// ==UserScript==
// @name           识别二维码 QR Reader
// @name:en        QR Reader - Decode QR Codes on Page
// @namespace      Runas_Ron/userscripts/decode-qr-code
// @version        1.0.0
// @author         Runas_Ron (forked from lovefqy)
// @description    右键图片或内联 SVG 即可识别二维码；多通道预处理（原生彩色、中值去噪、Sauvola 局部阈值）；分位数对比度拉伸对抗压缩发灰；支持剪贴板截图识别与多尺度自适应扫描。
// @description:en Right-click any image or inline SVG to decode QR codes. Multi-channel preprocessing (native color, median filter, Sauvola local threshold) with quantile contrast stretching. Supports clipboard decoding and multi-scale scanning.
// @license        MIT
// @match          http*://*/*
// @connect        *
// @require        https://unpkg.com/jsqr@1.4.0/dist/jsQR.js
// @grant          GM_registerMenuCommand
// @grant          GM_setClipboard
// @grant          GM_xmlhttpRequest
// @run-at         document-idle
// @noframes
// ==/UserScript==

(function () {
    'use strict';
    const jsQR = window.jsQR;
    if (!jsQR) {
        console.error('[decode-qr] jsQR 加载失败');
        toast('jsQR 加载失败，请检查网络连接后刷新页面重试。');
    }
    const gmSetClipboard = (typeof GM_setClipboard !== 'undefined') ? GM_setClipboard : null;
    const gmRegister = (typeof GM_registerMenuCommand !== 'undefined') ? GM_registerMenuCommand : null;
    const gmXmlHttpRequest = (typeof GM_xmlhttpRequest !== 'undefined') ? GM_xmlhttpRequest : null;
    const MEDIAN_FILTER_MAX_PX = 2_000_000;
    const SAUVOLA_MAX_PX = 2_000_000;
    let selDomRef = null;
    function setSel(el) { selDomRef = el ? new WeakRef(el) : null; }
    
    /* ======================== 基础工具 ======================== */
    function safeBtoa(str) {
        const bytes = new TextEncoder().encode(str);
        let bin = '';
        for (let i = 0; i < bytes.length; i++) bin += String.fromCharCode(bytes[i]);
        return btoa(bin);
    }
    function blobToImg(blob) {
        return new Promise((resolve, reject) => {
            const url = URL.createObjectURL(blob);
            const img = new Image();
            img.onload = () => { URL.revokeObjectURL(url); resolve(img); };
            img.onerror = () => { URL.revokeObjectURL(url); reject(new Error('图片加载失败')); };
            img.src = url;
        });
    }
    function loadImageCors(src) {
        return new Promise((resolve, reject) => {
            const img = new Image();
            img.crossOrigin = 'anonymous';
            img.onload = () => resolve(img);
            img.onerror = reject;
            img.src = src;
        });
    }
    function fetchImageBlob(url) {
        return new Promise((resolve, reject) => {
            if (gmXmlHttpRequest) {
                gmXmlHttpRequest({
                    method: 'GET', url, responseType: 'blob', timeout: 10000, anonymous: true,
                    onload: r => r.status === 200 ? resolve(r.response) : reject(new Error('HTTP ' + r.status)),
                    onerror: () => reject(new Error('network error')),
                    ontimeout: () => reject(new Error('timeout')),
                });
            } else {
                reject(new Error('GM_xmlhttpRequest unavailable'));
            }
        });
    }
    
