Preview links by hovering and pressing 'F' or long press, and adds preview buttons on Discourse forums like linux.do
// ==UserScript==
// @name 探索者视角MOD (for linux.do)
// @namespace http://tampermonkey.net/
// @version 1.8
// @description Preview links by hovering and pressing 'F' or long press, and adds preview buttons on Discourse forums like linux.do
// @author Your Name (Modified)
// @match https://linux.do/*
// @grant none
// @license MIT
// ==/UserScript==
(function() {
'use strict';
// --- Iframe Setup ---
const iframeContainer = document.createElement('div');
iframeContainer.style.cssText = 'position: fixed; top: 0; left: 0; width: 100vw; height: 100vh; display: none; align-items: center; justify-content: center; background: rgba(0, 0, 0, 0.7); z-index: 9999;';
const iframe = document.createElement('iframe');
iframe.style.cssText = 'width: 80vw; height: 80vh; border: none; background: white; box-shadow: 0 5px 15px rgba(0,0,0,0.3); border-radius: 5px;';
iframeContainer.appendChild(iframe);
document.body.appendChild(iframeContainer);
// --- Hover/Keypress/Longpress Logic (Unchanged from original) ---
let currentHoveredLink = null;
let keyDown = false;
let longPressTimer = null;
const longPressDuration = 500; // ms
document.addEventListener('keydown', function(event) {
if (event.key === 'F' || event.key === 'f') {
keyDown = true;
if (currentHoveredLink) {
iframe.src = currentHoveredLink.href;
iframeContainer.style.display = 'flex';
}
}
});
document.addEventListener('keyup', function(event) {
if (event.key === 'F' || event.key === 'f') {
keyDown = false;
// Optional: Close iframe when F is released and mouse is not over a link anymore?
// if (!currentHoveredLink) {
// iframeContainer.style.display = 'none';
// iframe.src = 'about:blank';
// }
}
});
document.body.addEventListener('mousedown', function(event) {
if (event.button === 0) { // Left mouse button
const aTag = event.target.closest('a[href]');
// Exclude javascript links and buttons/elements that might contain links but aren't primary content links
if (!aTag || aTag.href.startsWith('javascript:') || aTag.closest('.btn, .avatar, .badge-wrapper')) return;
clearTimeout(longPressTimer); // Clear any previous timer
longPressTimer = setTimeout(() => {
console.log('Long press detected on:', aTag.href);
iframe.src = aTag.href;
iframeContainer.style.display = 'flex';
longPressTimer = null; // Reset timer flag
}, longPressDuration);
}
});
document.body.addEventListener('mouseup', function(event) {
if (event.button === 0) { // Left mouse button
clearTimeout(longPressTimer);
}
});
// Prevent context menu on long press if preview opened
document.body.addEventListener('contextmenu', function(event) {
if (longPressTimer === null && iframeContainer.style.display === 'flex') {
// If timer is null, it means it fired and opened the iframe
// Check if the click originated from a link that could have triggered it
const aTag = event.target.closest('a[href]');
if (aTag && !aTag.href.startsWith('javascript:') && !aTag.closest('.btn, .avatar, .badge-wrapper')) {
event.preventDefault();
}
}
clearTimeout(longPressTimer); // Always clear timer on context menu
});
document.body.addEventListener('mouseover', function(event) {
const aTag = event.target.closest('a[href]');
// Exclude javascript links and buttons/elements that might contain links
if (!aTag || aTag.href.startsWith('javascript:') || aTag.closest('.btn, .avatar, .badge-wrapper')) {
currentHoveredLink = null; // Clear if not a valid link
return;
}
currentHoveredLink = aTag;
if (keyDown) {
iframe.src = currentHoveredLink.href;
iframeContainer.style.display = 'flex';
}
}, { passive: true });
document.body.addEventListener('mouseout', function(event) {
const relatedTargetIsLink = event.relatedTarget && event.relatedTarget.closest('a[href]');
// Only clear if mouse moves out of the link *entirely*
if (event.target.closest('a[href]') && !relatedTargetIsLink) {
currentHoveredLink = null;
// Optional: Close iframe if F key is up and mouse moves out?
