// ==UserScript==
// @name         京东图书定价查询助手
// @namespace    http://tampermonkey.net/
// @version      2.9
// @description  完美兼容详情页无刷新切换商品，自动清理旧标签并重新抓取。
// @author       M
// @match        *://t.jd.com/*
// @match        *://item.jd.com/*
// @grant        GM_xmlhttpRequest
// @connect      item.m.jd.com
// ==/UserScript==

(function() {
    'use strict';

    const CONFIG = {
        FOLLOW: {
            card: '.item-inner',
            price: '.p-price'
        },
        ITEM: {
            anchor: '.product-price-panel'
        }
    };

    const skuQueue = [];
    let activeRequests = 0;
    const CONCURRENCY = 3;
    let lastItemSku = null; // 🌟 新增：用于记录当前详情页的 SKU

    function getPageType() {
        const host = window.location.host;
        if (host.includes('item.jd.com')) return 'ITEM';
        return 'FOLLOW';
    }

    const currentPage = getPageType();
    console.log(`🚀 定价全能王 V2.9 启动！当前识别页面类型: ${currentPage}`);

    function fetchPrice(task) {
        const {sku, targetContainer} = task;
        activeRequests++;
        console.log(`⏳ [抓取中] 正在查询 SKU: ${sku}`);

        GM_xmlhttpRequest({
            method: "GET",
            url: `https://item.m.jd.com/product/${sku}.html`,
            timeout: 8000,
            onload: function(response) {
                if (response.finalUrl && response.finalUrl.includes('risk_handler')) {
                    console.error(`🚨🚨🚨 触发京东风控！SKU: ${sku} 的请求被拦截到了验证码页面！`);
                    activeRequests--;
                    processQueue();
                    return;
                }

                try {
                    const html = response.responseText;
                    let marketPrice = null;
                    let currentPrice = null;

                    let mMatch = html.match(/"linePrice"\s*:\s*\{[^}]*?"price"\s*:\s*["'](\d+\.\d{1,2})["']/i);
                    if (mMatch) marketPrice = parseFloat(mMatch[1]);

                    let pMatch = html.match(/"jdPrice"\s*:\s*["'](\d+\.\d{1,2})["']/i);
                    if (pMatch) currentPrice = parseFloat(pMatch[1]);

                    if (marketPrice && currentPrice) {
                        const discount = ((currentPrice / marketPrice) * 10).toFixed(2);
                        injectDisplay(targetContainer, marketPrice, discount, sku);
                    } else if (marketPrice) {
                        injectDisplay(targetContainer, marketPrice, null, sku);
                    } else {
                        console.log(`⚠️ SKU:${sku} 没有匹配到定价数据。`);
                    }
                } catch (e) { console.error(`❌ SKU:${sku} 解析报错`, e); }

                setTimeout(() => {
                    activeRequests--;
                    processQueue();
                }, Math.floor(Math.random() * 2000) + 1500);
            },
            onerror: function() {
                console.error(`🚨 网络请求彻底失败 (SKU: ${sku})`);
                activeRequests--; processQueue();
            }
        });
    }

    // 🎨 === 核心 UI 装修区 === 🎨
    function injectDisplay(container, mPrice, discount, sku) {
        if (document.querySelector(`.gemini-tag-${sku}`)) return;

        const isDetailPage = (currentPage === 'ITEM');
        const wrap = document.createElement('span');
        wrap.className = `gemini-price-tag gemini-tag-${sku}`;

        if (isDetailPage) {
            wrap.style.cssText = "display:inline-block; vertical-align:bottom; margin-left:10px; margin-right:10px; margin-bottom:2px;";
        } else {
            wrap.style.cssText = "display:inline-block;";
        }

        const mSpan = document.createElement('span');
        mSpan.style.cssText = `color:#999; font-size:13px; margin-left:8px;`;
        mSpan.innerText = `定价:￥${mPrice}`;
        wrap.appendChild(mSpan);

        if (discount) {
            const dSpan = document.createElement('span');
            dSpan.style.cssText = `color:#f30; margin-left:6px; font-size:13px; font-weight:bold; background:#fff1f1; padding:1px 5px; border-radius:3px; border:1px solid #ff000030;`;
            dSpan.innerText = `${discount}折`;
            wrap.appendChild(dSpan);
        }

        if (isDetailPage) {
            const priceGrayElem = document.querySelector('.product-price-gray-line-through');
            if (priceGrayElem && priceGrayElem.parentNode) {
                priceGrayElem.parentNode.insertBefore(wrap, priceGrayElem.nextSibling);
                console.log(`✅ SKU:${sku} 展示成功！(插在售价后面)`);
            } else {
                const commentElem = document.querySelector('.product-price-panel--options-comment');
                if (commentElem && commentElem.parentNode) {
                    commentElem.parentNode.insertBefore(wrap, commentElem);
                    console.log(`✅ SKU:${sku} 展示成功！(插在评论前面)`);
                } else {
                    container.appendChild(wrap);
                    console.log(`✅ SKU:${sku} 展示成功！(兜底插在面板末尾)`);
                }
            }
        } else {
            container.appendChild(wrap);
            console.log(`✅ SKU:${sku} 关注页展示成功！`);
        }
    }

    function processQueue() {
        if (activeRequests >= CONCURRENCY || skuQueue.length === 0) return;
        while (activeRequests < CONCURRENCY && skuQueue.length > 0) {
            fetchPrice(skuQueue.shift());
        }
    }

    function scan() {
        if (currentPage === 'ITEM') {
            const anchor = document.querySelector(CONFIG.ITEM.anchor);
            if (anchor) {
                const skuMatch = window.location.pathname.match(/\/(\d+)\.html/);
                if (skuMatch) {
                    const currentUrlSku = skuMatch[1];

                    // 🌟 核心侦测逻辑：发现页面被无刷新切换了！
                    if (lastItemSku && lastItemSku !== currentUrlSku) {
                        console.log(`🔄 侦测到无刷新切换商品: ${lastItemSku} -> ${currentUrlSku}，准备重置...`);

                        // 1. 撕掉旧的标签
                        const oldTags = document.querySelectorAll('.gemini-price-tag');
                        oldTags.forEach(tag => tag.remove());

                        // 2. 砸碎旧的查询锁
                        anchor.removeAttribute('data-price-fetching');
                    }

                    // 更新当前记录的 SKU
                    lastItemSku = currentUrlSku;

                    if (!document.querySelector(`.gemini-tag-${currentUrlSku}`) && !anchor.getAttribute('data-price-fetching')) {
                        anchor.setAttribute('data-price-fetching', 'true');
                        fetchPrice({sku: currentUrlSku, targetContainer: anchor});
                    }
                }
            }
        } else {
            const conf = CONFIG.FOLLOW;
            const cards = document.querySelectorAll(conf.card);

            cards.forEach(card => {
                if (card.getAttribute('data-price-queued')) return;
                const link = card.querySelector('a[href*="jd.com"]');
                const priceArea = card.querySelector(conf.price);

                if (link && priceArea) {
                    const match = link.href.match(/\/(\d{6,15})/);
                    if (match) {
                        card.setAttribute('data-price-queued', 'true');
                        skuQueue.push({sku: match[1], targetContainer: priceArea});
                    }
                }
            });
            processQueue();
        }
    }

    // 每 2 秒扫描一次地址栏和页面的变化
    setInterval(scan, 2000);
})();