import { JSXNode, JSXElement } from '../jsx'
import { Path, Patch, diff } from '../diff'
import { JSXAsync, JSXElementAsync } from './jsx'
import { jsxAsyncToSync } from './sync'

export const diffAsync = (jsx: JSXAsync, path: Path = []): Observable<Patch[]> => {
  const jsx$ = jsxAsyncToSync(jsx)

  return new Observable<Patch[]>(observer => {
    let ready = false
    let lastNode: JSXNode

    return jsx$.subscribe(
      nextNode => {
        if (ready) observer.next(diff(lastNode, nextNode, path))
        else ready = true
        lastNode = nextNode
      },
      error => observer.error(error),
      () => observer.complete()
    )
  })
}