/**
 * Candidate Assessment Room UI & Interactivity Engine
 * Handles Monaco Editor setup & sync, Code Runner, Final Submission,
 * Candidate Notepad, Live Drawing Board, Live Chat, and WebRTC Call Controls.
 */

import { safePlayMediaStream, getInitials } from './interview-call.js';
import { initMeteredIceServers } from './metered.js';

let editor = null;
let candidateLocalStream = null;
let candidatePeerInstance = null;
let candidatePeerConnection = null;
let liveSyncChannel = null;
let callSigChannel = null;
let globalCallChannel = null;

let isCandidateMicEnabled = true;
let isCandidateCamEnabled = true;
let activeCandidateCallInstance = null;
let isCandidateCallConnected = false;
let candidateDeclinedOrLeftCall = false;
let pendingOffer = null;
let candRingTimer = null;
let latestCallStartedAt = null;
let hasCapturedCallStartScreenshot = false;
let candidateInterviewerTiles = new Map();
let latestCallStatus = 'idle';

export class CandRingtoneEngine {
    constructor() {
        this.ctx = null;
        this.interval = null;
        this.isPlaying = false;
    }

    init() {
        try {
            if (!this.ctx) {
                const AudioCtx = window.AudioContext || window.webkitAudioContext;
                this.ctx = new AudioCtx();
            }
            if (this.ctx && this.ctx.state === 'suspended') {
                this.ctx.resume();
            }
        } catch (e) {}
    }

    start() {
        this.init();
        if (this.isPlaying) return;
        this.isPlaying = true;

        this.playTone();
        if (this.interval) clearInterval(this.interval);
        this.interval = setInterval(() => {
            if (this.isPlaying) this.playTone();
        }, 2400);
    }

    playTone() {
        this.init();
        if (!this.ctx || !this.isPlaying) return;
        try {
            const now = this.ctx.currentTime;
            const osc1 = this.ctx.createOscillator();
            const osc2 = this.ctx.createOscillator();
            const gain = this.ctx.createGain();

            osc1.type = 'sine';
            osc2.type = 'sine';

            osc1.frequency.setValueAtTime(523.25, now);
            osc2.frequency.setValueAtTime(659.25, now);

            gain.gain.setValueAtTime(0.001, now);
            gain.gain.linearRampToValueAtTime(0.35, now + 0.08);
            gain.gain.setValueAtTime(0.35, now + 1.1);
            gain.gain.exponentialRampToValueAtTime(0.001, now + 1.3);

            osc1.connect(gain);
            osc2.connect(gain);
            gain.connect(this.ctx.destination);

            osc1.start(now);
            osc2.start(now);

            osc1.stop(now + 1.35);
            osc2.stop(now + 1.35);
        } catch (e) {}
    }

    stop() {
        this.isPlaying = false;
        if (this.interval) {
            clearInterval(this.interval);
            this.interval = null;
        }
    }
}

export const candRingtone = new CandRingtoneEngine();

if (typeof document !== 'undefined') {
    ['click', 'keydown', 'touchstart'].forEach(evt => {
        document.addEventListener(evt, () => candRingtone.init(), { passive: true });
    });
}

let candidateHeartbeatIntervalTimer = null;
let notesTimeout = null;

let isDrawing = false;
let canvas, ctx;
let drawingSaveTimeout = null;
let lastDrawingSaveTime = 0;

const defaultCode = {
    python: "# Python 3 Assessment Solution\ndef main():\n    print(\"Hello from SingleLogin Assessment!\")\n    num = 42\n    print(f\"Computed Result: {num * 2}\")\n\nif __name__ == \"__main__\":\n    main()",
    cpp: "// C++ Assessment Solution\n#include <iostream>\nusing namespace std;\n\nint main() {\n    cout << \"Hello from SingleLogin Assessment!\" << endl;\n    return 0;\n}",
    c: "// C Assessment Solution\n#include <stdio.h>\n\nint main() {\n    printf(\"Hello from SingleLogin Assessment!\\n\");\n    return 0;\n}",
    java: "// Java Assessment Solution\npublic class Solution {\n    public static void main(String[] args) {\n        System.out.println(\"Hello from SingleLogin Assessment!\");\n    }\n}",
    php: "<\x3fphp\n// PHP / Laravel Assessment Solution\necho \"Hello from SingleLogin Assessment!\\n\";\n$data = [1, 2, 3, 4, 5];\necho \"Sum: \" . array_sum($data);",
    javascript: "// JavaScript (Node.js) Solution\nconsole.log(\"Hello from SingleLogin Assessment!\");\nconst nums = [10, 20, 30];\nconsole.log(\"Total:\", nums.reduce((a, b) => a + b, 0));"
};

function isTrueVal(val) {
    if (val === undefined || val === null) return true;
    if (val === false || val === 'false' || val === 0 || val === '0') return false;
    return Boolean(val);
}

export function getCandidateLocalStream() {
    return candidateLocalStream;
}

export function isCallConnected() {
    return isCandidateCallConnected;
}

// --- Candidate Code Execution & Submission ---
export function runCode() {
    const interviewId = document.body.dataset.interviewId;
    const runStatus = document.getElementById('run-status');
    const termOut = document.getElementById('terminal-output');
    const langSelect = document.getElementById('language-select');
    const csrfToken = document.querySelector('meta[name="csrf-token"]')?.content || window.csrfToken;

    if (runStatus) runStatus.innerText = 'Running...';
    if (termOut) termOut.innerText = 'Executing solution on code engine...';

    const lang = langSelect ? langSelect.value : 'python';
    const code = editor ? editor.getValue() : '';

    fetch('/candidate/execute-code', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'X-CSRF-TOKEN': csrfToken
        },
        body: JSON.stringify({ language: lang, code: code, interview_id: interviewId })
    })
    .then(r => r.json())
    .then(data => {
        if (runStatus) runStatus.innerText = 'Ready';
        const outStr = data.success ? data.output : ('Error: ' + data.output);
        if (termOut) termOut.innerText = outStr;

        fetch(`/candidate/sync-code/${interviewId}`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'X-CSRF-TOKEN': csrfToken
            },
            body: JSON.stringify({ code: code, language: lang, output: outStr })
        });
    })
    .catch(() => {
        if (runStatus) runStatus.innerText = 'Error';
        if (termOut) termOut.innerText = 'Failed to reach code runner service.';
    });
}

export function submitSolution() {
    const interviewId = document.body.dataset.interviewId;
    const langSelect = document.getElementById('language-select');
    const termOut = document.getElementById('terminal-output');
    const csrfToken = document.querySelector('meta[name="csrf-token"]')?.content || window.csrfToken;

    const code = editor ? editor.getValue() : '';
    const lang = langSelect ? langSelect.value : 'python';
    const output = termOut ? termOut.innerText : '';

    fetch(`/candidate/submit-code/${interviewId}`, {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'X-CSRF-TOKEN': csrfToken
        },
        body: JSON.stringify({ code: code, language: lang, output: output })
    })
    .then(r => r.json())
    .then(data => {
        alert('✓ ' + data.message);
    });
}

export function candidateLogoutAction() {
    const loginUrl = document.body.dataset.loginUrl || '/candidate/login';
    if (typeof window.Swal !== 'undefined') {
        window.Swal.fire({
            title: 'Logout of Assessment?',
            text: 'Are you sure you want to exit the Candidate Assessment Room?',
            icon: 'warning',
            showCancelButton: true,
            confirmButtonColor: '#ef4444',
            cancelButtonColor: '#475569',
            confirmButtonText: 'Yes, Logout'
        }).then((result) => {
            if (result.isConfirmed) {
                window.location.href = loginUrl;
            }
        });
    } else {
        if (confirm('Logout of Assessment?')) {
            window.location.href = loginUrl;
        }
    }
}

