import { describe, it, expect } from 'vitest';
import {
  formatMinutesAfter,
  toLocalDatetimeInputValue,
  formatElapsedTime,
  clampToDay,
  parseTime,
  formatMinutes,
  getDaysAgo,
  getToday,
} from '../../src/utils/time';

describe('formatMinutesAfter', () => {
  it('converts positive minutes after reference', () => {
    expect(formatMinutesAfter(75, '04:00')).toBe('05:15');
  });

  it('handles zero minutes', () => {
    expect(formatMinutesAfter(0, '04:00')).toBe('04:00');
  });

  it('wraps around midnight for large values', () => {
    expect(formatMinutesAfter(480, '04:00')).toBe('12:00');
  });

  it('handles null input', () => {
    expect(formatMinutesAfter(null, '04:00')).toBe('N/A');
  });

  it('handles negative minutes', () => {
    expect(formatMinutesAfter(-30, '04:00')).toBe('03:30');
  });
});

describe('toLocalDatetimeInputValue', () => {
  it('converts Date to datetime-local format', () => {
    const date = new Date('2024-01-15T21:30:00Z');
    const result = toLocalDatetimeInputValue(date);
    expect(result).toMatch(/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}$/);
  });
});

describe('formatElapsedTime', () => {
  it('formats hours and minutes', () => {
    const twoHoursAgo = new Date(Date.now() - 2 * 60 * 60 * 1000).toISOString();
    expect(formatElapsedTime(twoHoursAgo)).toBe('2h 0m');
  });

  it('formats minutes only', () => {
    const thirtyMinsAgo = new Date(Date.now() - 30 * 60 * 1000).toISOString();
    expect(formatElapsedTime(thirtyMinsAgo)).toBe('30m');
  });
});

describe('clampToDay', () => {
  it('clamps to start of day', () => {
    const date = new Date('2024-01-15T15:30:00');
    const result = clampToDay(date, 'start');
    expect(result.getHours()).toBe(0);
    expect(result.getMinutes()).toBe(0);
  });

  it('clamps to end of day', () => {
    const date = new Date('2024-01-15T15:30:00');
    const result = clampToDay(date, 'end');
    expect(result.getHours()).toBe(23);
    expect(result.getMinutes()).toBe(59);
  });
});

describe('parseTime', () => {
  it('parses HH:MM string to Date', () => {
    const result = parseTime('07:30');
    expect(result.getHours()).toBe(7);
    expect(result.getMinutes()).toBe(30);
  });
});

describe('formatMinutes', () => {
  it('formats hours and minutes', () => {
    expect(formatMinutes(90)).toBe('1h 30m');
  });

  it('formats hours only', () => {
    expect(formatMinutes(120)).toBe('2h');
  });

  it('formats minutes only', () => {
    expect(formatMinutes(45)).toBe('45m');
  });
});

describe('getDaysAgo', () => {
  it('returns date string for N days ago', () => {
    const result = getDaysAgo(7);
    expect(result).toMatch(/^\d{4}-\d{2}-\d{2}$/);
  });
});

describe('getToday', () => {
  it('returns today date string', () => {
    const result = getToday();
    const today = new Date().toISOString().split('T')[0];
    expect(result).toBe(today);
  });
});