class VoiceChannel {
    constructor(ws) {
        this.ws = ws;
        this.localStream = null;
        this.peers = {}; // userId -> RTCPeerConnection
        this.participants = {}; // userId -> username
        this.currentChannelId = null;
    }

    async join(channelId) {
        if (this.currentChannelId === channelId) return;
        if (this.currentChannelId) this.leave();

        console.log('Joining voice channel:', channelId);
        this.currentChannelId = channelId;

        try {
            this.localStream = await navigator.mediaDevices.getUserMedia({ audio: true, video: false });
            
            this.ws.send(JSON.stringify({
                type: 'voice_join',
                channel_id: channelId,
                user_id: window.currentUserId,
                username: window.currentUsername
            }));

            this.updateVoiceUI();
        } catch (e) {
            console.error('Failed to get local stream:', e);
            alert('Could not access microphone.');
            this.currentChannelId = null;
        }
    }

    leave() {
        if (!this.currentChannelId) return;

        this.ws.send(JSON.stringify({
            type: 'voice_leave',
            channel_id: this.currentChannelId,
            user_id: window.currentUserId
        }));

        if (this.localStream) {
            this.localStream.getTracks().forEach(track => track.stop());
            this.localStream = null;
        }

        Object.values(this.peers).forEach(pc => pc.close());
        this.peers = {};
        this.participants = {};
        this.currentChannelId = null;
        this.updateVoiceUI();
    }

    async handleSignaling(data) {
        const { type, from, to, offer, answer, candidate, channel_id, username } = data;

        if (channel_id != this.currentChannelId) return;
        if (to && to != window.currentUserId) return;

        switch (type) {
            case 'voice_join':
                if (from != window.currentUserId) {
                    this.participants[from] = username || `User ${from}`;
                    this.createPeerConnection(from, true);
                    this.updateVoiceUI();
                }
                break;
            case 'voice_offer':
                this.participants[from] = username || `User ${from}`;
                await this.handleOffer(from, offer);
                this.updateVoiceUI();
                break;
            case 'voice_answer':
                await this.handleAnswer(from, answer);
                break;
            case 'voice_ice_candidate':
                await this.handleCandidate(from, candidate);
                break;
            case 'voice_leave':
                if (this.peers[from]) {
                    this.peers[from].close();
                    delete this.peers[from];
                }
                delete this.participants[from];
                this.updateVoiceUI();
                break;
        }
    }

    createPeerConnection(userId, isOfferor) {
        if (this.peers[userId]) return this.peers[userId];

        const pc = new RTCPeerConnection({
            iceServers: [{ urls: 'stun:stun.l.google.com:19302' }]
        });

        this.peers[userId] = pc;

        this.localStream.getTracks().forEach(track => {
            pc.addTrack(track, this.localStream);
        });

        pc.onicecandidate = (event) => {
            if (event.candidate) {
                this.ws.send(JSON.stringify({
                    type: 'voice_ice_candidate',
                    to: userId,
                    from: window.currentUserId,
                    candidate: event.candidate,
                    channel_id: this.currentChannelId
                }));
            }
        };

        pc.ontrack = (event) => {
            const remoteAudio = new Audio();
            remoteAudio.srcObject = event.streams[0];
            remoteAudio.play();
        };

        if (isOfferor) {
            pc.createOffer().then(offer => {
                return pc.setLocalDescription(offer);
            }).then(() => {
                this.ws.send(JSON.stringify({
                    type: 'voice_offer',
                    to: userId,
                    from: window.currentUserId,
                    username: window.currentUsername,
                    offer: pc.localDescription,
                    channel_id: this.currentChannelId
                }));
            });
        }

        return pc;
    }

    async handleOffer(from, offer) {
        const pc = this.createPeerConnection(from, false);
        await pc.setRemoteDescription(new RTCSessionDescription(offer));
        const answer = await pc.createAnswer();
        await pc.setLocalDescription(answer);
        this.ws.send(JSON.stringify({
            type: 'voice_answer',
            to: from,
            from: window.currentUserId,
            answer: pc.localDescription,
            channel_id: this.currentChannelId
        }));
    }

    async handleAnswer(from, answer) {
        const pc = this.peers[from];
        if (pc) await pc.setRemoteDescription(new RTCSessionDescription(answer));
    }

    async handleCandidate(from, candidate) {
        const pc = this.peers[from];
        if (pc) await pc.addIceCandidate(new RTCIceCandidate(candidate));
    }

    updateVoiceUI() {
        document.querySelectorAll('.voice-users-list').forEach(el => el.innerHTML = '');
        
        if (this.currentChannelId) {
            const channelEl = document.querySelector(`.voice-item[data-channel-id="${this.currentChannelId}"]`);
            if (channelEl) {
                let listEl = channelEl.querySelector('.voice-users-list');
                if (!listEl) {
                    listEl = document.createElement('div');
                    listEl.className = 'voice-users-list ms-3';
                    channelEl.appendChild(listEl);
                }
                
                // Me
                this.addVoiceUserToUI(listEl, window.currentUserId, window.currentUsername);
                
                // Others
                Object.entries(this.participants).forEach(([uid, name]) => {
                    this.addVoiceUserToUI(listEl, uid, name);
                });
            }
        }
    }

    addVoiceUserToUI(container, userId, username) {
        const userEl = document.createElement('div');
        userEl.className = 'voice-user small text-muted d-flex align-items-center mb-1';
        userEl.innerHTML = `
            <div class="message-avatar me-2" style="width: 16px; height: 16px;"></div>
            <span>${username}</span>
        `;
        container.appendChild(userEl);
    }
}