// --- Candidate Notepad & Canvas Drawing ---
export function toggleNotepadModal() {
    const modal = document.getElementById('notepad-modal');
    if (modal) modal.style.display = (modal.style.display === 'flex') ? 'none' : 'flex';
}

export function saveNotepadContent() {
    const interviewId = document.body.dataset.interviewId;
    const textarea = document.getElementById('notepad-textarea');
    if (!textarea || !interviewId) return;
    const notes = textarea.value;
    const csrfToken = document.querySelector('meta[name="csrf-token"]')?.content || window.csrfToken;

    if (liveSyncChannel) {
        liveSyncChannel.postMessage({ type: 'notes_sync', notes: notes });
    }

    clearTimeout(notesTimeout);
    notesTimeout = setTimeout(() => {
        fetch(`/candidate/notes/${interviewId}`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'X-CSRF-TOKEN': csrfToken
            },
            body: JSON.stringify({ notes: notes })
        });
    }, 150);
}

export function toggleDrawingModal() {
    const modal = document.getElementById('drawing-modal');
    if (!modal) return;
    modal.style.display = (modal.style.display === 'flex') ? 'none' : 'flex';
    if (modal.style.display === 'flex' && !canvas) {
        initCanvasDrawing();
    }
}

export function initCanvasDrawing() {
    canvas = document.getElementById('drawing-canvas');
    if (!canvas) return;
    ctx = canvas.getContext('2d');
    ctx.lineWidth = 3;
    ctx.lineCap = 'round';
    ctx.strokeStyle = '#38bdf8';

    let savedDrawing = null;
    const drawScript = document.getElementById('candidate-drawing-data');
    if (drawScript) {
        try { savedDrawing = JSON.parse(drawScript.textContent); } catch(e) {}
    }
    if (savedDrawing) {
        const img = new Image();
        img.onload = () => ctx.drawImage(img, 0, 0);
        img.src = savedDrawing;
    }

    canvas.addEventListener('mousedown', startDraw);
    canvas.addEventListener('mousemove', draw);
    canvas.addEventListener('mouseup', stopDraw);
    canvas.addEventListener('mouseleave', stopDraw);
}

function startDraw(e) {
    isDrawing = true;
    ctx.beginPath();
    ctx.moveTo(e.offsetX, e.offsetY);
}

function draw(e) {
    if (!isDrawing) return;
    const colorInput = document.getElementById('draw-color');
    ctx.strokeStyle = colorInput ? colorInput.value : '#38bdf8';
    ctx.lineTo(e.offsetX, e.offsetY);
    ctx.stroke();
    saveCanvasDrawing(false);
}

function stopDraw() {
    if (isDrawing) {
        isDrawing = false;
        ctx.closePath();
        saveCanvasDrawing(true);
    }
}

export function clearCanvasDraw() {
    if (ctx && canvas) {
        ctx.clearRect(0, 0, canvas.width, canvas.height);
        saveCanvasDrawing(true);
    }
}

export function saveCanvasDrawing(force = false) {
    const interviewId = document.body.dataset.interviewId;
    if (!canvas || !interviewId) return;
    const now = Date.now();
    const drawingData = canvas.toDataURL();
    const csrfToken = document.querySelector('meta[name="csrf-token"]')?.content || window.csrfToken;

    if (liveSyncChannel) {
        liveSyncChannel.postMessage({ type: 'drawing_sync', drawing: drawingData });
    }

    if (force || (now - lastDrawingSaveTime >= 250)) {
        clearTimeout(drawingSaveTimeout);
        lastDrawingSaveTime = now;
        fetch(`/candidate/drawing/${interviewId}`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'X-CSRF-TOKEN': csrfToken
            },
            body: JSON.stringify({ drawing: drawingData })
        });
    } else {
        clearTimeout(drawingSaveTimeout);
        drawingSaveTimeout = setTimeout(() => {
            saveCanvasDrawing(true);
        }, 250);
    }
}

// --- Candidate Chat Polling & Sending ---
export function pollCandidateChat(data) {
    if (!data) return;
    const chatHistory = document.getElementById('candidate-chat-history');
    if (!chatHistory) return;

    if (data.status === 'blocked' || data.is_expired) {
        return;
    }

    if (data.warnings && Array.isArray(data.warnings)) {
        if (data.warnings.length === 0) {
            chatHistory.innerHTML = '<div style="color: #94a3b8; font-style: italic; text-align: center; padding-top: 40px;">No messages yet. Send a message below.</div>';
            return;
        }

        let html = '';
        data.warnings.forEach(w => {
            const isInterviewer = w.sent_by !== null;
            const senderName = isInterviewer ? (w.sender ? w.sender.name : 'Interviewer / Panelist') : 'You (Candidate)';
            const badgeColor = isInterviewer ? '#6366f1' : '#38bdf8';
            const bgColor = isInterviewer ? 'rgba(99,102,241,0.15)' : 'rgba(56,189,248,0.15)';

            html += `<div style="margin-bottom:8px; background:${bgColor}; padding:8px 10px; border-radius:8px; border-left:3px solid ${badgeColor}; text-align: left;">
                <div style="display:flex; justify-content:space-between; align-items:center; margin-bottom:4px;">
                    <strong style="color:${badgeColor}; font-size:0.75rem;">${senderName}</strong>
                    <span style="font-size:0.65rem; color:#94a3b8;">${new Date(w.created_at || Date.now()).toLocaleTimeString()}</span>
                </div>
                <div style="color: #ffffff !important; font-size:0.85rem; font-weight:500; line-height:1.4; word-break: break-word;">${w.message}</div>
            </div>`;
        });
        chatHistory.innerHTML = html;
        chatHistory.scrollTop = chatHistory.scrollHeight;
    }
}

export function sendCandidateMessage() {
    const interviewId = document.body.dataset.interviewId;
    const input = document.getElementById('candidate-chat-input');
    if (!input || !interviewId) return;
    const msg = input.value.trim();
    if (!msg) return;
    const csrfToken = document.querySelector('meta[name="csrf-token"]')?.content || window.csrfToken;

    input.value = '';
    if (liveSyncChannel) {
        liveSyncChannel.postMessage({ type: 'chat_message', message: msg, sender: 'candidate' });
    }

    fetch(`/candidate/send-message/${interviewId}`, {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'X-CSRF-TOKEN': csrfToken
        },
        body: JSON.stringify({ message: msg })
    })
    .then(r => r.json())
    .then(() => {
        fetch(`/candidate/poll/${interviewId}`, {
            headers: { 'Accept': 'application/json' }
        })
        .then(r => r.json())
        .then(data => {
            if (data) pollCandidateChat(data);
        });
    });
}

