// ===== 页面元素 =====
const elEngineModel = document.getElementById('engineModel');
const elModelServiceUrl = document.getElementById('modelServiceUrl');
const elSpeakerStatus = document.getElementById('speakerStatus');
const elDisplayMerge = document.getElementById('displayMerge');
const elSpeakerDiarization = document.getElementById('speakerDiarization');
const elDiarizationLabel = document.getElementById('diarizationLabel');
const elSentenceStrategy = document.getElementById('sentenceStrategy');
const elBtnStart = document.getElementById('btnStart');
const elBtnStop = document.getElementById('btnStop');
const elResultMeta = document.getElementById('resultMeta');
const elVoiceIdDisplay = document.getElementById('voiceIdDisplay');
const elBtnCopyVoiceId = document.getElementById('btnCopyVoiceId');
const elBtnExportWav = document.getElementById('btnExportWav');
const elStatusDot = document.getElementById('statusDot');
const elStatusText = document.getElementById('statusText');
const elResultArea = document.getElementById('resultArea');
const elResultPlaceholder = document.getElementById('resultPlaceholder');
const elLogArea = document.getElementById('logArea');
const elBtnClearLog = document.getElementById('btnClearLog');
const elMicStatus = document.getElementById('micStatus');
const elMicTimer = document.getElementById('micTimer');
const elMicElapsed = document.getElementById('micElapsed');

// 输入模式标签页
const elTabMic = document.getElementById('tabMic');
const elTabFile = document.getElementById('tabFile');
const elPanelMic = document.getElementById('panelMic');
const elPanelFile = document.getElementById('panelFile');

// 文件选择区域
const elAudioFile = document.getElementById('audioFile');
const elFileInfo = document.getElementById('fileInfo');
const elAudioMeta = document.getElementById('audioMeta');
const elMetaFormat = document.getElementById('metaFormat');
const elMetaSampleRate = document.getElementById('metaSampleRate');
const elMetaDuration = document.getElementById('metaDuration');
const elSpeedControl = document.getElementById('speedControl');
const elSpeedSlider = document.getElementById('speedSlider');
const elSpeedValue = document.getElementById('speedValue');

// ===== 说话人分离开关 =====
elSpeakerDiarization.addEventListener('change', () => {
    elDiarizationLabel.textContent = elSpeakerDiarization.checked ? '开启' : '关闭';
});

// ===== 日志区域 =====
elBtnClearLog.addEventListener('click', () => { elLogArea.innerHTML = ''; });

function appendLog(msg) {
    const now = new Date();
    const ts = [now.getHours(), now.getMinutes(), now.getSeconds()]
        .map(n => String(n).padStart(2, '0')).join(':')
        + '.' + String(now.getMilliseconds()).padStart(3, '0');
    const typeClass = 'log-type-' + (msg.type || 'unknown');
    const entry = document.createElement('div');
    entry.className = 'log-entry';
    // 原始文本不作为 HTML 解释，转写中的标签也应原样显示。
    const stamp = document.createElement('span');
    stamp.className = 'log-time';
    stamp.textContent = ts;
    const content = document.createElement('span');
    content.className = typeClass;
    content.textContent = JSON.stringify(msg);
    entry.append(stamp, content);
    elLogArea.appendChild(entry);
    while (elLogArea.childNodes.length > 300) elLogArea.firstChild.remove();
    elLogArea.scrollTop = elLogArea.scrollHeight;
}

// ===== 会话状态 =====
let ws = null;
let sending = false;
let stoppingByUser = false;
let currentVoiceId = null;
let audioChunks = [];
let sessionId = 0;

let micStream = null;
let micAudioContext = null;
let micWorklet = null;
let micTimerInterval = null;
let micStartTime = 0;

// 输入模式（麦克风 / 文件）
let inputMode = 'mic';
let selectedFile = null;

