import * as WebSocket from 'ws';
import 藍 from '../../ai';
import IModule from '../../module';
import serifs from '../../serifs';
import config from '../../config';
const ReconnectingWebSocket = require('reconnecting-websocket');

export default class ServerModule implements IModule {
	public readonly name = 'server';

	private ai: 藍;
	private connection?: any;
	private recentStat: any;
	private warned = false;
	private lastWarnedAt: number;

	/**
	 * 1秒毎のログ1分間分
	 */
	private statsLogs: any[] = [];

	public install = (ai: 藍) => {
		this.ai = ai;

		this.connection = new ReconnectingWebSocket(`${config.wsUrl}/server-stats`, [], {
			constructor: WebSocket
		});

		this.connection.addEventListener('open', () => {
			console.log('server-stats stream opened');
		});

		this.connection.addEventListener('close', () => {
			console.log('server-stats stream closed');
		});

		this.connection.addEventListener('message', message => {
			const msg = JSON.parse(message.data);

			this.onConnectionMessage(msg);
		});

		setInterval(() => {
			this.statsLogs.unshift(this.recentStat);
			if (this.statsLogs.length > 60) this.statsLogs.pop();
		}, 1000);

		setInterval(() => {
			this.check();
		}, 3000);
	}

	private check = () => {
		const average = (arr) => arr.reduce((a, b) => a + b) / arr.length;

		const cpuPercentages = this.statsLogs.map(s => s.cpu_usage * 100);
		const cpuPercentage = average(cpuPercentages);
		if (cpuPercentage >= 70) {
			this.warn();
		} else if (cpuPercentage <= 30) {
			this.warned = false;
		}
	}

	private onConnectionMessage = (msg: any) => {
		switch (msg.type) {

			case 'stats': {
				this.onStats(msg.body);
				break;
			}

			default:
				break;
		}
	}

	private onStats = async (stats: any) => {
		this.recentStat = stats;
	}

	private warn = () => {
		//#region 前に警告したときから一旦落ち着いた状態を経験していなければ警告しない
		// 常に負荷が高いようなサーバーで無限に警告し続けるのを防ぐため
		if (this.warned) return;
		//#endregion

		//#region 前の警告から1時間経っていない場合は警告しない
		const now = Date.now();

		if (this.lastWarnedAt != null) {
			if (now - this.lastWarnedAt < (1000 * 60 * 60)) return;
		}

		this.lastWarnedAt = now;
		//#endregion

		this.ai.post({
			text: serifs.server.cpu
		});

		this.warned = true;
	}
}