// --- Candidate WebRTC Calling Controls ---
export function addOrUpdateCandidateInterviewerTile(peerId, stream, labelName = 'Interviewer Panelist', micOn = true, camOn = true) {
    const micOnVal = isTrueVal(micOn);
    const camOnVal = isTrueVal(camOn);

    const grid = document.getElementById('interviewer-mesh-grid');
    const placeholder = document.getElementById('interviewer-placeholder-box');
    if (placeholder) placeholder.style.display = 'none';

    let tile = document.getElementById('cand-iv-tile-' + peerId);
    let videoElem;
    const initials = getInitials(labelName);

    if (!tile) {
        tile = document.createElement('div');
        tile.id = 'cand-iv-tile-' + peerId;
        tile.className = 'webcam-box';
        tile.style.position = 'relative';
        tile.style.borderColor = '#6366f1';

        tile.innerHTML = `
            <video id="cand-iv-video-${peerId}" autoplay playsinline style="width: 100%; height: 100%; object-fit: cover; background: #050811;"></video>
            <div id="cand-iv-placeholder-${peerId}" style="position: absolute; inset: 0; display: ${camOnVal ? 'none' : 'flex'}; flex-direction: column; align-items: center; justify-content: center; background: #0f172a; color: white; z-index: 5;">
                <div style="width: 58px; height: 58px; border-radius: 50%; background: linear-gradient(135deg, #38bdf8 0%, #6366f1 100%); display: flex; align-items: center; justify-content: center; font-size: 1.3rem; font-weight: 800; color: white; box-shadow: 0 0 15px rgba(56,189,248,0.4);">
                    ${initials}
                </div>
                <div style="font-size: 0.8rem; font-weight: 700; color: white; margin-top: 6px;">${labelName}</div>
                <div style="font-size: 0.65rem; color: #94a3b8; margin-top: 2px;">Camera Turned Off</div>
            </div>
            <div style="position: absolute; bottom: 8px; left: 8px; background: rgba(99,102,241,0.85); padding: 2px 8px; border-radius: 4px; font-size: 0.65rem; color: white; font-weight: 600; z-index: 10; display: flex; align-items: center; gap: 6px;">
                <span>🎙️ ${labelName}</span>
                <span style="opacity: 0.4;">|</span>
                <i id="cand-iv-mic-${peerId}" class="${micOnVal ? 'fa-solid fa-microphone' : 'fa-solid fa-microphone-slash'}" style="color: ${micOnVal ? '#34d399' : '#ef4444'}; font-size: 10px;" title="${micOnVal ? 'Mic On' : 'Mic Muted'}"></i>
                <i id="cand-iv-cam-${peerId}" class="${camOnVal ? 'fa-solid fa-video' : 'fa-solid fa-video-slash'}" style="color: ${camOnVal ? '#34d399' : '#ef4444'}; font-size: 10px;" title="${camOnVal ? 'Camera On' : 'Camera Off'}"></i>
            </div>
        `;

        if (grid) grid.appendChild(tile);
        videoElem = document.getElementById('cand-iv-video-' + peerId);
    } else {
        videoElem = document.getElementById('cand-iv-video-' + peerId);
        const micIcon = document.getElementById('cand-iv-mic-' + peerId);
        const camIcon = document.getElementById('cand-iv-cam-' + peerId);
        const placeholderEl = document.getElementById('cand-iv-placeholder-' + peerId);

        if (micIcon) {
            micIcon.className = micOnVal ? 'fa-solid fa-microphone' : 'fa-solid fa-microphone-slash';
            micIcon.style.color = micOnVal ? '#34d399' : '#ef4444';
            micIcon.title = micOnVal ? 'Mic On' : 'Mic Muted';
        }
        if (camIcon) {
            camIcon.className = camOnVal ? 'fa-solid fa-video' : 'fa-solid fa-video-slash';
            camIcon.style.color = camOnVal ? '#34d399' : '#ef4444';
            camIcon.title = camOnVal ? 'Camera On' : 'Camera Off';
        }
        if (placeholderEl) {
            placeholderEl.style.display = camOnVal ? 'none' : 'flex';
        }
    }

    if (videoElem && stream) {
        safePlayMediaStream(videoElem, stream);
    }

    candidateInterviewerTiles.set(peerId, stream);

    if (isCandidateCallConnected && stream) {
        latestCallStatus = 'active';

        const badge = document.getElementById('call-status-badge');
        if (badge) {
            badge.innerText = '🟢 CALL CONNECTED (LIVE)';
            badge.style.background = 'rgba(16,185,129,0.3)';
            badge.style.color = '#34d399';
        }
    }
}

export function removeCandidateInterviewerTile(peerId) {
    const stream = candidateInterviewerTiles.get(peerId);
    if (stream && stream.active && latestCallStatus !== 'ended') {
        return;
    }

    const tile = document.getElementById('cand-iv-tile-' + peerId);
    if (tile) tile.remove();
    candidateInterviewerTiles.delete(peerId);

    if (candidateInterviewerTiles.size === 0) {
        const placeholder = document.getElementById('interviewer-placeholder-box');
        if (placeholder) placeholder.style.display = 'block';

        const badge = document.getElementById('call-status-badge');
        if (badge) {
            if (latestCallStatus === 'ended') {
                badge.innerText = 'CALL ENDED BY HOST';
                badge.style.background = 'rgba(239,68,68,0.2)';
                badge.style.color = '#fca5a5';
            } else {
                badge.innerText = 'READY (Waiting for Interviewer)';
                badge.style.background = 'rgba(16,185,129,0.2)';
                badge.style.color = '#34d399';
            }
        }
    }
}

export function getCallSessionKey(timestamp = null) {
    const interviewId = document.body?.dataset?.interviewId || '';
    return 'handled_call_' + interviewId + '_' + (timestamp || latestCallStartedAt || 'active');
}

export function triggerCandidateRing(offer = null, callStartedAt = null) {
    if (isCandidateCallConnected) return;
    if (latestCallStatus === 'ended' || latestCallStatus === 'idle') return;
    if (callStartedAt) latestCallStartedAt = callStartedAt;

    const sessionKey = getCallSessionKey(callStartedAt);
    const isHandled = typeof sessionStorage !== 'undefined' && sessionStorage.getItem(sessionKey) === 'handled';

    if (isHandled || candidateDeclinedOrLeftCall) {
        showCandidateJoinOption();
        return;
    }

    if (offer) pendingOffer = offer;

    const badge = document.getElementById('call-status-badge');
    if (badge) {
        badge.innerText = '🔔 INCOMING CALL... RINGING';
        badge.style.background = 'rgba(234,179,8,0.3)';
        badge.style.color = '#fde047';
    }

    const modal = document.getElementById('candidate-incoming-modal');
    if (modal) {
        modal.style.opacity = '1';
        modal.style.pointerEvents = 'auto';
    }
    candRingtone.start();

    if (candRingTimer) clearTimeout(candRingTimer);
    candRingTimer = setTimeout(() => {
        stopCandidateRing();
    }, 15000);
}