// 文件扩展名 → SDK VoiceFormat 常量
const EXT_FORMAT_MAP = {
    'pcm': 1, 'wav': 12, 'mp3': 8, 'm4a': 14,
    'aac': 16, 'opus': 10, 'ogg': 10, 'silk': 6, 'speex': 4
};
// PCM/WAV 的默认发送倍速；实时验证默认按 1 倍速输入。
const DEFAULT_SPEED = {
    'pcm': 1.0, 'wav': 1.0,
    'mp3': 2.0, 'm4a': 2.0, 'aac': 2.0,
    'opus': 3.0, 'ogg': 3.0, 'silk': 3.0, 'speex': 3.0
};
const MAX_SPEED = 3.0;
// 实时 WebSocket 需要服务端逐帧读取音频；压缩格式必须等文件完整后才能解码，
// 因此本次流式验证只允许 PCM/WAV，避免把整段上传伪装成实时识别。
const STREAMABLE_AUDIO_EXTENSIONS = new Set(['pcm', 'wav']);

const SPEAKER_COLORS = ['#4a7dff', '#52c41a', '#faad14', '#ff4d4f', '#9254de', '#13c2c2'];

let sentenceMap = {};
let speakerOrderMap = {};
let speakerOrderCounter = 0;
let displayStateSupported = false;
let displayRevision = -1;

// ===== 输入模式标签页 =====
function switchMode(mode) {
    if (ws) return;
    inputMode = mode;
    elTabMic.classList.toggle('active', mode === 'mic');
    elTabFile.classList.toggle('active', mode === 'file');
    elPanelMic.style.display = mode === 'mic' ? '' : 'none';
    elPanelFile.style.display = mode === 'file' ? '' : 'none';
    if (mode === 'file') {
        elBtnStart.disabled = !selectedFile;
    } else {
        elBtnStart.disabled = false;
    }
}
elTabMic.addEventListener('click', () => switchMode('mic'));
elTabFile.addEventListener('click', () => switchMode('file'));

// ===== 文件选择 =====
elAudioFile.addEventListener('change', (e) => {
    const file = e.target.files[0];
    if (!file) return;
    const ext = getFileExt(file.name);
    if (!STREAMABLE_AUDIO_EXTENSIONS.has(ext)) {
        selectedFile = null;
        e.target.value = '';
        elFileInfo.textContent = '实时测试只支持 PCM 或 WAV，请先转换音频格式';
        elFileInfo.classList.remove('has-file');
        elAudioMeta.style.display = 'none';
        elSpeedControl.style.display = 'none';
        elBtnStart.disabled = true;
        showToast('压缩音频不能按当前实时 WebSocket 逐帧识别，请转成 PCM 或 WAV', true);
        return;
    }
    selectedFile = file;
    const sizeMB = (file.size / 1024 / 1024).toFixed(1);
    elFileInfo.textContent = `${file.name} (${sizeMB}MB)`;
    elFileInfo.classList.add('has-file');
    elBtnStart.disabled = false;
    parseAudioMeta(file);
});

// 发送速度滑块
elSpeedSlider.addEventListener('input', () => {
    elSpeedValue.textContent = parseFloat(elSpeedSlider.value).toFixed(1) + 'x';
});

// ===== 音频元数据解析 =====
function getFileExt(filename) {
    const parts = filename.split('.');
    return parts.length > 1 ? parts[parts.length - 1].toLowerCase() : '';
}

function formatDuration(seconds) {
    if (!seconds || !isFinite(seconds)) return '—';
    const min = Math.floor(seconds / 60);
    const sec = Math.floor(seconds % 60);
    const ms = Math.round((seconds % 1) * 10);
    return `${String(min).padStart(2, '0')}:${String(sec).padStart(2, '0')}.${ms}`;
}

async function parseAudioMeta(file) {
    const ext = getFileExt(file.name);
    elMetaFormat.textContent = ext.toUpperCase();
    // 根据格式设默认倍速
    const defaultSpeed = Math.min(DEFAULT_SPEED[ext] || 1.0, MAX_SPEED);
    elSpeedSlider.value = defaultSpeed;
    elSpeedValue.textContent = defaultSpeed.toFixed(1) + 'x';
    elAudioMeta.style.display = '';
    elSpeedControl.style.display = '';

