// uBlock Origin - a browser extension to block requests.
// Copyright (C) 2019-present Raymond Hill
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see {http://www.gnu.org/licenses/}.
//
// Home: https://github.com/gorhill/uBlock

(function() {
  "use strict";
  // https://developers.google.com/analytics/devguides/collection/analyticsjs/
  const noopfn = function() {
  };
  //
  const Tracker = function() {
  };
  const p = Tracker.prototype;
  p.get = noopfn;
  p.set = noopfn;
  p.send = noopfn;
  //
  const w = window;
  const gaName = w.GoogleAnalyticsObject || "ga";
  const gaQueue = w[gaName];
  // https://github.com/uBlockOrigin/uAssets/pull/4115
  const ga = function() {
    const len = arguments.length;
    if (len === 0) return;
    const args = Array.from(arguments);
    let fn;
    let a = args[len - 1];
    if (a instanceof Object && a.hitCallback instanceof Function) {
      fn = a.hitCallback;
    } else if (a instanceof Function) {
      fn = () => {
        a(ga.create());
      };
    } else {
      const pos = args.indexOf("hitCallback");
      if (pos !== -1 && args[pos + 1] instanceof Function) {
        fn = args[pos + 1];
      }
    }
    if (fn instanceof Function === false) return;
    try {
      fn();
    } catch (ex) {
    }
  };
  ga.create = function() {
    return new Tracker();
  };
  ga.getByName = function() {
    return new Tracker();
  };
  ga.getAll = function() {
    return [new Tracker()];
  };
  ga.remove = noopfn;
  // https://github.com/uBlockOrigin/uAssets/issues/2107
  ga.loaded = true;
  w[gaName] = ga;
  // https://github.com/gorhill/uBlock/issues/3075
  const dl = w.dataLayer;
  if (dl instanceof Object) {
    if (dl.hide instanceof Object && typeof dl.hide.end === "function") {
      dl.hide.end();
      dl.hide.end = () => { };
    }
    if (typeof dl.push === "function") {
      const doCallback = function(item) {
        if (item instanceof Object === false) return;
        if (typeof item.eventCallback !== "function") return;
        setTimeout(item.eventCallback, 1);
        item.eventCallback = () => { };
      };
      dl.push = new Proxy(dl.push, {
        apply: function(target, thisArg, args) {
          doCallback(args[0]);
          return Reflect.apply(target, thisArg, args);
        },
      });
      if (Array.isArray(dl)) {
        const q = dl.slice();
        for (const item of q) {
          doCallback(item);
        }
      }
    }
  }
  // empty ga queue
  if (gaQueue instanceof Function && Array.isArray(gaQueue.q)) {
    const q = gaQueue.q.slice();
    gaQueue.q.length = 0;
    for (const entry of q) {
      ga(...entry);
    }
  }
})();