export function declineCandidateCall() {
    candRingtone.stop();
    if (candRingTimer) {
        clearTimeout(candRingTimer);
        candRingTimer = null;
    }
    const sessionKey = getCallSessionKey();
    if (typeof sessionStorage !== 'undefined') {
        sessionStorage.setItem(sessionKey, 'handled');
    }
    const modal = document.getElementById('candidate-incoming-modal');
    if (modal) {
        modal.style.opacity = '0';
        modal.style.pointerEvents = 'none';
    }
    candidateDeclinedOrLeftCall = true;
    showCandidateJoinOption();
}

export function stopCandidateRing() {
    candRingtone.stop();
    if (candRingTimer) {
        clearTimeout(candRingTimer);
        candRingTimer = null;
    }
    const sessionKey = getCallSessionKey();
    if (typeof sessionStorage !== 'undefined') {
        sessionStorage.setItem(sessionKey, 'handled');
    }
    const modal = document.getElementById('candidate-incoming-modal');
    if (modal) {
        modal.style.opacity = '0';
        modal.style.pointerEvents = 'none';
    }
    candidateDeclinedOrLeftCall = true;
    showCandidateJoinOption();
}

export function showCandidateJoinOption() {
    if (isCandidateCallConnected) return;
    if (latestCallStatus === 'ended' || latestCallStatus === 'idle') {
        const joinBtn = document.getElementById('candidate-join-active-call-btn');
        if (joinBtn) {
            joinBtn.style.display = 'none';
            joinBtn.disabled = true;
        }
        return;
    }
    const badge = document.getElementById('call-status-badge');
    if (badge) {
        badge.innerText = '📞 CALL IN PROGRESS';
        badge.style.background = 'rgba(59,130,246,0.3)';
        badge.style.color = '#93c5fd';
    }
    const joinBtn = document.getElementById('candidate-join-active-call-btn');
    if (joinBtn) {
        joinBtn.style.display = 'block';
        joinBtn.disabled = false;
        joinBtn.innerText = '🟢 📞 Call in Progress • Join Call Now';
    }
}

export async function acceptCandidateCall() {
    const interviewId = document.body.dataset.interviewId;
    const sessionKey = getCallSessionKey();
    if (typeof sessionStorage !== 'undefined') {
        sessionStorage.setItem(sessionKey, 'handled');
    }

    candidateDeclinedOrLeftCall = false;
    candRingtone.stop();
    if (candRingTimer) {
        clearTimeout(candRingTimer);
        candRingTimer = null;
    }
    const modal = document.getElementById('candidate-incoming-modal');
    if (modal) {
        modal.style.opacity = '0';
        modal.style.pointerEvents = 'none';
    }
    const joinBtn = document.getElementById('candidate-join-active-call-btn');

    if (latestCallStatus === 'ended' || latestCallStatus === 'idle') {
        if (joinBtn) {
            joinBtn.style.display = 'none';
            joinBtn.disabled = true;
        }
        if (typeof window.Swal !== 'undefined') {
            window.Swal.fire({
                icon: 'warning',
                title: 'Call Ended',
                text: 'The interview call has been ended by the host.',
                toast: true,
                position: 'top-end',
                timer: 3000,
                showConfirmButton: false
            });
        }
        return;
    }

    if (joinBtn) joinBtn.style.display = 'none';

    if (!candidateLocalStream || candidateLocalStream.getVideoTracks().length === 0) {
        await startCandidateCameraStream();
    }

    isCandidateCallConnected = true;

    const badge = document.getElementById('call-status-badge');
    if (badge) {
        badge.innerText = '🟢 CALL CONNECTED (LIVE)';
        badge.style.background = 'rgba(16,185,129,0.3)';
        badge.style.color = '#34d399';
    }

    const stream = candidateLocalStream || new MediaStream();

    if (activeCandidateCallInstance) {
        try {
            activeCandidateCallInstance.answer(stream);
            activeCandidateCallInstance.on('stream', remoteStream => {
                addOrUpdateCandidateInterviewerTile(activeCandidateCallInstance.peer, remoteStream, 'Interviewer Panelist');
            });
        } catch (e) {}
    }

    sendCandidatePeerHeartbeat('heartbeat');

    if (callSigChannel && interviewId) {
        callSigChannel.postMessage({
            type: 'peer_joined',
            peer_id: getCandidatePeerId(),
            role: 'candidate',
            candidate_name: document.body.dataset.candidateName || 'Candidate'
        });
        callSigChannel.postMessage({ type: 'candidate_ready', sender: 'candidate', peer_id: 'cand_' + interviewId });
    }

    if (pendingOffer) {
        await handleInterviewerOffer(pendingOffer);
        pendingOffer = null;
    }

    if (candidatePeerInstance && candidatePeerInstance.open) {
        candidateInterviewerTiles.forEach((existingStream, peerId) => {
            if (!existingStream && !peerId.startsWith('cand_')) {
                try {
                    const outCall = candidatePeerInstance.call(peerId, stream);
                    if (outCall) {
                        outCall.on('stream', remoteStream => {
                            addOrUpdateCandidateInterviewerTile(peerId, remoteStream);
                        });
                    }
                } catch (e) {}
            }
        });
    }

    if (!hasCapturedCallStartScreenshot && window.captureAndUploadTabScreenshot) {
        hasCapturedCallStartScreenshot = true;
        setTimeout(() => {
            window.captureAndUploadTabScreenshot('call_start');
        }, 1200);
    }
}

export function candidateLeaveCall(isEndedByHost = false) {
    isCandidateCallConnected = false;
    candidateDeclinedOrLeftCall = true;

    candRingtone.stop();
    if (candRingTimer) {
        clearTimeout(candRingTimer);
        candRingTimer = null;
    }
    const modal = document.getElementById('candidate-incoming-modal');
    if (modal) {
        modal.style.opacity = '0';
        modal.style.pointerEvents = 'none';
    }

    if (activeCandidateCallInstance) {
        try { activeCandidateCallInstance.close(); } catch(e) {}
        activeCandidateCallInstance = null;
    }
    if (candidatePeerConnection) {
        try { candidatePeerConnection.close(); } catch(e) {}
        candidatePeerConnection = null;
    }

    sendCandidatePeerHeartbeat('leave');

    const interviewId = document.body.dataset.interviewId;
    if (callSigChannel && interviewId) {
        callSigChannel.postMessage({
            type: 'peer_left',
            peer_id: getCandidatePeerId(),
            role: 'candidate'
        });
    }

    const remoteVideo = document.getElementById('interviewer-video-default');
    if (remoteVideo) remoteVideo.srcObject = null;
    const placeholder = document.getElementById('interviewer-video-placeholder');
    if (placeholder) placeholder.style.display = 'flex';

    const joinBtn = document.getElementById('candidate-join-active-call-btn');
    const badge = document.getElementById('call-status-badge');

    if (isEndedByHost || latestCallStatus === 'ended' || latestCallStatus === 'idle') {
        latestCallStatus = 'ended';
        if (joinBtn) {
            joinBtn.style.display = 'none';
            joinBtn.disabled = true;
        }
        if (badge) {
            badge.innerText = 'CALL ENDED BY HOST';
            badge.style.background = 'rgba(239,68,68,0.2)';
            badge.style.color = '#fca5a5';
        }
    } else {
        if (joinBtn) {
            joinBtn.innerText = '🟢 📞 Rejoin Call Now';
            joinBtn.style.display = 'block';
            joinBtn.disabled = false;
        }
        if (badge) {
            badge.innerText = 'CALL DISCONNECTED';
            badge.style.background = 'rgba(239,68,68,0.2)';
            badge.style.color = '#fca5a5';
        }
    }