    if (ext === 'pcm') {
        elMetaSampleRate.textContent = '16000 Hz (假设)';
        const durationSec = file.size / (16000 * 2 * 1);
        elMetaDuration.textContent = formatDuration(durationSec) + ' (估算)';
    } else if (ext === 'wav') {
        try {
            const headerBuf = await file.slice(0, 44).arrayBuffer();
            const view = new DataView(headerBuf);
            const sampleRate = view.getUint32(24, true);
            const bitsPerSample = view.getUint16(34, true);
            const numChannels = view.getUint16(22, true);
            const byteRate = sampleRate * numChannels * (bitsPerSample / 8);
            const dataSize = file.size - 44;
            const durationSec = dataSize / byteRate;
            elMetaSampleRate.textContent = sampleRate + ' Hz, ' + bitsPerSample + 'bit, ' + numChannels + 'ch';
            elMetaDuration.textContent = formatDuration(durationSec);
        } catch {
            elMetaSampleRate.textContent = '解析失败';
            elMetaDuration.textContent = '—';
        }
    } else {
        elMetaSampleRate.textContent = '—';
        elMetaDuration.textContent = '解析中...';
        try {
            const url = URL.createObjectURL(file);
            const audio = new Audio();
            audio.preload = 'metadata';
            audio.src = url;
            await new Promise((resolve, reject) => {
                audio.onloadedmetadata = resolve;
                audio.onerror = reject;
                setTimeout(reject, 5000);
            });
            elMetaDuration.textContent = formatDuration(audio.duration);
            URL.revokeObjectURL(url);
        } catch {
            elMetaDuration.textContent = '无法解析';
        }
    }
}

// ===== 复制和提示 =====
function showToast(message, isError) {
    const toast = document.createElement('div');
    toast.className = 'copy-toast' + (isError ? ' copy-toast-error' : '');
    toast.textContent = message;
    document.body.appendChild(toast);
    requestAnimationFrame(() => { toast.classList.add('visible'); });
    setTimeout(() => {
        toast.classList.remove('visible');
        setTimeout(() => toast.remove(), 300);
    }, 1500);
}

function handleCopyClick(btn, textEl) {
    const text = textEl.textContent.trim();
    if (!text || text === '—') { showToast('暂无内容可复制', true); return; }
    navigator.clipboard.writeText(text).then(() => {
        btn.textContent = '✅';
        showToast('已复制到剪贴板');
        setTimeout(() => { btn.textContent = '📋'; }, 1500);
    }).catch(() => showToast('复制失败', true));
}

elBtnCopyVoiceId.addEventListener('click', () => handleCopyClick(elBtnCopyVoiceId, elVoiceIdDisplay));

// ===== WAV 导出 =====
function buildWavBlob(pcmChunks) {
    let totalLen = 0;
    for (const c of pcmChunks) totalLen += c.byteLength;
    const buf = new ArrayBuffer(44 + totalLen);
    const view = new DataView(buf);
    const writeStr = (off, str) => { for (let i = 0; i < str.length; i++) view.setUint8(off + i, str.charCodeAt(i)); };
    const sampleRate = 16000, bitsPerSample = 16, numChannels = 1;
    const byteRate = sampleRate * numChannels * bitsPerSample / 8;
    const blockAlign = numChannels * bitsPerSample / 8;
    writeStr(0, 'RIFF');
    view.setUint32(4, 36 + totalLen, true);
    writeStr(8, 'WAVE');
    writeStr(12, 'fmt ');
    view.setUint32(16, 16, true);
    view.setUint16(20, 1, true);
    view.setUint16(22, numChannels, true);
    view.setUint32(24, sampleRate, true);
    view.setUint32(28, byteRate, true);
    view.setUint16(32, blockAlign, true);
    view.setUint16(34, bitsPerSample, true);
    writeStr(36, 'data');
    view.setUint32(40, totalLen, true);
    let offset = 44;
    for (const chunk of pcmChunks) {
        const src = new Uint8Array(chunk instanceof ArrayBuffer ? chunk : chunk.buffer || chunk);
        new Uint8Array(buf, offset).set(src);
        offset += src.byteLength;
    }
    return new Blob([buf], { type: 'audio/wav' });
}

elBtnExportWav.addEventListener('click', () => {
    if (audioChunks.length === 0) { showToast('暂无音频数据', true); return; }
    const blob = buildWavBlob(audioChunks);
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = (currentVoiceId || 'audio') + '.wav';
    document.body.appendChild(a);
    a.click();
    a.remove();
    URL.revokeObjectURL(url);
    showToast('WAV 已导出');
});

// ===== 辅助函数 =====
function formatTime(ms) {
    const totalSec = Math.floor(ms / 1000);
    const min = String(Math.floor(totalSec / 60)).padStart(2, '0');
    const sec = String(totalSec % 60).padStart(2, '0');
    return `${min}:${sec}`;
}

function formatTimeRange(startMs, endMs) {
    return `${formatTime(startMs)} - ${formatTime(endMs)}`;
}

function setStatus(state, text) {
    elStatusDot.className = 'status-dot ' + state;
    elStatusText.textContent = text;
}

