import { describe, expect, test } from 'bun:test'
import {
  formatFileSize,
  formatSecondsShort,
  formatDuration,
  formatNumber,
  formatTokens,
  formatRelativeTime,
  formatRelativeTimeAgo,
  formatLogMetadata,
} from '../format'

describe('formatFileSize', () => {
  test('formats bytes', () => {
    expect(formatFileSize(500)).toBe('500 bytes')
  })

  test('formats kilobytes', () => {
    expect(formatFileSize(1536)).toBe('1.5KB')
  })

  test('formats megabytes', () => {
    expect(formatFileSize(1.5 * 1024 * 1024)).toBe('1.5MB')
  })

  test('formats gigabytes', () => {
    expect(formatFileSize(2 * 1024 * 1024 * 1024)).toBe('2GB')
  })

  test('removes trailing .0', () => {
    expect(formatFileSize(1024)).toBe('1KB')
  })
})

describe('formatSecondsShort', () => {
  test('formats milliseconds to seconds', () => {
    expect(formatSecondsShort(1234)).toBe('1.2s')
  })

  test('formats zero', () => {
    expect(formatSecondsShort(0)).toBe('0.0s')
  })

  test('formats sub-second', () => {
    expect(formatSecondsShort(500)).toBe('0.5s')
  })
})

describe('formatDuration', () => {
  test('formats 0 as 0s', () => {
    expect(formatDuration(0)).toBe('0s')
  })

  test('formats seconds', () => {
    expect(formatDuration(5000)).toBe('5s')
  })

  test('formats minutes and seconds', () => {
    expect(formatDuration(125000)).toBe('2m 5s')
  })

  test('formats hours', () => {
    expect(formatDuration(3661000)).toBe('1h 1m 1s')
  })

  test('formats days', () => {
    expect(formatDuration(90000000)).toBe('1d 1h 0m')
  })

  test('hideTrailingZeros removes zero components', () => {
    expect(formatDuration(3600000, { hideTrailingZeros: true })).toBe('1h')
    expect(formatDuration(60000, { hideTrailingZeros: true })).toBe('1m')
  })

  test('mostSignificantOnly returns largest unit', () => {
    expect(formatDuration(90000000, { mostSignificantOnly: true })).toBe('1d')
    expect(formatDuration(3661000, { mostSignificantOnly: true })).toBe('1h')
  })
})

describe('formatNumber', () => {
  test('formats small numbers as-is', () => {
    expect(formatNumber(900)).toBe('900')
  })

  test('formats thousands with k suffix', () => {
    expect(formatNumber(1321)).toBe('1.3k')
  })

  test('formats millions', () => {
    expect(formatNumber(1500000)).toBe('1.5m')
  })

  test('formats 0 as-is', () => {
    expect(formatNumber(0)).toBe('0')
  })

  test('formats billions', () => {
    expect(formatNumber(1500000000)).toBe('1.5b')
  })
})

describe('formatTokens', () => {
  test('removes .0 from formatted number', () => {
    expect(formatTokens(1000)).toBe('1k')
  })

  test('formats small numbers', () => {
    expect(formatTokens(500)).toBe('500')
  })

  test('formats 1000 without .0', () => {
    expect(formatTokens(1000)).toBe('1k')
  })

  test('formats 1500 as 1.5k', () => {
    expect(formatTokens(1500)).toBe('1.5k')
  })
})

describe('formatRelativeTime', () => {
  const now = new Date('2026-01-15T12:00:00Z')

  test('formats seconds ago', () => {
    const date = new Date('2026-01-15T11:59:30Z')
    expect(formatRelativeTime(date, { now })).toBe('30s ago')
  })

  test('formats minutes ago', () => {
    const date = new Date('2026-01-15T11:55:00Z')
    expect(formatRelativeTime(date, { now })).toBe('5m ago')
  })

  test('formats future time', () => {
    const date = new Date('2026-01-15T13:00:00Z')
    expect(formatRelativeTime(date, { now })).toBe('in 1h')
  })

  test('handles zero difference', () => {
    expect(formatRelativeTime(now, { now })).toBe('0s ago')
  })

  test('formats hours ago', () => {
    const date = new Date('2026-01-15T09:00:00Z')
    expect(formatRelativeTime(date, { now })).toBe('3h ago')
  })

