import { describe, expect, it } from 'vitest'

import {
  buildCompactMetaLabel,
  filenameFromUrl,
  formatFileSize,
  getFileExtensionLabel,
} from './fileMeta'

describe('formatFileSize', () => {
  it('formats sub-kilobyte sizes as bytes', () => {
    expect(formatFileSize(0)).toBe('0 B')
    expect(formatFileSize(512)).toBe('512 B')
  })

  it('formats kilobytes / megabytes / gigabytes with sensible precision', () => {
    expect(formatFileSize(1024)).toBe('1.0 KB')
    expect(formatFileSize(388_658)).toBe('379.5 KB')
    expect(formatFileSize(2_457_600)).toBe('2.34 MB')
    expect(formatFileSize(1024 ** 3)).toBe('1.00 GB')
  })

  it('returns empty string for invalid input', () => {
    expect(formatFileSize(NaN)).toBe('')
    expect(formatFileSize(Infinity)).toBe('')
    expect(formatFileSize(-1)).toBe('')
  })

  it('handles unit boundaries without crossing into the next unit early', () => {
    expect(formatFileSize(1023)).toBe('1023 B')
    expect(formatFileSize(1024 * 1024 - 1)).toBe('1024.0 KB')
    expect(formatFileSize(1024 * 1024)).toBe('1.00 MB')
    expect(formatFileSize(1024 ** 3 - 1)).toBe('1024.00 MB')
    expect(formatFileSize(1024 ** 3)).toBe('1.00 GB')
  })
})

describe('getFileExtensionLabel', () => {
  it('prefers the filename extension when present', () => {
    expect(getFileExtensionLabel(undefined, 'notes.pdf')).toBe('PDF')
    expect(getFileExtensionLabel('application/pdf', 'oops.docx')).toBe('DOCX')
  })

  it('falls back to MIME-derived label when filename has no extension', () => {
    expect(getFileExtensionLabel('application/pdf')).toBe('PDF')
    expect(getFileExtensionLabel('application/zip')).toBe('ZIP')
    expect(getFileExtensionLabel('application/json')).toBe('JSON')
  })

  it('returns undefined for unknown / generic MIME without filename', () => {
    expect(getFileExtensionLabel('application/octet-stream')).toBeUndefined()
    expect(getFileExtensionLabel()).toBeUndefined()
  })

  it('handles dot boundaries, extension length, and MIME fallbacks', () => {
    expect(getFileExtensionLabel('text/plain', '.gitignore')).toBe('TXT')
    expect(getFileExtensionLabel('text/plain', 'notes.')).toBe('TXT')
    expect(getFileExtensionLabel('image/webp', 'photo.webp')).toBe('WEBP')
    expect(getFileExtensionLabel('image/webp', 'photo.abcdef')).toBe('WEBP')
    expect(getFileExtensionLabel('application/json', 'data.12345')).toBe(
      '12345'
    )
    expect(getFileExtensionLabel('image/*')).toBeUndefined()
    expect(getFileExtensionLabel('application/octet-stream')).toBeUndefined()
  })
})

describe('buildCompactMetaLabel', () => {
  it('joins extension and size with a middle dot', () => {
    expect(buildCompactMetaLabel('application/pdf', 'notes.pdf', 388_658)).toBe(
      'PDF · 379.5 KB'
    )
  })

  it('drops the size when missing', () => {
    expect(buildCompactMetaLabel('application/pdf', 'notes.pdf')).toBe('PDF')
  })

  it('returns undefined when nothing is renderable', () => {
    expect(buildCompactMetaLabel()).toBeUndefined()
  })

  it('drops non-positive and non-number sizes while retaining size-only labels', () => {
    expect(buildCompactMetaLabel('application/pdf', 'report.pdf', 0)).toBe(
      'PDF'
    )
    expect(buildCompactMetaLabel('application/pdf', 'report.pdf', -1)).toBe(
      'PDF'
    )
    expect(buildCompactMetaLabel(undefined, undefined, 1024)).toBe('1.0 KB')
    expect(
      buildCompactMetaLabel(
        'application/octet-stream',
        undefined,
        '1024' as never
      )
    ).toBeUndefined()
  })
})

describe('filenameFromUrl', () => {
  it('extracts the last path segment', () => {
    expect(filenameFromUrl('https://cdn.example.com/folder/notes.pdf')).toBe(
      'notes.pdf'
    )
  })

  it('decodes URI-encoded segments', () => {
    expect(
      filenameFromUrl('https://cdn.example.com/folder/My%20Notes.pdf')
    ).toBe('My Notes.pdf')
  })

  it('falls back to a default when the URL cannot be parsed', () => {
    expect(filenameFromUrl('not a url at all')).toBe('download')
  })

  it('handles trailing slashes, deep paths, and query strings', () => {
    expect(filenameFromUrl('https://cdn.example.com/folder/')).toBe('download')
    expect(
      filenameFromUrl('https://cdn.example.com/a/b/c/report.pdf?download=1')
    ).toBe('report.pdf')
  })
})