// ===== 渲染字幕（关闭说话人分离） =====
// 每个 sentence_id 对应一个独立气泡：
// - 中间态（sentence_type===0）：实时更新该气泡文本，末尾加 "..." 表示未定。
// - 稳态（sentence_type===1）：去掉 "..." 并定格，下一个 sentence_id 自动创建新气泡。
function renderSubtitle(sentence) {
    const id = 'subtitle-' + sentence.sentence_id;
    const isInterim = sentence.sentence_type === 0;
    let entry = sentenceMap[id];

    if (!entry) {
        const el = document.createElement('div');
        el.className = 'subtitle-item subtitle-interim';
        el.id = id;
        const timeSpan = document.createElement('span');
        timeSpan.className = 'subtitle-time';
        el.appendChild(timeSpan);
        const textSpan = document.createElement('span');
        textSpan.className = 'subtitle-text';
        el.appendChild(textSpan);
        elResultArea.appendChild(el);
        entry = { el: el };
        sentenceMap[id] = entry;
    }

    const el = entry.el;
    el.querySelector('.subtitle-time').textContent = formatTimeRange(sentence.start_time, sentence.end_time);
    const textSpan = el.querySelector('.subtitle-text');
    if (isInterim) {
        textSpan.textContent = sentence.sentence + ' ...';
        textSpan.className = 'subtitle-text interim';
    } else {
        textSpan.textContent = sentence.sentence;
        textSpan.className = 'subtitle-text';
        el.className = 'subtitle-item'; // 去掉 interim 类名，定格
    }
    elResultArea.scrollTop = elResultArea.scrollHeight;
}

// ===== 渲染说话人气泡 =====
// 未确认片段独立展示，不能临时塞进上一位说话人的气泡。
function renderBubble(sentence) {
    const id = 'sent-' + sentence.sentence_id;
    const speakerId = Number(sentence.speaker_id);
    const trusted = Number.isInteger(speakerId) && speakerId >= 0
        && ['fresh', 'confirmed'].includes(sentence.speaker_evidence);
    const isInterim = sentence.sentence_type === 0;
    let entry = sentenceMap[id];
    if (!entry) {
        const el = document.createElement('div');
        el.id = id;
        const wrapper = document.createElement('div');
        wrapper.className = 'bubble-wrapper';
        const header = document.createElement('div');
        header.className = 'bubble-header';
        for (const name of ['speaker-badge', 'speaker-name', 'bubble-time']) {
            const span = document.createElement('span');
            span.className = name;
            header.appendChild(span);
        }
        const body = document.createElement('div');
        body.className = 'bubble-body';
        wrapper.append(header, body);
        el.appendChild(wrapper);
        elResultArea.appendChild(el);
        entry = { el };
        sentenceMap[id] = entry;
    }
    if (trusted && !(speakerId in speakerOrderMap)) speakerOrderMap[speakerId] = speakerOrderCounter++;
    const order = trusted ? speakerOrderMap[speakerId] : 0;
    const color = order % SPEAKER_COLORS.length;
    const el = entry.el;
    el.className = trusted ? `bubble-row speaker-${order % 2 ? 'right' : 'left'} speaker-${color}`
        : 'bubble-row speaker-left speaker-unknown';
    el.querySelector('.speaker-badge').className = 'speaker-badge speaker-color-' + (trusted ? color : 'unknown');
    // 未获得当前片段的可靠声纹证据时，标题保持简短；详细原因放到悬停提示，
    // 这样不会把“有效语音不足……”等内部诊断信息挤进说话人名称区域。
    const speakerName = el.querySelector('.speaker-name');
    speakerName.textContent = trusted
        ? (sentence.speaker_name || `说话人 ${speakerId + 1}`)
        : '未知说话人';
    speakerName.title = trusted ? '' : (sentence.speaker_reason || '未匹配到说话人');
    el.querySelector('.bubble-time').textContent = formatTimeRange(sentence.start_time, sentence.end_time);
    const body = el.querySelector('.bubble-body');
    body.textContent = sentence.sentence + (isInterim ? ' ...' : '');
    body.className = 'bubble-body' + (isInterim ? ' interim' : '');
    elResultArea.scrollTop = elResultArea.scrollHeight;
}

