aicyclingcoach-go/mode-ascii_chart_visualization.md

ASCII Chart Visualization Mode Rules

Core Principles

• Charts must render efficiently with minimal terminal flickering
• Support datasets up to 10,000 points with smooth downsampling
• Responsive to terminal resize events
• Consistent styling with lipgloss
• Graceful degradation for terminals with limited width/height

Implementation Guidelines

Data Processing

1. Downsample large datasets using Largest-Triangle-Three-Buckets algorithm
2. Normalize values to terminal height minus chart margins
3. Handle missing data points gracefully (interpolate or skip)

Rendering

• Use Unicode block characters (▁▂▃▄▅▆▇█) for vertical resolution
• Implement horizontal scaling based on terminal width
• Add axis labels with metric units and scale indicators
• Color-code different metrics:
  • Heart Rate: Red
  • Power: Yellow
  • Elevation: Cyan

Performance Optimization

• Pre-calculate downsampled data when possible
• Limit re-rendering to when data changes or terminal resizes
• Use efficient string building with strings.Builder
• Implement rendering caching for static charts

Error Handling

• Display "No Data" message when dataset is empty
• Show "Rendering Error" with details in debug mode
• Handle terminal size too small with informative message

Testing Requirements

• 90% test coverage for chart logic
• Golden tests for various chart configurations
• Performance benchmarks for downsampling and rendering
• Edge case tests: single point, empty data, negative values

Required Components

1. Downsampling module (internal/types/downsample.go)
2. Chart component (internal/tui/components/chart.go)
3. Chart model for state management
4. Integration with activity detail screen (internal/tui/screens/activity_detail.go)

Integration Example

// In activity_detail.go
func (m *ActivityDetailModel) renderCharts() string {
    hrChart := components.NewChart(m.activity.HRData, "HR (bpm)")
    powerChart := components.NewChart(m.activity.PowerData, "Power (w)")
    elevationChart := components.NewChart(m.activity.ElevationData, "Elevation (m)")
    
    return lipgloss.JoinVertical(
        lipgloss.Left,
        hrChart.View(),
        powerChart.View(),
        elevationChart.View(),
    )
}

Dependencies

• Requires populated activity data model
• Relies on downsampling functionality
• Uses terminal dimensions from bubbletea

Quality Standards

• Zero memory leaks
• Handle datasets up to 10,000 points efficiently
• Responsive rendering (<100ms for full redraw)
• Accessible color schemes
• Comprehensive test coverage