function main() {
  //This script excludes Tier 3 locations from campaigns, making it useful for businesses that struggle to operate in areas with higher Covid restrictions.
  //It uses a spreadsheet as its data source, which features Google locations ids for each of the 40+ counties/cities in Tier 3.
  //This data is updated manually, using the information provided on the .gov site (https://www.gov.uk/guidance/full-list-of-local-restriction-tiers-by-area).
  //This data will be monitored and updated on a regular basis.

  //As the data is subject to change, the script first removes all excluded locations.
  //If the account does not run ads in certain regions/cities, please make a copy of this spreadsheet: https://docs.google.com/spreadsheets/d/108KJskfOoBVZd5MWDxGFmLckc4PQIsehn3_VIs56WPc/edit#gid=0.
  //You will find a list of Google Ad region/city codes attached to the sheet.
  //Add the codes of the regions you wish to stay excluded and replace the url in the exclusionDataURL variable.

  //If the account does not have any data in it, leave the url in the exclusionDataURL variable as it is.

  var exclusionDataURL =
    "https://docs.google.com/spreadsheets/d/108KJskfOoBVZd5MWDxGFmLckc4PQIsehn3_VIs56WPc/edit#gid=0"; //If you have a list of excluded locations, paste it here - otherwise leave this url as is

  var tierDataURL =
    "https://docs.google.com/spreadsheets/d/1e8ji10sO3EP_4LJt2HmRx1m6qUNLKixGlACmM27xA70/edit?usp=sharing";

  //Pass in a nested array and return a flattened array
  function flatten(array) {
    var flat = [];
    for (var i = 0; i < arguments.length; i += 1) {
      if (arguments[i] instanceof Array) {
        flat.push.apply(flat, flatten.apply(this, arguments[i]));
      } else {
        flat.push(arguments[i]);
      }
    }
    return flat;
  }

  //Get data from each sheet
  function pullSheetData(url, rowStart) {
    var results = [];
    var spreadsheet = SpreadsheetApp.openByUrl(url);
    var ss = spreadsheet.getActiveSheet();
    var values = ss.getRange(rowStart, 2, ss.getLastRow()).getValues();
    if (values) {
      results.push(values);
      var mergeResults = flatten(results).slice(0, -1);
      return mergeResults;
    }
  }

  //Check for values in an array
  function notInArray(array, value) {
    return array.indexOf(value) === -1;
  }

  //Call pullSheetData for each sheet
  var tierData = pullSheetData(tierDataURL, 1);
  var exclusionData = pullSheetData(exclusionDataURL, 2);

  //Remove excluded locations from the campaign in case they have moved tiers
  function resetCampaigns() {
    var campaignIterator = AdsApp.campaigns()
      .withCondition("Status = ENABLED")
      .get();
    while (campaignIterator.hasNext()) {
      var campaign = campaignIterator.next();
      var currentExclusions = campaign.targeting().excludedLocations().get();
      while (currentExclusions.hasNext()) {
        var resetLocation = currentExclusions.next();
        var resetLocationId = resetLocation.getId();
        if (notInArray(exclusionData, resetLocationId)) {
          resetLocation.remove();
        }
      }
    }
    Logger.log("Campaigns re-enabled");
  }

  //Add Tier locations to all campaigns
  function removeLocations() {
    var campaignIterator = AdsApp.campaigns()
      .withCondition("Status = ENABLED")
      .get();
    while (campaignIterator.hasNext()) {
      var campaign = campaignIterator.next();
      for (var i = 0; i < tierData.length; i += 1) { 
        campaign.excludeLocation(tierData[i]);
      }
    }
    Logger.log("Campaigns paused in areas under Tier 3 restrictions");
  }

  //Run campaigns
  if (!tierData) {
    resetCampaigns();
    Logger.log("No more Tier 3 locations - hooray");
  } else {
    resetCampaigns();
    removeLocations();
  }
}

/*
Created by Analysts at Adapt - https://www.adaptworldwide.com/
Written by Tom Meyrick
      
   Change log:
    - version 1.0 (initial version)
    
*/