// 按完整快照重建相邻块；序号防止两个后台 worker 的旧快照覆盖新状态。
function renderDisplayState(msg, useSpeaker) {
    if (msg.revision != null && msg.revision <= displayRevision) return;
    if (msg.revision != null) displayRevision = msg.revision;
    elResultArea.replaceChildren();
    sentenceMap = {};
    const raw = msg.raw_segments || msg.sentences || [];
    if (useSpeaker) {
        for (const block of msg.display_blocks || []) renderBubble({ ...block, sentence_id: block.block_id });
        const confirmed = raw.filter(s => s.speaker_status === 'confirmed').length;
        const failed = raw.filter(s => ['service_error', 'service_unavailable', 'no_embedding', 'evidence_rejected'].includes(s.speaker_status)).length;
        elSpeakerStatus.textContent = `说话人：已确认 ${confirmed} / ${raw.length} 段` + (failed ? `，${failed} 段未识别成功（原因见气泡及日志）` : '');
    } else {
        raw.forEach(renderSubtitle);
        elSpeakerStatus.textContent = '说话人分离已关闭';
    }
}

elBtnStart.addEventListener('click', () => {
    if (inputMode === 'file' && !selectedFile) return;
    startRecognition();
});

async function startRecognition() {
    if (ws) return;
    if (inputMode === 'file' && selectedFile) {
        const ext = getFileExt(selectedFile.name);
        if (!STREAMABLE_AUDIO_EXTENSIONS.has(ext)) {
            showToast('实时流式测试只支持 PCM 或 WAV，请转换后再试', true);
            return;
        }
    }

    elResultArea.innerHTML = '';
    elLogArea.innerHTML = '';
    sentenceMap = {};
    speakerOrderMap = {};
    speakerOrderCounter = 0;
    displayStateSupported = false;
    displayRevision = -1;
    elSpeakerStatus.textContent = '正在检查说话人服务…';
    audioChunks = [];
    elBtnExportWav.disabled = true;
    elResultPlaceholder?.remove();
    elResultMeta.style.display = 'flex';
    elVoiceIdDisplay.textContent = '—';
    setStatus('connecting', '连接中...');

    elBtnStart.disabled = true;
    elBtnStop.disabled = false;
    sending = true;

    const currentSession = ++sessionId;
    const useSpeaker = elSpeakerDiarization.checked;
    let receivedTerminal = false;

    // 构造 WebSocket 首条 start 消息。
    let voiceFormat = 0, fileName = '', speedFactor = 0;
    if (inputMode === 'file') {
        const ext = getFileExt(selectedFile.name);
        voiceFormat = EXT_FORMAT_MAP[ext] || 0;
        fileName = selectedFile.name;
        speedFactor = Math.min(parseFloat(elSpeedSlider.value) || 1.0, MAX_SPEED);
    }

    const startPayload = {
        type: 'start',
        model: elEngineModel.value,
        model_service_url: elModelServiceUrl.value,
        display_merge: elDisplayMerge.checked,
        speaker_diarization: useSpeaker ? 1 : 0,
        sentence_strategy: parseInt(elSentenceStrategy.value),
        source: inputMode,
        voice_format: voiceFormat,
        file_name: fileName,
        speed_factor: speedFactor
    };

    const protocol = location.protocol === 'https:' ? 'wss:' : 'ws:';
    ws = new WebSocket(`${protocol}//${location.host}/ws`);
    ws.binaryType = 'arraybuffer';

    ws.onopen = () => {
        if (currentSession !== sessionId) return;
        ws.send(JSON.stringify(startPayload));
        // 在连接尚未建立时点击停止，也要在 start 后补发停止信号。
        if (!sending) ws.send(JSON.stringify({ type: 'stop' }));
    };

    ws.onmessage = (event) => {
        if (currentSession !== sessionId) return;
        const msg = JSON.parse(event.data);
        if (msg.type === 'end' || msg.type === 'error') receivedTerminal = true;
        if (msg.type !== 'sentences') {
            console.log('[ws] type=' + msg.type, msg);
        }
        appendLog(msg);
        handleServerMessage(msg, useSpeaker);
    };

    ws.onerror = (err) => {
        if (currentSession !== sessionId) return;
        console.error('WebSocket error:', err);
        setStatus('error', '连接错误');
        stopMicCapture();
        resetControls();
    };

