// --- Configuration ---
var USE_INTERNET_TRANSLATION = true;

// https://en.wikipedia.org/wiki/List_of_ISO_639_language_codes
var SOURCE_LANG = 'en';
var TARGET_LANG = 'zh';

// Define the remote translation provider order using initials, in descending preference:
// D (DeepSeek - paid but recommended)  L (Lingva - free), M (MyMemory - free), G (Google - free but firewalled in China)
// 1) Pick one or more providers in any order (d, dm, dg, gm, dlmg etc)
// 2) Use Deepseek only after having a) obtained a DEEPSEEK_API_KEY b) paid into this key. Otherwise, the key will not work
var TRANSLATION_ORDER = 'dlmg';

// DeepSeek API Key（请替换为您的实际密钥,付费了才能用,一分钱能用很多天） https://platform.deepseek.com
var DEEPSEEK_API_KEY = 'sk-';

// Tells Translator which elements to translate
var TRANSLATION_CSS_SELECTOR = '.definition, .quotation-text, .etymology-note, .small-type-note, p.txt-example, p.txt-variant-label-short, .txt-example';


/*******************************************************************************************************************/
/*******************************************************************************************************************/
/******************************************   TABS AND NAVS  *******************************************************/
/*******************************************************************************************************************/
/*******************************************************************************************************************/

// Tab Click Handler for Nested Trees
function zngq_clk(t, targetId) {
    var bar = t.parentNode;
    var grp = bar.parentNode;
    var tabs = bar.children;

    // Are we clicking the already-active tab? (Toggle Show All)
    var isShowAll = (t.classList.contains('active') && grp.getAttribute('data-showall') !== 'true');

    // Reset all tabs in this specific bar
    for(var i = 0; i < tabs.length; i++) {
        tabs[i].classList.remove('active');
    }

    // Find content panels that belong ONLY to this specific group level
    var cnts =[];
    for(var i = 0; i < grp.children.length; i++) {
        if(grp.children[i].classList.contains('zngq-cnt')) {
            cnts.push(grp.children[i]);
        }
    }

    if (isShowAll) {
        grp.setAttribute('data-showall', 'true');
        for(var i = 0; i < cnts.length; i++) {
            cnts[i].classList.add('active');
            cnts[i].style.display = 'block';
        }
    } else {
        grp.setAttribute('data-showall', 'false');
        t.classList.add('active');
        for(var i = 0; i < cnts.length; i++) {
            if(cnts[i].id === targetId) {
                cnts[i].classList.add('active');
                cnts[i].style.display = 'block';
            } else {
                cnts[i].classList.remove('active');
                cnts[i].style.display = 'none';
            }
        }
    }
}

// Previous Button
function zngq_p(btn) {
    var grp = btn.parentNode.parentNode;
    var bars = grp.getElementsByClassName('zngq-bar');
    if(bars.length === 0) return;
    var bar = bars[0]; // get the immediate bar for this group
    var tabs = bar.children;
    var activeIdx = -1;
    for(var i = 0; i < tabs.length; i++) {
        if(tabs[i].classList.contains('active')) {
            activeIdx = i;
            break;
        }
    }
    if (activeIdx === -1) activeIdx = 1; // Default to next from 0 if none active, or handle showall
    var nextIdx = (activeIdx - 1 + tabs.length) % tabs.length;

    // Automatically hide siblings if nested nav causes an isolation event
    var cnt = grp.parentNode;
    if (cnt && cnt.classList.contains('zngq-cnt')) {
        var parentGrp = cnt.parentNode;
        if (parentGrp && parentGrp.getAttribute('data-showall') === 'true') {
            parentGrp.setAttribute('data-showall', 'false');
            var parentBars = parentGrp.getElementsByClassName('zngq-bar');
            if (parentBars.length > 0) {
                var pTabs = parentBars[0].children;
                for (var t = 0; t < pTabs.length; t++) {
                     if (pTabs[t].getAttribute('onclick') && pTabs[t].getAttribute('onclick').indexOf("'" + cnt.id + "'") !== -1) {
                         pTabs[t].click();
                         break;
                     }
                }
            }
        }
    }

    grp.setAttribute('data-showall', 'false');
    tabs[nextIdx].click();
}

// Next Button
function zngq_n(btn) {
    var grp = btn.parentNode.parentNode;
    var bars = grp.getElementsByClassName('zngq-bar');
    if(bars.length === 0) return;
    var bar = bars[0]; // get the immediate bar for this group
    var tabs = bar.children;
    var activeIdx = -1;
    for(var i = 0; i < tabs.length; i++) {
        if(tabs[i].classList.contains('active')) {
            activeIdx = i;
            break;
        }
    }
    var nextIdx = (activeIdx + 1) % tabs.length;

