// ==UserScript==
// @name         FUCK CSDN（去除csdn搜索结果—百度/Google/Bing）
// @version      1.6
// @namespace    https://greasyfork.org/users/timmy
// @license      MIT
// @icon         https://free.picui.cn/free/2026/04/27/69eefef831bfd.png
// @description  搜索时自动注入 -site:csdn.net 过滤CSDN
// @author       timmy
// @match        *://www.google.com/*
// @match        *://www.google.com.hk/*
// @match        *://www.google.co.jp/*
// @match        *://www.baidu.com/*
// @match        *://www.bing.com/*
// @run-at       document-start
// @grant        none
// @downloadURL https://update.greasyfork.icu/scripts/575596/FUCK%20CSDN%EF%BC%88%E5%8E%BB%E9%99%A4csdn%E6%90%9C%E7%B4%A2%E7%BB%93%E6%9E%9C%E2%80%94%E7%99%BE%E5%BA%A6GoogleBing%EF%BC%89.user.js
// @updateURL https://update.greasyfork.icu/scripts/575596/FUCK%20CSDN%EF%BC%88%E5%8E%BB%E9%99%A4csdn%E6%90%9C%E7%B4%A2%E7%BB%93%E6%9E%9C%E2%80%94%E7%99%BE%E5%BA%A6GoogleBing%EF%BC%89.meta.js
// ==/UserScript==

(function () {
  'use strict';

  const BLOCKED = ['csdn.net'];
  const EXCLUDE_SUFFIX = BLOCKED.map(d => `-site:${d}`).join(' ');

  function getEngine() {
    const h = location.hostname;
    if (h.includes('baidu.com'))  return 'baidu';
    if (h.includes('google.'))    return 'google';
    if (h.includes('bing.com'))   return 'bing';
    return null;
  }

  function getInputSelector(engine) {
    if (engine === 'baidu')  return '#kw';
    if (engine === 'google') return 'input[name="q"]';
    if (engine === 'bing')   return '#sb_form_q';
    return null;
  }

  function getParamName(engine) {
    if (engine === 'baidu') return 'wd';
    return 'q';
  }

  function stripExclude(val) {
    if (!val) return '';
    return BLOCKED.reduce((acc, d) => {
      return acc.replace(new RegExp(`\\s*-site:${d.replace('.', '\\.')}`, 'gi'), '');
    }, val).trimEnd();
  }

  function injectExclude(val) {
    const base = stripExclude(val).trimEnd();
    if (!base) return base;
    return base + ' ' + EXCLUDE_SUFFIX;
  }

  // 注入 URL 字符串里的搜索参数
  function injectUrl(url) {
    try {
      const urlObj = new URL(url, location.origin);
      // 只处理百度搜索路径
      if (!urlObj.pathname.startsWith('/s') && urlObj.pathname !== '/') return url;
      const params = ['wd', 'word', 'kw'];
      let changed = false;
      for (const p of params) {
        const val = urlObj.searchParams.get(p);
        if (val) {
          const injected = injectExclude(val);
          if (injected !== val) {
            urlObj.searchParams.set(p, injected);
            changed = true;
          }
        }
      }
      return changed ? urlObj.toString() : url;
    } catch (e) {
      return url;
    }
  }

  // 拦截百度的 XHR 请求
  function interceptXHR() {
    const OrigOpen = XMLHttpRequest.prototype.open;
    XMLHttpRequest.prototype.open = function (method, url, ...rest) {
      const newUrl = injectUrl(url);
      return OrigOpen.call(this, method, newUrl, ...rest);
    };
  }

  // 拦截百度的 fetch 请求
  function interceptFetch() {
    const origFetch = window.fetch;
    window.fetch = function (input, init) {
      if (typeof input === 'string') {
        input = injectUrl(input);
      } else if (input instanceof Request) {
        const newUrl = injectUrl(input.url);
        if (newUrl !== input.url) {
          input = new Request(newUrl, input);
        }
      }
      return origFetch.call(this, input, init);
    };
  }

  // 拦截 history.pushState / replaceState（百度结果页跳转用这个）
  function interceptHistory() {
    ['pushState', 'replaceState'].forEach(method => {
      const orig = history[method];
      history[method] = function (state, title, url) {
        if (url) {
          url = injectUrl(url);
        }
        return orig.call(this, state, title, url);
      };
    });
  }

  function checkUrlOnLoad(engine) {
    const isResultPage =
      (engine === 'baidu'  && /\/s\b/.test(location.pathname)) ||
      (engine === 'google' && location.pathname === '/search')  ||
      (engine === 'bing'   && location.pathname === '/search');

    if (!isResultPage) return;

    const sp = new URLSearchParams(location.search);
    const param = getParamName(engine);
    const raw = sp.get(param) || sp.get('word') || sp.get('kw');
    if (!raw) return;

    const injected = injectExclude(raw);
    if (injected === raw) return;

    sp.set(param, injected);
    location.replace(`${location.pathname}?${sp}`);
  }

  function waitForElement(selector, cb, timeout = 8000) {
    const el = document.querySelector(selector);
    if (el) { cb(el); return; }
    const obs = new MutationObserver((_, o) => {
      const found = document.querySelector(selector);
      if (found) { o.disconnect(); cb(found); }
    });
    obs.observe(document.documentElement, { childList: true, subtree: true });
    setTimeout(() => obs.disconnect(), timeout);
  }

  function setupInputHandler(inputEl) {
    if (inputEl.dataset.filterEnabled) return;
    inputEl.dataset.filterEnabled = '1';

    let userVal = stripExclude(inputEl.value);

    inputEl.addEventListener('focus', () => {
      inputEl.value = userVal;
    });
    inputEl.addEventListener('input', () => {
      userVal = stripExclude(inputEl.value);
    });
    inputEl.addEventListener('blur', () => {
      userVal = stripExclude(inputEl.value);
      if (userVal) inputEl.value = injectExclude(userVal);
    });
    inputEl.addEventListener('keydown', (e) => {
      if (e.key !== 'Enter') return;
      userVal = stripExclude(inputEl.value);
      inputEl.value = injectExclude(userVal);
    });

    const form = inputEl.closest('form');
    if (form) {
      form.addEventListener('submit', () => {
        userVal = stripExclude(inputEl.value);
        inputEl.value = injectExclude(userVal);
      }, { capture: true });
    }

    ['#su', '#search-form .btn', 'input[type=submit]', 'button[type=submit]'].forEach(sel => {
      document.querySelectorAll(sel).forEach(btn => {
        btn.addEventListener('click', () => {
          userVal = stripExclude(inputEl.value);
          inputEl.value = injectExclude(userVal);
        }, { capture: true });
      });
    });
  }

  function watchInputRebind(selector) {
    let lastEl = null;
    const obs = new MutationObserver(() => {
      const el = document.querySelector(selector);
      if (el && el !== lastEl) {
        lastEl = el;
        setupInputHandler(el);
      }
    });
    obs.observe(document.documentElement, { childList: true, subtree: true });
  }

  const engine = getEngine();
  if (!engine) return;

  // 百度专项：document-start 阶段拦截所有网络请求和历史跳转
  if (engine === 'baidu') {
    interceptXHR();
    interceptFetch();
    interceptHistory();
  }

  checkUrlOnLoad(engine);

  const selector = getInputSelector(engine);
  if (!selector) return;

  function initDom() {
    waitForElement(selector, setupInputHandler);
    if (engine === 'baidu') {
      watchInputRebind(selector);
    }
  }

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', initDom);
  } else {
    initDom();
  }

})();