// ==UserScript==
// @name         一键下载Steam云存档（增强版）
// @namespace    SteamCloudSaveEnhanced
// @version      1.0.0
// @description  Auto download Steam Cloud Save - Enhanced: parallel download, retry, error handling, progress bar
// @author       DreamNya / SmallFork (enhanced)
// @match        https://store.steampowered.com/account/remotestorageapp?appid=*
// @match        https://store.steampowered.com/account/remotestorageapp/?appid=*
// @require      https://cdn.jsdelivr.net/npm/jszip@3.9.1/dist/jszip.min.js
// @grant        GM_xmlhttpRequest
// @grant        GM_download
// @grant        GM_addStyle
// @run-at       document-end
// @license      MIT
// @connect      steampowered.com
// @connect      steamusercontent.com
// ==/UserScript==

/* global JSZip */
/* eslint-disable no-constant-condition */

(function () {
    'use strict';

    // ==================== 配置 ====================
    const settings = {
        globalDelay: 100,          // 存档下载间隔 单位：ms
        concurrency: 3,            // 并发下载数
        maxRetry: 2,               // 失败重试次数
        retryDelay: 1000,          // 重试间隔 ms
        requestTimeout: 30000,     // 单文件请求超时 30s
        pageSize: 50,              // Steam 每页文件数
    };

    const $ = unsafeWindow.jQuery;
    let _cancelled = false;       // 取消标志

    // ==================== UI ====================
    GM_addStyle(`
        #AutoDownload {
            display: inline-block;
            padding: 10px 20px;
            border-radius: 8px;
            background: #2ECC71;
            color: #ffffff;
            font-size: 15px;
            border: 1px solid #2ECC71;
            transition: background .2s, transform .1s;
            cursor: pointer;
        }
        #AutoDownload:hover { background: #27AE60; }
        #AutoDownload:active { transform: scale(0.97); }
        #AutoDownload.disabled { cursor: not-allowed; opacity: 0.7; }
        #AutoDownload.cancel-mode { background: #E74C3C; border-color: #E74C3C; }
        #AutoDownload.cancel-mode:hover { background: #C0392B; }

        #csProgressWrap {
            margin-top: 12px;
            display: none;
        }
        #csProgressBar {
            width: 100%;
            height: 6px;
            background: rgba(255,255,255,0.1);
            border-radius: 3px;
            overflow: hidden;
        }
        #csProgressFill {
            height: 100%;
            background: linear-gradient(90deg, #2ECC71, #27AE60);
            border-radius: 3px;
            transition: width .3s ease;
            width: 0%;
        }
        #csProgressText {
            margin-top: 6px;
            font-size: 12px;
            color: #8a9ba8;
        }
        #csLog {
            margin-top: 8px;
            max-height: 150px;
            overflow-y: auto;
            font-size: 12px;
            font-family: monospace;
            color: #8a9ba8;
            display: none;
        }
        #csLog .log-fail { color: #E74C3C; }
        #csLog .log-ok { color: #27AE60; }
        #csLog .log-warn { color: #F39C12; }
    `);

    // 插入按钮和进度条
    const button = $('<button id="AutoDownload">一键下载（增强版）</button>').prependTo('#main_content');
    const progressWrap = $(`
        <div id="csProgressWrap">
            <div id="csProgressBar"><div id="csProgressFill"></div></div>
            <div id="csProgressText">准备中...</div>
        </div>
        <div id="csLog"></div>
    `).insertAfter(button);

    const $progressFill = $('#csProgressFill');
    const $progressText = $('#csProgressText');
    const $log = $('#csLog');

    button.on('click', async function () {
        if ($(this).hasClass('disabled') && !$(this).hasClass('cancel-mode')) return;
        if ($(this).hasClass('cancel-mode')) {
            _cancelled = true;
            $(this).removeClass('cancel-mode disabled').text('取消中...').prop('disabled', true);
            return;
        }
        $(this).addClass('disabled').text('下载中... 点击取消');
        // 第二次点击进入取消模式
        setTimeout(() => {
            if (!_cancelled) $(this).addClass('cancel-mode').text('取消下载');
        }, 500);
        progressWrap.show();
        $log.show();
        try {
            await main();
            if (!_cancelled) {
                button.text('下载完成');
                button.removeClass('disabled cancel-mode');
            } else {
                button.text('已取消');
                button.removeClass('disabled cancel-mode');
            }
        } catch (e) {
            log('致命错误: ' + (e.message || e), 'fail');
            button.text('下载失败').removeClass('disabled cancel-mode');
        }
    });