    // Automatically hide siblings if nested nav causes an isolation event
    var cnt = grp.parentNode;
    if (cnt && cnt.classList.contains('zngq-cnt')) {
        var parentGrp = cnt.parentNode;
        if (parentGrp && parentGrp.getAttribute('data-showall') === 'true') {
            parentGrp.setAttribute('data-showall', 'false');
            var parentBars = parentGrp.getElementsByClassName('zngq-bar');
            if (parentBars.length > 0) {
                var pTabs = parentBars[0].children;
                for (var t = 0; t < pTabs.length; t++) {
                     if (pTabs[t].getAttribute('onclick') && pTabs[t].getAttribute('onclick').indexOf("'" + cnt.id + "'") !== -1) {
                         pTabs[t].click();
                         break;
                     }
                }
            }
        }
    }

    grp.setAttribute('data-showall', 'false');
    tabs[nextIdx].click();
}

// Default to Show All Panels on Load
window.onload = function() {
    var groups = document.getElementsByClassName('zngq-grp');
    for(var g = 0; g < groups.length; g++) {
        groups[g].setAttribute('data-showall', 'true');

        var children = groups[g].children;
        for(var i = 0; i < children.length; i++) {
            // Remove highlight from default active tabs
            if(children[i].classList.contains('zngq-bar')) {
                var tabs = children[i].children;
                for(var t = 0; t < tabs.length; t++) tabs[t].classList.remove('active');
            }
            // Show all contents
            if(children[i].classList.contains('zngq-cnt')) {
                children[i].classList.add('active');
                children[i].style.display = 'block';
            }
        }
    }
};
(function() {
    // ---------------------------------------------------------
    // Global Tooltip Engine (Bulletproof viewport tracking)
    // ---------------------------------------------------------
    var tooltip;

    function initTooltip() {
        tooltip = document.getElementById('oed-chart-tooltip-el');
        if (!tooltip) {
            tooltip = document.createElement('div');
            tooltip.id = 'oed-chart-tooltip-el';
            tooltip.className = 'oed-chart-tooltip';

            tooltip.style.position = 'fixed';
            tooltip.style.display = 'none';
            tooltip.style.zIndex = '10000';
            tooltip.style.pointerEvents = 'none';

            document.body.appendChild(tooltip);
        }

        function handleMouseMove(e) {
            e = e || window.event;
            var target = e.target || e.srcElement;

            var isHitArea = false;
            if (target && target.getAttribute) {
                var cls = target.getAttribute('class') || target.className;
                if (typeof cls === 'object' && cls.baseVal !== undefined) cls = cls.baseVal;
                if (typeof cls === 'string' && cls.indexOf('oed-hit-area') !== -1) {
                    isHitArea = true;
                }
            }

            if (isHitArea) {
                var xVal = target.getAttribute('data-x');
                var yVal = target.getAttribute('data-y');

                // Formatted: 0.001 PMW 1970s
                tooltip.innerHTML = '<div style="font-size:13px;">   ' +
                                    '<strong style="color:#A35C33;">' + yVal + '</strong> ' +
                                    '<span style="font-size:11px; color:#888;"> / M </span> ' +
                                    '<strong style="color:#333; margin-left:4px;">' + xVal + 's</strong>' +
                                    '</div>';
                tooltip.style.display = 'block';

                tooltip.style.left = (e.clientX + 15) + 'px';
                tooltip.style.top = (e.clientY + 15) + 'px';
            } else {
                tooltip.style.display = 'none';
            }
        }

        if (document.addEventListener) {
            document.addEventListener('mousemove', handleMouseMove, false);
        } else if (document.attachEvent) {
            document.attachEvent('onmousemove', handleMouseMove);
        }
    }

    // ---------------------------------------------------------
    // Chart Utility: Generates exact OED-style numerical ticks
    // ---------------------------------------------------------
    function getNeatMax(max) {
        if (max === 0) return 1;
        var magnitude = Math.pow(10, Math.floor(Math.log(max) / Math.LN10));
        var normalized = max / magnitude;
        var targetInterval = normalized / 4;
        var interval;

        if (targetInterval <= 0.25) interval = 0.25;
        else if (targetInterval <= 0.5) interval = 0.5;
        else if (targetInterval <= 1) interval = 1;
        else if (targetInterval <= 2) interval = 2;
        else interval = 2.5;

        return interval * 4 * magnitude;
    }

    // ---------------------------------------------------------
    // Chart Parsing & Initialization
    // ---------------------------------------------------------
    function initCharts() {
        var tables = document.getElementsByTagName('table');
        var targetTables =[];

        for (var i = 0; i < tables.length; i++) {
            if (tables[i].className && tables[i].className.indexOf('frequency-table') !== -1) {
                targetTables.push(tables[i]);
            }
        }

        var hasSVG = !!(document.createElementNS && !!document.createElementNS('http://www.w3.org/2000/svg', 'svg').createSVGRect);

        for (var i = 0; i < targetTables.length; i++) {
            var table = targetTables[i];
            if (!table.id) continue;

            var containerId = 'chart-' + table.id;
            var container = document.getElementById(containerId);
            if (!container) continue;

            var dataX =[];
            var dataY =[];
            var dataYText =[];

            var tbody = table.getElementsByTagName('tbody')[0];
            var rows = tbody ? tbody.getElementsByTagName('tr') : table.getElementsByTagName('tr');

            for (var j = 0; j < rows.length; j++) {
                var cols = rows[j].getElementsByTagName('td');
                if (cols.length >= 2) {
                    var xText = cols[0].innerText || cols[0].textContent || "";
                    var yText = cols[1].innerText || cols[1].textContent || "";

                    var cleanXText = xText.replace(/^\s+|\s+$/g, '');
                    var cleanYText = yText.replace(/^\s+|\s+$/g, '');
                    var freqNum = parseFloat(cleanYText);

                    if (!isNaN(freqNum)) {
                        dataX.push(cleanXText);
                        dataY.push(freqNum);
                        dataYText.push(cleanYText);
                    }
                }
            }

            if (dataX.length === 0) continue;

            if (hasSVG) {
                renderSVGChart(container, dataX, dataY, dataYText);
            } else {
                renderDOMChart(container, dataX, dataY, dataYText);
            }
        }
    }