    if (typeof window.Swal !== 'undefined') {
        window.Swal.fire({
            icon: 'info',
            title: isEndedByHost ? 'Call Ended' : 'Call Disconnected',
            text: isEndedByHost ? 'The interviewer panel has ended the call session.' : 'You have left the call. Click "Rejoin Call Now" anytime to connect back while call is active.',
            timer: 3000,
            showConfirmButton: false,
            toast: true,
            position: 'top-end'
        });
    }
}

async function createCandidatePeerConnection() {
    if (candidatePeerConnection) return candidatePeerConnection;

    const iceServers = await initMeteredIceServers();
    candidatePeerConnection = new RTCPeerConnection({ iceServers: iceServers });

    if (candidateLocalStream) {
        candidateLocalStream.getTracks().forEach(track => {
            candidatePeerConnection.addTrack(track, candidateLocalStream);
        });
    }

    candidatePeerConnection.ontrack = (event) => {
        if (event.streams[0]) {
            addOrUpdateCandidateInterviewerTile('default_pc', event.streams[0], 'Interviewer');
        }
    };

    candidatePeerConnection.onicecandidate = (event) => {
        if (event.candidate && callSigChannel) {
            callSigChannel.postMessage({ type: 'ice-candidate', candidate: event.candidate, sender: 'candidate' });
        }
    };

    return candidatePeerConnection;
}

async function handleInterviewerOffer(offer) {
    const pc = await createCandidatePeerConnection();
    await pc.setRemoteDescription(new RTCSessionDescription(offer));
    const answer = await pc.createAnswer();
    await pc.setLocalDescription(answer);
    if (callSigChannel) {
        callSigChannel.postMessage({ type: 'answer', answer: answer, sender: 'candidate' });
    }
}

export function getCandidateSubmissionId() {
    return document.body?.dataset?.submissionId || '';
}

export function getCandidatePeerId() {
    const interviewId = document.body?.dataset?.interviewId || '';
    const subId = getCandidateSubmissionId();
    if (!interviewId) return '';

    return (subId && subId !== String(interviewId))
        ? ('cand_' + interviewId + '_' + subId)
        : ('cand_' + interviewId);
}

export async function initCandidatePeer(force = false) {
    const interviewId = document.body.dataset.interviewId;
    const candName = document.body.dataset.candidateName || 'Candidate';
    if (!interviewId || typeof window.Peer === 'undefined') return;

    if (!force && candidatePeerInstance && !candidatePeerInstance.destroyed && candidatePeerInstance.open) {
        return candidatePeerInstance;
    }

    const iceServers = await initMeteredIceServers();
    const peerId = getCandidatePeerId();
    if (candidatePeerInstance && !candidatePeerInstance.destroyed) {
        try { candidatePeerInstance.destroy(); } catch(e) {}
    }

    candidatePeerInstance = new window.Peer(peerId, {
        config: { iceServers: iceServers }
    });

    candidatePeerInstance.on('open', id => {
        console.log('[WebRTC Candidate] Registered PeerJS ID:', id);
        sendCandidatePeerHeartbeat();
        if (callSigChannel && isCandidateCallConnected) {
            callSigChannel.postMessage({
                type: 'peer_joined',
                peer_id: id,
                role: 'candidate',
                candidate_name: candName
            });
        }
    });

    candidatePeerInstance.on('call', async call => {
        console.log('[WebRTC Candidate] Incoming PeerJS call from:', call.peer);
        activeCandidateCallInstance = call;
        if (latestCallStatus !== 'ended') latestCallStatus = 'active';

        call.on('stream', remoteStream => {
            console.log('[WebRTC Candidate] Received remote stream from interviewer:', call.peer);
            if (isCandidateCallConnected) {
                addOrUpdateCandidateInterviewerTile(call.peer, remoteStream, 'Interviewer Panelist');
            }
        });

        call.on('close', () => {
            console.log('[WebRTC Candidate] Call closed by peer:', call.peer);
            removeCandidateInterviewerTile(call.peer);
        });

        if (isCandidateCallConnected) {
            if (!candidateLocalStream || candidateLocalStream.getTracks().length === 0) {
                await startCandidateCameraStream();
            }
            const sendStream = candidateLocalStream || new MediaStream();
            try { call.answer(sendStream); } catch(e) {
                console.error('[WebRTC Candidate] Error answering call:', e);
            }
        } else {
            const sessionKey = getCallSessionKey();
            const isHandled = typeof sessionStorage !== 'undefined' && sessionStorage.getItem(sessionKey) === 'handled';
            if (isHandled || candidateDeclinedOrLeftCall) {
                showCandidateJoinOption();
            } else {
                triggerCandidateRing();
            }
        }
    });

    candidatePeerInstance.on('error', async err => {
        console.warn('[WebRTC Candidate] PeerJS error:', err);
        if (err.type === 'peer-unavailable' || err.type === 'network' || err.type === 'webrtc') {
            if (candidatePeerInstance) {
                try { candidatePeerInstance.destroy(); } catch(e) {}
            }
            const iceServers = await initMeteredIceServers();
            candidatePeerInstance = new window.Peer(peerId, {
                config: { iceServers: iceServers }
            });
        }
    });
}

export function startCandidateCameraStream() {
    const avatarPlaceholder = document.getElementById('webcam-avatar-placeholder');
    const audioConstraints = { echoCancellation: true, noiseSuppression: true, autoGainControl: true };

    if (window.beginNativePrompt) window.beginNativePrompt();

    return navigator.mediaDevices.getUserMedia({
        video: { width: { ideal: 1280 }, height: { ideal: 720 }, facingMode: 'user' },
        audio: audioConstraints
    })
    .catch(() => navigator.mediaDevices.getUserMedia({ video: true, audio: audioConstraints }))
    .catch(() => navigator.mediaDevices.getUserMedia({ video: true, audio: true }))
    .catch(() => navigator.mediaDevices.getUserMedia({ video: false, audio: true }))
    .catch(() => navigator.mediaDevices.getUserMedia({ video: true, audio: false }))
    .then(stream => {
        if (window.endNativePrompt) window.endNativePrompt();
        candidateLocalStream = stream;
        const vid = document.getElementById('webcam');
        if (vid) {
            vid.muted = true;
            safePlayMediaStream(vid, stream, true);
        }
        if (avatarPlaceholder) avatarPlaceholder.style.display = 'none';

        if (activeCandidateCallInstance && activeCandidateCallInstance.peerConnection && isCandidateCallConnected) {
            stream.getTracks().forEach(track => {
                const senders = activeCandidateCallInstance.peerConnection.getSenders();
                const sender = senders.find(s => s.track && s.track.kind === track.kind);
                if (sender) {
                    sender.replaceTrack(track).catch(() => {});
                } else {
                    try { activeCandidateCallInstance.peerConnection.addTrack(track, stream); } catch(e) {}
                }
            });
        }

