MCP ASCII Charts

import { ChartData, ChartResult } from '../types/index.js'; import { colorize } from '../utils/colors.js'; import { ASCII_CHARS, normalize, createGrid, gridToString, center, padLeft } from '../utils/ascii.js'; export interface HistogramOptions { bins?: number; showFrequency?: boolean; } interface HistogramBin { min: number; max: number; count: number; frequency: number; } export function createHistogram(data: ChartData, options: HistogramOptions = {}): ChartResult { const { data: values, title, width = 60, height = 15, color = 'white' } = data; const { bins = 10, showFrequency = true } = options; if (values.length === 0) { throw new Error('Data array cannot be empty'); } // Calculate histogram bins const histogramBins = calculateHistogramBins(values, bins); const maxCount = Math.max(...histogramBins.map(bin => bin.count)); const chartWidth = width - 12; // Reserve space for y-axis labels const chartHeight = height - 3; // Reserve space for x-axis and title // Create the chart grid const grid = createGrid(width, height); // Draw y-axis labels (counts or frequencies) for (let y = 0; y < chartHeight; y++) { const value = maxCount - (y / (chartHeight - 1)) * maxCount; const label = showFrequency ? ((value / values.length) * 100).toFixed(1) + '%' : Math.round(value).toString(); const labelStr = padLeft(label, 10); // Place y-axis label for (let i = 0; i < Math.min(labelStr.length, 10); i++) { if (10 - i < width) { grid[y][10 - i] = labelStr[i]; } } // Draw y-axis line if (11 < width) { grid[y][11] = y === chartHeight - 1 ? ASCII_CHARS.bottomLeft : y === 0 ? ASCII_CHARS.topLeft : ASCII_CHARS.teeRight; } // Draw horizontal grid lines for (let x = 12; x < width; x++) { if (y === chartHeight - 1) { grid[y][x] = ASCII_CHARS.horizontal; } else if (y % 2 === 0) { grid[y][x] = '·'; // Light grid dots } } } // Draw histogram bars const barWidth = Math.max(1, Math.floor(chartWidth / histogramBins.length)); for (let i = 0; i < histogramBins.length; i++) { const bin = histogramBins[i]; const barStartX = 12 + Math.floor(i * chartWidth / histogramBins.length); const normalizedCount = maxCount === 0 ? 0 : normalize(bin.count, 0, maxCount); const barHeight = Math.floor(normalizedCount * chartHeight); // Draw bar from bottom up for (let y = 0; y < barHeight; y++) { const gridY = chartHeight - 1 - y; if (gridY >= 0 && gridY < chartHeight) { for (let x = 0; x < barWidth && barStartX + x < width; x++) { grid[gridY][barStartX + x] = ASCII_CHARS.fullBlock; } } } // Add count/frequency on top of bar if space allows if (barHeight < chartHeight - 1) { const valueStr = showFrequency ? ((bin.count / values.length) * 100).toFixed(0) : bin.count.toString(); const valueY = chartHeight - barHeight - 1; if (valueY >= 0 && valueY < chartHeight) { for (let j = 0; j < valueStr.length && barStartX + j < width; j++) { grid[valueY][barStartX + j] = valueStr[j]; } } } } // Draw x-axis labels (bin ranges) for (let i = 0; i < Math.min(histogramBins.length, 6); i++) { // Limit labels to avoid crowding const bin = histogramBins[i]; const barStartX = 12 + Math.floor(i * chartWidth / histogramBins.length); const labelY = height - 1; // Create range label const rangeLabel = `${bin.min.toFixed(1)}-${bin.max.toFixed(1)}`; const label = rangeLabel.substring(0, Math.min(rangeLabel.length, barWidth + 2)); if (labelY >= 0) { for (let j = 0; j < label.length && barStartX + j < width; j++) { grid[labelY][barStartX + j] = label[j]; } } } // Convert grid to string and apply coloring let chart = gridToString(grid); if (color !== 'white') { chart = colorize(chart, color); } // Add title and statistics let result = ''; if (title) { result += center(title, width) + '\n'; } result += chart; // Add summary statistics const mean = values.reduce((a, b) => a + b, 0) / values.length; const sortedValues = [...values].sort((a, b) => a - b); const median = sortedValues.length % 2 === 0 ? (sortedValues[sortedValues.length / 2 - 1] + sortedValues[sortedValues.length / 2]) / 2 : sortedValues[Math.floor(sortedValues.length / 2)]; const statsLine = `n=${values.length}, μ=${mean.toFixed(2)}, median=${median.toFixed(2)}`; result += '\n' + center(statsLine, width); return { chart: result, title, dimensions: { width, height: height + 1 } // Account for stats line }; } function calculateHistogramBins(values: number[], numBins: number): HistogramBin[] { const minValue = Math.min(...values); const maxValue = Math.max(...values); const range = maxValue - minValue; const binWidth = range / numBins; const bins: HistogramBin[] = []; // Create bins for (let i = 0; i < numBins; i++) { const min = minValue + i * binWidth; const max = i === numBins - 1 ? maxValue : minValue + (i + 1) * binWidth; bins.push({ min, max, count: 0, frequency: 0 }); } // Count values in each bin for (const value of values) { for (let i = 0; i < bins.length; i++) { const bin = bins[i]; if (value >= bin.min && (value <= bin.max || (i === bins.length - 1 && value === bin.max))) { bin.count++; break; } } } // Calculate frequencies for (const bin of bins) { bin.frequency = bin.count / values.length; } return bins; }