import { describe, expect, test, beforeAll, afterAll } from 'bun:test'
import { formatBriefTimestamp } from '../formatBriefTimestamp'

let savedLcAll: string | undefined
beforeAll(() => {
  savedLcAll = process.env.LC_ALL
  process.env.LC_ALL = 'en_US.UTF-8'
})
afterAll(() => {
  if (savedLcAll === undefined) delete process.env.LC_ALL
  else process.env.LC_ALL = savedLcAll
})

describe('formatBriefTimestamp', () => {
  // Fixed "now" for deterministic tests: 2026-04-02T14:00:00Z (Thursday)
  const now = new Date('2026-04-02T14:00:00Z')

  test('same day timestamp returns time only (contains colon)', () => {
    const result = formatBriefTimestamp('2026-04-02T10:30:00Z', now)
    expect(result).toContain(':')
    // Should NOT contain a weekday name since it's the same day
    expect(result).not.toMatch(
      /Monday|Tuesday|Wednesday|Thursday|Friday|Saturday|Sunday/,
    )
  })

  test('yesterday returns weekday and time', () => {
    // 2026-04-01 is Wednesday
    const result = formatBriefTimestamp('2026-04-01T16:15:00Z', now)
    expect(result).toContain('Wednesday')
    expect(result).toContain(':')
  })

  test('3 days ago returns weekday and time', () => {
    // 2026-03-30 is Monday
    const result = formatBriefTimestamp('2026-03-30T09:00:00Z', now)
    expect(result).toContain('Monday')
    expect(result).toContain(':')
  })

  test('6 days ago returns weekday and time (still within 6-day window)', () => {
    // 2026-03-27 is Friday
    const result = formatBriefTimestamp('2026-03-27T12:00:00Z', now)
    expect(result).toContain('Friday')
    expect(result).toContain(':')
  })

  test('7+ days ago returns weekday, month, day, and time', () => {
    // 2026-03-20 is Friday, 13 days ago
    const result = formatBriefTimestamp('2026-03-20T14:30:00Z', now)
    expect(result).toContain('Friday')
    expect(result).toContain(':')
    // Should contain month abbreviation (Mar)
    expect(result).toMatch(/Mar/)
  })

  test('much older date returns full format with month', () => {
    const result = formatBriefTimestamp('2025-12-25T08:00:00Z', now)
    expect(result).toContain(':')
    expect(result).toMatch(/Dec/)
  })

  test('invalid ISO string returns empty string', () => {
    expect(formatBriefTimestamp('not-a-date', now)).toBe('')
  })

  test('empty string returns empty string', () => {
    expect(formatBriefTimestamp('', now)).toBe('')
  })

  test('same day early morning returns time format', () => {
    const result = formatBriefTimestamp('2026-04-02T01:05:00Z', now)
    expect(result).toContain(':')
    // Should be time-only format
    expect(result.length).toBeLessThan(20)
  })

  test('uses current time as default when now is not provided', () => {
    // Just verify it returns a non-empty string for a recent timestamp
    const recent = new Date()
    recent.setMinutes(recent.getMinutes() - 5)
    const result = formatBriefTimestamp(recent.toISOString())
    expect(result).not.toBe('')
    expect(result).toContain(':')
  })
})