import { fireEvent, render, screen, waitFor } from '@testing-library/react'
import { SWRConfig } from 'swr'
import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
import { AgentViewPage } from '../src/pages/AgentViewPage'
import { browse } from '../src/api/browse'
import type { Snapshot } from '../src/api/browse'

/* Page-level wiring: the api module is mocked, everything else (SWR, the
   markdown renderer, tabs, the ?url= loop) is real. */
vi.mock('../src/api/browse', () => ({
  browse: vi.fn(),
}))

const browseMock = vi.mocked(browse)

function snapshot(overrides: Partial<Snapshot> = {}): Snapshot {
  return {
    requestedUrl: 'https://example.test',
    finalUrl: 'https://example.test/',
    status: 200,
    contentType: 'text/html; charset=utf-8',
    durationMs: 210,
    fetchedAt: '2026-09-16T10:00:00Z',
    page: {
      title: 'Example Site',
      description: 'An example.',
      canonical: '',
      robotsMeta: '',
      lang: 'en',
      h1: 'Welcome',
      linkCount: 1,
      deadLinks: 0,
      scriptCount: 1,
      imageCount: 0,
      wordCount: 12,
      textLength: 80,
    },
    markdown: '# Welcome\n\nRead the [docs](https://example.test/docs).',
    markdownTruncated: false,
    files: {
      llmsTxt: {
        url: 'https://example.test/llms.txt',
        status: 200,
        contentType: 'text/markdown',
        content: '# Example Site\n\n## Docs\n\n- [Guide](https://example.test/guide): the guide\n',
        truncated: false,
        llmsDoc: {
          title: 'Example Site',
          description: '',
          sections: [
            {
              heading: 'Docs',
              description: '',
              links: [{ title: 'Guide', url: 'https://example.test/guide', description: 'the guide' }],
            },
          ],
          linkCount: 1,
        },
      },
      llmsFullTxt: null,
      wellKnownLlmsTxt: null,
      robotsTxt: {
        url: 'https://example.test/robots.txt',
        status: 200,
        contentType: 'text/plain',
        content: 'User-agent: *\nAllow: /\n',
        truncated: false,
      },
    },
    checks: [
      { id: 'page.status', label: 'Page reachable', severity: 'ok', detail: '200 OK' },
      { id: 'llms.txt', label: '/llms.txt', severity: 'ok', detail: 'found' },
      { id: 'page.description', label: 'Meta description', severity: 'warn', detail: 'thin' },
    ],
    ...overrides,
  }
}

function renderPage() {
  return render(
    <SWRConfig value={{ provider: () => new Map(), dedupingInterval: 0 }}>
      <AgentViewPage />
    </SWRConfig>,
  )
}

beforeEach(() => {
  window.history.replaceState(null, '', '/')
  browseMock.mockReset()
})

afterEach(() => {
  vi.clearAllMocks()
})

describe('AgentViewPage', () => {
  it('stays on the explainer until a domain is submitted', () => {
    browseMock.mockResolvedValue(snapshot())
    renderPage()
    expect(screen.getByText(/What does your site look like to an LLM/i)).toBeInTheDocument()
    expect(browseMock).not.toHaveBeenCalled()
  })

  it('fetches the domain and renders the markdown with live links', async () => {
    browseMock.mockResolvedValue(snapshot())
    renderPage()

    fireEvent.change(screen.getByLabelText(/domain or url/i), { target: { value: 'example.test' } })
    fireEvent.click(screen.getByRole('button', { name: /view as agent/i }))

    await waitFor(() => expect(browseMock).toHaveBeenCalledWith('example.test'))
    expect(await screen.findByRole('heading', { level: 1, name: 'Welcome' })).toBeInTheDocument()

    const link = screen.getByRole('link', { name: 'docs' })
    expect(link).toHaveAttribute('href', 'https://example.test/docs')

    expect(screen.getByText(/210 ms/i)).toBeInTheDocument()
  })

  it('re-enters the viewer when a markdown link is clicked', async () => {
    browseMock.mockResolvedValue(snapshot())
    renderPage()

    fireEvent.change(screen.getByLabelText(/domain or url/i), { target: { value: 'example.test' } })
    fireEvent.click(screen.getByRole('button', { name: /view as agent/i }))
    fireEvent.click(await screen.findByRole('link', { name: 'docs' }))

    await waitFor(() => expect(browseMock).toHaveBeenCalledWith('https://example.test/docs'))
  })

  it('shows the parsed llms.txt and the checks', async () => {
    browseMock.mockResolvedValue(snapshot())
    renderPage()

    fireEvent.change(screen.getByLabelText(/domain or url/i), { target: { value: 'example.test' } })
    fireEvent.click(screen.getByRole('button', { name: /view as agent/i }))

	fireEvent.click(await screen.findByRole('tab', { name: /llms\.txt/i }))
	expect((await screen.findAllByText('Example Site')).length).toBeGreaterThan(0)
	expect(screen.getByText('Guide')).toBeInTheDocument()

    fireEvent.click(screen.getByRole('tab', { name: /checks/i }))
    expect(await screen.findByText('Page reachable')).toBeInTheDocument()
	expect(screen.getByText(/warnings/)).toBeInTheDocument()
  })

  it('surfaces fetch failures with a retry', async () => {
    browseMock.mockRejectedValue(
      new (await import('../src/api/client')).ApiError(502, 'unavailable', 'could not fetch https://down.test/'),
    )
    renderPage()

    fireEvent.change(screen.getByLabelText(/domain or url/i), { target: { value: 'down.test' } })
    fireEvent.click(screen.getByRole('button', { name: /view as agent/i }))

    expect(await screen.findByText(/the site did not answer/i)).toBeInTheDocument()
    fireEvent.click(screen.getByRole('button', { name: /try again/i }))
    await waitFor(() => expect(browseMock).toHaveBeenCalledTimes(2))
  })
})