    // ---------------------------------------------------------
    // Modern SVG Engine
    // ---------------------------------------------------------
    function renderSVGChart(container, dataX, dataY, dataYText) {
        var maxFreq = 0;
        for (var i = 0; i < dataY.length; i++) {
            if (dataY[i] > maxFreq) maxFreq = dataY[i];
        }
        maxFreq = getNeatMax(maxFreq);

        var svgW = 800;
        var svgH = 300;

        // Increased bottom padding from 40 to 60 to comfortably fit the "Decade" legend
        var padding = { top: 20, right: 20, bottom: 60, left: 80 };
        var w = svgW - padding.left - padding.right;
        var h = svgH - padding.top - padding.bottom;

        var stepX = w / Math.max(1, dataX.length - 1);

        var points =[];
        for (var i = 0; i < dataY.length; i++) {
            var px = (i * stepX).toFixed(1);
            var py = (h - (dataY[i] / maxFreq) * h).toFixed(1);
            points.push(px + ',' + py);
        }

        var polyPoints = points.join(' ');
        var polygonPoints = '0,' + h + ' ' + polyPoints + ' ' + w + ',' + h;

        var svg = '<svg viewBox="0 0 ' + svgW + ' ' + svgH + '" style="width:100%; height:100%;">';

        svg += '<defs><linearGradient id="grad-' + container.id + '" x1="0%" y1="0%" x2="0%" y2="100%">' +
               '<stop offset="0%" style="stop-color:#cccccc;stop-opacity:0.6" />' +
               '<stop offset="100%" style="stop-color:#cccccc;stop-opacity:0.1" />' +
               '</linearGradient></defs>';

        svg += '<g transform="translate(' + padding.left + ',' + padding.top + ')">';

        // Y-Axis Legend
        svg += '<text transform="rotate(-90)" x="-' + (h/2) + '" y="-50" text-anchor="middle" font-size="12" fill="#888888" font-family="Arial">Frequency per million words</text>';

        // X-Axis Legend (Decade) - Placed below the tick labels
        svg += '<text x="' + (w/2) + '" y="' + (h + 45) + '" text-anchor="middle" font-size="12" fill="#888888" font-family="Arial">Decade</text>';

        // Horizontal Y-Axis Grids
        for(var k = 0; k <= 4; k++) {
            var yPos = h - (h * (k / 4));
            var yValRaw = maxFreq * (k / 4);
            var yVal = parseFloat(yValRaw.toFixed(5));
            if (yValRaw === 0) yVal = "0";

            svg += '<line x1="0" y1="' + yPos + '" x2="' + w + '" y2="' + yPos + '" stroke="#ebebeb" stroke-width="1" />';
            svg += '<text x="-10" y="' + (yPos + 4) + '" text-anchor="end" font-size="11" fill="#888888" font-family="Arial">' + yVal + '</text>';
        }

        // Vertical X-Axis Grids
        for (var i = 0; i < dataX.length; i++) {
            var px = (i * stepX).toFixed(1);
            svg += '<line x1="' + px + '" y1="0" x2="' + px + '" y2="' + h + '" stroke="#ebebeb" stroke-width="1" />';
        }

        // Draw Area & Line
        svg += '<polygon points="' + polygonPoints + '" fill="url(#grad-' + container.id + ')" />';
        svg += '<polyline points="' + polyPoints + '" fill="none" stroke="#A35C33" stroke-width="2.5"/>';

        // Draw Interactive Elements
        for (var i = 0; i < dataY.length; i++) {
            var px = (i * stepX).toFixed(1);
            var py = (h - (dataY[i] / maxFreq) * h).toFixed(1);

            // X-Axis tick label
            svg += '<text x="' + px + '" y="' + (h + 20) + '" text-anchor="middle" font-size="11" fill="#888888" font-family="Arial">' + dataX[i] + '</text>';

            // Visible Marker
            svg += '<circle class="oed-hit-area" data-x="' + dataX[i] + '" data-y="' + dataYText[i] + '" cx="' + px + '" cy="' + py + '" r="4" fill="#ffffff" stroke="#A35C33" stroke-width="2"></circle>';

            // Invisible oversized hit-area
            svg += '<circle class="oed-hit-area" data-x="' + dataX[i] + '" data-y="' + dataYText[i] + '" cx="' + px + '" cy="' + py + '" r="15" fill="#ffffff" fill-opacity="0" style="cursor:pointer;"></circle>';
        }

        svg += '</g></svg>';
        container.innerHTML = svg;
    }

    // ---------------------------------------------------------
    // Legacy Engine: IE8 fallback
    // ---------------------------------------------------------
    function renderDOMChart(container, dataX, dataY, dataYText) {
        var maxFreq = 0;
        for (var i = 0; i < dataY.length; i++) {
            if (dataY[i] > maxFreq) maxFreq = dataY[i];
        }
        maxFreq = getNeatMax(maxFreq);

