/**
 * Elements should have unique field "id"
 */
export class UniqueList {
  constructor() {
    this.elements = {}
  }

  update(dataList, addCallback, removeCallback, updateCallback) {
    const elementsToAdd = dataList.filter((it) => this.elements[it.id] === undefined)
    const elementsToRemove = Object.keys(this.elements)
      .filter((it) => dataList.find((up) => String(up.id) === it) === undefined)
      .map((id) => this.elements[id])
    if (removeCallback) {
      elementsToRemove.forEach((it) => removeCallback(it))
    }
    if (updateCallback) {
      dataList.forEach((newElement) => {
        const oldElement = this.elements[newElement.id]
        if (oldElement) {
          updateCallback(oldElement, newElement)
        }
      })
    }
    if (addCallback) {
      elementsToAdd.forEach((it) => addCallback(it))
    }
    elementsToRemove.forEach((it) => delete this.elements[it.id])
    elementsToAdd.forEach((it) => (this.elements[it.id] = it))
  }

  getElements() {
    return Object.values(this.elements)
  }

  byId(id) {
    return this.elements[id]
  }
}