feat: add terminal chart visualization for financial data

src/utils/charts.test.ts

@@ -0,0 +1,255 @@
+import { describe, expect, test } from 'bun:test';
+import {
+  formatCompactNumber,
+  parseNumericValue,
+  detectChartOpportunity,
+  renderBarChart,
+  renderSparkline,
+  transformChartsInResponse,
+} from './charts.js';
+
+describe('formatCompactNumber', () => {
+  test('formats billions', () => {
+    expect(formatCompactNumber(394_300_000_000)).toBe('$394.3B');
+  });
+
+  test('formats millions', () => {
+    expect(formatCompactNumber(1_200_000)).toBe('$1.2M');
+  });
+
+  test('formats thousands', () => {
+    expect(formatCompactNumber(45_000)).toBe('$45K');
+  });
+
+  test('formats small numbers without suffix', () => {
+    expect(formatCompactNumber(999)).toBe('$999');
+  });
+
+  test('formats whole billions without decimal', () => {
+    expect(formatCompactNumber(2_000_000_000)).toBe('$2B');
+  });
+
+  test('formats trillions', () => {
+    expect(formatCompactNumber(1_500_000_000_000)).toBe('$1.5T');
+  });
+
+  test('handles negative values', () => {
+    expect(formatCompactNumber(-500_000_000)).toBe('$-500M');
+  });
+});
+
+describe('parseNumericValue', () => {
+  test('parses plain number', () => {
+    expect(parseNumericValue('1234')).toBe(1234);
+  });
+
+  test('parses dollar amount with commas', () => {
+    expect(parseNumericValue('$1,234,567')).toBe(1234567);
+  });
+
+  test('parses value with B suffix', () => {
+    expect(parseNumericValue('$394.3B')).toBe(394_300_000_000);
+  });
+
+  test('parses value with M suffix', () => {
+    expect(parseNumericValue('$1.2M')).toBe(1_200_000);
+  });
+
+  test('parses value with K suffix', () => {
+    expect(parseNumericValue('45K')).toBe(45_000);
+  });
+
+  test('returns null for non-numeric text', () => {
+    expect(parseNumericValue('Apple')).toBeNull();
+  });
+
+  test('returns null for empty string', () => {
+    expect(parseNumericValue('')).toBeNull();
+  });
+
+  test('parses negative with parentheses', () => {
+    const result = parseNumericValue('($500M)');
+    expect(result).toBe(-500_000_000);
+  });
+});
+
+describe('detectChartOpportunity', () => {
+  test('detects bar chart for label + value columns', () => {
+    const headers = ['Company', 'Revenue'];
+    const rows = [
+      ['Apple', '$394.3B'],
+      ['Google', '$307.4B'],
+      ['Microsoft', '$245.1B'],
+    ];
+    const result = detectChartOpportunity(headers, rows);
+    expect(result).not.toBeNull();
+    expect(result!.type).toBe('bar');
+    expect(result!.data.labels).toEqual(['Apple', 'Google', 'Microsoft']);
+  });
+
+  test('detects sparkline for date + value columns', () => {
+    const headers = ['Year', 'Revenue'];
+    const rows = [
+      ['2020', '$274.5B'],
+      ['2021', '$365.8B'],
+      ['2022', '$394.3B'],
+    ];
+    const result = detectChartOpportunity(headers, rows);
+    expect(result).not.toBeNull();
+    expect(result!.type).toBe('sparkline');
+  });
+
+  test('detects sparkline for quarter dates', () => {
+    const headers = ['Period', 'EPS'];
+    const rows = [
+      ['Q1 2024', '$1.50'],
+      ['Q2 2024', '$1.62'],
+      ['Q3 2024', '$1.78'],
+    ];
+    const result = detectChartOpportunity(headers, rows);
+    expect(result).not.toBeNull();
+    expect(result!.type).toBe('sparkline');
+  });
+
+  test('returns null for single row', () => {
+    const result = detectChartOpportunity(['A', 'B'], [['x', '1']]);
+    expect(result).toBeNull();
+  });
+
+  test('returns null for non-numeric data', () => {
+    const headers = ['Name', 'Status'];
+    const rows = [
+      ['Alice', 'Active'],
+      ['Bob', 'Inactive'],
+    ];
+    expect(detectChartOpportunity(headers, rows)).toBeNull();
+  });
+
+  test('returns null for single column', () => {