        // Increased bottom padding here as well
        var padding = { top: 20, right: 20, bottom: 60, left: 80 };

        var html = '<div style="position:absolute; left:' + padding.left + 'px; top:' + padding.top + 'px; right:' + padding.right + 'px; bottom:' + padding.bottom + 'px;">';

        var n = dataX.length;
        var widthPct = 100 / Math.max(1, n - 1);

        // Y-Axis Legend
        html += '<div style="position:absolute; top:50%; left:-110px; width:140px; height:20px; margin-top:-10px; text-align:center; font-size:12px; color:#888888; font-family:Arial; transform:rotate(-90deg); filter:progid:DXImageTransform.Microsoft.BasicImage(rotation=3);">Frequency per million words</div>';

        // X-Axis Legend (Decade)
        html += '<div style="position:absolute; bottom:-50px; left:0; width:100%; text-align:center; font-size:12px; color:#888888; font-family:Arial;">Decade</div>';

        for(var k = 0; k <= 4; k++) {
            var bottomPct = (k / 4) * 100;
            var yValRaw = maxFreq * (k / 4);
            var yVal = parseFloat(yValRaw.toFixed(5));
            if (yValRaw === 0) yVal = "0";

            html += '<div style="position:absolute; bottom:' + bottomPct + '%; left:0; width:100%; border-bottom:1px solid #ebebeb; z-index:0;"></div>';
            html += '<div style="position:absolute; bottom:' + (bottomPct - 3) + '%; left:-60px; width:50px; text-align:right; font-size:11px; color:#888888; font-family:Arial;">' + yVal + '</div>';
        }

        for (var i = 0; i < n; i++) {
            var leftPct = i * widthPct;
            html += '<div style="position:absolute; bottom:0; left:' + leftPct + '%; height:100%; border-left:1px solid #ebebeb; z-index:0;"></div>';
        }

        for (var i = 0; i < n; i++) {
            var leftPct = i * widthPct;
            var heightPct = (dataY[i] / maxFreq) * 100;

            var blockWidth = (i === n - 1) ? 0 : widthPct;
            html += '<div class="oed-dom-bar" style="left:' + leftPct + '%; width:' + blockWidth + '%; height:' + heightPct + '%;"></div>';

            html += '<div class="oed-dom-point oed-hit-area" data-x="' + dataX[i] + '" data-y="' + dataYText[i] + '" style="left:' + leftPct + '%; bottom:' + heightPct + '%;"></div>';

            // X-Axis tick label
            html += '<div style="position:absolute; bottom:-25px; left:' + (leftPct - (widthPct/2)) + '%; width:' + widthPct + '%; text-align:center; font-size:11px; color:#888888; font-family:Arial;">' + dataX[i] + '</div>';
        }

        html += '</div>';
        container.innerHTML = html;
    }

    var oldLoad = window.onload;
    window.onload = function() {
        if (typeof oldLoad === 'function') oldLoad();
        initTooltip();
        initCharts();
    };

})();

var AudioSequencer = (function() {
    var queue = [];
    var currentIndex = 0;
    var player = new Audio(); // Persistent player to avoid clipping

    player.onended = function() {
        currentIndex++;
        playNext();
    };

    function playNext() {
        if (currentIndex < queue.length) {
            var url = queue[currentIndex];
            player.src = url;
            player.play();
        } else {
            console.log("Sequence complete.");
            currentIndex = 0; // Reset for next time
            queue = [];
        }
    }

    return {
        // Pass a selector for the anchor buttons
        playButtons: function(selector) {
            var anchors = document.querySelectorAll(selector);
            queue = [];
            currentIndex = 0;

            for (var i = 0; i < anchors.length; i++) {
                // Extract the URL from the onclick string
                // e.g., "new Audio('sound.mp3').play()" -> "sound.mp3"
                var onclickStr = anchors[i].getAttribute('onclick') || "";
                var match = onclickStr.match(/'([^']+)'/);
                if (match && match[1]) {
                    queue.push(match[1]);
                }
            }

            if (queue.length > 0) playNext();
        }
    };
})();


/*******************************************************************************************************************/
/*******************************************************************************************************************/
/******************************************ONLINE TRANSLATION*******************************************************/
/*******************************************************************************************************************/
/*******************************************************************************************************************/
/* stuff to make ancient browsers work */
function addClass(el, className) {
    if (el.className.indexOf(className) === -1) {
        el.className += (el.className ? ' ' : '') + className;
    }
}

function removeClass(el, className) {
    var reg = new RegExp('(\\s|^)' + className + '(\\s|$)');
    el.className = el.className.replace(reg, ' ').replace(/^\s+|\s+$/g, '');
}

function hasClass(el, className) {
    return el.className.indexOf(className) !== -1;
}

// Custom IE9 Cross-Domain AJAX Engine (now returning specific HTTP codes and JSON body data)
function ajaxGet(url, timeoutMs, onSuccess, onError) {
    var xhr = new XMLHttpRequest();

    if ("withCredentials" in xhr) {
        xhr.open("GET", url, true);
    } else if (typeof XDomainRequest !== "undefined") {
        xhr = new XDomainRequest();
        xhr.open("GET", url);
    } else {
        return onError(new Error("CORS not supported on this browser version"));
    }

    var isDone = false;
    var timer = setTimeout(function() {
        if (isDone) return;
        isDone = true;
        xhr.abort();
        onError(new Error("Timeout after " + timeoutMs + "ms"));
    }, timeoutMs);

    xhr.onload = function() {
        if (isDone) return;
        isDone = true;
        clearTimeout(timer);

