import { describe, it, expect, beforeEach } from 'vitest';
import { renderHeatmap } from '../src/heatmap';
import type { HeatmapData } from '../src/types';

function makeMockData(overrides: Partial<HeatmapData> = {}): HeatmapData {
  return {
    days: [
      { date: '2025-01-06', hours: 2.5, count: 3 },
      { date: '2025-01-07', hours: 5.0, count: 5 },
      { date: '2025-01-08', hours: 1.0, count: 1 },
      { date: '2025-01-13', hours: 8.0, count: 4 },
      { date: '2025-01-20', hours: 3.5, count: 2 },
    ],
    range: {
      begin: '2025-01-01',
      end: '2025-01-31',
    },
    ...overrides,
  };
}

describe('renderHeatmap', () => {
  let container: HTMLDivElement;

  beforeEach(() => {
    container = document.createElement('div');
    document.body.appendChild(container);
  });

  it('renders an SVG element', () => {
    renderHeatmap(container, makeMockData());
    const svg = container.querySelector('svg');
    expect(svg).not.toBeNull();
  });

  it('renders correct number of rect elements for date range', () => {
    renderHeatmap(container, makeMockData());
    const rects = container.querySelectorAll('rect.heatmap-cell');
    // Jan 1 to Jan 31 = 31 days
    expect(rects.length).toBe(31);
  });

  it('applies heatmap-empty class to cells with no data', () => {
    renderHeatmap(container, makeMockData());
    const emptyRects = container.querySelectorAll('rect.heatmap-empty');
    // 31 days total, 5 with data = 26 empty
    expect(emptyRects.length).toBe(26);
  });

  it('applies fill attribute to cells with data', () => {
    renderHeatmap(container, makeMockData());
    const allRects = container.querySelectorAll('rect.heatmap-cell:not(.heatmap-empty)');
    expect(allRects.length).toBe(5);
    allRects.forEach((rect) => {
      expect(rect.getAttribute('fill')).toBeTruthy();
    });
  });

  it('renders day labels (Mon, Wed, Fri)', () => {
    renderHeatmap(container, makeMockData());
    const dayLabels = container.querySelectorAll('text.day-label');
    expect(dayLabels.length).toBe(7); // all 7 slots rendered
    const texts = Array.from(dayLabels).map((el) => el.textContent);
    expect(texts).toContain('Mon');
    expect(texts).toContain('Wed');
    expect(texts).toContain('Fri');
  });

  it('renders month labels', () => {
    // Use a range spanning two months
    const data = makeMockData({
      range: { begin: '2025-01-01', end: '2025-02-28' },
      days: [
        { date: '2025-01-15', hours: 3.0, count: 2 },
        { date: '2025-02-10', hours: 4.0, count: 1 },
      ],
    });
    renderHeatmap(container, data);
    const monthLabels = container.querySelectorAll('text.month-label');
    expect(monthLabels.length).toBeGreaterThan(0);
    const texts = Array.from(monthLabels).map((el) => el.textContent);
    expect(texts).toContain('Feb');
  });

  it('creates tooltip on mouseenter', () => {
    renderHeatmap(container, makeMockData());
    const rect = container.querySelector(
      'rect.heatmap-cell:not(.heatmap-empty)',
    );
    expect(rect).not.toBeNull();

    // Simulate mouseenter
    const event = new MouseEvent('mouseenter', { bubbles: true });
    // jsdom getBoundingClientRect returns zeros, which is fine for structure test
    rect!.dispatchEvent(event);

    const tooltip = document.body.querySelector('.heatmap-tooltip') as HTMLDivElement;
    expect(tooltip).not.toBeNull();
    expect(tooltip.style.display).toBe('block');
    expect(tooltip.innerHTML).toContain('h');
    expect(tooltip.innerHTML).toContain('entries');
  });

  it('hides tooltip on mouseleave', () => {
    renderHeatmap(container, makeMockData());
    const rect = container.querySelector(
      'rect.heatmap-cell:not(.heatmap-empty)',
    );

    rect!.dispatchEvent(new MouseEvent('mouseenter', { bubbles: true }));
    rect!.dispatchEvent(new MouseEvent('mouseleave', { bubbles: true }));

    const tooltip = document.body.querySelector('.heatmap-tooltip') as HTMLDivElement;
    expect(tooltip.style.display).toBe('none');
  });

  it('handles empty days array gracefully', () => {
    renderHeatmap(container, makeMockData({ days: [] }));
    const svg = container.querySelector('svg');
    expect(svg).toBeNull();
    expect(container.textContent).toContain('No tracking data available');
  });

  it('only renders cells within the begin/end range', () => {
    const data: HeatmapData = {
      days: [
        { date: '2025-03-01', hours: 2.0, count: 1 },
        { date: '2025-03-05', hours: 4.0, count: 2 },
      ],
      range: { begin: '2025-03-01', end: '2025-03-07' },
    };
    renderHeatmap(container, data);
    const rects = container.querySelectorAll('rect.heatmap-cell');
    expect(rects.length).toBe(7);
  });
});