// ==UserScript==
// @name         nyaa.si/sukebei.nyaa.si helper
// @namespace    https://nyaa.si/
// @version      0.1
// @description  infinite scroll and image previews of torrents, hold SHIFT key and move mouse over the torrent row to start loading images, white loader means it's loading, so wait, red loader means that you have hit request limit (can't do anything about that), wait a bit (half a second) and try again, to load next page, scroll at the bottom (scrollbar needs to hit the bottom), left most top corner has page information - current page and total known pages (updates upon loading next page)
// @author       Mossshine
// @match        https://sukebei.nyaa.si/*
// @match        https://nyaa.si/*
// @grant        none
// @downloadURL none
// ==/UserScript==



(function() {
    'use strict';

    const BASE_URL = `${window.location.protocol}//${window.location.hostname}`;
    const IMAGE_REGEXP = /http(.*jpg|.*png)/g;
    const NEW_LINES = /\]/g;

    $('body').prepend(`
<style>
    .preloader {
        display: inline-block;
        position: relative;
        width: auto;
        height: 10px;
    }
    .preloader:after {
        content: " ";
        display: block;
        border-radius: 50%;
        width: 0;
        height: 0;
        position: relative;
        top: -8px;
        left: 31px;
        box-sizing: border-box;
        border: 12px solid #fff;
        border-color: #fff transparent #fff transparent;
        animation: preloader 1.2s infinite;
    }
    .total-known-pages .preloader:after {
        left: 0px !important;
    }
    .preloader.error:after {
        border-color: #fb2b48 transparent #fb2b48 transparent;
    }
    @keyframes preloader {
        0% {
            transform: rotate(0);
            animation-timing-function: cubic-bezier(0.55, 0.055, 0.675, 0.19);
        }
        50% {
            transform: rotate(900deg);
            animation-timing-function: cubic-bezier(0.215, 0.61, 0.355, 1);
        }
        100% {
            transform: rotate(1800deg);
        }
    }

    .loaded {
        background: black !important;
    }
    .torrent-previews .image {
        height: 125px;
        width: auto;
        object-fit: contain;
        padding: 5px;
    }
    .torrent-previews::-webkit-scrollbar {
        width: 0;
        height: 0;
    }
    .torrent-previews {
        display: flex;
        overflow-x: scroll;
        scrollbar-width: none;
    }
    .paginator-status .out-of {
        display: block;
        border-bottom: 2px solid #afafaf;
        margin-bottom: 3px;
    }
    .paginator-status {
        z-index: 999999999;
        position: fixed;
        display: flex;
        flex-direction: column;
        font-size: 25px;
        text-align: center;
        padding: 10px;
        background: #0000007a;
        border-bottom-right-radius: 10px;
    }
</style>   
<div class="paginator-status" style="display: none;">
    <span class="actual-page">1</span>
    <span class="out-of"></span>
    <span class="total-known-pages">1</span>
</div> 
    `);

    function Utilities() {}

    Utilities.prototype = {
        constructor: Utilities,
        nextPage: function (uri) {
            if(uri.has('p')) {
                uri.set('p', (parseInt(uri.get('p')) + 1).toString())
            } else {
                uri.set('p', '2');
            }
            return uri;
        },
        currentPage: function (uri) {
            if(uri.has('p')) {
                return uri.get('p');
            } else {
                return 1;
            }
        }
    };

    const Utils = new Utilities();

    let uri = new URLSearchParams(window.location.search);

    let isLoadingNextPage = false;
    $(window).on('wheel', function () {
        if(isLoadingNextPage === true) {
            return;
        }
        if(($(window).scrollTop() + $(window).height()) === $(document).height()) {
            Utils.nextPage(uri);

            isLoadingNextPage = true;
            $('.total-known-pages').html(`<div class="preloader"></div>`);

            $.ajax({
                url: BASE_URL + '/?' + uri.toString(),
                type: "GET",
                success: function (rawHtml) {
                    isLoadingNextPage = false;
                    let table = $(rawHtml).find('.torrent-list');
                    $('.torrent-list').find('tbody').append(table.find('tbody').html());

                    let currentHighest = 0;
                    $(rawHtml).find('ul.pagination a').each(function () {
                        let page = parseInt($(this).html());
                        if(page > currentHighest) {
                            currentHighest = page;
                        }
                    })

                    $('.actual-page').html(Utils.currentPage(uri));
                    $('.total-known-pages').html(currentHighest);
                    bindPreviews();
                }
            })
        }
    });

    let currentHighest = 0;
    $('ul.pagination').find('a').each(function () {
        let page = parseInt($(this).html());
        if(page > currentHighest) {
            currentHighest = page;
        }
    })

    $('.actual-page').html(Utils.currentPage(uri));
    $('.total-known-pages').html(currentHighest);
    $('.paginator-status').css('display', 'flex');

    bindPreviews();
    function bindPreviews()
    {
        $(".torrent-list tr:not(.loaded)").off().on('mouseover',function (e) {
            if(e.shiftKey === false) {
                return;
            }
            let row = $(this);
            if(row.hasClass('loaded') || row.hasClass('loading')) {
                return;
            }

            let torrentUrl = row.find("td[colspan='2'] > a");
            if(torrentUrl.length === 0) {
                return;
            }
            row.addClass('loading');

            let category = row.find('td:first-child > a');

            $.ajax({
                url: BASE_URL + torrentUrl.attr('href'),
                type: "GET",
                beforeSend: function () {
                    let preloader = category.find('.preloader');
                    if(preloader.length === 0) {
                        category.find('img').css('display', 'none');
                        category.append(`<div class="preloader"></div>`);
                    } else {
                        preloader.removeClass('error');
                    }
                },
                statusCode: {
                    429: function () {
                        row.removeClass('loading');
                        let preloader = category.find('.preloader');
                        if(preloader.length !== 0) {
                            preloader.addClass('error');
                        }
                    }
                },
                error: function () {
                    row.removeClass('loading');
                    let preloader = category.find('.preloader');
                    if(preloader.length !== 0) {
                        preloader.addClass('error');
                    }
                },
                success: function (rawHtml) {
                    row.removeClass('loading');
                    if(row.hasClass('loaded')) {
                        return;
                    }
                    row.addClass('loaded');
                    let rawDescription = $(rawHtml).find('#torrent-description').html();

                    rawDescription = rawDescription.replace(NEW_LINES, "\n");

                    let m;
                    let images = [];

                    while ((m = IMAGE_REGEXP.exec(rawDescription)) !== null) {
                        if (m.index === IMAGE_REGEXP.lastIndex) {
                            IMAGE_REGEXP.lastIndex++;
                        }

                        m.forEach((match, groupIndex) => {
                            if(groupIndex === 0) {
                                images.push(`<img class="image" src="${match}">`);
                            }
                        });
                    }
                    category.find('.preloader').each(function () {
                        $(this).remove();
                    })
                    category.find('img').css('display', 'block');

                    if(images.length > 0) {
                        row.after(`<tr><td colspan="9"><div class="torrent-previews">${images.join('\n')}</div></td></tr>`);
                    }
                }
            })
        });
    }
})();