import 藍 from '../../ai';
import IModule from '../../module';
import serifs from '../../serifs';
import config from '../../config';

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) => {
		if (!config.serverMonitoring) return;

		this.ai = ai;

		this.connection = this.ai.connection.useSharedConnection('serverStats');
		this.connection.on('stats', this.onStats);

		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 && s.cpu_usage * 100 || 0);
		const cpuPercentage = average(cpuPercentages);
		if (cpuPercentage >= 70) {
			this.warn();
		} else if (cpuPercentage <= 30) {
			this.warned = false;
		}
	}

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

	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;
	}
}