import { times } from 'lodash';
import { compress } from 'lz4js';
import { argv } from 'process';
import ProgressBar from 'progress';
import { Region, REGIONS } from '../src/constants/regions';
import getTankStats from '../src/core/blitz/getTankStats';
import { idToRegion, MAX_IDS, MIN_IDS } from '../src/core/blitz/idToRegion';
import { asset } from '../src/core/blitzkit/asset';
import {
  AverageDefinitions,
  AverageDefinitionsAllStats,
} from '../src/core/blitzkit/averageDefinitions';
import { averageDefinitionsAllStatsKeys } from '../src/core/blitzkit/averageDefinitions/constants';
import { commitAssets } from '../src/core/blitzkit/commitAssets';
import { superCompress } from '../src/core/blitzkit/superCompress';
import { DidsReadStream, DidsWriteStream } from '../src/core/streams/dids';
import { IndividualTankStats } from '../src/types/tanksStats';

const RUN_TIME = 1000 * 0;
const MAX_REQUESTS = 10;

const production = argv.includes('--production');
const startTime = Date.now();
const fields = 'all,tank_id,battle_life_time';

const players: IndividualTankStats[][] = [];
const preDiscovered = await fetch(asset('averages/discovered.dids.lz4')).then(
  async (response) => {
    if (response.status === 200) {
      const buffer = await response.arrayBuffer();
      return new DidsReadStream(buffer).dids();
    }

    return undefined;
  },
);
const discoveredIds: number[] = [];
let processes = 0;

if (preDiscovered) {
  console.log(
    `Revalidating ${preDiscovered.length} pre-discovered ids with ${MAX_REQUESTS} chains...`,
  );

  const preDiscoveredBar = new ProgressBar(':bar', {
    total: preDiscovered.length,
  });
  let preDiscoveredIndex = 0;

  async function chainPreDiscovery() {
    processes++;

    if (preDiscoveredIndex === preDiscovered!.length) {
      processes--;

      if (processes !== 0) return;

      console.log(
        `Rediscovered ${discoveredIds.length} / ${preDiscovered!.length} ids in ${Date.now() - startTime}ms`,
      );
      discover();

      return;
    }

    const id = preDiscovered![preDiscoveredIndex++];
    const region = idToRegion(id);

    if (id > MAX_IDS[region]) return;

    const stats = await getTankStats(region, id, { fields });

    if (stats !== null && stats.length > 0) {
      discoveredIds.push(id);
      players.push(stats);
      preDiscoveredBar.tick();
    }

    processes--;
    setTimeout(chainPreDiscovery); // circumvent max call stack
  }

  times(MAX_REQUESTS, chainPreDiscovery);
} else {
  console.log('No pre-discovered ids found :(');
  discover();
}

function discover() {
  const index: Record<Region, number> = {
    asia:
      preDiscovered?.find((id) => idToRegion(id) === 'asia') ?? MIN_IDS.asia,
    com: preDiscovered?.find((id) => idToRegion(id) === 'com') ?? MIN_IDS.com,
    eu: preDiscovered?.find((id) => idToRegion(id) === 'eu') ?? MIN_IDS.eu,
  };

  let regionIndex = 0;
  let done = 0;

  async function chainDiscovery() {
    regionIndex = (regionIndex + 1) % REGIONS.length;
    const region = REGIONS[regionIndex];
    const id = index[region]++;

    if (Date.now() - startTime > RUN_TIME || id === MAX_IDS[region]) {
      if (++done !== MAX_REQUESTS) return;

      console.log(
        `Total discovery run time: ${
          Date.now() - startTime
        }ms\nDiscovered ids: ${discoveredIds.length}`,
      );

      postWork();

      return;
    }

    if (id > MAX_IDS[region]) return;

    const stats = await getTankStats(region, id, { fields });

    if (stats !== null && stats.length > 0) {
      discoveredIds.push(id);
      players.push(stats);

      console.log(`discovered ${id} in ${region}`);
    }

    setTimeout(chainDiscovery); // circumvent max call stack
  }

  console.log(`Spawning ${MAX_REQUESTS} discovery chains...`);
  times(MAX_REQUESTS, chainDiscovery);
}

function postWork() {
  const tankIds: number[] = [];
  const sorted: Record<number, IndividualTankStats[]> = {};

