collectHistory function

List<List<String>> collectHistory(List<Message> list)

Implementation

List<List<String>> collectHistory(List<Message> list) {
  List<List<String>> result = [];
  for (int i = list.length - 1; i >= 0; i -= 2) {
    //只添加最近的会话
    if (i - 1 > 0) {
      result.insert(0, [list[i - 1].text, list[i].text]);
    }
    if (result.length > 3) {
      //放太多轮次也没啥意思
      break;
    }
  }
  return result;
}