// Top-level block reuse (Phase 16.2 D-03): after an edit, every top-level
// block the edit did not touch is emitted as its original source bytes,
// with the white space and comments between blocks, whatever the edit was
// (one changed block, a deletion, an insertion).
import { afterEach, describe, expect, it } from 'vitest'
import { getSchema } from '@tiptap/core'
import { preservationExtensions } from '../../assets/src/blogeditor/extensions'
import { captureBlocks } from '../../assets/src/blogeditor/serializer'
import { insertAtBlock, mount } from './helpers'

afterEach(() => {
  document.body.replaceChildren()
})

// Source formatting the schema serializer would not reproduce: upper-case
// tags, single quotes, unquoted and reordered attributes, entities,
// self-closing void tags and odd white space.
const blocks = [
  "<P CLASS='lead'>Pierwszy&nbsp;akapit &amp; więcej</P>",
  '<h2  id=intro >Wstęp</h2>',
  '<p>Drugi <a title="t" href="/x">link</a></p>',
  '<ul>\n  <li>jeden</li>\n  <li>dwa</li>\n</ul>',
  '<p>Trzeci<br/>wiersz</p>',
  '<footer class="author-footer"><p>Autor</p></footer>',
]
const separators = ['\n\n', '\n<!-- komentarz -->\n', '\r\n', '\n  \n', '\n']
const source = blocks.map((block, i) => block + (separators[i] ?? '')).join('') + '\n<!-- end -->\n'

/** topLevel returns the editor document's top-level node types. */
function topLevel(el: ReturnType<typeof mount>['editor']): string[] {
  const out: string[] = []
  el.state.doc.forEach((node) => out.push(node.type.name))
  return out
}

describe('block reuse', () => {
  it('returns the source unchanged before any edit', () => {
    const { el, editor } = mount(source)
    expect(topLevel(editor)).toEqual(['paragraph', 'heading', 'paragraph', 'bulletList', 'paragraph', 'rawHtml'])
    expect(el.value).toBe(source)
  })

  it('keeps every other block, separator and comment byte for byte after one edit', () => {
    const { el, editor } = mount(source)
    insertAtBlock(editor, 2, 'X')
    const value = el.value
    expect(value).not.toBe(source)
    for (const [i, block] of blocks.entries()) {
      if (i === 2) continue
      expect(value).toContain(block)
    }
    for (const separator of separators) expect(value).toContain(separator)
    expect(value).toContain('<p>XDrugi')
    expect(value.endsWith('\n<!-- end -->\n')).toBe(true)
    // Only the edited block differs from the source.
    expect(value.replace(/<p>XDrugi[^]*?<\/p>/, blocks[2]!)).toBe(source)
  })

  it('keeps the remaining blocks after a deletion', () => {
    const { el, editor } = mount(source)
    let from = 0
    let to = 0
    editor.state.doc.forEach((node, offset, index) => {
      if (index === 1) {
        from = offset
        to = offset + node.nodeSize
      }
    })
    editor.view.dispatch(editor.state.tr.delete(from, to))
    const value = el.value
    expect(value).not.toContain('Wstęp')
    for (const [i, block] of blocks.entries()) {
      if (i !== 1) expect(value).toContain(block)
    }
    expect(value.startsWith(blocks[0]!)).toBe(true)
  })

  it('keeps every block around an insertion and serializes only the new one', () => {
    const { el, editor } = mount(source)
    let at = 0
    editor.state.doc.forEach((_node, offset, index) => {
      if (index === 3) at = offset
    })
    const paragraph = editor.schema.nodes.paragraph!.create(null, editor.schema.text('Nowy'))
    editor.view.dispatch(editor.state.tr.insert(at, paragraph))
    const value = el.value
    for (const block of blocks) expect(value).toContain(block)
    const inserted = value.indexOf('<p>Nowy</p>')
    expect(inserted).toBeGreaterThan(value.indexOf(blocks[2]!))
    expect(inserted).toBeLessThan(value.indexOf(blocks[3]!))
  })

  it('keeps reused blocks after several edits and an undo returns the exact source', () => {
    const { el, editor } = mount(source)
    insertAtBlock(editor, 0, 'A')
    insertAtBlock(editor, 4, 'B')
    const value = el.value
    for (const i of [1, 2, 3, 5]) expect(value).toContain(blocks[i]!)
    editor.commands.undo()
    editor.commands.undo()
    expect(el.value).toBe(source)
  })

  it('serializes every block when the document is replaced entirely', () => {
    const { el, editor } = mount(source)
    editor.commands.setContent('<p>Inny</p>')
    expect(el.value).toBe('<p>Inny</p>')
  })
})

describe('captureBlocks', () => {
  const schema = getSchema(preservationExtensions())

  it('records each block with the text before it and the trailing text', () => {
    const captured = captureBlocks('\n<p>a</p>\n<!-- c -->\n<h2>b</h2>  ', schema)!
    expect(captured.blocks.map((b) => [b.before, b.html])).toEqual([
      ['\n', '<p>a</p>'],
      ['\n<!-- c -->\n', '<h2>b</h2>'],
    ])
    expect(captured.trailing).toBe('  ')
    expect(captured.blocks.map((b) => b.nodes.map((n) => n.type.name))).toEqual([['paragraph'], ['heading']])
  })

  it('splits raw text elements and nested elements by source position', () => {
    const html = '<style>p > a { x: "</p>" }</style><div><div>a</div><p>b</p></div><p>c<!-- </p> --></p>'
    const captured = captureBlocks(html, schema)!
    expect(captured.blocks.map((b) => b.html)).toEqual(['<style>p > a { x: "</p>" }</style>', '<div><div>a</div><p>b</p></div>', '<p>c<!-- </p> --></p>'])
  })

  it.each([
    ['an unclosed comment', '<p>a</p><!-- open'],
    ['an unclosed element', '<p>a</p><div><p>b'],
    ['an unclosed tag', '<p>a</p><p class="x'],
  ])('gives up on %s, and the element still returns the untouched source', (_name, html) => {
    expect(captureBlocks(html, schema)).toBeNull()
    const { el } = mount(html)
    expect(el.value).toBe(html)
  })

  it('gives up on implied end tags it cannot split by source position', () => {
    // The second <p> closes the first only in the HTML parser's context.
    expect(captureBlocks('<p>a<p>b', schema)).toBeNull()
    const { el, editor } = mount('<p>a<p>b')
    expect(el.value).toBe('<p>a<p>b')
    // An edit serializes the whole document from the model.
    insertAtBlock(editor, 0, 'X')
    expect(el.value).toBe('<p>Xa</p><p>b</p>')
  })

  it('handles an empty value', () => {
    const captured = captureBlocks('', schema)!
    expect(captured.blocks).toEqual([])
    expect(captured.trailing).toBe('')
  })
})