  players.forEach((tanks) => {
    tanks.forEach((tank) => {
      if (tank.all.battles === 0) return;

      if (!sorted[tank.tank_id]) {
        tankIds.push(tank.tank_id);
        sorted[tank.tank_id] = [];
      }
      sorted[tank.tank_id].push(tank);
    });
  });

  console.log(
    `Generating statistics based off ${players.length} players and ${tankIds.length} tanks...`,
  );

  const averages: AverageDefinitions = {};

  tankIds.forEach((id) => {
    const tanks = sorted[id];
    const samples = tanks.length;

    function sum(slice: (tank: AverageDefinitionsAllStats) => number) {
      return tanks.reduce((acc, tank) => {
        return (
          acc + slice({ battle_life_time: tank.battle_life_time, ...tank.all })
        );
      }, 0);
    }

    const denominator = sum((tank) => tank.battles);

    function moment(slice: (tank: AverageDefinitionsAllStats) => number) {
      return tanks.reduce((acc, tank) => {
        return (
          acc +
          tank.all.battles *
            slice({ battle_life_time: tank.battle_life_time, ...tank.all })
        );
      }, 0);
    }

    function weightedAverage(
      slice: (tank: AverageDefinitionsAllStats) => number,
    ) {
      return moment(slice) / denominator;
    }

    const mu = averageDefinitionsAllStatsKeys.reduce<
      Partial<AverageDefinitionsAllStats>
    >((acc, key) => {
      acc[key] = weightedAverage((tank) => tank[key]);
      return acc;
    }, {}) as AverageDefinitionsAllStats;
    const sigma = averageDefinitionsAllStatsKeys.reduce<
      Partial<AverageDefinitionsAllStats>
    >((acc, key) => {
      acc[key] = Math.sqrt(sum((tank) => (tank[key] - mu[key]) ** 2) / samples);
      return acc;
    }, {}) as AverageDefinitionsAllStats;
    const r = averageDefinitionsAllStatsKeys.reduce<
      Partial<AverageDefinitionsAllStats>
    >((acc, key) => {
      acc[key] =
        (samples *
          sum(
            (tank) => (tank[key] / tank.battles) * (tank.wins / tank.battles),
          ) -
          sum((tank) => tank[key] / tank.battles) *
            sum((tank) => tank.wins / tank.battles)) /
        Math.sqrt(
          (samples * sum((tank) => (tank[key] / tank.battles) ** 2) -
            sum((tank) => tank[key] / tank.battles) ** 2) *
            (samples * sum((tank) => (tank.wins / tank.battles) ** 2) -
              sum((tank) => tank.wins / tank.battles) ** 2),
        );
      return acc;
    }, {}) as AverageDefinitionsAllStats;
    const m = averageDefinitionsAllStatsKeys.reduce<
      Partial<AverageDefinitionsAllStats>
    >((acc, key) => {
      acc[key] =
        (samples *
          sum(
            (tank) => (tank[key] / tank.battles) * (tank.wins / tank.battles),
          ) -
          sum((tank) => tank[key] / tank.battles) *
            sum((tank) => tank.wins / tank.battles)) /
        (samples * sum((tank) => (tank[key] / tank.battles) ** 2) -
          sum((tank) => tank[key] / tank.battles) ** 2);
      return acc;
    }, {}) as AverageDefinitionsAllStats;
    const b = averageDefinitionsAllStatsKeys.reduce<
      Partial<AverageDefinitionsAllStats>
    >((acc, key) => {
      acc[key] =
        (sum((tank) => tank.wins / tank.battles) -
          m[key] * sum((tank) => tank[key] / tank.battles)) /
        samples;
      return acc;
    }, {}) as AverageDefinitionsAllStats;

    averages[id] = { samples, mu, sigma, r, m, b };
  });

  commitAssets(
    'averages',
    [
      {
        path: 'definitions/averages.cdon.lz4',
        content: superCompress(averages),
        encoding: 'base64',
      },
      {
        path: 'definitions/discovered.dids.lz4',
        content: Buffer.from(
          compress(new DidsWriteStream().dids(discoveredIds).uint8Array),
        ).toString('base64'),
        encoding: 'base64',
      },
    ],
    production,
  );
}