Prevents invalid configurations with helpful feedback

Command System Integration

• CreateGroupCommand: Full undo/redo support with state preservation
• Command History: Integrates seamlessly with existing command infrastructure
• Composite Operations: Ready for future multi-group operations

Validation System

• Selection Validation: Ensures minimum node count, valid types, no duplicates
• Type Checking: Robust handling of different import paths and test scenarios
• Error Messaging: Clear, actionable feedback for users

Technical Implementation

New Files Added (5 files)

• src/core/group.py - Group class, validation, and utility functions
• src/ui/dialogs/group_creation_dialog.py - Group configuration dialog
• src/commands/create_group_command.py - Undo/redo command implementation
• tests/test_group_system.py - Unit tests (20 test cases)
• tests/test_group_ui_integration.py - UI integration tests

Files Modified (2 files)

• src/core/node_graph.py - Added Ctrl+G shortcut and group workflow
• src/ui/editor/node_editor_view.py - Added context menu group integration

Documentation

• docs/stories/3.1.story.md - Complete story documentation with implementation details

Testing Coverage

• Unit Tests: 20 test cases covering group functionality, validation, and commands
• Integration Tests: UI workflow testing for context menu and keyboard shortcuts
• Validation Tests: Comprehensive edge case testing for selection validation
• Command Tests: Undo/redo functionality verification

Code Quality

• Windows Compatibility: No Unicode characters, Windows-specific paths handled
• Import Flexibility: Robust import handling for different execution contexts
• Error Handling: Graceful degradation with user feedback
• Documentation: Comprehensive docstrings and code comments
• Professional Standards: Follows established project patterns and conventions

Future Ready

This implementation provides the foundation for:

• Visual group representation and styling (Story 3.2)
• Group input/output pin generation (Story 3.3)
• Advanced group operations and nesting
• Group persistence in markdown flow format

Integration Notes

• Builds on Epic 2 undo/redo infrastructure
• Leverages existing selection system and context menu patterns
• Compatible with current node types and connection system
• Ready for future Epic 3 story implementations

All acceptance criteria met with comprehensive testing and professional implementation quality.