const admin = require("firebase-admin");
const firebase_tools = require("firebase-tools");

const timeDiff = (ds1, ds2) => {
  const d1 = new Date(ds1);
  const d2 = new Date(ds2);
  var diff = (d2.getTime() - d1.getTime()) / 1000;
  diff /= 60 * 60;
  return Math.abs(Math.round(diff));
};

const roomIdList = async (refs) => {
  const startedTime = new Date();
  return await admin
    .firestore()
    .getAll(...refs)
    .then((roomDataList) =>
      roomDataList.map((roomData) => {
        if (
          !roomData.exists ||
          (timeDiff(roomData.createTime.toDate(), startedTime) >= 24 &&
            timeDiff(roomData.updateTime.toDate(), startedTime) >= 4) ||
          timeDiff(roomData.updateTime.toDate(), startedTime) >= 12
        ) {
          return roomData.id;
        }
      })
    )
    .then((ids) => ids.filter((v) => v !== undefined));
};

const batchDeleteRooms = async (roomList, totalNumber) => {
  setTimeout(async () => {
    if (roomList.length > 0) {
      await firebase_tools.firestore
        .delete(`rooms/${roomList.splice(0, 1)[0]}`, {
          project: process.env.GCLOUD_PROJECT,
          recursive: true,
          yes: true,
        })
        .catch((err) =>
          console.error(
            `[ERROR]\tWEBHOOKS/Room Clean Up\t# OF ROOMS ${roomList.length} REMAINING,\tERROR:${err}`
          )
        );
      console.info(
        `[DONE]\tWEBHOOKS/Room Clean Up\t# OF ROOMS ${
          totalNumber - roomList.length
        }/${totalNumber}`
      );
      batchDeleteRooms(roomList, totalNumber);
    } else {
      console.info(
        `[DONE]\tWEBHOOKS/Room Clean Up\tDeleted all ${totalNumber} rooms`
      );
    }
  }, 1000);
};

module.exports = async (req, res) => {
  res.status(200).send({ message: "Started processing" });

  const roomList = await admin
    .firestore()
    .collection("rooms")
    .listDocuments()
    .then((rL) => rL)
    .catch((err) => {
      console.error(
        `Failed to run auto clean up (get room list) @ ${new Date().toLocaleTimeString()}`,
        err
      );
    });

  if (roomList.length > 0) {
    var ids = await roomIdList(roomList);
    if (ids.length > 0) {
      batchDeleteRooms(ids, ids.length);
    }
  }

  return;
};