Function printCalendarHeatmap

apps/cli/src/utils/format.ts:275–388

(
  data: CalendarDay[],
  options?: { label?: string; title?: string },
)

 * Each column is a week, rows are weekdays (Mon-Sun).
 */
export function printCalendarHeatmap(
  data: CalendarDay[],
  options?: { label?: string; title?: string },
) {
  if (data.length === 0) return;

  // Build a value map
  const valueMap = new Map<string, number>();
  let maxVal = 0;
  for (const d of data) {
    valueMap.set(d.day, d.value);
    if (d.value > maxVal) maxVal = d.value;
  }

  // Determine date range - pad to full weeks
  const sorted = [...data].sort((a, b) => a.day.localeCompare(b.day));
  const firstDate = new Date(sorted[0].day);
  const lastDate = new Date(sorted.at(-1).day);

  // Adjust to start on Monday
  const startDay = firstDate.getDay(); // 0=Sun, 1=Mon, ...
  const mondayOffset = startDay === 0 ? 6 : startDay - 1;
  const start = new Date(firstDate);
  start.setDate(start.getDate() - mondayOffset);

  // Adjust to end on Sunday
  const endDay = lastDate.getDay();
  const sundayOffset = endDay === 0 ? 0 : 7 - endDay;
  const end = new Date(lastDate);
  end.setDate(end.getDate() + sundayOffset);

  // Build grid: 7 rows (Mon-Sun) x N weeks
  const weeks: string[][] = [];
  const current = new Date(start);
  let weekCol: string[] = [];

  while (current <= end) {
    const key = current.toISOString().slice(0, 10);
    const val = valueMap.get(key) || 0;

    // Quantize to block level
    let level: number;
    if (val === 0) {
      level = 0;
    } else if (maxVal > 0) {
      level = Math.ceil((val / maxVal) * 4);
      if (level < 1) level = 1;
      if (level > 4) level = 4;
    } else {
      level = 0;
    }

    // Color the block
    const block = HEATMAP_BLOCKS[level];
    const colored = level > 0 ? pc.green(block) : pc.dim(block);

    weekCol.push(colored);