    // ==================== 日志 ====================
    function log(msg, type) {
        const cls = type === 'fail' ? 'log-fail' : type === 'ok' ? 'log-ok' : type === 'warn' ? 'log-warn' : '';
        $log.append(`<div class="${cls}">[${new Date().toLocaleTimeString()}] ${msg}</div>`);
        $log.scrollTop($log[0].scrollHeight);
    }

    function updateProgress(current, total) {
        const pct = total > 0 ? Math.round((current / total) * 100) : 0;
        $progressFill.css('width', pct + '%');
        $progressText.text(`下载进度 ${current}/${total} (${pct}%)`);
    }

    // ==================== 主流程 ====================
    async function main() {
        _cancelled = false;
        const appid = location.href.match(/appid=(\d+)/)[1];
        const tittle = ($('h2:last').text().trim() || `appid${appid}`).replace(/[\\/:*?"<>|]/g, '_');
        let index = 0;
        const filesInfos = [];

        // Phase 1: 分页抓取文件列表
        log(`开始获取 AppID ${appid} 的云存档文件列表...`);
        while (true) {
            if (_cancelled) { log('用户取消', 'warn'); break; }
            const url = `https://store.steampowered.com/account/remotestorageapp?appid=${appid}&index=${index}`;
            const dom = await GetPage(url);
            const filesInfo = GetFilesInfo(dom, index);
            filesInfos.push(...filesInfo);
            log(`第 ${Math.floor(index / settings.pageSize) + 1} 页: 获取 ${filesInfo.length} 个文件`, 'ok');

            const nextPage = CheckNextPage(dom, index);
            if (nextPage) {
                index += settings.pageSize;
                await sleep(200);
            } else {
                break;
            }
        }

        log(`共发现 ${filesInfos.length} 个文件，开始下载...`);
        updateProgress(0, filesInfos.length);

        // Phase 2: 并发下载所有文件
        await DownloadFiles(filesInfos, tittle);
    }

    // ==================== 页面获取 ====================
    function GetPage(url) {
        return new Promise((resolve, reject) => {
            GM_xmlhttpRequest({
                url,
                method: 'GET',
                responseType: 'text',
                timeout: settings.requestTimeout,
                onload: (xhr) => {
                    if (xhr.status === 200) {
                        const dom = new DOMParser().parseFromString(xhr.responseText, 'text/html');
                        // 检测是否被重定向到登录页
                        if (dom.querySelector('input[name="username"]') && !dom.querySelector('#main_content')) {
                            reject(new Error('Steam 登录态已过期，请重新登录'));
                            return;
                        }
                        resolve(dom);
                    } else {
                        reject(new Error(`页面获取失败 status:${xhr.status} url:${url}`));
                    }
                },
                onerror: () => reject(new Error(`网络错误: ${url}`)),
                ontimeout: () => reject(new Error(`请求超时: ${url}`)),
            });
        });
    }

    // ==================== 解析文件信息 ====================
    function GetFilesInfo(dom, globalIndex) {
        // 使用原生 children 替代非标准的 childElements()
        return [...dom.querySelectorAll('tr')].slice(1).map((node, index) => {
            const childrens = [...node.children];
            if (childrens.length < 5) return null;

            const mainFolder = childrens[0].innerText.trim();
            const subFolder = childrens[1].innerText.trim();
            const path = mainFolder ? `${mainFolder}/${subFolder}` : subFolder;
            const size = childrens[2].innerText.trim();
            const date = childrens[3].innerText.trim();
            const href = childrens[4].querySelector('a')?.href || '';

            return { index: globalIndex + index, path, size, date, href };
        }).filter(Boolean);
    }

