// ==UserScript==
// @name         Random screenshot button
// @namespace    http://tampermonkey.net/
// @version      0.2
// @description  try to take over the world!
// @author       You
// @include      http*://prnt.sc/*
// @grant        none
// ==/UserScript==

(function() {
    const chars = 'abcdefghijklmnopqrstuvwxyz0123456789';
    const randomLength = 4;
    const urlBase = 'https://prnt.sc/nr';

    function randomPage() {
      let randomPage = [];
      for (let i = 0; i < randomLength; i++) {
        randomPage[i] = chars[Math.floor(Math.random() * chars.length)]
      }
      return urlBase + randomPage.join('');
    }
    function getRandomPage() {
        const r = randomPage();
        this.innerText = r;
        fetch(r).then(res => res.text())
            .then(text => {
                let src = text.match(/class="no-click screenshot-image" src="(.*?)"/)[1]
                document.getElementById("screenshot-image").src = src;
                window.history.pushState({}, "", r);
            })

    }
    window.onload = () => {
        let place = document.getElementsByClassName("image-constrain")[0];
        if (!place) {
            place = document.getElementsByClassName("page-constrain")[1];
        }
        const button = document.createElement("button");
        const block = document.createElement("div");
        block.classList.add("page-constrain");
        button.innerText = "Get Random";
        button.classList.add("image__title");
        button.onclick = getRandomPage;
        block.appendChild(button);
        place.prepend(block);
    }
})();