    ws.onclose = () => {
        if (currentSession !== sessionId) return;
        stopMicCapture();
        if (!receivedTerminal) setStatus('error', '连接中断，最终识别结果可能尚未完成');
        if (audioChunks.length > 0) elBtnExportWav.disabled = false;
        ws = null;
        resetControls();
    };
}

function handleServerMessage(msg, useSpeaker) {
    switch (msg.type) {
        case 'voice_id':
            if (msg.voice_id) {
                currentVoiceId = msg.voice_id;
                elVoiceIdDisplay.textContent = msg.voice_id;
            }
            break;

        case 'start':
            displayStateSupported = Boolean(msg.display_state_supported);
            currentVoiceId = msg.session_id;
            elVoiceIdDisplay.textContent = currentVoiceId || '—';
            elSpeakerStatus.textContent = useSpeaker
                ? `说话人服务：${msg.speaker_service_url || '未配置'}；片段结束后提取声纹`
                : '说话人分离已关闭';
            if (!sending) break;
            setStatus('running', '识别中...');
            if (inputMode === 'file') sendAudioFile(selectedFile).catch(handleInputError);
            else startMicCapture().catch(handleInputError);
            break;

        case 'display_state':
            renderDisplayState(msg, useSpeaker);
            break;

        case 'draining':
            setStatus('running', msg.message || '等待最终识别结果…');
            break;

        case 'sentences':
            if (displayStateSupported) break;
            if (msg.sentences) {
                msg.sentences.forEach(s => {
                    if (useSpeaker) renderBubble(s);
                    else renderSubtitle(s);
                });
            }
            break;

        case 'speaker_warning':
            // ASR 仍可继续输出，但必须让测试人员立即知道说话人链路没有生效。
            elSpeakerStatus.textContent = '说话人服务异常：' + msg.message;
            showToast('说话人服务异常，详见状态和片段原因', true);
            break;

        case 'end':
            if (msg.display_blocks) renderDisplayState(msg, useSpeaker);
            setStatus('done', '识别完成');
            sending = false;
            if (audioChunks.length > 0) elBtnExportWav.disabled = false;
            resetControls();
            if (ws) { ws.close(); ws = null; }
            break;

        case 'error':
            setStatus('error', `错误: ${msg.message}`);
            sending = false;
            stopMicCapture();
            if (ws) { ws.close(); ws = null; }
            resetControls();
            break;
    }
}

// ===== 停止识别 =====
elBtnStop.addEventListener('click', () => stopRecognition());

function stopRecognition() {
    sending = false;
    stoppingByUser = true;
    stopMicCapture();
    setStatus('running', '停止中...');
    elBtnStop.disabled = true;

    if (ws && ws.readyState === WebSocket.OPEN) {
        try { ws.send(JSON.stringify({ type: 'stop' })); } catch (e) {}
    }

    // 等待服务端排空 ASR/声纹队列后发送 end，不能用五秒计时器截断更新。

}

function resetControls() {
    sending = false;
    stoppingByUser = false;
    currentVoiceId = null;
    if (inputMode === 'file') {
        elBtnStart.disabled = !selectedFile;
    } else {
        elBtnStart.disabled = false;
    }
    elBtnStop.disabled = true;
}

// ===== 发送音频文件 =====
// 按 16KB 切片发送，并按照音频实际时长等待，确保文件模式也是真实的
// 实时输入，而不是瞬间上传完整文件后再由服务端批量切片。
const UPLOAD_CHUNK_SIZE = 16000;
async function sendAudioFile(file) {
    const ownerSession = sessionId;
    const buffer = await file.arrayBuffer();
    if (ownerSession !== sessionId || !sending) return;
    const totalBytes = buffer.byteLength;
    let offset = 0;
    const ext = getFileExt(file.name);
    const isPcm = (ext === 'pcm');
    let bytesPerSecond = 16000 * 2;
    if (ext === 'wav' && totalBytes >= 44) {
        const header = new DataView(buffer, 0, 44);
        const byteRate = header.getUint32(28, true);
        if (byteRate > 0) bytesPerSecond = byteRate;
    }
    const speedFactor = Math.max(parseFloat(elSpeedSlider.value) || 1.0, 0.1);
    while (ownerSession === sessionId && offset < totalBytes && sending && ws && ws.readyState === WebSocket.OPEN) {
        const end = Math.min(offset + UPLOAD_CHUNK_SIZE, totalBytes);
        const chunk = buffer.slice(offset, end);
        // 仅 PCM 数据可直接拼成 WAV 导出；当前实时模式不会接收压缩格式。
        if (isPcm) audioChunks.push(chunk.slice(0));
        ws.send(chunk);
        offset = end;
        const chunkDurationMs = (chunk.byteLength / bytesPerSecond) * 1000 / speedFactor;
        await new Promise(r => setTimeout(r, Math.max(0, Math.round(chunkDurationMs))));
    }
    if (ownerSession === sessionId && ws && ws.readyState === WebSocket.OPEN && sending) {
        sending = false;
        setStatus('running', '音频已发送，等待最终结果…');
        ws.send(JSON.stringify({ type: 'eof' }));
    }
}

