import { change, emptyChange, init, type Doc } from '@automerge/automerge'
import { describe, expect, it } from 'vitest'

import { createEditorSource } from '../../src/sync/sources/editorSource.js'

interface TestDoc {
  text?: string
}

function emptyDoc(): Doc<TestDoc> {
  return emptyChange(init<TestDoc>(), undefined)
}

function withText(text: string): Doc<TestDoc> {
  return change(emptyChange(init<TestDoc>(), undefined), (d) => {
    d.text = text
  })
}

describe('editor Source (a Source that is also a Handle)', () => {
  it('change() updates doc(), notifies listeners, and delivers to the session', () => {
    const editor = createEditorSource<TestDoc>('doc1', emptyDoc())
    let notified = 0
    editor.on('change', () => {
      notified += 1
    })
    const delivered: Doc<unknown>[] = []
    editor.subscribe((_id, doc) => {
      delivered.push(doc)
    })

    editor.change((d) => {
      d.text = 'hi'
    })

    expect(editor.doc().text).toBe('hi')
    expect(notified).toBe(1)
    expect((delivered[0] as Doc<TestDoc>).text).toBe('hi')
  })

  it('push() from the session updates doc() + notifies, but is NOT delivered back (no loop)', async () => {
    const editor = createEditorSource<TestDoc>('doc1', emptyDoc())
    let notified = 0
    editor.on('change', () => {
      notified += 1
    })
    const delivered: unknown[] = []
    editor.subscribe((_id, doc) => {
      delivered.push(doc)
    })

    await editor.push('doc1', withText('remote'))

    expect(editor.doc().text).toBe('remote')
    expect(notified).toBe(1)
    expect(delivered.length).toBe(0)
  })

  it('off() removes a listener', () => {
    const editor = createEditorSource<TestDoc>('doc1', emptyDoc())
    let n = 0
    const listener = (): void => {
      n += 1
    }
    editor.on('change', listener)
    editor.change((d) => {
      d.text = 'a'
    })
    editor.off('change', listener)
    editor.change((d) => {
      d.text = 'b'
    })
    expect(n).toBe(1)
  })
})