const socket = io();
const peerConnections = {};
const startBtn = document.getElementById('startBtn');
const localVideo = document.getElementById('localVideo');
const statusDot = document.getElementById('statusDot');
const statusText = document.getElementById('statusText');
const passwordInput = document.getElementById('broadcasterPassword');
const authContainer = document.getElementById('authContainer');

let activeStream;

const config = {
    iceServers: [
        { urls: "stun:localhost:3478" },
        {
            urls: "turn:localhost:3478",
            username: "myuser",
            credential: "mypassword"
        }
    ]
};

socket.on('authError', (msg) => {
    alert(msg);
    stopSharing();
});

socket.on('viewer', id => {
    if (!activeStream) return;
    
    const peerConnection = new RTCPeerConnection(config);
    peerConnections[id] = peerConnection;

    activeStream.getTracks().forEach(track => {
        const sender = peerConnection.addTrack(track, activeStream);
        
        // Force high bitrate for best possible 1080p60 quality
        if (track.kind === 'video') {
            const params = sender.getParameters();
            if (!params.encodings) params.encodings = [{}];
            
            // Set max bandwidth to 10 Mbps (10,000,000 bps)
            params.encodings[0].maxBitrate = 10000000; 
            
            sender.setParameters(params).catch(e => console.error("Could not set high bitrate:", e));
        }
    });

    peerConnection.onicecandidate = event => {
        if (event.candidate) {
            socket.emit('candidate', id, event.candidate);
        }
    };

    peerConnection
        .createOffer()
        .then(sdp => {
            // Force VP8/H264 on the SDP offer to maximize compatibility with Chromium
            if (window.RTCRtpSender && window.RTCRtpSender.getCapabilities) {
                const capabilities = window.RTCRtpSender.getCapabilities('video');
                if (capabilities && capabilities.codecs) {
                    const preferredCodecs = capabilities.codecs.filter(c => 
                        c.mimeType.toLowerCase() === 'video/vp8' || 
                        c.mimeType.toLowerCase() === 'video/h264'
                    );
                    if (preferredCodecs.length > 0) {
                        const transceivers = peerConnection.getTransceivers();
                        transceivers.forEach(transceiver => {
                            if (transceiver.receiver.track.kind === 'video') {
                                try {
                                    transceiver.setCodecPreferences(preferredCodecs);
                                } catch (e) {
                                    console.warn('Failed to set codec preferences:', e);
                                }
                            }
                        });
                    }
                }
            }
            return peerConnection.setLocalDescription(sdp);
        })
        .then(() => {
            socket.emit('offer', id, peerConnection.localDescription);
        });
});

socket.on('answer', (id, description) => {
    if (peerConnections[id]) {
        peerConnections[id].setRemoteDescription(description);
    }
});

socket.on('candidate', (id, candidate) => {
    if (peerConnections[id]) {
        peerConnections[id].addIceCandidate(new RTCIceCandidate(candidate));
    }
});

socket.on('disconnectPeer', id => {
    if (peerConnections[id]) {
        peerConnections[id].close();
        delete peerConnections[id];
    }
});

startBtn.addEventListener('click', async () => {
    const password = passwordInput.value;
    if (!password) {
        alert("Please enter the stream password to broadcast.");
        return;
    }

    try {
        const stream = await navigator.mediaDevices.getDisplayMedia({
            video: {
                width: { ideal: 1920 },
                height: { ideal: 1080 },
                frameRate: { ideal: 60 }
            },
            audio: false 
        });

        activeStream = stream;
        localVideo.srcObject = stream;
        localVideo.classList.add('active');
        
        startBtn.style.display = 'none';
        authContainer.style.display = 'none';
        statusDot.classList.add('active');
        statusText.innerText = 'Sharing Screen (1080p60)';

        socket.emit('broadcaster', password);

        stream.getVideoTracks()[0].onended = () => {
            stopSharing();
        };

    } catch (err) {
        console.error("Error accessing display media.", err);
        statusText.innerText = 'Failed to access screen';
        statusDot.style.backgroundColor = 'var(--error-color)';
    }
});

function stopSharing() {
    startBtn.style.display = 'inline-block';
    authContainer.style.display = 'block';
    localVideo.classList.remove('active');
    statusDot.classList.remove('active');
    statusText.innerText = 'Not Sharing';
    activeStream = null;
    socket.emit('disconnect'); 
}