    // ==================== 翻页检测（null 安全） ====================
    function CheckNextPage(dom, index) {
        try {
            const nextLink = dom.querySelector('#main_content > a:last-child');
            if (!nextLink || !nextLink.href) return false;
            const match = nextLink.href.match(/index=(\d+)/);
            if (!match) return false;
            const nextIndex = parseInt(match[1], 10) || 0;
            return nextIndex > index;
        } catch {
            return false;
        }
    }

    // ==================== 并发下载+打包 ====================
    async function DownloadFiles(filesInfos, tittle) {
        const zip = new JSZip();
        const csvRows = [['序号', '文件名', '文件大小', '写入日期', '下载状态']];
        const total = filesInfos.length;
        let completed = 0;
        let successCount = 0;
        let failCount = 0;

        // 并发池：N 个 worker 从队列取任务
        let taskIdx = 0;
        async function worker(workerId) {
            while (taskIdx < filesInfos.length) {
                if (_cancelled) break;
                const myIdx = taskIdx++;
                const fileInfo = filesInfos[myIdx];
                const { blob, status } = await DownloadFileWithRetry(fileInfo.href);

                const statusText = status === 200 ? 'OK' : `Fail(${status})`;
                csvRows.push([
                    String(myIdx + 1),
                    csvEscape(fileInfo.path),
                    csvEscape(fileInfo.size),
                    csvEscape(fileInfo.date),
                    `${status} ${statusText}`
                ]);

                if (status === 200 && blob) {
                    zip.file(fileInfo.path, blob);
                    successCount++;
                } else {
                    failCount++;
                    log(`[W${workerId}] 失败: ${fileInfo.path} (status:${status})`, 'fail');
                }

                completed++;
                updateProgress(completed, total);
                await sleep(settings.globalDelay);
            }
        }

        // 启动并发 worker
        const workers = [];
        for (let i = 0; i < Math.min(settings.concurrency, filesInfos.length); i++) {
            workers.push(worker(i));
        }
        await Promise.all(workers);

        log(`下载完成: 成功 ${successCount}, 失败 ${failCount}`, successCount > 0 ? 'ok' : 'fail');

        // 即使部分失败也打包已下载的文件
        // CSV 带 BOM 防止 Excel 乱码，字段双引号包裹防止逗号破坏
        const csvContent = '\uFEFF' + csvRows.map(row =>
            row.map(cell => `"${String(cell).replace(/"/g, '""')}"`).join(',')
        ).join('\n');
        zip.file('下载结果.csv', csvContent);

        log('正在生成压缩包...');
        const content = await zip.generateAsync({ type: 'blob' });
        const blobUrl = URL.createObjectURL(content);
        GM_download(blobUrl, `${tittle} ${Date.now()}.zip`);
        log(`压缩包已生成并触发下载: ${tittle}.zip`, 'ok');

        // 延迟 revoke（GM_download 异步触发浏览器下载）
        setTimeout(() => URL.revokeObjectURL(blobUrl), 60000);
    }

    // ==================== 单文件下载（带重试） ====================
    function DownloadFileWithRetry(url) {
        return new Promise((resolve) => {
            let attempt = 0;
            function tryFetch() {
                GM_xmlhttpRequest({
                    url,
                    method: 'GET',
                    responseType: 'blob',
                    timeout: settings.requestTimeout,
                    onload: (xhr) => {
                        resolve({ blob: xhr.response, status: xhr.status });
                    },
                    onerror: () => {
                        if (attempt < settings.maxRetry) {
                            attempt++;
                            log(`重试 ${attempt}/${settings.maxRetry}: ${url}`, 'warn');
                            setTimeout(tryFetch, settings.retryDelay * attempt);
                        } else {
                            resolve({ blob: null, status: 0 });
                        }
                    },
                    ontimeout: () => {
                        if (attempt < settings.maxRetry) {
                            attempt++;
                            log(`超时重试 ${attempt}/${settings.maxRetry}: ${url}`, 'warn');
                            setTimeout(tryFetch, settings.retryDelay * attempt);
                        } else {
                            resolve({ blob: null, status: 408 });
                        }
                    },
                });
            }
            tryFetch();
        });
    }

    // ==================== 工具函数 ====================
    function sleep(ms) {
        return new Promise((resolve) => setTimeout(resolve, ms ?? settings.globalDelay));
    }

    function csvEscape(str) {
        return String(str || '');
    }

})();