// The tab title names the record, and the two writers do not fight.
//
// The router can only name the KIND of page - it runs before the view has
// fetched anything - so a detail view names the record itself once it loads.
// That leaves two writers for one string, and the router's is asynchronous
// (it awaits the site settings), so on a cold load it can finish LAST and
// overwrite a good title with the generic one. These pin that ordering.

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

// The real getFacilityName caches, so only the first call is slow and every
// later one is instant. Mirror that: pending calls are held until the test
// releases them, and the value is served synchronously from then on. A mock
// that hands out a fresh unresolved promise per call hangs the moment a test
// navigates twice.
let pending = []
let settled = null

function resolveFacility(value) {
  settled = value
  const waiting = pending
  pending = []
  waiting.forEach((resolve) => resolve(value))
}

vi.mock('@/utils/siteSettings', () => ({
  getFacilityName: () => (settled !== null
    ? Promise.resolve(settled)
    : new Promise((resolve) => { pending.push(resolve) })),
}))

import {
  beginNavigation, applyGenericTitle, setRecordTitle, _reset,
} from './pageTitle'

beforeEach(() => {
  _reset()
  document.title = ''
  pending = []
  settled = null
})

describe('the generic title', () => {
  it('names the section when no record has been set', async () => {
    beginNavigation('/machines')
    const done = applyGenericTitle('/machines', 'Machines')
    resolveFacility('West Jefferson')
    await done

    expect(document.title).toBe('West Jefferson ShopDB - Machines')
  })

  it('falls back to plain ShopDB when the facility is unset', async () => {
    beginNavigation('/machines')
    const done = applyGenericTitle('/machines', 'Machines')
    resolveFacility('ShopDB')
    await done

    expect(document.title).toBe('ShopDB - Machines')
  })

  it('drops the site name entirely on the dashboard', async () => {
    beginNavigation('/')
    const done = applyGenericTitle('/', 'Home')
    resolveFacility('West Jefferson')
    await done

    expect(document.title).toBe('West Jefferson ShopDB')
  })
})

describe('a record title', () => {
  it('names the record once the view has loaded it', async () => {
    beginNavigation('/machines/12')
    const done = applyGenericTitle('/machines/12', 'Machines')
    resolveFacility('West Jefferson')
    await done

    setRecordTitle('CSF16')

    expect(document.title).toBe('West Jefferson ShopDB - CSF16')
  })

  it('SURVIVES a slow router that resolves afterwards', async () => {
    // The regression this file exists for. The view wins the race, the
    // settings fetch lands second, and the generic write must stand down.
    beginNavigation('/machines/12')
    const done = applyGenericTitle('/machines/12', 'Machines')

    setRecordTitle('CSF16')          // view got there first
    resolveFacility('West Jefferson')
    await done                        // router finishes last

    expect(document.title).toBe('West Jefferson ShopDB - CSF16')
  })

  it('is ignored when the record has no usable name', async () => {
    beginNavigation('/machines/12')
    const done = applyGenericTitle('/machines/12', 'Machines')
    resolveFacility('West Jefferson')
    await done

    setRecordTitle('')
    setRecordTitle(null)
    setRecordTitle(undefined)
    setRecordTitle('   ')

    // the section name is a better tab than a blank or a bare id
    expect(document.title).toBe('West Jefferson ShopDB - Machines')
  })

  it('shortens a name too long for a tab, at a word boundary', async () => {
    // Knowledge base articles are named with a sentence of description, and a
    // browser truncates those mid-word wherever it happens to run out.
    beginNavigation('/knowledgebase/2')
    const done = applyGenericTitle('/knowledgebase/2', 'Knowledge Base')
    resolveFacility('West Jefferson')
    await done

    const full = 'Documentation on how to image a Standard or Business PC '
                 + 'in GCC High using MediaCreator Lite'
    setRecordTitle(full)

    expect(document.title.length).toBeLessThan(90)
    expect(document.title.startsWith('West Jefferson ShopDB - ')).toBe(true)
    expect(document.title.endsWith('...')).toBe(true)

    // what survives is a whole-word prefix of the original: the character
    // following the cut in the source is a space, so no word was split
    const kept = document.title
      .replace('West Jefferson ShopDB - ', '')
      .replace(/\.\.\.$/, '')
    expect(full.startsWith(kept)).toBe(true)
    expect(full[kept.length]).toBe(' ')
  })

  it('leaves a name that already fits alone', async () => {
    beginNavigation('/machines/14')
    const done = applyGenericTitle('/machines/14', 'Machines')
    resolveFacility('West Jefferson')
    await done

    setRecordTitle('0600')

    expect(document.title).toBe('West Jefferson ShopDB - 0600')
  })

  it('does not leak onto the next page', async () => {
    beginNavigation('/machines/12')
    const first = applyGenericTitle('/machines/12', 'Machines')
    resolveFacility('West Jefferson')
    await first
    setRecordTitle('CSF16')

    beginNavigation('/printers')
    const second = applyGenericTitle('/printers', 'Printers')
    await second

    expect(document.title).toBe('West Jefferson ShopDB - Printers')
  })

  it('is discarded when the user navigates away mid-flight', async () => {
    // Two navigations overlap; the first one's late generic write must not
    // land on the second page.
    beginNavigation('/machines/12')
    const stale = applyGenericTitle('/machines/12', 'Machines')

    beginNavigation('/printers/3')
    const fresh = applyGenericTitle('/printers/3', 'Printers')
    setRecordTitle('WJPRT04')

    resolveFacility('West Jefferson')
    await Promise.all([stale, fresh])

    expect(document.title).toBe('West Jefferson ShopDB - WJPRT04')
  })
})