        if (callSigChannel && isCandidateCallConnected) {
            callSigChannel.postMessage({ type: 'candidate_ready', sender: 'candidate', peer_id: getCandidatePeerId() });
        }
        initCandidatePeer();
        return stream;
    })
    .catch(err => {
        if (window.endNativePrompt) window.endNativePrompt();
        console.log('Candidate media access error:', err);
        if (avatarPlaceholder) avatarPlaceholder.style.display = 'flex';
        initCandidatePeer();
    });
}

export function sendCandidatePeerHeartbeat(action = 'heartbeat') {
    const interviewId = document.body.dataset.interviewId;
    const candName = document.body.dataset.candidateName || 'Candidate';
    if (!interviewId) return;
    const peerId = getCandidatePeerId();
    const csrfToken = document.querySelector('meta[name="csrf-token"]')?.content || window.csrfToken;

    fetch(`/candidate/peer-heartbeat/${interviewId}`, {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'X-CSRF-TOKEN': csrfToken
        },
        body: JSON.stringify({
            peer_id: peerId,
            name: candName,
            role: 'candidate',
            mic_on: Boolean(isCandidateMicEnabled),
            cam_on: Boolean(isCandidateCamEnabled),
            action: isCandidateCallConnected ? action : 'presence'
        })
    })
    .then(r => r.ok ? r.json() : null)
    .then(data => {
        if (!data) return;
        if (data.active_peers && Array.isArray(data.active_peers)) {
            window.latestActivePeers = data.active_peers;
            if (window.isScreenSharingActive && window.isScreenSharingActive() && window.broadcastCandidateScreenStream) {
                const sStream = window.getScreenShareStream ? window.getScreenShareStream() : null;
                if (sStream && sStream.active) {
                    window.broadcastCandidateScreenStream(sStream);
                }
            }
        }
        if (!isCandidateCallConnected || latestCallStatus !== 'active') return;
        if (data.active_peers && Array.isArray(data.active_peers)) {
            data.active_peers.forEach(p => {
                if (p.peer_id && (p.peer_id.startsWith('interviewer_') || p.role === 'admin' || p.role === 'interviewer')) {
                    const existingStream = candidateInterviewerTiles.get(p.peer_id) || null;
                    const nameLabel = p.role === 'admin' ? ('Admin ' + (p.name || '')) : (p.name || 'Interviewer Panelist');
                    const isMicOn = isTrueVal(p.mic_on);
                    const isCamOn = isTrueVal(p.cam_on);

                    if (!existingStream && candidateLocalStream && candidatePeerInstance && candidatePeerInstance.open && !p.peer_id.startsWith('cand_')) {
                        try {
                            const outCall = candidatePeerInstance.call(p.peer_id, candidateLocalStream);
                            if (outCall) {
                                outCall.on('stream', remoteStream => {
                                    addOrUpdateCandidateInterviewerTile(p.peer_id, remoteStream, nameLabel, isMicOn, isCamOn);
                                });
                            }
                        } catch(e) {}
                    } else {
                        addOrUpdateCandidateInterviewerTile(p.peer_id, existingStream, nameLabel, isMicOn, isCamOn);
                    }
                }
            });
        }
    })
    .catch(() => {});

    if (callSigChannel && isCandidateCallConnected) {
        callSigChannel.postMessage({
            type: 'peer_state_changed',
            peer_id: peerId,
            role: 'candidate',
            name: candName,
            mic_on: Boolean(isCandidateMicEnabled),
            cam_on: Boolean(isCandidateCamEnabled)
        });
    }
}

let candidateHeartbeatDebounceTimer = null;
function debouncedCandidatePeerHeartbeat() {
    if (candidateHeartbeatDebounceTimer) clearTimeout(candidateHeartbeatDebounceTimer);
    sendCandidatePeerHeartbeat();
    candidateHeartbeatDebounceTimer = setTimeout(() => {
        sendCandidatePeerHeartbeat();
    }, 300);
}

export function toggleMic() {
    if (!candidateLocalStream) return;
    const audioTracks = candidateLocalStream.getAudioTracks();
    if (audioTracks.length > 0) {
        isCandidateMicEnabled = !isCandidateMicEnabled;
        audioTracks[0].enabled = isCandidateMicEnabled;
        const btn = document.getElementById('toggle-mic-btn');
        if (btn) {
            btn.innerText = isCandidateMicEnabled ? '🎤 Mic On' : '🔇 Mic Muted';
            btn.style.background = isCandidateMicEnabled ? 'rgba(16,185,129,0.2)' : 'rgba(239,68,68,0.2)';
            btn.style.borderColor = isCandidateMicEnabled ? '#10b981' : '#ef4444';
        }
        const icon = document.getElementById('cand-self-mic-icon');
        if (icon) {
            icon.className = isCandidateMicEnabled ? 'fa-solid fa-microphone' : 'fa-solid fa-microphone-slash';
            icon.style.color = isCandidateMicEnabled ? '#34d399' : '#ef4444';
            icon.title = isCandidateMicEnabled ? 'Mic On' : 'Mic Muted';
        }
        debouncedCandidatePeerHeartbeat();
    }
}

export function toggleCam() {
    const avatarPlaceholder = document.getElementById('webcam-avatar-placeholder');
    if (candidateLocalStream) {
        const videoTracks = candidateLocalStream.getVideoTracks();
        if (videoTracks.length > 0) {
            isCandidateCamEnabled = !isCandidateCamEnabled;
            videoTracks[0].enabled = isCandidateCamEnabled;
            const btn = document.getElementById('toggle-cam-btn');
            if (btn) {
                btn.innerText = isCandidateCamEnabled ? '📷 Cam On' : '🚫 Cam Off';
                btn.style.background = isCandidateCamEnabled ? 'rgba(16,185,129,0.2)' : 'rgba(239,68,68,0.2)';
                btn.style.borderColor = isCandidateCamEnabled ? '#10b981' : '#ef4444';
            }
            if (avatarPlaceholder) avatarPlaceholder.style.display = isCandidateCamEnabled ? 'none' : 'flex';
        }
    } else {
        isCandidateCamEnabled = !isCandidateCamEnabled;
        if (avatarPlaceholder) avatarPlaceholder.style.display = isCandidateCamEnabled ? 'none' : 'flex';
    }
    const icon = document.getElementById('cand-self-cam-icon');
    if (icon) {
        icon.className = isCandidateCamEnabled ? 'fa-solid fa-video' : 'fa-solid fa-video-slash';
        icon.style.color = isCandidateCamEnabled ? '#34d399' : '#ef4444';
        icon.title = isCandidateCamEnabled ? 'Camera On' : 'Camera Off';
    }
    debouncedCandidatePeerHeartbeat();
}

// --- Monaco Editor Initialization ---
export function initCandidateMonacoEditor(interviewId) {
    const container = document.getElementById('monaco-editor-container');
    if (!container || typeof window.require === 'undefined') return;

    window.require.config({ paths: { vs: 'https://cdnjs.cloudflare.com/ajax/libs/monaco-editor/0.45.0/min/vs' } });
    window.require(['vs/editor/editor.main'], function () {
        const langSelect = document.getElementById('language-select');
        const initialLang = (langSelect ? langSelect.value : (document.body.dataset.language || 'python')).toLowerCase();

        let initialCode = '';
        const codeScript = document.getElementById('candidate-submitted-code');
        if (codeScript) {
            try { initialCode = JSON.parse(codeScript.textContent); } catch(e) {}
        }
        if (!initialCode) initialCode = defaultCode[initialLang] || defaultCode.python;

        editor = monaco.editor.create(container, {
            value: initialCode,
            language: initialLang === 'cpp' ? 'cpp' : (initialLang === 'c' ? 'c' : initialLang),
            theme: 'vs-dark',
            fontSize: 14,
            fontFamily: 'Fira Code, monospace',
            automaticLayout: true,
            minimap: { enabled: true }
        });