+    expect(detectChartOpportunity(['A'], [['x'], ['y']])).toBeNull();
+  });
+});
+
+describe('renderBarChart', () => {
+  test('renders non-empty output', () => {
+    const result = renderBarChart({
+      labels: ['Apple', 'Google', 'MSFT'],
+      values: [394.3e9, 307.4e9, 245.1e9],
+      header: 'Company',
+      valueHeader: 'Revenue',
+    });
+    expect(result).toContain('📊');
+    expect(result).toContain('Revenue');
+    expect(result).toContain('Apple');
+    expect(result).toContain('Google');
+    expect(result).toContain('MSFT');
+  });
+
+  test('returns empty string for empty data', () => {
+    expect(renderBarChart({ labels: [], values: [], header: '', valueHeader: '' })).toBe('');
+  });
+
+  test('returns empty string when all values are zero', () => {
+    expect(
+      renderBarChart({ labels: ['A', 'B'], values: [0, 0], header: '', valueHeader: 'X' }),
+    ).toBe('');
+  });
+
+  test('truncates long labels', () => {
+    const result = renderBarChart({
+      labels: ['A very long company name here'],
+      values: [100],
+      header: 'Name',
+      valueHeader: 'Val',
+    });
+    // Label should be truncated to 16 chars
+    expect(result.length).toBeGreaterThan(0);
+  });
+});
+
+describe('renderSparkline', () => {
+  test('renders trend with start/end values', () => {
+    const result = renderSparkline({
+      labels: ['2020', '2021', '2022', '2023', '2024'],
+      values: [274.5e9, 365.8e9, 394.3e9, 383.3e9, 391e9],
+      header: 'Year',
+      valueHeader: 'AAPL Revenue',
+    });
+    expect(result).toContain('📈');
+    expect(result).toContain('AAPL Revenue');
+    expect(result).toContain('2020');
+    expect(result).toContain('2024');
+    expect(result).toContain('→');
+  });
+
+  test('shows positive change in green', () => {
+    const result = renderSparkline({
+      labels: ['2020', '2024'],
+      values: [100, 200],
+      header: 'Year',
+      valueHeader: 'Revenue',
+    });
+    expect(result).toContain('+');
+  });
+
+  test('returns empty for single data point', () => {
+    expect(
+      renderSparkline({ labels: ['2024'], values: [100], header: '', valueHeader: '' }),
+    ).toBe('');
+  });
+
+  test('handles first value of zero without crashing', () => {
+    const result = renderSparkline({
+      labels: ['2020', '2024'],
+      values: [0, 100],
+      header: 'Year',
+      valueHeader: 'Revenue',
+    });
+    expect(result).toContain('+0.0%');
+  });
+});
+
+describe('transformChartsInResponse', () => {
+  test('appends bar chart below a qualifying table', () => {
+    const markdown = [
+      '| Company | Revenue |',
+      '|---------|---------|',
+      '| Apple | $394.3B |',
+      '| Google | $307.4B |',
+      '| MSFT | $245.1B |',
+    ].join('\n');
+
+    const result = transformChartsInResponse(markdown);
+    expect(result).toContain('📊');
+    expect(result).toContain(markdown); // original table preserved
+  });
+
+  test('appends sparkline for time-series table', () => {
+    const markdown = [
+      '| Year | Revenue |',
+      '|------|---------|',
+      '| 2020 | $274.5B |',
+      '| 2021 | $365.8B |',
+      '| 2022 | $394.3B |',
+    ].join('\n');
+
+    const result = transformChartsInResponse(markdown);
+    expect(result).toContain('📈');
+  });
+
+  test('does not modify text without tables', () => {
+    const text = 'Hello world, no tables here.';
+    expect(transformChartsInResponse(text)).toBe(text);
+  });
+
+  test('does not modify non-chartable tables', () => {
+    const markdown = [
+      '| Name | Status |',
+      '|------|--------|',
+      '| Alice | Active |',
+      '| Bob | Inactive |',
+    ].join('\n');
+
+    expect(transformChartsInResponse(markdown)).toBe(markdown);
+  });
+});