// changes.mjs sorts what a transaction touched into what the editor
// has to do about it: text on a slide flows through y-prosemirror,
// structure on a slide means the stage re-fetches it, and a change to
// the slide list means the strip re-syncs. Driven with a real Y.Doc
// and real observeDeep events, because the walk from an event's target
// up to its slide is the whole of the module.
import test from 'node:test'
import assert from 'node:assert/strict'
import * as Y from 'yjs'
import { applyOps } from './ops.mjs'
import { classify } from './changes.mjs'
import { blockFragment } from './stage.mjs'

function deck () {
  const doc = new Y.Doc({ guid: 'changes-test' })
  doc.clientID = 3
  applyOps(doc, [
    { op: 'add_slide', id: 's1', layout: 'flow' },
    { op: 'add_block', slide: 's1', id: 'b1', type: 'text', region: 'body', markdown: 'one' },
    { op: 'add_slide', id: 's2', layout: 'flow' },
    { op: 'add_block', slide: 's2', id: 'b2', type: 'heading', region: 'heading', markdown: 'two' }
  ], 'setup')
  const slides = doc.getArray('slides')
  let last = null
  slides.observeDeep(events => { last = classify(events, slides) })
  return { doc, take: () => last }
}

test('typing into a block is a text change on its slide only', () => {
  const { doc, take } = deck()
  const f = blockFragment(doc, 's1', 'b1')
  doc.transact(() => { f.get(0).get(0).insert(0, 'x') }, 'typing')
  assert.deepEqual(take(), { text: ['s1'], structure: [], order: false })
})

test('a block\'s props changing is structure on its slide', () => {
  const { doc, take } = deck()
  applyOps(doc, [{ op: 'set_block', slide: 's2', id: 'b2', props: { level: 2 } }], 'ops')
  assert.deepEqual(take(), { text: [], structure: ['s2'], order: false })
})

test('adding, moving or removing a block is structure on its slide', () => {
  const { doc, take } = deck()
  applyOps(doc, [{ op: 'add_block', slide: 's1', id: 'b3', type: 'text', region: 'body', markdown: 'three' }], 'ops')
  assert.deepEqual(take(), { text: [], structure: ['s1'], order: false })
  applyOps(doc, [{ op: 'remove_block', slide: 's1', id: 'b3' }], 'ops')
  assert.deepEqual(take(), { text: [], structure: ['s1'], order: false })
})

test('the notes are text on their slide', () => {
  const { doc, take } = deck()
  applyOps(doc, [{ op: 'set_notes', id: 's2', markdown: 'note' }], 'ops')
  assert.deepEqual(take(), { text: ['s2'], structure: [], order: false })
})

test('a slide added, removed or moved is an order change', () => {
  const { doc, take } = deck()
  applyOps(doc, [{ op: 'add_slide', id: 's3', layout: 'flow', after: 's1' }], 'ops')
  assert.deepEqual(take(), { text: [], structure: [], order: true })
  applyOps(doc, [{ op: 'move_slide', id: 's3', after: 's2' }], 'ops')
  assert.deepEqual(take(), { text: [], structure: [], order: true })
  applyOps(doc, [{ op: 'remove_slide', id: 's3' }], 'ops')
  assert.deepEqual(take(), { text: [], structure: [], order: true })
})

test('one transaction touching several things reports each once', () => {
  const { doc, take } = deck()
  applyOps(doc, [
    { op: 'set_slide', id: 's1', template: 'section' },
    { op: 'set_block', slide: 's1', id: 'b1', props: { size: 'l' } },
    { op: 'set_text', slide: 's2', id: 'b2', markdown: 'changed' }
  ], 'ops')
  assert.deepEqual(take(), { text: ['s2'], structure: ['s1'], order: false })
})