  test('formats days ago', () => {
    const date = new Date('2026-01-13T12:00:00Z')
    expect(formatRelativeTime(date, { now })).toBe('2d ago')
  })

  test('formats weeks ago', () => {
    const date = new Date('2026-01-01T12:00:00Z')
    expect(formatRelativeTime(date, { now })).toBe('2w ago')
  })
})

describe('formatRelativeTimeAgo', () => {
  const now = new Date('2026-01-15T12:00:00Z')

  test("formats past date with 'ago' suffix", () => {
    const date = new Date('2026-01-15T11:59:30Z')
    const result = formatRelativeTimeAgo(date, { now })
    expect(result).toBe('30s ago')
  })

  test("formats future date without 'ago' suffix", () => {
    const date = new Date('2026-01-15T13:00:00Z')
    const result = formatRelativeTimeAgo(date, { now })
    expect(result).toBe('in 1h')
  })

  test('formats minutes ago', () => {
    const date = new Date('2026-01-15T11:55:00Z')
    const result = formatRelativeTimeAgo(date, { now })
    expect(result).toBe('5m ago')
  })

  test('formats hours ago', () => {
    const date = new Date('2026-01-15T09:00:00Z')
    const result = formatRelativeTimeAgo(date, { now })
    expect(result).toBe('3h ago')
  })

  test('formats days ago', () => {
    const date = new Date('2026-01-13T12:00:00Z')
    const result = formatRelativeTimeAgo(date, { now })
    expect(result).toBe('2d ago')
  })

  test('handles date equal to now as past', () => {
    // date === now, treated as past (not future)
    const result = formatRelativeTimeAgo(now, { now })
    expect(result).toBe('0s ago')
  })

  test('uses numeric always for past dates', () => {
    // Should always use numeric format for past dates
    const date = new Date('2026-01-15T11:59:00Z')
    const result = formatRelativeTimeAgo(date, { now })
    expect(result).toContain('ago')
  })

  test("future date does not contain 'ago'", () => {
    const date = new Date('2026-01-15T14:00:00Z')
    const result = formatRelativeTimeAgo(date, { now })
    expect(result).not.toContain('ago')
  })
})

describe('formatLogMetadata', () => {
  // Use a date very recently in the past so it always shows "Xs ago" or similar
  const modified = new Date(Date.now() - 5 * 60 * 1000) // 5 minutes ago

  test('includes relative time and message count', () => {
    const result = formatLogMetadata({
      modified,
      messageCount: 10,
    })
    expect(result).toContain('ago')
    expect(result).toContain('10 messages')
  })

  test('uses fileSize instead of messageCount when provided', () => {
    const result = formatLogMetadata({
      modified,
      messageCount: 5,
      fileSize: 1536,
    })
    expect(result).toContain('1.5KB')
    expect(result).not.toContain('messages')
  })

  test('includes gitBranch when provided', () => {
    const result = formatLogMetadata({
      modified,
      messageCount: 3,
      gitBranch: 'main',
    })
    expect(result).toContain('main')
  })

  test('omits gitBranch when not provided', () => {
    const result = formatLogMetadata({
      modified,
      messageCount: 3,
    })
    // Should not have a dangling separator from missing branch
    expect(result).not.toMatch(/^ · | · $/)
  })

  test('includes tag when provided', () => {
    const result = formatLogMetadata({
      modified,
      messageCount: 3,
      tag: 'my-tag',
    })
    expect(result).toContain('#my-tag')
  })

  test('includes agentSetting when provided', () => {
    const result = formatLogMetadata({
      modified,
      messageCount: 3,
      agentSetting: 'custom-agent',
    })
    expect(result).toContain('@custom-agent')
  })

  test('includes prNumber when provided', () => {
    const result = formatLogMetadata({
      modified,
      messageCount: 3,
      prNumber: 42,
    })
    expect(result).toContain('#42')
  })

  test('includes prRepository with prNumber when both provided', () => {
    const result = formatLogMetadata({
      modified,
      messageCount: 3,
      prNumber: 99,
      prRepository: 'owner/repo',
    })
    expect(result).toContain('owner/repo#99')
  })

  test("parts are joined with ' · ' separator", () => {
    const result = formatLogMetadata({
      modified,
      messageCount: 5,
      gitBranch: 'feat/x',
    })
    expect(result).toContain(' · ')
  })
})