import { isObservableArray, isObservableObject, remove } from "mobx"
import { BuiltInAction } from "../action/builtInActions"
import { ActionContextActionType } from "../action/context"
import { wrapInAction } from "../action/wrapInAction"
import { assertTweakedObject } from "../tweaker/core"
import { failure, lazy } from "../utils"
import { fastGetParentPathIncludingDataObjects } from "./path"

/**
 * Detaches a given object from a tree.
 * If the parent is an object / model, detaching will delete the property.
 * If the parent is an array detaching will remove the node by splicing it.
 * If there's no parent it will throw.
 *
 * @param node Object to be detached.
 */
export function detach(node: object): void {
  assertTweakedObject(node, "node")

  wrappedInternalDetach().call(node)
}

const wrappedInternalDetach = lazy(() =>
  wrapInAction({
    nameOrNameFn: BuiltInAction.Detach,
    fn: internalDetach,
    actionType: ActionContextActionType.Sync,
  })
)

function internalDetach(this: object): void {
  const node = this

  const parentPath = fastGetParentPathIncludingDataObjects(node)
  if (!parentPath) return

  const { parent, path } = parentPath
  if (isObservableArray(parent)) {
    parent.splice(+path, 1)
  } else if (isObservableObject(parent)) {
    remove(parent, "" + path)
  } else {
    throw failure("parent must be an observable object or an observable array")
  }
}