        // IE8/9 XDomainRequest doesn't supply a status, so default to 200 on load.
        var status = ('status' in xhr) ? xhr.status : 200;

        if (status >= 200 && status < 300) {
            try {
                var data = JSON.parse(xhr.responseText);
                onSuccess(data);
            } catch (e) {
                var snippet = xhr.responseText ? xhr.responseText.substring(0, 150) : "(empty)";
                onError(new Error("JSON Parse Error: " + e.message + " | Response: " + snippet));
            }
        } else {
            var snippet = xhr.responseText ? xhr.responseText.substring(0, 200) : "(empty response)";
            onError(new Error("HTTP Error " + status + " | Body: " + snippet));
        }
    };

    xhr.onerror = function() {
        if (isDone) return;
        isDone = true;
        clearTimeout(timer);
        onError(new Error("Network Error, DNS failure, or CORS blocked for GET: " + url.split('?')[0]));
    };

    if (xhr.constructor === window.XDomainRequest) {
        xhr.onprogress = function() {};
        xhr.ontimeout = function() {};
    }

    setTimeout(function() { xhr.send(); }, 0);
}

// --- CSS Injector ---
function injectTranslationStyles() {
    // Prevent duplicate style tags on repeated DOM scans
    if (document.getElementById('zngq-ai-styles')) return;

    var css =
        /* The Invisible Bridge Wrapper */
        ".ai-btn-wrapper { display: none; padding-left: 8px; padding-right: 4px; }" +

        /* Show wrapper when Javascript adds the ai-show-btn class OR when active */
        ".ai-hover-target.ai-show-btn .ai-btn-wrapper, .ai-hover-target.ai-btn-active .ai-btn-wrapper { display: inline-block; }" +

        /* Makes the button look like a real, graphical button */
        ".ai-translate-btn { cursor: pointer; background: #ffffff; border: 1px solid #b0b0b0; border-radius: 4px; font-size: 11px; padding: 3px 8px; color: #333; font-family: Arial, sans-serif; box-shadow: 0 1px 2px rgba(0,0,0,0.1); user-select: none; -ms-user-select: none; vertical-align: middle; line-height: 1; text-decoration: none; }" +
        ".ai-translate-btn:hover { background: #f5f5f5; border-color: #888; }" +
        ".ai-translate-btn:active { background: #ebebeb; box-shadow: inset 0 1px 2px rgba(0,0,0,0.1); }" +

        /* Updated with line-height to support multi-line segmented translations gracefully */
        ".translation-result { display: inline; color: #2e7d32; font-weight: bold; margin-left: 6px; padding-left: 6px; border-left: 2px solid #ccc; font-size: 0.95em; line-height: 1.5; }" +
        ".translation-result.translation-error { display: block; margin-top: 8px; margin-bottom: 4px; color: #d32f2f; border-left-color: #f44336; white-space: pre-wrap; font-family: monospace; font-size: 0.85em; font-weight: normal; line-height: 1.4; }" +
        ".api-marker { font-size: 0.85em; filter: alpha(opacity=60); opacity: 0.6; margin-right: 4px; cursor: help; }" +

        /* CSS Spinner Animation */
        "@keyframes ai-spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } }" +
        ".ai-spinner { display: inline-block; width: 8px; height: 8px; border: 2px solid rgba(0,0,0,0.2); border-top-color: #007bff; border-radius: 50%; vertical-align: middle; margin-right: 5px; animation: ai-spin 0.8s linear infinite; }";

    var head = document.head || document.getElementsByTagName('head')[0];
    var style = document.createElement('style');
    style.id = 'zngq-ai-styles'; // ID assigned here
    style.type = 'text/css';
    if (style.styleSheet) { // IE8/9 specific logic
        style.styleSheet.cssText = css;
    } else {
        style.appendChild(document.createTextNode(css));
    }
    head.appendChild(style);
}

// --- Text Extraction Logic (Slices distinct elements with newlines) ---
function extractDelimitedText(element) {
    // Exact word-boundary matching prevents 't' from triggering on 'mw_t_wi'
    var blockClasses = /(^|\s)(ex-sent|d-block|dtText|t|sub-content-thread|little_gems|syns_discussion|faqs|etymology-content-section)(\s|$)/i;

    function traverse(node) {
        if (node.nodeType === 3) { // Text node
            // FIX: Strip out invisible HTML source-code line breaks and indentation.
            // Convert them to simple spaces, exactly as a browser visually renders them.
            return node.nodeValue.replace(/[\r\n]+/g, ' ');
        }
        if (node.nodeType === 1) { // Element node
            var tag = node.tagName.toUpperCase();
            if (tag === 'BR') return '\n';

