import { describe, it, expect, afterEach } from 'vitest'
import { act, cleanup, render, screen, waitFor } from '@testing-library/react'
import { useActiveMarkdownView } from '../App'
import { Workspace } from '../plugin/workspace'
import { MarkdownView } from '../plugin/views/markdown-view'
import { createTFile } from '../plugin/files'

function ActiveEditorProbe({
  workspace,
  firstView,
  secondView,
}: {
  workspace: Workspace
  firstView: MarkdownView
  secondView: MarkdownView
}) {
  const view = useActiveMarkdownView(workspace)
  const label = view === firstView ? 'first' : view === secondView ? 'second' : 'none'
  return <div data-testid="active-editor">{label}</div>
}

describe('useActiveMarkdownView', () => {
  afterEach(() => {
    cleanup()
  })

  it('reacts when the active editor is replaced on the same leaf', async () => {
    const workspace = new Workspace(document.createElement('div'))
    const leaf = workspace.getLeaf()
    const file = createTFile('same.md', null, { ctime: 0, mtime: 0, size: 0 })
    const firstView = new MarkdownView(leaf)
    const secondView = new MarkdownView(leaf)

    leaf.file = file
    firstView.file = file
    secondView.file = file

    await act(async () => {
      await leaf.open(firstView)
    })
    workspace.setActiveLeaf(leaf)

    render(<ActiveEditorProbe workspace={workspace} firstView={firstView} secondView={secondView} />)
    expect(screen.getByTestId('active-editor')).toHaveTextContent('first')

    await act(async () => {
      await leaf.open(secondView)
    })

    await waitFor(() => {
      expect(screen.getByTestId('active-editor')).toHaveTextContent('second')
    })
  })

  it('reacts when a failed open clears activeEditor without a layout change', async () => {
    class FailingMarkdownView extends MarkdownView {
      override async onOpen(): Promise<void> {
        throw new Error('view open failed')
      }
    }

    const workspace = new Workspace(document.createElement('div'))
    const leaf = workspace.getLeaf()
    const file = createTFile('same.md', null, { ctime: 0, mtime: 0, size: 0 })
    const firstView = new MarkdownView(leaf)
    const failingView = new FailingMarkdownView(leaf)

    leaf.file = file
    firstView.file = file
    failingView.file = file

    await act(async () => {
      await leaf.open(firstView)
    })
    workspace.setActiveLeaf(leaf)
    workspace.registerViewType('failing-markdown', (targetLeaf) => {
      const view = new FailingMarkdownView(targetLeaf)
      view.file = file
      return view
    })

    render(<ActiveEditorProbe workspace={workspace} firstView={firstView} secondView={failingView} />)
    expect(screen.getByTestId('active-editor')).toHaveTextContent('first')

    let openError: unknown = null
    await act(async () => {
      try {
        await leaf.setViewState({ type: 'failing-markdown' })
      } catch (err) {
        openError = err
      }
    })

    expect(openError).toBeInstanceOf(Error)
    expect((openError as Error).message).toBe('view open failed')

    await waitFor(() => {
      expect(screen.getByTestId('active-editor')).toHaveTextContent('none')
    })
  })
})