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/*
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 *  This file is part of CoCalc: Copyright © 2020 Sagemath, Inc.
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 *  License: MS-RSL – see LICENSE.md for details
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 */
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import getTime, { getLastSkew, getLastPingTime } from "@cocalc/conat/time";
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const PING_INTERVAL_MS = 10000;
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export class TimeClient {
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  private client;
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  private closed: boolean = false;
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  private interval;
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  private lastPingtime: number | null = null;
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  constructor(client: any) {
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    this.client = client;
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    this.interval = setInterval(this.emitPingTime, PING_INTERVAL_MS);
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  }
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  close(): void {
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    if (this.closed) {
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      return;
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    }
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    if (this.interval) {
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      clearInterval(this.interval);
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      delete this.interval;
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    }
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    this.closed = true;
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  }
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  // everything related to sync should directly use conat getTime, which
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  // throws an error if it doesn't know the correct server time.
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  server_time = (): Date => {
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    try {
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      return new Date(getTime());
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    } catch {
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      return new Date();
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    }
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  };
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  private emitPingTime = () => {
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    if (!window.document.hasFocus()) {
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      // console.log("latency: not in focus")
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      return;
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    }
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    const ping = getLastPingTime();
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    if (ping == null || ping == this.lastPingtime) {
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      return;
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    }
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    this.lastPingtime = ping;
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    // networking/pinging slows down a lot when browser not in focus...
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    if (ping > 10000) {
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      // console.log("ping: discarding huge ping", ping)
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      // We get some ridiculous values from Primus when the browser
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      // tab gains focus after not being in focus for a while (say on ipad but on many browsers)
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      // that throttle.  Just discard them, since otherwise they lead to ridiculous false
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      // numbers displayed in the browser.
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      return;
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    }
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    this.client.emit("ping", ping, getLastSkew());
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  };
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}
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