// if (!keyDown) {
// iframeContainer.style.display = 'none';
// iframe.src = 'about:blank';
// }
}
});
iframeContainer.addEventListener('click', function(event) {
if (event.target === iframeContainer) { // Click on background closes it
iframeContainer.style.display = 'none';
iframe.src = 'about:blank'; // Stop loading/clear content
}
});
// --- Preview Button Logic (MODIFIED) ---
function addPreviewButtons() {
// More specific selector for Discourse topic list items (usually <tr>)
// Check common structures for the topic list table body
const topicListBody = document.querySelector('.topic-list tbody, .latest-topic-list tbody');
if (!topicListBody) return; // Don't proceed if the list body isn't found
const posts = topicListBody.querySelectorAll('tr.topic-list-item');
posts.forEach(post => {
// Check if button already exists using a data attribute for robustness
if (post.dataset.previewButtonAdded === 'true') {
return;
}
// Find the link - common selectors for Discourse topic titles
const link = post.querySelector('td.main-link a.title, a.topic-link, .topic-list-data a.title, a.raw-topic-link');
if (!link || link.href.startsWith('javascript:')) {
// console.warn('Preview Button: Could not find a valid link in:', post);
return; // Skip if no valid link found in this row
}
// Find the cell containing the link to append the button to
// Try td.main-link first, then the first available td as a fallback
const targetCell = post.querySelector('td.main-link, .topic-list-data'); // Adjust if needed based on actual structure
if (!targetCell) {
console.warn('Preview Button: Could not find target cell for link:', link.href);
return; // Skip if we can't find where to put the button
}
const button = document.createElement('button');
button.innerHTML = '🔍'; // Magnifying glass emoji for preview
//button.innerHTML = '预览'; // Magnifying glass emoji for preview
button.title = '预览帖子 (Preview Post)'; // Tooltip
button.className = 'btn btn-default topicpreview-btn'; // Use Discourse's button classes if possible
// Add custom styling - adjust as needed
button.style.cssText = `
margin-left: 8px;
padding: 2px 6px;
font-size: 12px;
line-height: 1.2;
vertical-align: middle; /* Align with text */
background-color: #e9e9e9;
color: #555;
border: 1px solid #ccc;
border-radius: 4px;
cursor: pointer;
flex-shrink: 0; /* Prevent shrinking if cell is tight */
`;
button.addEventListener('mouseover', () => { button.style.backgroundColor = '#d0d0d0'; });
button.addEventListener('mouseout', () => { button.style.backgroundColor = '#e9e9e9'; });
// Button click event
button.addEventListener('click', function(event) {
event.preventDefault(); // Prevent default link navigation if button is inside <a> somehow
event.stopPropagation(); // Prevent triggering other clicks on the row/cell
iframe.src = link.href;
iframeContainer.style.display = 'flex';
});
// Append the button within the target cell
// We append it to the cell itself, often after the main title span/link
// targetCell.appendChild(button);
link.insertAdjacentElement('afterend', button);
// Mark the row as processed to prevent adding duplicate buttons
post.dataset.previewButtonAdded = 'true';
});
}
// --- Mutation Observer Setup (MODIFIED) ---
// Function to initialize or re-initialize the observer
function observeTopicList() {
// Target a more stable parent, like the main content area or the specific topic list container
// #main-outlet is common in Discourse
// '.topic-list-container' or '.latest-topic-list' might also exist
const targetNode = document.querySelector('#main-outlet .topic-list, #main-outlet .latest-topic-list');
if (targetNode) {
// console.log('Observer: Found target node:', targetNode);
addPreviewButtons(); // Initial run for content already present
const observer = new MutationObserver((mutationsList) => {
// Check if new topic list items (<tr>) were added
for (const mutation of mutationsList) {
if (mutation.type === 'childList') {
let addedNodes = Array.from(mutation.addedNodes);
// Check if any added node is a topic item or contains one
if (addedNodes.some(node => node.nodeType === 1 && (node.matches('tr.topic-list-item') || node.querySelector('tr.topic-list-item')))) {
// console.log('Observer: Detected new topic items, running addPreviewButtons.');
addPreviewButtons(); // Re-run when new items are potentially added
break; // No need to check other mutations if we found relevant changes
}
}
}
});
// Observe the target node for added/removed children (e.g., topic rows)
// Observing subtree might be needed if rows are added deeply nested
observer.observe(targetNode, { childList: true, subtree: true });
console.log('Observer: Attached to', targetNode);
} else {
// If the target isn't found immediately, retry after a short delay
// This handles cases where the list itself is loaded asynchronously
// console.log('Observer: Target node not found yet, retrying...');
setTimeout(observeTopicList, 500); // Retry after 500ms
}
}
// Start the process
// Use DOMContentLoaded or window.onload if needed, but often direct call + observer retry works
observeTopicList();
})();
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