background.js

var DELAY = 1;
{
  chrome.runtime.onInstalled.addListener(function(tab) {
    console.log("Installed");
  });


  chrome.action.onClicked.addListener(function(activeTab) {
    var newURL = "https://app.osmosis.zone/pools";
    chrome.tabs.create({
      url: newURL
    });
  });

  // initial setup:
  chrome.action.setBadgeText({
    text: "..."
  });
  chrome.action.setBadgeBackgroundColor({
    color: "#8E00BA"
  });

  // Timer setup
  // TODO: make timer syncronize with the real countdown...
  chrome.alarms.create("countdown", {
    delayInMinutes: DELAY,
    periodInMinutes: DELAY
  });

  chrome.alarms.onAlarm.addListener((alarm) => {
    // get epoch and defer it to promises...
    chrome.storage.local.get("epoch_end_unix", gotEpochFromStorage_callback);
  });


  function gotEpochFromStorage_callback(result) {
    let epoch_end_unix = result.epoch_end_unix;

    // if it is in storage, then proceed to handle it with updateTimeDisplay...
    if (epoch_end_unix) {
      updateCountdownDisplay(epoch_end_unix);
    } else { // if not in local storage, get it from API...
      updateEpochFromAPI();
    }
  }

  function updateCountdownDisplay(epoch_end_unix) {
    var now_unix = Date.now();
    var totSecs = Math.floor((epoch_end_unix - now_unix) / 1000)
    var strTime = new Date(totSecs * 1000).toISOString();
    var prettyPrint = "";
    if (totSecs > 3600) {
      strTime = strTime.substr(11, 5);
      prettyPrint = strTime.substr(0, 2) + " hours, " + strTime.substr(3, 2) + " minutes"; //,"+strTime.substr(6, 2)+" seconds.";
    } else {
      strTime = strTime.substr(14, 2) + "m"; //strTime.substr(14, 5);
      prettyPrint = strTime + " minutes.";
    }

    if (totSecs > 0) {

      // refresh badge text
      chrome.action.setBadgeText({
        text: strTime
      });
      // refresh tooltip text
      chrome.action.setTitle({
        title: "Osmosis Companion\n\nNext $OSMO rewards in:\n" + prettyPrint + "\n\n"
      });

    } else {
      chrome.action.setBadgeText({
        text: "dist..."
      });

      // only call API again after ~20 minutes, as it seems to be delayed during rewards...
      if (totSecs > -600) {

        chrome.action.setTitle({
          title: "Osmosis Companion\n\nClaim your rewards now!\n\n\nGetting next epoch from API in " + Math.floor((600 + totSecs) / 60) + " minutes...\n\n"
        });

      } else {
        rewardDistribution();
      }
    }
  }

  function rewardDistribution() {
    // if epoch is met, call API and save to localstorage.
    console.log("rewards distributed! Getting next epoch from API endpoint...");
    updateEpochFromAPI();
  }

  let badgeText = "load...";
  chrome.action.setBadgeText({
    text: badgeText
  });


  function updateEpochFromAPI() {
    fetchEpochs()
      .then((res) => res.json())
      .then((data) => {
        let new_epoch_end_unix = calculate_epoch_end_unix(data.epochs);


        // set storage:
        chrome.storage.local.set({
          "epoch_end_unix": new_epoch_end_unix
        });

        // update the badge
        updateCountdownDisplay(new_epoch_end_unix);
      });
  }


  var fetchEpochs = function() {
    return fetch("https://lcd-osmosis.keplr.app/osmosis/epochs/v1beta1/epochs", {
      "headers": {
        "accept": "application/json, text/plain, */*",
        "accept-language": "en-US,en;q=0.9",
        "sec-fetch-dest": "empty",
        "sec-fetch-mode": "cors",
        "sec-fetch-site": "cross-site",
        "sec-gpc": "1"
      },
      "referrer": "https://app.osmosis.zone/",
      "referrerPolicy": "strict-origin-when-cross-origin",
      "body": null,
      "method": "GET",
      "mode": "cors",
      "credentials": "omit"
    });
  };

  var calculate_epoch_end_unix = function(epochs) {
    // time of epoch:
    var epoch_start_unix = null;
    var epoch_end_unix = null;
    var epoch_duration = "86400"; // 1 day's seconds
    // calculate end time of epoch
    epochs.forEach((epoch, i) => {
      if (epoch.identifier == "day") {
        epoch_start_unix = Date.parse(epoch.current_epoch_start_time);
        epoch_end_unix = epoch_start_unix + parseInt(epoch_duration * 1000);
      }
    });
    return epoch_end_unix;
  }

}