    /* ======================== 错误处理与 UI ======================== */
    const ERR = {
        NO_TARGET:    { title: '未找到有效图片', hint: '请先右键一张 <img> 图片或 <svg>（等其加载完成）再执行本命令；或截图后用「从剪贴板识别」。' },
        DECODE_FAILED:{ title: '未检测到二维码', hint: '可能原因：旋转、模糊、过小（<60px）、艺术码识别率天然较低。建议放大后重试或截图识别。' },
        CORS_TAINTED: { title: '图片被跨域拦截', hint: '若弹出授权提示请允许；仍失败请截图后用「从剪贴板识别」。' },
        CLIP_NO_IMG:  { title: '剪贴板中没有图片', hint: '请先截图（Win+Shift+S / Cmd+Shift+4）再试。' },
        CLIP_FAIL:    { title: '读取剪贴板失败', hint: '可能是权限被拒、浏览器不支持（Firefox/Safari）或页面失焦。建议改用右键图片识别。' },
        SVG_FAIL:     { title: 'SVG 转换失败', hint: '若引用了外部资源会渲染失败。建议单独打开该 SVG 或截图识别。' },
        UNKNOWN:      { title: '发生未知错误', hint: '详见控制台 [decode-qr] 日志。' },
    };
    
    function fail(code, detail) {
        const e = ERR[code] || ERR.UNKNOWN;
        const msg = detail ? `${e.title}\n\n${e.hint}\n\n细节：${detail}` : `${e.title}\n\n${e.hint}`;
        console.warn('[decode-qr] FAIL', { code, detail });
        alert(msg);
    }
    
    function toast(msg, ms = 2000) {
        if (!document.body) return;
        const d = document.createElement('div');
        Object.assign(d.style, {
            position: 'fixed', bottom: '24px', left: '50%', transform: 'translateX(-50%)',
            background: 'rgba(0,0,0,.78)', color: '#fff', padding: '10px 20px',
            borderRadius: '8px', fontSize: '14px', zIndex: '2147483647',
            pointerEvents: 'none', transition: 'opacity .3s'
        });
        d.textContent = msg;
        document.body.appendChild(d);
        setTimeout(() => {
            d.style.opacity = '0';
            setTimeout(() => d.remove(), 300);
        }, ms);
    }
    
    function showResultModal(text, label, engine) {
        if (!document.body) { fail('UNKNOWN'); return; }
        const wrap = document.createElement('div');
        Object.assign(wrap.style, {
            position: 'fixed', inset: '0', background: 'rgba(0,0,0,.5)',
            zIndex: '2147483647', display: 'flex', flexDirection: 'column',
            alignItems: 'center', justifyContent: 'center', backdropFilter: 'blur(2px)'
        });
        const box = document.createElement('div');
        Object.assign(box.style, {
            background: '#fff', borderRadius: '12px', padding: '20px',
            width: 'min(600px, 90vw)', maxHeight: '80vh',
            display: 'flex', flexDirection: 'column', gap: '12px',
            boxShadow: '0 8px 32px rgba(0,0,0,.3)', boxSizing: 'border-box'
        });
        const title = document.createElement('div');
        title.textContent = `识别成功（${label} | 引擎: ${engine}）`;
        Object.assign(title.style, { fontSize: '14px', color: '#333', fontWeight: '600' });
        const ta = document.createElement('textarea');
        ta.value = text;
        ta.readOnly = true;
        Object.assign(ta.style, {
            flex: '1', minHeight: '80px', padding: '10px', fontSize: '14px',
            borderRadius: '8px', border: '1px solid #ddd', resize: 'vertical',
            boxSizing: 'border-box', wordBreak: 'break-all', outline: 'none'
        });
        const btnRow = document.createElement('div');
        Object.assign(btnRow.style, { display: 'flex', gap: '10px', justifyContent: 'flex-end' });
        const mkBtn = (txt, bg, onClick) => {
            const b = document.createElement('button');
            b.textContent = txt;
            Object.assign(b.style, {
                padding: '8px 18px', borderRadius: '8px', border: 'none',
                background: bg, color: '#fff', fontSize: '14px', cursor: 'pointer',
                transition: 'opacity 0.2s'
            });
            b.addEventListener('mouseover', () => b.style.opacity = '0.8');
            b.addEventListener('mouseout', () => b.style.opacity = '1');
            b.addEventListener('click', onClick);
            return b;
        };
        const escHandler = (e) => { if (e.key === 'Escape') close(); };
        const close = () => {
            wrap.remove();
            document.removeEventListener('keydown', escHandler);
        };
        
