/**
 * 成员卡片的「保存后会怎样」预览。
 *
 * 配置草稿和已保存内容不一致时，卡片区不再显示内核现状，而是显示按草稿保存后组里
 * 会有谁：留下的照常、将移除的标出来、新增的追加在后面。放在组件外面是为了让
 * bun test 够得着——这是纯集合运算，写进 computed 就没人测了。
 */
import type { ProxyInfo } from './api'

export interface MemberPreview {
  name: string
  info: ProxyInfo | undefined
  /** 现在是成员，保存后不再是 */
  removed: boolean
  /** 现在不是成员，保存后才加入 */
  added: boolean
}

export function mergeMemberPreview(
  current: Array<{ name: string; info: ProxyInfo | undefined }>,
  future: string[],
  lookup: (name: string) => ProxyInfo | undefined,
): MemberPreview[] {
  const futureSet = new Set(future)
  const currentNames = new Set(current.map((item) => item.name))
  return [
    ...current.map((item) => ({
      name: item.name,
      info: item.info,
      removed: !futureSet.has(item.name),
      added: false,
    })),
    ...future
      .filter((name) => !currentNames.has(name))
      .map((name) => ({ name, info: lookup(name), removed: false, added: true })),
  ]
}