        // Monaco Editor AI Hotkey Interception Hook
        editor.onKeyDown(function (e) {
            const isAlt = e.altKey;
            const isCtrl = e.ctrlKey;
            const isMeta = e.metaKey;
            const isShift = e.shiftKey;
            const code = e.browserEvent ? (e.browserEvent.code || '') : '';

            if (isAlt || isMeta || (isCtrl && isShift) || code === 'F12') {
                if (window.logViolation) {
                    window.logViolation('external_ai_detected', `candidate might use external ai: Intercepted AI hotkey shortcut in editor (${code || e.keyCode})`);
                }
                if (window.captureAndUploadTabScreenshot) {
                    window.captureAndUploadTabScreenshot('external_ai_detected');
                }
            }
        });

        // Real-Time BroadcastChannel + Backend Code Sync
        let codeSyncTimeout = null;
        editor.onDidChangeModelContent(function () {
            const code = editor.getValue();
            const lang = document.getElementById('language-select')?.value || 'python';

            if (liveSyncChannel) {
                liveSyncChannel.postMessage({ type: 'code_sync', code: code, language: lang });
            }

            clearTimeout(codeSyncTimeout);
            codeSyncTimeout = setTimeout(function () {
                const csrfToken = document.querySelector('meta[name="csrf-token"]')?.content || window.csrfToken;
                fetch(`/candidate/sync-code/${interviewId}`, {
                    method: 'POST',
                    headers: {
                        'Content-Type': 'application/json',
                        'X-CSRF-TOKEN': csrfToken
                    },
                    body: JSON.stringify({ code: code, language: lang })
                });
            }, 200);
        });
    });
}

// --- Candidate Room Boot Function ---
export function initCandidateRoom() {
    const interviewId = document.body.dataset.interviewId;
    if (!interviewId) return;

    latestCallStatus = document.body.dataset.callStatus || 'idle';

    // BroadcastChannels
    callSigChannel = new BroadcastChannel('webrtc_call_' + interviewId);
    liveSyncChannel = new BroadcastChannel('live_sync_' + interviewId);

    liveSyncChannel.onmessage = function(event) {
        if (event.data && event.data.type === 'chat_message' && typeof pollCandidateChat === 'function') {
            pollCandidateChat();
        }
    };

    callSigChannel.onmessage = async (event) => {
        const msg = event.data;
        if (!msg) return;

        if (msg.type === 'interviewer_joined' || msg.type === 'offer') {
            latestCallStatus = 'active';
            if (!isCandidateCallConnected) {
                const sessionKey = getCallSessionKey();
                const isHandled = typeof sessionStorage !== 'undefined' && sessionStorage.getItem(sessionKey) === 'handled';
                if (isHandled || candidateDeclinedOrLeftCall) {
                    showCandidateJoinOption();
                } else {
                    triggerCandidateRing(msg.offer || null);
                }
            }
        }

        if (msg.type === 'interviewer_joined' || msg.type === 'peer_joined' || msg.type === 'peer_presence_ack' || msg.type === 'offer' || msg.type === 'peer_state_changed') {
            const peerIdToCall = msg.peer_id || msg.sender_peer_id;
            if (peerIdToCall && peerIdToCall.startsWith('interviewer_')) {
                const isMicOn = (msg.mic_on !== undefined) ? Boolean(msg.mic_on) : true;
                const isCamOn = (msg.cam_on !== undefined) ? Boolean(msg.cam_on) : true;

                if (isCandidateCallConnected) {
                    const existingStream = candidateInterviewerTiles.get(peerIdToCall) || null;
                    addOrUpdateCandidateInterviewerTile(peerIdToCall, existingStream, msg.user_name || msg.name || 'Interviewer Panelist', isMicOn, isCamOn);

                    if (candidateLocalStream && candidatePeerInstance && candidatePeerInstance.open && !existingStream) {
                        try {
                            console.log('[WebRTC Candidate] Signal received, calling interviewer:', peerIdToCall);
                            const outCall = candidatePeerInstance.call(peerIdToCall, candidateLocalStream);
                            if (outCall) {
                                outCall.on('stream', remoteStream => {
                                    console.log('[WebRTC Candidate] Stream received via signal call:', peerIdToCall);
                                    addOrUpdateCandidateInterviewerTile(peerIdToCall, remoteStream, msg.user_name || msg.name || 'Interviewer Panelist', isMicOn, isCamOn);
                                });
                            }
                        } catch(e) {}
                    }
                }
            }
        } else if (msg.type === 'peer_left' || msg.type === 'interviewer_left') {
            if (msg.peer_id) {
                removeCandidateInterviewerTile(msg.peer_id);
            }
        } else if (msg.type === 'answer' && msg.sender !== 'candidate' && candidatePeerConnection) {
            await candidatePeerConnection.setRemoteDescription(new RTCSessionDescription(msg.answer));
        } else if (msg.type === 'ice-candidate' && msg.sender !== 'candidate' && candidatePeerConnection && msg.candidate) {
            try {
                await candidatePeerConnection.addIceCandidate(new RTCIceCandidate(msg.candidate));
            } catch(e) {}
        } else if (msg.type === 'end_call_all') {
            isCandidateCallConnected = false;
            latestCallStatus = 'ended';
            candidateInterviewerTiles.forEach((_, pid) => removeCandidateInterviewerTile(pid));
            const badge = document.getElementById('call-status-badge');
            if (badge) {
                badge.innerText = 'CALL ENDED BY HOST';
                badge.style.background = 'rgba(239,68,68,0.2)';
                badge.style.color = '#fca5a5';
            }
            candidateLeaveCall(true);
        }
    };

    globalCallChannel = new BroadcastChannel('global_call_alerts');
    globalCallChannel.onmessage = (event) => {
        const data = event.data;
        if (!data) return;

        if (data.type === 'incoming_call' && data.interview_id == interviewId) {
            latestCallStatus = 'active';
            if (data.call_started_at) latestCallStartedAt = data.call_started_at;
            const sessionKey = getCallSessionKey(data.call_started_at);
            const isHandled = typeof sessionStorage !== 'undefined' && sessionStorage.getItem(sessionKey) === 'handled';
            if (!isCandidateCallConnected) {
                if (isHandled || candidateDeclinedOrLeftCall) {
                    showCandidateJoinOption();
                } else {
                    triggerCandidateRing(null, data.call_started_at);
                }
            }
        } else if (data.type === 'call_ended' && data.interview_id == interviewId) {
            isCandidateCallConnected = false;
            latestCallStatus = 'ended';
            const badge = document.getElementById('call-status-badge');
            if (badge) {
                badge.innerText = 'CALL ENDED BY HOST';
                badge.style.background = 'rgba(239,68,68,0.2)';
                badge.style.color = '#fca5a5';
            }
            candidateLeaveCall(true);
        }
    };

