// ==UserScript==
// @name         页面自动滑动 懒人阅读神器
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  添加一个开关按钮来控制页面自动滚动到底部
// @author       Your name
// @match        *://*/*
// @license           AGPL License
// @grant        GM_addStyle
// @downloadURL https://update.greasyfork.icu/scripts/535288/%E9%A1%B5%E9%9D%A2%E8%87%AA%E5%8A%A8%E6%BB%91%E5%8A%A8%20%E6%87%92%E4%BA%BA%E9%98%85%E8%AF%BB%E7%A5%9E%E5%99%A8.user.js
// @updateURL https://update.greasyfork.icu/scripts/535288/%E9%A1%B5%E9%9D%A2%E8%87%AA%E5%8A%A8%E6%BB%91%E5%8A%A8%20%E6%87%92%E4%BA%BA%E9%98%85%E8%AF%BB%E7%A5%9E%E5%99%A8.meta.js
// ==/UserScript==

(function() {
    'use strict';

    // 调试日志函数
    const debug = (msg) => {
        console.log(`[自动滚动] ${msg}`);
    };

    // 添加样式
    const styles = `
        .auto-scroll-btn {
            position: fixed;
            z-index: 2147483647;
            padding: 10px 20px;
            background: #4CAF50;
            color: white !important;
            border: none;
            border-radius: 5px;
            cursor: pointer !important;
            font-size: 14px;
            top: 20px;
            right: 20px;
            box-shadow: 0 2px 5px rgba(0,0,0,0.2);
            transition: all 0.3s ease;
            user-select: none;
            pointer-events: auto !important;
            opacity: 1 !important;
            visibility: visible !important;
            font-family: Arial, sans-serif !important;
        }
        .auto-scroll-btn:hover {
            opacity: 0.8 !important;
            transform: scale(1.05);
        }
        .auto-scroll-btn.active {
            background: #f44336;
        }
    `;

    // 创建style元素
    const styleSheet = document.createElement('style');
    styleSheet.textContent = styles;
    document.head.appendChild(styleSheet);

    // 创建按钮
    const button = document.createElement('button');
    button.className = 'auto-scroll-btn';
    button.textContent = '自动滚动';
    document.body.appendChild(button);

    let scrollInterval = null;
    let isScrolling = false;
    let scrollSpeed = 1; // 初始滚动速度

    // 获取文档实际高度
    function getDocHeight() {
        return Math.max(
            document.documentElement.scrollHeight,
            document.body.scrollHeight,
            document.documentElement.offsetHeight,
            document.body.offsetHeight
        );
    }

    // 获取当前滚动位置
    function getCurrentScroll() {
        return window.pageYOffset || document.documentElement.scrollTop;
    }

    // 检查是否到达底部
    function isBottomReached() {
        const windowHeight = window.innerHeight;
        const scrollTop = getCurrentScroll();
        const docHeight = getDocHeight();
        return (windowHeight + scrollTop >= docHeight - 50); // 添加50px缓冲区
    }

    // 滚动函数
    function autoScroll() {
        try {
            if (isBottomReached()) {
                debug('已到达底部，停止滚动');
                stopScrolling();
                return;
            }
            window.scrollBy({
                top: scrollSpeed,
                behavior: 'auto'
            });
        } catch (error) {
            debug('滚动出错：' + error.message);
            stopScrolling();
        }
    }

    // 开始滚动
    function startScrolling() {
        try {
            if (!isScrolling) {
                debug('开始滚动');
                isScrolling = true;
                button.classList.add('active');
                button.textContent = '停止滚动';
                scrollInterval = setInterval(autoScroll, 10);
            }
        } catch (error) {
            debug('启动滚动失败：' + error.message);
            stopScrolling();
        }
    }

    // 停止滚动
    function stopScrolling() {
        try {
            if (isScrolling) {
                debug('停止滚动');
                isScrolling = false;
                button.classList.remove('active');
                button.textContent = '自动滚动';
                if (scrollInterval) {
                    clearInterval(scrollInterval);
                    scrollInterval = null;
                }
            }
        } catch (error) {
            debug('停止滚动失败：' + error.message);
        }
    }

    // 状态检查
    function checkScrollingState() {
        if (isScrolling && !scrollInterval) {
            debug('检测到异常状态，重置滚动');
            stopScrolling();
        }
    }

    // 按钮点击事件
    button.addEventListener('click', function(e) {
        try {
            if (!e) e = window.event;
            e.preventDefault();
            e.stopPropagation();
            
            if (isScrolling) {
                stopScrolling();
            } else {
                startScrolling();
            }
        } catch (error) {
            debug('点击事件处理出错：' + error.message);
            stopScrolling();
        }
        return false;
    }, true);

    // 键盘事件 - 空格暂停/继续
    document.addEventListener('keydown', function(e) {
        if (e.code === 'Space' && e.target === document.body) {
            e.preventDefault();
            if (isScrolling) {
                stopScrolling();
            } else {
                startScrolling();
            }
        }
    });

    // 清理函数
    function cleanup() {
        try {
            stopScrolling();
            button.remove();
            styleSheet.remove();
        } catch (error) {
            debug('清理失败：' + error.message);
        }
    }

    // 页面卸载时清理
    window.addEventListener('unload', cleanup);

    // 定期检查滚动状态
    setInterval(checkScrollingState, 1000);

    debug('脚本初始化完成');
})();