// ===== 麦克风采集 =====
async function startMicCapture() {
    const ownerSession = sessionId;
    let stream;
    try {
        stream = await navigator.mediaDevices.getUserMedia({
            audio: { sampleRate: 16000, channelCount: 1, echoCancellation: true, noiseSuppression: true }
        });
    } catch (err) {
        if (ownerSession !== sessionId) return;
        handleInputError(err);
        console.error('getUserMedia error:', err);
        setStatus('error', '无法获取麦克风权限');
        elMicStatus.textContent = '无法获取麦克风: ' + err.message;
        resetControls();
        return;
    }

    if (ownerSession !== sessionId || !sending) {
        stream.getTracks().forEach(track => track.stop());
        return;
    }
    micStream = stream;
    micAudioContext = new (window.AudioContext || window.webkitAudioContext)({ sampleRate: 16000 });
    const source = micAudioContext.createMediaStreamSource(micStream);
    const processor = micAudioContext.createScriptProcessor(4096, 1, 1);

    processor.onaudioprocess = (e) => {
        if (!sending || !ws || ws.readyState !== WebSocket.OPEN) return;
        const float32 = e.inputBuffer.getChannelData(0);
        const int16 = new Int16Array(float32.length);
        for (let i = 0; i < float32.length; i++) {
            let s = Math.max(-1, Math.min(1, float32[i]));
            int16[i] = s < 0 ? s * 0x8000 : s * 0x7FFF;
        }
        ws.send(int16.buffer);
        audioChunks.push(int16.buffer.slice(0));
    };

    source.connect(processor);
    processor.connect(micAudioContext.destination);
    micWorklet = { source, processor };

    micStartTime = Date.now();
    elMicStatus.style.display = 'none';
    elMicTimer.style.display = '';
    micTimerInterval = setInterval(() => {
        const elapsed = Math.floor((Date.now() - micStartTime) / 1000);
        const mm = String(Math.floor(elapsed / 60)).padStart(2, '0');
        const ss = String(elapsed % 60).padStart(2, '0');
        elMicElapsed.textContent = `${mm}:${ss}`;
    }, 200);
}

function stopMicCapture() {
    if (micWorklet) {
        micWorklet.processor.disconnect();
        micWorklet.source.disconnect();
        micWorklet = null;
    }
    if (micAudioContext) {
        micAudioContext.close().catch(() => {});
        micAudioContext = null;
    }
    if (micStream) {
        micStream.getTracks().forEach(t => t.stop());
        micStream = null;
    }
    if (micTimerInterval) {
        clearInterval(micTimerInterval);
        micTimerInterval = null;
    }
    elMicTimer.style.display = 'none';
    elMicStatus.style.display = '';
    elMicStatus.textContent = '点击下方按钮开始录音';
    elMicElapsed.textContent = '00:00';
}

// 展示实际部署端点及模型，避免沿用旧 SDK 的无效引擎配置。
fetch('/api/config').then(response => response.json()).then(config => {
    if (!ws) {
        elEngineModel.value = config.model;
        elModelServiceUrl.value = config.model_service_url;
        elSpeakerStatus.textContent = '说话人辅助服务：' + (config.speaker_service_url || '未配置');
    }
}).catch(error => { elSpeakerStatus.textContent = '读取服务配置失败：' + error.message; });

// 输入端失败必须释放空会话，避免用户再次开始时留下旧连接。
function handleInputError(error) {
    sending = false;
    setStatus('error', error.message);
    stopMicCapture();
    if (ws) { ws.close(); ws = null; }
    resetControls();
}