        // 移除静默覆盖剪贴板的逻辑，统一交由用户点击处理
        btnRow.appendChild(mkBtn('复制', '#4285f4', async () => {
            try {
                if (gmSetClipboard) gmSetClipboard(text, 'text');
                else await navigator.clipboard.writeText(text);
                ta.select();
                toast('已复制到剪贴板 ✓');
                close();
            } catch (_) {
                ta.select();
                toast('自动复制失败，请按 Ctrl+C 手动复制');
            }
        }));
        
        btnRow.appendChild(mkBtn('关闭', '#888', close));
        box.appendChild(title);
        box.appendChild(ta);
        box.appendChild(btnRow);
        wrap.appendChild(box);
        wrap.addEventListener('click', e => { if (e.target === wrap) close(); });
        document.addEventListener('keydown', escHandler);
        document.body.appendChild(wrap);
        ta.focus();
        ta.select();
    }
    
    /* ================= 图像预处理算法 ================= */
    function analyzeAndGrayscale(rgba, len) {
        const gray = new Uint8Array(len);
        let colorScoreSum = 0;
        const step = Math.max(1, Math.floor(len / 50000));
        let sampleCount = 0;
        for (let i = 0; i < len; i += step) {
            const j = i * 4;
            const r = rgba[j], g = rgba[j + 1], b = rgba[j + 2];
            colorScoreSum += Math.max(r, g, b) - Math.min(r, g, b);
            sampleCount++;
        }
        const isColorful = (colorScoreSum / sampleCount) > 12;
        for (let i = 0; i < len; i++) {
            const j = i * 4;
            gray[i] = (0.299 * rgba[j] + 0.587 * rgba[j + 1] + 0.114 * rgba[j + 2]) | 0;
        }
        const hist = new Uint32Array(256);
        for (let i = 0; i < len; i++) hist[gray[i]]++;
        const cut = Math.max(1, (len * 0.005) | 0);
        let acc = 0, lo = 0, hi = 255;
        for (let v = 0; v < 256; v++) { acc += hist[v]; if (acc >= cut) { lo = v; break; } }
        acc = 0;
        for (let v = 255; v >= 0; v--) { acc += hist[v]; if (acc >= cut) { hi = v; break; } }
        const range = hi - lo;
        if (range > 10 && range < 120) {
            const scale = 255 / range;
            for (let i = 0; i < len; i++) {
                let v = gray[i] - lo;
                v = v <= 0 ? 0 : (v * scale) | 0;
                gray[i] = v > 255 ? 255 : v;
            }
        }
        return { gray, isColorful };
    }
    
    function sauvolaBinarize(gray, w, h, window = 25, k = 0.34) {
        const out = new Uint8Array(gray.length);
        const I = new Uint32Array((w + 1) * (h + 1));
        const I2 = new Float64Array((w + 1) * (h + 1));
        for (let y = 0; y < h; y++) {
            let rs = 0, rs2 = 0;
            for (let x = 0; x < w; x++) {
                const v = gray[y * w + x];
                rs += v; rs2 += v * v;
                I[(y + 1) * (w + 1) + x + 1] = I[y * (w + 1) + x + 1] + rs;
                I2[(y + 1) * (w + 1) + x + 1] = I2[y * (w + 1) + x + 1] + rs2;
            }
        }
        const r = window >> 1;
        const maxStd = 64;
        const FLAT_EPS = 10;
        for (let y = 0; y < h; y++) {
            const y0 = Math.max(0, y - r), y1 = Math.min(h - 1, y + r);
            for (let x = 0; x < w; x++) {
                const x0 = Math.max(0, x - r), x1 = Math.min(w - 1, x + r);
                const area = (y1 - y0 + 1) * (x1 - x0 + 1);
                const s1 = I[(y1 + 1) * (w + 1) + x1 + 1] - I[y0 * (w + 1) + x1 + 1]
                         - I[(y1 + 1) * (w + 1) + x0] + I[y0 * (w + 1) + x0];
                const s2 = I2[(y1 + 1) * (w + 1) + x1 + 1] - I2[y0 * (w + 1) + x1 + 1]
                         - I2[(y1 + 1) * (w + 1) + x0] + I2[y0 * (w + 1) + x0];
                const m = s1 / area;
                const std = Math.sqrt(Math.max(0, s2 / area - m * m));
                let bin;
                if (std < FLAT_EPS) {
                    bin = m < 128 ? 0 : 255;
                } else {
                    const t = m * (1 + k * (std / maxStd - 1));
                    bin = gray[y * w + x] < t ? 0 : 255;
                }
                out[y * w + x] = bin;
            }
        }
        return out;
    }
    
