// Copyright 2023 - 2024 Gnuxie <Gnuxie@protonmail.com>
//
// SPDX-License-Identifier: Apache-2.0

import { MatrixClient } from "matrix-bot-sdk";

/**
 * This is a test for the response times for various endpoints querying the
 * members in a room so that they can be banned.
 *
 * Below are some results from MatrixHQ using a home connection with only 26Mbps down.
 * Which is probably a major limiting factor of these results given the size just encoding the usernames
 * in MatrixHQ alone.
 *
 * /joined_members: total time elapsed 29.655seconds,  mean time 5931ms,    median time 4744ms
 * /state:          total time elapsed 141.353seconds, mean time 28270.6ms, median time 23354ms
 * /members:        total time elapsed 164.845seconds, mean time 32969ms,   median time 28258ms
 *
 * To run the script use `yarn ts-node -P tsconfig.json test/scripts/memberQueryTest.ts`.
 */
//
const accessToken = "redacted";
const client = new MatrixClient(
  "https://matrix-client.matrix.org",
  accessToken
);
const roomId = "!OGEhHVWSdvArJzumhm:matrix.org";

enum MemberFetchMethod {
  JoinedMembers = "/joined_members",
  Members = "/members",
  State = "/state",
}

const shuffledMethods = [
  MemberFetchMethod.JoinedMembers,
  MemberFetchMethod.Members,
  MemberFetchMethod.State,
].reduce((acc: MemberFetchMethod[], method: MemberFetchMethod) => {
  return [...acc, ...[...Array(5)].map((_) => method)];
}, []);

// shuffle https://stackoverflow.com/a/12646864
for (let i = shuffledMethods.length - 1; i > 0; i--) {
  const j = Math.floor(Math.random() * (i + 1));
  const [methodJ, methodI] = [shuffledMethods[j], shuffledMethods[i]];
  if (methodJ && methodI) {
    [shuffledMethods[i], shuffledMethods[j]] = [methodJ, methodI];
  }
}

async function fetchStateWithMethod(method: MemberFetchMethod) {
  switch (method) {
    case MemberFetchMethod.JoinedMembers:
      return await client.getJoinedRoomMembers(roomId);
    case MemberFetchMethod.Members:
      return await client.getRoomMembers(roomId, undefined, undefined, [
        "leave",
        "ban",
      ]);
    case MemberFetchMethod.State:
      return await client.getRoomState(roomId);
    default:
      throw new TypeError();
  }
}

const times = new Map<MemberFetchMethod, number[]>([
  [MemberFetchMethod.JoinedMembers, []],
  [MemberFetchMethod.Members, []],
  [MemberFetchMethod.State, []],
]);

function addTime(method: MemberFetchMethod, time: number) {
  const entry = times.get(method);
  if (entry === undefined) {
    throw new TypeError();
  }
  entry.push(time);
}

function getTimes(method: MemberFetchMethod) {
  return times.get(method);
}

function evenMedian(s: number[], mid: number): number | undefined {
  const leftMid = s[mid - 1];
  const rightMid = s[mid];
  if (leftMid === undefined || rightMid === undefined) {
    throw new TypeError(`Code is wrong bozo`);
  }
  return (leftMid + rightMid) / 2;
}

// https://stackoverflow.com/a/70806192
function calculateMedian(arr: number[]): number | undefined {
  if (!arr.length) return undefined;
  const s = [...arr].sort((a, b) => a - b);
  const mid = Math.floor(s.length / 2);
  return s.length % 2 === 0 ? evenMedian(s, mid) : s[mid];
}

void (async () => {
  for (const method of shuffledMethods) {
    const start = Date.now();
    await fetchStateWithMethod(method);
    const elapsedMs = Date.now() - start;
    addTime(method, elapsedMs);
  }

  for (const method of [
    MemberFetchMethod.JoinedMembers,
    MemberFetchMethod.Members,
    MemberFetchMethod.State,
  ]) {
    const nextTimes = getTimes(method);
    if (nextTimes === undefined) {
      throw new TypeError(`Times shouldn't be undefined matey`);
    }
    const sum = nextTimes.reduce((a, b) => a + b, 0);
    const mean = sum / nextTimes.length || 0;
    const median = calculateMedian(nextTimes);
    console.log(
      `${method}: total time elapsed ${sum / 1000}seconds, mean time ${mean}ms, median time ${median}ms`
    );
  }
})();