// ==UserScript==
// @name        Amazon CPU Tamer
// @name:ja     Amazon CPU Tamer
// @name:zh-CN  Amazon CPU Tamer
// @namespace   knoa.jp
// @description It reduces CPU usage on Amazon shopping pages. Enjoy your snappy shopping.
// @description:ja AmazonのショッピングページでのCPU使用率を削減します。お買いものをサクサク楽しみましょう。
// @description:zh-CN 减少Amazon购物页面上的CPU利用率。顺利地享受买东西吧。
// @include     https://www.amazon.*
// @exclude     */cart/*
// @exclude     */buy/*
// @version     1.1.2
// @grant       none
// @run-at      document-start
// @downloadURL none
// ==/UserScript==

/*
[update] 1.1.2
minor fix.

*/
(function(){
  const SCRIPTNAME = 'Amazon Cpu Tamer';
  console.log(SCRIPTNAME);
  const TAMEDINTERVAL = 60*1000;
  /* tame quick intervals */
  window.originalSetInterval = window.setInterval;
  window.setInterval = function(f, interval, ...args){
    if(interval < TAMEDINTERVAL){
      console.log(SCRIPTNAME, 'interval:', interval, 'to', TAMEDINTERVAL);
      interval = TAMEDINTERVAL;
    }
    return window.originalSetInterval(f, interval, ...args);
  };
  /* add an associate tag */
  switch(location.host){
    case('www.amazon.com'):
      addTag('knoa-20');
      break;
    case('www.amazon.co.jp'):
      addTag('knoa-22');
      break;
  }
  function addTag(tag){
    const url = new URL(location.href);
    if(url.searchParams.get('tag') !== null) return;/* do not overwrite */
    const separator = (url.search === '') ? '?' : '&';
    console.log(SCRIPTNAME, 'associate tag:', tag);
    history.replaceState(null, document.title, location.href + separator + 'tag=' + tag);
  }
})();