    function grayToImageData(gray, w, h) {
        const data = new Uint8ClampedArray(w * h * 4);
        for (let i = 0; i < gray.length; i++) {
            data[i * 4] = gray[i];
            data[i * 4 + 1] = gray[i];
            data[i * 4 + 2] = gray[i];
            data[i * 4 + 3] = 255;
        }
        return { data, width: w, height: h };
    }
    
    function medianFilter(gray, w, h) {
        const out = new Uint8Array(gray.length);
        const win = new Uint8Array(9);
        for (let y = 1; y < h - 1; y++) {
            for (let x = 1; x < w - 1; x++) {
                let n = 0;
                for (let ky = -1; ky <= 1; ky++)
                    for (let kx = -1; kx <= 1; kx++)
                        win[n++] = gray[(y + ky) * w + (x + kx)];
                for (let i = 1; i < 9; i++) {
                    const v = win[i];
                    let j = i - 1;
                    while (j >= 0 && win[j] > v) { win[j + 1] = win[j]; j--; }
                    win[j + 1] = v;
                }
                out[y * w + x] = win[4];
            }
        }
        for (let x = 0; x < w; x++) {
            out[x] = gray[x];
            out[(h - 1) * w + x] = gray[(h - 1) * w + x];
        }
        for (let y = 0; y < h; y++) {
            out[y * w] = gray[y * w];
            out[y * w + w - 1] = gray[y * w + w - 1];
        }
        return out;
    }
    
    /* ================= 解码核心 ================= */
    function safeJsQR(data, w, h) {
        try {
            return jsQR(data, w, h);
        } catch (e) {
            console.warn('[decode-qr] jsQR throw:', e.message || e);
            return null;
        }
    }
    
    function decodeJsQR(rawData, w, h, s) {
        if (!jsQR) throw new Error('jsQR not loaded');
        const { gray, isColorful } = analyzeAndGrayscale(rawData, w * h);
        
        if (isColorful) {
            const code0 = safeJsQR(rawData, w, h);
            if (code0) return { data: code0.data, channel: '通道1-原生彩色直出' };
        }
        const code1 = safeJsQR(grayToImageData(gray, w, h).data, w, h);
        if (code1) return { data: code1.data, channel: '通道1-灰度直出(块自适应)' };
        
        let filtered = null;
        if (w * h <= MEDIAN_FILTER_MAX_PX && s > 0.25) {
            filtered = medianFilter(gray, w, h);
            const code2 = safeJsQR(grayToImageData(filtered, w, h).data, w, h);
            if (code2) return { data: code2.data, channel: '通道2-中值去噪(块自适应)' };
        }
        
        if (w * h <= SAUVOLA_MAX_PX) {
            const win = (s <= 0.25) ? 15 : Math.max(15, Math.round(Math.min(w, h) / 40) | 1);
            const sauvolaInput = filtered || gray;
            const bin3 = sauvolaBinarize(sauvolaInput, w, h, win, 0.34);
            const code3 = safeJsQR(grayToImageData(bin3, w, h).data, w, h);
            if (code3) return { data: code3.data, channel: '通道3-Sauvola局部阈值' };
        }
        return null;
    }
    