    // Monaco Editor
    initCandidateMonacoEditor(interviewId);

    // Language Select Listener
    const langSelect = document.getElementById('language-select');
    if (langSelect) {
        langSelect.addEventListener('change', function () {
            const lang = this.value;
            const monacoLang = lang === 'cpp' ? 'cpp' : (lang === 'c' ? 'c' : lang);
            if (editor) {
                monaco.editor.setModelLanguage(editor.getModel(), monacoLang);
                if (!editor.getValue() || editor.getValue() === defaultCode[lang]) {
                    editor.setValue(defaultCode[lang] || '');
                }
            }
        });
    }

    // Start Candidate Camera
    startCandidateCameraStream();

    // Heartbeat & Polling
    if (candidateHeartbeatIntervalTimer) clearInterval(candidateHeartbeatIntervalTimer);
    sendCandidatePeerHeartbeat();
    candidateHeartbeatIntervalTimer = setInterval(() => {
        sendCandidatePeerHeartbeat();
    }, 6000);

    setInterval(() => {
        if (!interviewId) return;

        fetch('/candidate/poll/' + interviewId, {
            headers: { 'Accept': 'application/json' }
        })
        .then(r => r.json())
        .then(data => {
            if (!data) return;

            pollCandidateChat(data);

            if (data.call_status === 'active' && latestCallStatus !== 'ended') {
                latestCallStatus = 'active';
                if (data.call_started_at) latestCallStartedAt = data.call_started_at;

                const sessionKey = getCallSessionKey(data.call_started_at);
                const isHandledInSession = typeof sessionStorage !== 'undefined' && sessionStorage.getItem(sessionKey) === 'handled';

                if (!isCandidateCallConnected) {
                    if (isHandledInSession || candidateDeclinedOrLeftCall) {
                        showCandidateJoinOption();
                    } else {
                        triggerCandidateRing(null, data.call_started_at);
                    }
                }
            } else if (data.call_status === 'ended' || data.call_status === 'idle') {
                latestCallStatus = data.call_status;
                hasCapturedCallStartScreenshot = false;
                candidateDeclinedOrLeftCall = false;
                candRingtone.stop();
                if (candRingTimer) clearTimeout(candRingTimer);
                isCandidateCallConnected = false;

                // Clear session storage handled keys for ended/idle call sessions
                if (typeof sessionStorage !== 'undefined') {
                    for (let i = sessionStorage.length - 1; i >= 0; i--) {
                        const key = sessionStorage.key(i);
                        if (key && key.startsWith('handled_call_' + interviewId)) {
                            sessionStorage.removeItem(key);
                        }
                    }
                }

                const modal = document.getElementById('candidate-incoming-modal');
                if (modal) {
                    modal.style.opacity = '0';
                    modal.style.pointerEvents = 'none';
                }
                const joinBtn = document.getElementById('candidate-join-active-call-btn');
                if (joinBtn) {
                    joinBtn.style.display = 'none';
                    joinBtn.disabled = true;
                }
                const badge = document.getElementById('call-status-badge');
                if (badge && candidateInterviewerTiles.size === 0) {
                    badge.innerText = (data.call_status === 'ended') ? 'CALL ENDED BY HOST' : 'READY';
                    badge.style.background = (data.call_status === 'ended') ? 'rgba(239,68,68,0.2)' : 'rgba(16,185,129,0.2)';
                    badge.style.color = (data.call_status === 'ended') ? '#fca5a5' : '#34d399';
                }
            }

            if (data.active_peers && Array.isArray(data.active_peers) && latestCallStatus !== 'ended') {
                window.latestActivePeers = data.active_peers;
                if (window.isScreenSharingActive && window.isScreenSharingActive() && window.broadcastCandidateScreenStream) {
                    const sStream = window.getScreenShareStream ? window.getScreenShareStream() : null;
                    if (sStream && sStream.active) {
                        window.broadcastCandidateScreenStream(sStream);
                    }
                }
                const activePeerIds = new Set(data.active_peers.map(p => p.peer_id));

                if (isCandidateCallConnected) {
                    data.active_peers.forEach(p => {
                        if (p.peer_id && p.peer_id.startsWith('interviewer_')) {
                            let roleLabel = p.role === 'admin' ? ('Admin ' + (p.name || '')) : ('Interviewer ' + (p.name || ''));
                            const isMicOn = isTrueVal(p.mic_on);
                            const isCamOn = isTrueVal(p.cam_on);

                            if (candidateLocalStream && candidatePeerInstance && candidatePeerInstance.open) {
                                if (!candidateInterviewerTiles.has(p.peer_id)) {
                                    try {
                                        const outCall = candidatePeerInstance.call(p.peer_id, candidateLocalStream);
                                        if (outCall) {
                                            outCall.on('stream', remoteStream => {
                                                addOrUpdateCandidateInterviewerTile(p.peer_id, remoteStream, roleLabel, isMicOn, isCamOn);
                                            });
                                        }
                                    } catch(e) {}
                                } else {
                                    const existingStream = candidateInterviewerTiles.get(p.peer_id);
                                    addOrUpdateCandidateInterviewerTile(p.peer_id, existingStream, roleLabel, isMicOn, isCamOn);
                                }
                            }
                        }
                    });

                    candidateInterviewerTiles.forEach((_, pid) => {
                        if (!activePeerIds.has(pid)) {
                            removeCandidateInterviewerTile(pid);
                        }
                    });
                }
            }
        })
        .catch(() => {});
    }, 6000);
}

// Window Bindings
if (typeof window !== 'undefined') {
    window.runCode = runCode;
    window.submitSolution = submitSolution;
    window.candidateLogoutAction = candidateLogoutAction;
    window.toggleNotepadModal = toggleNotepadModal;
    window.saveNotepadContent = saveNotepadContent;
    window.toggleDrawingModal = toggleDrawingModal;
    window.initCanvasDrawing = initCanvasDrawing;
    window.clearCanvasDraw = clearCanvasDraw;
    window.saveCanvasDrawing = saveCanvasDrawing;
    window.acceptCandidateCall = acceptCandidateCall;
    window.declineCandidateCall = declineCandidateCall;
    window.candidateLeaveCall = candidateLeaveCall;
    window.triggerCandidateRing = triggerCandidateRing;
    window.stopCandidateRing = stopCandidateRing;
    window.showCandidateJoinOption = showCandidateJoinOption;
    window.getCallSessionKey = getCallSessionKey;
    window.candRingtone = candRingtone;
    window.toggleMic = toggleMic;
    window.toggleCam = toggleCam;
    window.sendCandidateMessage = sendCandidateMessage;
    window.pollCandidateChat = pollCandidateChat;
    window.initCandidateRoom = initCandidateRoom;
    window.getCandidateLocalStream = getCandidateLocalStream;
    window.isCallConnected = isCallConnected;

    const bootCandidate = () => {
        if (document.body && document.body.dataset.interviewId && document.getElementById('monaco-editor-container')) {
            initCandidateRoom();
        }
    };

    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', bootCandidate);
    } else {
        bootCandidate();
    }
}