            // Skip over our own injected UI elements if scanning repeats
            if (node.className && typeof node.className === 'string' &&
                (node.className.indexOf('ai-btn-wrapper') > -1 || node.className.indexOf('translation-result') > -1)) {
                return '';
            }

            var isBlock = false;
            // Native block elements or custom dictionary blocks
            if (tag === 'DIV' || tag === 'P' || tag === 'LI' || tag === 'TR' || tag === 'UL' || tag === 'H1' || tag === 'H2' || tag === 'H3') {
                isBlock = true;
            } else if (node.className && typeof node.className === 'string' && blockClasses.test(node.className)) {
                isBlock = true;
            }

            var text = '';
            for (var i = 0; i < node.childNodes.length; i++) {
                text += traverse(node.childNodes[i]);
            }

            // Bookend semantic blocks with newlines to segregate sentences
            if (isBlock) {
                return '\n' + text + '\n';
            }
            return text;
        }
        return '';
    }

    var raw = traverse(element);

    // Normalize step 1: Collapse multiple spaces into one
    raw = raw.replace(/[ \t]+/g, ' ');
    // Normalize step 2: Clean up spaces immediately clinging to our newlines
    raw = raw.replace(/[ \t]*\n[ \t]*/g, '\n');
    // Normalize step 3: Collapse consecutive newlines into a single strict separator
    raw = raw.replace(/\n+/g, '\n');

    // Trim edges
    return raw.replace(/^\s+|\s+$/g, '');
}

// --- DOM Event Logic ---
function initializeTranslator() {
    injectTranslationStyles();

    var rawElements = document.querySelectorAll(TRANSLATION_CSS_SELECTOR);
    var elements =[]; // Array to hold the filtered result

    // Phase 1: Filter out duplicates, already-processed elements, and nested children
    for (var i = 0; i < rawElements.length; i++) {
        var el = rawElements[i];

        // 1. Skip if already processed during a previous scan
        if (hasClass(el, 'ai-hover-target')) {
            continue;
        }

        var isNested = false;
        var parent = el.parentNode;

        // 2. Traverse up to see if any ancestor takes precedence
        while (parent && parent !== document) {
            // Check A: Is the parent already processed in a previous scan?
            if (parent.className && typeof parent.className === 'string' && parent.className.indexOf('ai-hover-target') !== -1) {
                isNested = true;
                break;
            }

            // Check B: Is the parent part of the current raw query selection?
            for (var j = 0; j < rawElements.length; j++) {
                if (parent === rawElements[j]) {
                    isNested = true;
                    break;
                }
            }

            if (isNested) break;
            parent = parent.parentNode;
        }

        if (!isNested) {
            // 3. Ensure absolute uniqueness (prevent duplicates inside array)
            var isDuplicate = false;
            for (var k = 0; k < elements.length; k++) {
                if (elements[k] === el) {
                    isDuplicate = true; break;
                }
            }
            if (!isDuplicate) elements.push(el);
        }
    }

    // Phase 2: Attach Logic
    for (var i = 0; i < elements.length; i++) {
        (function(el) {
            // Apply the custom structural text extraction
            var rawText = extractDelimitedText(el);
            el.setAttribute('data-original-text', rawText);

            // Allow JS to identify the element
            addClass(el, 'ai-hover-target');

            // 1. Create the invisible bridge wrapper
            var btnWrapper = document.createElement('span');
            btnWrapper.className = 'ai-btn-wrapper';

            // 2. Create the UI button itself
            var btn = document.createElement('span');
            btn.className = 'ai-translate-btn';
            btn.innerHTML = 'AI';
            btn.setAttribute('title', 'Translate to Chinese');

            // Assemble
            btnWrapper.appendChild(btn);
            el.appendChild(btnWrapper);

            // --- JAVASCRIPT HOVER DELAY TIMER ---
            var hoverTimer = null;

            el.onmouseenter = function() {
                // When mouse enters text or button, clear countdown and show immediately
                if (hoverTimer) clearTimeout(hoverTimer);
                addClass(el, 'ai-show-btn');
            };

            el.onmouseleave = function() {
                // When mouse leaves, wait 2 seconds (2000ms) before hiding button
                hoverTimer = setTimeout(function() {
                    removeClass(el, 'ai-show-btn');
                }, 2000);
            };
            // ------------------------------------

            // Click listener attached ONLY to the button
            btn.onclick = function(event) {
                var e = event || window.event;
                if (e.stopPropagation) { e.stopPropagation(); } else { e.cancelBubble = true; }

                if (hasClass(el, 'ai-translating')) return;

                var currentState = el.getAttribute('data-translation-state');

                // State 1: VISIBLE -> Hide it
                if (currentState === 'visible') {
                    var spanVis = el.querySelector('.translation-result');
                    if (spanVis) spanVis.style.display = 'none';

                    el.setAttribute('data-translation-state', 'hidden');
                    removeClass(el, 'ai-btn-active');
                    btn.innerHTML = 'Show';
                    return;
                }

                // State 2: HIDDEN -> Show it instantly
                if (currentState === 'hidden') {
                    var spanHid = el.querySelector('.translation-result');
                    // Setting to empty string reverts back to the CSS class definition (inline vs block)
                    if (spanHid) spanHid.style.display = '';

                    el.setAttribute('data-translation-state', 'visible');
                    addClass(el, 'ai-btn-active');
                    btn.innerHTML = 'Hide';
                    return;
                }

                // State 3: Fetch translation
                var textToTranslate = el.getAttribute('data-original-text');
                if (!textToTranslate || textToTranslate === '') return;