    async function decodeQrCodeImg(img) {
        let nw = img.naturalWidth || img.width || 0;
        let nh = img.naturalHeight || img.height || 0;
        if (nw === 0 || nh === 0) throw Object.assign(new Error('ZERO_SIZE'), { name: 'ZERO_SIZE' });
        let sourceImg = img;
        let sourceSrc = (img instanceof HTMLImageElement) ? img.src : null;
        const MAX_SIZE = 2000;
        if ((nw > MAX_SIZE || nh > MAX_SIZE) && !(img instanceof HTMLCanvasElement)) {
            const ratio = Math.min(MAX_SIZE / nw, MAX_SIZE / nh);
            const preCanvas = document.createElement('canvas');
            preCanvas.width = Math.round(nw * ratio);
            preCanvas.height = Math.round(nh * ratio);
            preCanvas.getContext('2d').drawImage(img, 0, 0, preCanvas.width, preCanvas.height);
            sourceImg = preCanvas;
            nw = preCanvas.width;
            nh = preCanvas.height;
        }
        const scales = [1, 0.5, 0.25, 2];
        let triedCors = false;
        for (let scaleIdx = 0; scaleIdx < scales.length; scaleIdx++) {
            const s = scales[scaleIdx];
            if (s > 1 && Math.max(nw, nh) >= 1500) continue;
            if (scaleIdx > 0) await new Promise(r => setTimeout(r, 0));
            try {
                const sw = Math.max(1, Math.round(nw * s));
                const sh = Math.max(1, Math.round(nh * s));
                const canvas = document.createElement('canvas');
                canvas.width = sw;
                canvas.height = sh;
                const ctx = canvas.getContext('2d', { willReadFrequently: true });
                ctx.imageSmoothingEnabled = true;
                if (s < 1) ctx.imageSmoothingQuality = 'high';
                ctx.drawImage(sourceImg, 0, 0, sw, sh);
                let imageData;
                try {
                    imageData = ctx.getImageData(0, 0, sw, sh);
                } catch (e) {
                    if (e.name === 'SecurityError' || String(e.message).includes('cross-origin')) {
                        if (!triedCors && sourceSrc) {
                            triedCors = true;
                            try {
                                let fetchedImg;
                                if (gmXmlHttpRequest) {
                                    try {
                                        const blob = await fetchImageBlob(sourceSrc);
                                        fetchedImg = await blobToImg(blob);
                                    } catch (gmErr) {
                                        fetchedImg = await loadImageCors(sourceSrc);
                                    }
                                } else {
                                    fetchedImg = await loadImageCors(sourceSrc);
                                }
                                sourceImg = fetchedImg;
                                scaleIdx--; // 核心修复：CORS 成功后，回退索引重新以原图缩放
                                continue;
                            } catch (_) {
                                throw Object.assign(new Error('CORS'), { name: 'SecurityError' });
                            }
                        } else {
                            throw Object.assign(new Error('CORS'), { name: 'SecurityError' });
                        }
                    } else {
                        throw e;
                    }
                }
                const result = decodeJsQR(imageData.data, sw, sh, s);
                if (result) return { data: result.data, engine: 'jsQR+' + result.channel, scale: s, w: sw, h: sh };
            } catch (e) {
                if (e.name === 'SecurityError') throw e;
            }
        }
        throw Object.assign(new Error('DECODE_FAILED'), { name: 'DECODE_FAILED' });
    }
    
