stack/GANTT_IMPLEMENTATION_SUMMARY.md

Gantt Chart Implementation Summary

Issue

#15: Implement Gantt Chart Component

• Repository: #15
• Milestone: M3-Features (0.0.3)
• Priority: P0

Implementation Complete ✅

Files Created/Modified

Component Files

1. apps/web/src/components/gantt/GanttChart.tsx (299 lines)

   • Main Gantt chart component
   • Timeline visualization with task bars
   • Status-based color coding
   • Interactive task selection
   • Accessible with ARIA labels

2. apps/web/src/components/gantt/types.ts (95 lines)

   • Type definitions for GanttTask, TimelineRange, etc.
   • Helper functions: toGanttTask(), toGanttTasks()
   • Converts base Task to GanttTask with start/end dates

3. apps/web/src/components/gantt/index.ts (7 lines)

   • Module exports

Test Files

4. apps/web/src/components/gantt/GanttChart.test.tsx (401 lines)

   • 22 comprehensive component tests
   • Tests rendering, interactions, accessibility, edge cases
   • Tests PDA-friendly language

5. apps/web/src/components/gantt/types.test.ts (204 lines)

   • 11 tests for helper functions
   • Tests type conversions and edge cases

Demo Page

6. apps/web/src/app/demo/gantt/page.tsx (316 lines)
   • Interactive demo with sample project data
   • Shows 7 sample tasks with various statuses
   • Task selection and details display
   • Statistics dashboard

Test Results

✓ All 33 tests passing (100%)
  - 22 component tests
  - 11 helper function tests

Coverage: 96.18% (exceeds 85% requirement)
  - GanttChart.tsx: 97.63%
  - types.ts: 91.3%
  - Overall gantt module: 96.18%

Features Implemented

Core Features ✅

• Task name, start date, end date display
• Visual timeline bars
• Status-based color coding
  • Completed: Green
  • In Progress: Blue
  • Paused: Yellow
  • Not Started: Gray
  • Archived: Light Gray
• Interactive task selection (onClick callback)
• Responsive design with customizable height

PDA-Friendly Design ✅

• "Target passed" instead of "OVERDUE"
• "Approaching target" for near-deadline tasks
• Non-judgmental, supportive language throughout

Accessibility ✅

• Proper ARIA labels for all interactive elements
• Keyboard navigation support (Tab + Enter)
• Screen reader friendly
• Semantic HTML structure

Technical Requirements ✅

• Next.js 16 + React 19
• TypeScript with strict typing (NO any types)
• TailwindCSS + Shadcn/ui patterns
• Follows ~/.claude/agent-guides/frontend.md
• Follows ~/.claude/agent-guides/typescript.md

Testing (TDD) ✅

• Tests written FIRST before implementation
• 96.18% coverage (exceeds 85% requirement)
• All edge cases covered
• Accessibility tests included

Dependencies (Stretch Goals)

• Visual dependency lines (planned for future)
• Drag-to-resize task dates (planned for future)

Note: Dependencies infrastructure is in place (tasks can have dependencies array), but visual rendering is not yet implemented. The showDependencies prop is accepted and ready for future implementation.

Integration

The component integrates seamlessly with existing Task model from Prisma:

// Convert existing tasks to Gantt format
import { toGanttTasks } from '@/components/gantt';

const tasks: Task[] = await fetchTasks();
const ganttTasks = toGanttTasks(tasks);

// Use the component
<GanttChart 
  tasks={ganttTasks} 
  onTaskClick={(task) => console.log(task)}
  height={500}
/>

Demo

View the interactive demo at: /demo/gantt

The demo includes:

• 7 sample tasks representing a typical project
• Various task statuses (completed, in-progress, paused, not started)
• Statistics dashboard
• Task selection and detail view
• Toggle for dependencies (UI placeholder)

Git Commit

Branch: feature/15-gantt-chart
Commit: 9ff7718
Message: feat(#15): implement Gantt chart component

Next Steps

1. Merge to develop - Ready for code review
2. Integration testing - Test with real task data from API
3. Future enhancements:
   • Implement visual dependency lines
   • Add drag-to-resize functionality
   • Add task grouping by project
   • Add zoom controls for timeline
   • Add export to image/PDF

Blockers/Decisions

No Blockers ✅

All requirements met without blockers.

Decisions Made:

1. Start/End Dates: Used metadata.startDate for flexibility. If not present, falls back to createdAt. This avoids schema changes while supporting proper Gantt visualization.

2. Dependencies: Stored in metadata.dependencies as string array. Visual rendering deferred to future enhancement.

3. Timeline Range: Auto-calculated from task dates with 5% padding for better visualization.

4. Color Scheme: Based on existing TaskItem component patterns for consistency.

5. Accessibility: Full ARIA support with keyboard navigation as first-class feature.

Summary

✅ Complete - Gantt chart component fully implemented with:

• 96.18% test coverage (33 tests passing)
• PDA-friendly language
• Full accessibility support
• Interactive demo page
• Production-ready code
• Strict TypeScript (no any types)
• Follows all coding standards

Ready for code review and merge to develop.