                // Apply Loading State
                addClass(el, 'ai-translating');
                addClass(el, 'ai-btn-active');

                // Show CSS Spinner inside button
                btn.innerHTML = '<span class="ai-spinner"></span> ...';
                btn.style.cursor = 'wait';

                // Trigger native OS "Spinning Beach Ball"
                document.body.style.cursor = 'wait';

                translateWaterfall(textToTranslate, SOURCE_LANG, TARGET_LANG,
                    function(result) {
                        // Success Callback
                        var translationSpan = document.createElement('span');
                        translationSpan.className = 'translation-result';

                        var markerNode = document.createElement('span');
                        markerNode.className = 'api-marker';
                        markerNode.title = 'Translated by ' + result.apiName;
                        markerNode.appendChild(document.createTextNode('[' + result.marker + '] '));

                        translationSpan.appendChild(markerNode);

                        // --- NEW: Handle rendering separated strings dynamically ---
                        var lines = result.text.split('\n');
                        var isFirstLine = true;

                        for (var j = 0; j < lines.length; j++) {
                            var cleanLine = lines[j].replace(/^\s+|\s+$/g, '');
                            if (cleanLine !== '') {
                                if (!isFirstLine) {
                                    // Use a hard line break for separation
                                    translationSpan.appendChild(document.createElement('br'));

                                    // Inject a spacer block to align trailing lines past the marker width cleanly
                                    var indent = document.createElement('span');
                                    indent.style.display = 'inline-block';
                                    indent.style.width = '24px';
                                    translationSpan.appendChild(indent);
                                }
                                translationSpan.appendChild(document.createTextNode(cleanLine));
                                isFirstLine = false;
                            }
                        }

                        el.appendChild(translationSpan);

                        // Reset States
                        el.setAttribute('data-translation-state', 'visible');
                        removeClass(el, 'ai-translating');
                        btn.innerHTML = 'Hide';

                        // Remove OS Beach Ball
                        btn.style.cursor = 'pointer';
                        document.body.style.cursor = '';
                    },
                    function(errorList) {
                        // Failure Callback (Shows specific dynamic errors directly inline)
                        var errStr = (errorList && errorList.length > 0) ? errorList.join('\n') : "Unknown structural failure.";
                        console.error("Translation Waterfall Failed:\n" + errStr);

                        var errorSpan = document.createElement('span');
                        // Tag it with both classes so it can still toggle but takes on block/monospace styles
                        errorSpan.className = 'translation-result translation-error';

                        var markerNode = document.createElement('span');
                        markerNode.className = 'api-marker';
                        markerNode.title = 'All Translation Networks Failed';
                        markerNode.appendChild(document.createTextNode('[Error]'));

                        var textNode = document.createTextNode(" Translation Failed:\n" + errStr);

                        errorSpan.appendChild(markerNode);
                        errorSpan.appendChild(textNode);

                        el.appendChild(errorSpan);

                        // Reset States so the user has the option to click "Hide"
                        el.setAttribute('data-translation-state', 'visible');
                        removeClass(el, 'ai-translating');
                        btn.innerHTML = 'Hide';

                        // Remove OS Beach Ball
                        btn.style.cursor = 'pointer';
                        document.body.style.cursor = '';
                    }
                );
            };
        })(elements[i]);
    }
}

if (USE_INTERNET_TRANSLATION === true) {
    // Ensure script works even if loaded in <head>
    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', initializeTranslator);
    } else {
        initializeTranslator();
    }
}

// --- THE WATERFALL ENGINE (Dynamic Async Loop) ---
function translateWaterfall(text, sourceLang, targetLang, onComplete, onUltimateFail) {
    var order = TRANSLATION_ORDER.toUpperCase();
    var currentIndex = 0;
    var accumulatedErrors =[];

    // This internal function acts as our async loop, catching actual raw error messages
    function tryNext(err) {
        if (err) {
            var prevProvider = order.charAt(currentIndex - 1);
            var errMessage = err.message || err.toString();
            accumulatedErrors.push("[" + prevProvider + " Provider] " + errMessage);
        }

        // If we've reached the end of the string, all fallbacks failed
        if (currentIndex >= order.length) {
            return onUltimateFail(accumulatedErrors);
        }

        // Get the current letter and advance the index for the next potential failure
        var currentProvider = order.charAt(currentIndex);
        currentIndex++;

        // Route to the correct API based on the letter
        if (currentProvider === 'D') {
            fetchDeepSeek(text, sourceLang, targetLang, function(res) {
                onComplete({ text: res, marker: 'D', apiName: 'DeepSeek' });
            }, tryNext);
        } else if (currentProvider === 'L') {
            fetchLingva(text, sourceLang, targetLang, function(res) {
                onComplete({ text: res, marker: 'L', apiName: 'Lingva' });
            }, tryNext); // Pass tryNext as the error callback
        } else if (currentProvider === 'Y') {
            fetchYoudao(text, function(res) {
                onComplete({ text: res, marker: 'Y', apiName: 'Youdao' });
            }, tryNext);

        } else if (currentProvider === 'M') {
            fetchMyMemory(text, sourceLang, targetLang, function(res) {
                onComplete({ text: res, marker: 'M', apiName: 'MyMemory' });
            }, tryNext);