    /* ================= 统一入口与菜单 ================= */
    function svgToImg(el, callback, onError) {
        let svg = null;
        if (el instanceof SVGSVGElement) svg = el;
        else {
            let node = el && el.parentElement;
            for (let i = 0; i < 32 && node; i++) {
                if (node instanceof SVGSVGElement) { svg = node; break; }
                node = node.parentElement;
            }
        }
        if (!svg) { onError && onError({ code: 'SVG_FAIL', detail: '未找到 SVG 根节点' }); return; }
        try {
            const clone = svg.cloneNode(true);
            const wAttr = svg.getAttribute('width');
            const hAttr = svg.getAttribute('height');
            let w = parseFloat(wAttr), h = parseFloat(hAttr);
            if (!w || !h || isNaN(w) || isNaN(h) ||
                (typeof wAttr === 'string' && wAttr.includes('%')) ||
                (typeof hAttr === 'string' && hAttr.includes('%'))) {
                const rect = svg.getBoundingClientRect();
                if (rect.width > 0 && rect.height > 0) { w = rect.width; h = rect.height; }
                else {
                    const vb = svg.viewBox && svg.viewBox.baseVal;
                    if (vb && vb.width > 0) { w = vb.width; h = vb.height; }
                    else { w = 512; h = 512; }
                }
            }
            clone.setAttribute('width', String(w));
            clone.setAttribute('height', String(h));
            const img = new Image();
            img.onload = () => callback(img);
            img.onerror = () => onError && onError({ code: 'SVG_FAIL', detail: `渲染失败 size=${w}x${h}` });
            img.src = 'data:image/svg+xml;base64,' + safeBtoa(new XMLSerializer().serializeToString(clone));
        } catch (e) {
            onError && onError({ code: 'SVG_FAIL', detail: '序列化异常: ' + String(e.message || e) });
        }
    }
    
    async function handleImageSource(source, label) {
        try {
            let img;
            if (source instanceof Blob) img = await blobToImg(source);
            else if (source instanceof SVGElement) img = await new Promise((resolve, reject) => {
                svgToImg(source, resolve, reject);
            });
            else if (source instanceof HTMLImageElement) img = source;
            else { fail('NO_TARGET', '目标非 img 或 svg 元素'); return; }
            
            const result = await decodeQrCodeImg(img);
            console.log('[decode-qr] OK', {
                engine: result.engine, scale: result.scale,
                size: result.w + 'x' + result.h,
                text: result.data.slice(0, 200)
            });
            showResultModal(result.data, label, result.engine);
        } catch (e) {
            const msg = String(e.message || e);
            if (e.name === 'SecurityError') fail('CORS_TAINTED', msg);
            else if (msg === 'ZERO_SIZE') fail('NO_TARGET', '图片尺寸为 0（可能尚未加载完成）');
            else if (msg === 'DECODE_FAILED') fail('DECODE_FAILED');
            else if (e && e.code) fail(e.code, e.detail);
            else { console.error('[decode-qr]', e); fail('UNKNOWN', msg); }
        }
    }
    
    if (gmRegister) {
        gmRegister('Decode QR Code（右键图片）', async () => {
            if (!jsQR) { alert('jsQR 未加载，请检查网络后刷新页面重试。'); return; }
            const dom = selDomRef && selDomRef.deref ? selDomRef.deref() : null;
            if (!dom) { fail('NO_TARGET'); return; }
            await handleImageSource(dom, '右键图片');
            selDomRef = null;
        });
        
        gmRegister('从剪贴板识别', async () => {
            if (!jsQR) { alert('jsQR 未加载，请检查网络后刷新页面重试。'); return; }
            if (navigator.clipboard && navigator.clipboard.read) {
                try {
                    const items = await navigator.clipboard.read();
                    let blob = null, type = '';
                    for (const item of items) {
                        const t = item.types.find(t => /^image\/(png|jpe?g|webp|bmp|svg\+xml)$/i.test(t));
                        if (t) { blob = await item.getType(t); type = t; break; }
                    }
                    if (!blob) { fail('CLIP_NO_IMG'); return; }
                    await handleImageSource(blob, '剪贴板(' + type + ')');
                } catch (e) {
                    fail('CLIP_FAIL', e.message || e.name || String(e));
                }
            } else {
                fail('CLIP_FAIL', '浏览器未提供 navigator.clipboard.read API');
            }
        });
    }
    
    document.addEventListener('contextmenu', (event) => {
        const t = event.target;
        if (t instanceof HTMLImageElement) setSel(t);
        else if (t instanceof SVGElement) {
            if (t instanceof SVGSVGElement) {
                setSel(t);
            } else {
                let node = t.parentElement;
                for (let i = 0; i < 32 && node; i++) {
                    if (node instanceof SVGSVGElement) { setSel(node); return; } // 修复：存储根节点
                    node = node.parentElement;
                }
                setSel(null);
            }
        } else setSel(null);
    });
})();