// ==UserScript==
// @name         osu! Beatmap Download Link Replacer
// @namespace    http://tampermonkey.net/
// @version      1.1
// @description  将 osu!direct 谱面页面的 supporter 链接替换为osu://dl/[id] (方便lazer用户下载谱面，stable用户仍需开通supporter才能在游戏内使用osu!direct)
// @author       theinspired with 豆包
// @match        https://osu.ppy.sh/*
// @grant        none
// @license      MIT
// @run-at       document-start
// ==/UserScript==

(function() {
    'use strict';

    // 1. 从URL中提取beatmapset ID
    function getBeatmapSetId() {
        const regex = /https:\/\/osu\.ppy\.sh\/beatmapsets\/(\d+)/;
        const match = window.location.href.match(regex);

        if (!match || !match[1]) {
            console.error("无法从URL中提取beatmapset ID");
            return null;
        }
        return match[1];
    }

    // 2. 替换页面中的support链接（核心逻辑）
    function replaceSupportLinks() {
        const beatmapId = getBeatmapSetId();
        if (!beatmapId) return;

        const targetLink = `osu://dl/${beatmapId}`;
        const originalLink = "https://osu.ppy.sh/home/support";

        // 查找并替换所有相关链接
        const links = document.querySelectorAll(`a[href*="${originalLink}"]`);
        links.forEach(link => {
            link.href = targetLink;
            console.log(`已替换链接: ${originalLink} -> ${targetLink}`);
        });
    }

    // 3. 监听页面动态加载的元素
    function setupMutationObserver() {
        const observer = new MutationObserver((mutations) => {
            mutations.forEach((mutation) => {
                if (mutation.addedNodes.length > 0) {
                    replaceSupportLinks();
                }
            });
        });

        observer.observe(document.body, {
            childList: true,
            subtree: true
        });

        return observer;
    }

    // 4. 监听URL变化（解决SPA跳转问题）
    function setupUrlChangeListener() {
        // 保存当前URL，用于对比变化
        let currentUrl = window.location.href;

        // 监听popstate事件（浏览器前进/后退）
        window.addEventListener('popstate', () => {
            if (window.location.href !== currentUrl) {
                currentUrl = window.location.href;
                setTimeout(replaceSupportLinks, 100); // 延迟确保DOM已更新
            }
        });

        // 重写pushState和replaceState（SPA跳转核心）
        const originalPushState = history.pushState;
        const originalReplaceState = history.replaceState;

        history.pushState = function(...args) {
            originalPushState.apply(this, args);
            currentUrl = window.location.href;
            setTimeout(replaceSupportLinks, 100);
        };

        history.replaceState = function(...args) {
            originalReplaceState.apply(this, args);
            currentUrl = window.location.href;
            setTimeout(replaceSupportLinks, 100);
        };
    }

    // 初始化
    window.addEventListener('DOMContentLoaded', () => {
        replaceSupportLinks(); // 首次加载执行
        setupMutationObserver(); // 监听动态元素
        setupUrlChangeListener(); // 监听URL变化
    });

})();