import { describe, it, expect } from 'vitest';
import { buildDateMap, generateCells, getWeekInterval } from '../src/shared/date-utils';
import { timeMonday, timeSunday } from 'd3-time';
import type { DayEntry } from '../src/types';

describe('date-utils', () => {
  const days: DayEntry[] = [
    { date: '2025-01-06', hours: 4, count: 2 },
    { date: '2025-01-07', hours: 2, count: 1 },
  ];

  describe('buildDateMap', () => {
    it('creates Map keyed by date string', () => {
      const map = buildDateMap(days);
      expect(map).toBeInstanceOf(Map);
      expect(map.size).toBe(2);
      expect(map.get('2025-01-06')).toEqual(days[0]);
      expect(map.get('2025-01-07')).toEqual(days[1]);
      expect(map.get('2025-01-08')).toBeUndefined();
    });
  });

  describe('getWeekInterval', () => {
    it('returns timeMonday for monday', () => {
      expect(getWeekInterval('monday')).toBe(timeMonday);
    });

    it('returns timeSunday for sunday', () => {
      expect(getWeekInterval('sunday')).toBe(timeSunday);
    });
  });

  describe('generateCells', () => {
    it('returns correct count for a 7-day range', () => {
      const begin = new Date('2025-01-06'); // Monday
      const end = new Date('2025-01-12');   // Sunday
      const map = buildDateMap(days);
      const cells = generateCells(begin, end, map, 'monday');
      expect(cells.length).toBe(7);
    });

    it('marks weekend cells correctly', () => {
      const begin = new Date('2025-01-06');
      const end = new Date('2025-01-12');
      const map = buildDateMap(days);
      const cells = generateCells(begin, end, map, 'monday');
      const weekendCells = cells.filter(c => c.isWeekend);
      expect(weekendCells.length).toBe(2); // Saturday + Sunday
    });

    it('links entries from dateMap', () => {
      const begin = new Date('2025-01-06');
      const end = new Date('2025-01-08');
      const map = buildDateMap(days);
      const cells = generateCells(begin, end, map, 'monday');
      expect(cells[0].entry).toEqual(days[0]);
      expect(cells[1].entry).toEqual(days[1]);
      expect(cells[2].entry).toBeNull();
    });
  });
});