// The URL-prefix i18n helpers — the load-bearing pure functions that drive the
// [locale] mirror routing + the language switcher. `useUrlLocale` (the one hook
// in this module) reads useLocation from @voltro/web; the rest are pure string
// functions we can exercise directly.

import { describe, expect, test } from 'vitest'
import {
  SUPPORTED_LOCALES,
  DEFAULT_LOCALE,
  getCatalog,
  localeFromPathname,
  withLocalePrefix,
  stripLocalePrefix,
} from './locale'

describe('locale constants', () => {
  test('supports en + de with en as the default', () => {
    expect(SUPPORTED_LOCALES).toEqual(['en', 'de'])
    expect(DEFAULT_LOCALE).toBe('en')
  })
})

describe('getCatalog', () => {
  test('returns the matching catalog for a supported locale', () => {
    expect(getCatalog('de')['nav.language']).toBe('Sprache')
    expect(getCatalog('en')['nav.language']).toBe('Language')
  })

  test('falls back to the default catalog for an unsupported locale', () => {
    expect(getCatalog('zz')['nav.language']).toBe('Language')
  })
})

describe('localeFromPathname', () => {
  test('extracts a prefixed locale', () => {
    expect(localeFromPathname('/de')).toBe('de')
    expect(localeFromPathname('/de/about')).toBe('de')
  })

  test('defaults to en for the bare path or an unknown prefix', () => {
    expect(localeFromPathname('/')).toBe('en')
    expect(localeFromPathname('/about')).toBe('en')
    expect(localeFromPathname('/fr/about')).toBe('en')
  })
})

describe('withLocalePrefix', () => {
  test('leaves default-locale paths bare', () => {
    expect(withLocalePrefix('/about', 'en')).toBe('/about')
    expect(withLocalePrefix('/', 'en')).toBe('/')
  })

  test('prefixes non-default locales, mapping / to /<locale>', () => {
    expect(withLocalePrefix('/about', 'de')).toBe('/de/about')
    expect(withLocalePrefix('/', 'de')).toBe('/de')
  })
})

describe('stripLocalePrefix', () => {
  test('removes a locale prefix, mapping /<locale> back to /', () => {
    expect(stripLocalePrefix('/de/about')).toBe('/about')
    expect(stripLocalePrefix('/de')).toBe('/')
  })

  test('leaves an unprefixed path unchanged', () => {
    expect(stripLocalePrefix('/about')).toBe('/about')
  })

  test('round-trips with withLocalePrefix', () => {
    expect(stripLocalePrefix(withLocalePrefix('/about', 'de'))).toBe('/about')
  })
})