        } else if (currentProvider === 'G') {
            fetchGoogle(text, sourceLang, targetLang, function(res) {
                onComplete({ text: res, marker: 'G', apiName: 'Google Translate' });
            }, tryNext);

        } else {
            // Unrecognized letter code
            tryNext(new Error("Unrecognized provider code '" + currentProvider + "' in TRANSLATION_ORDER string."));
        }
    }

    // Kick off the loop
    tryNext();
}


// --- THE API ENDPOINTS ---

// --- DeepSeek API（POST 请求，非流式）---
function fetchDeepSeek(text, sourceLang, targetLang, onSuccess, onError) {
    var url = 'https://api.deepseek.com/chat/completions';
    var data = {
        model: 'deepseek-chat',
        messages:[
            { role: 'system', content: 'You are an internationally renowned maven for the ultimate 信达雅 in the art of translation. ' +
                'Translate the given text from ' + sourceLang + ' to ' + targetLang + '. Preserve the exact line breaks of the original text. ' +
                'Output only the translation, no explanation.' },
            { role: 'user', content: text }
        ],
        temperature: 0.1,
        stream: false
    };
    var xhr = new XMLHttpRequest();
    var isDone = false;
    var timer = setTimeout(function() {
        if (isDone) return;
        isDone = true;
        xhr.abort();
        onError(new Error("Timeout after 5000ms"));
    }, 5000);

    xhr.open('POST', url, true);
    xhr.setRequestHeader('Content-Type', 'application/json');
    xhr.setRequestHeader('Authorization', 'Bearer ' + DEEPSEEK_API_KEY);

    xhr.onload = function() {
        if (isDone) return;
        isDone = true;
        clearTimeout(timer);

        if (xhr.status >= 200 && xhr.status < 300) {
            try {
                var response = JSON.parse(xhr.responseText);
                if (response && response.choices && response.choices[0] && response.choices[0].message) {
                    var translation = response.choices[0].message.content;
                    onSuccess(translation);
                } else {
                    onError(new Error("Invalid JSON structure: " + xhr.responseText.substring(0, 150)));
                }
            } catch(e) {
                onError(new Error("JSON Parsing failure: " + e.message));
            }
        } else {
            // e.g. This will natively capture "402 Insufficient Balance", "401 Unauthorized"
            var bodySnippet = xhr.responseText ? xhr.responseText.substring(0, 200) : "(empty response body)";
            onError(new Error("HTTP Error " + xhr.status + " | " + bodySnippet));
        }
    };

    xhr.onerror = function() {
        if (isDone) return;
        isDone = true;
        clearTimeout(timer);
        onError(new Error("Network Error, DNS failure, or CORS blocked for POST: " + url));
    };
    xhr.send(JSON.stringify(data));
}

function fetchLingva(text, sourceLang, targetLang, onSuccess, onError) {
    var servers =[
        'https://translate.plausibility.cloud',
        'https://lingva.lunar.icu',
        'https://lingva.garudalinux.org'
    ];
    var index = 0;
    var lingvaErrors =[];

    function tryNextServer(err) {
        if (err) {
            lingvaErrors.push(servers[index - 1] + " -> " + (err.message || err.toString()));
        }
        if (index >= servers.length) {
            return onError(new Error("All mirrors failed: \n   - " + lingvaErrors.join('\n   - ')));
        }
        var url = servers[index] + '/api/v1/' + sourceLang + '/' + targetLang + '/' + encodeURIComponent(text);
        index++;

        ajaxGet(url, 3000, function(data) {
            if (data && data.translation) {
                onSuccess(data.translation);
            } else {
                tryNextServer(new Error("Missing 'translation' node in JSON: " + JSON.stringify(data).substring(0, 100)));
            }
        }, tryNextServer);
    }
    tryNextServer();
}

function fetchMyMemory(text, sourceLang, targetLang, onSuccess, onError) {
    var email = 'fallback@example.com';
    var url = 'https://api.mymemory.translated.net/get?q=' + encodeURIComponent(text) + '&langpair=' + sourceLang + '|' + targetLang + '&de=' + email;
    ajaxGet(url, 3500, function(data) {
        if (data && data.responseData && data.responseData.translatedText) {
            onSuccess(data.responseData.translatedText);
        } else {
            onError(new Error("Invalid API JSON layout received: " + JSON.stringify(data).substring(0, 150)));
        }
    }, onError);
}

function fetchGoogle(text, sourceLang, targetLang, onSuccess, onError) {
    var url = 'https://translate.googleapis.com/translate_a/single?client=gtx&sl=' + sourceLang + '&tl=' + targetLang + '&dt=t&q=' + encodeURIComponent(text);
    ajaxGet(url, 4000, function(data) {
        if (data && data[0]) {
            var combined = "";
            for(var i=0; i < data[0].length; i++) {
                combined += data[0][i][0];
            }
            onSuccess(combined);
        } else {
            onError(new Error("Unexpected Google array structure: " + JSON.stringify(data).substring(0, 150)));
        }
    }, onError);
}

// 占位函数：若原页面未定义 fetchYoudao，此空实现保证不会崩溃
function fetchYoudao(text, onSuccess, onError) {
    onError(new Error("Youdao API endpoint not yet implemented in script"));
}