/**
 * WebSocket-based Live Updates for ANNOTATE
 * Provides real-time chart updates and model predictions
 */

class LiveUpdatesWebSocket {
    constructor() {
        this.socket = null;
        this.connected = false;
        this.reconnectAttempts = 0;
        this.maxReconnectAttempts = 5;
        this.reconnectDelay = 1000; // Start with 1 second
        this.subscriptions = new Set();
        
        // Callbacks
        this.onChartUpdate = null;
        this.onPredictionUpdate = null;
        this.onConnectionChange = null;
        
        console.log('LiveUpdatesWebSocket initialized');
    }
    
    connect() {
        if (this.connected) {
            console.log('Already connected to WebSocket');
            return;
        }
        
        try {
            // Initialize SocketIO connection
            this.socket = io({
                transports: ['websocket', 'polling'],
                upgrade: true,
                rememberUpgrade: true
            });
            
            this._setupEventHandlers();
            console.log('Connecting to WebSocket...');
            
        } catch (error) {
            console.error('Failed to initialize WebSocket:', error);
            this._scheduleReconnect();
        }
    }
    
    _setupEventHandlers() {
        // Connection events
        this.socket.on('connect', () => {
            console.log('✅ WebSocket connected');
            this.connected = true;
            this.reconnectAttempts = 0;
            this.reconnectDelay = 1000;
            
            if (this.onConnectionChange) {
                this.onConnectionChange(true);
            }
            
            // Resubscribe to previous subscriptions
            this.subscriptions.forEach(sub => {
                this._subscribe(sub.symbol, sub.timeframe);
            });
        });
        
        this.socket.on('disconnect', () => {
            console.log('❌ WebSocket disconnected');
            this.connected = false;
            
            if (this.onConnectionChange) {
                this.onConnectionChange(false);
            }
            
            this._scheduleReconnect();
        });
        
        this.socket.on('connection_response', (data) => {
            console.log('Connection response:', data);
        });
        
        this.socket.on('subscription_confirmed', (data) => {
            console.log('Subscription confirmed:', data);
        });
        
        // Data events
        this.socket.on('chart_update', (data) => {
            console.debug('Chart update received:', data);
            if (this.onChartUpdate) {
                this.onChartUpdate(data);
            }
        });
        
        this.socket.on('prediction_update', (data) => {
            console.debug('Prediction update received:', data);
            if (this.onPredictionUpdate) {
                this.onPredictionUpdate(data);
            }
        });
        
        this.socket.on('prediction_error', (data) => {
            console.error('Prediction error:', data);
        });
        
        // Error events
        this.socket.on('connect_error', (error) => {
            console.error('WebSocket connection error:', error);
            this._scheduleReconnect();
        });
        
        this.socket.on('error', (error) => {
            console.error('WebSocket error:', error);
        });
    }
    
    _scheduleReconnect() {
        if (this.reconnectAttempts >= this.maxReconnectAttempts) {
            console.error('Max reconnection attempts reached. Please refresh the page.');
            return;
        }
        
        this.reconnectAttempts++;
        const delay = this.reconnectDelay * Math.pow(2, this.reconnectAttempts - 1); // Exponential backoff
        
        console.log(`Reconnecting in ${delay}ms (attempt ${this.reconnectAttempts}/${this.maxReconnectAttempts})...`);
        
        setTimeout(() => {
            if (!this.connected) {
                this.connect();
            }
        }, delay);
    }
    
    subscribe(symbol, timeframe) {
        this.subscriptions.add({ symbol, timeframe });
        
        if (this.connected) {
            this._subscribe(symbol, timeframe);
        }
    }
    
    _subscribe(symbol, timeframe) {
        if (!this.socket || !this.connected) {
            console.warn('Cannot subscribe - not connected');
            return;
        }
        
        console.log(`Subscribing to live updates: ${symbol} ${timeframe}`);
        this.socket.emit('subscribe_live_updates', {
            symbol: symbol,
            timeframe: timeframe
        });
    }
    
    requestPrediction(symbol, timeframe, predictionSteps = 1) {
        if (!this.socket || !this.connected) {
            console.warn('Cannot request prediction - not connected');
            return;
        }
        
        console.log(`Requesting prediction: ${symbol} ${timeframe} (${predictionSteps} steps)`);
        this.socket.emit('request_prediction', {
            symbol: symbol,
            timeframe: timeframe,
            prediction_steps: predictionSteps
        });
    }
    
    disconnect() {
        if (this.socket) {
            console.log('Disconnecting WebSocket...');
            this.socket.disconnect();
            this.socket = null;
            this.connected = false;
            this.subscriptions.clear();
        }
    }
    
    isConnected() {
        return this.connected;
    }
}

// Global instance
window.liveUpdatesWS = null;

// Initialize on page load
document.addEventListener('DOMContentLoaded', function() {
    // Check if SocketIO is available
    if (typeof io === 'undefined') {
        console.warn('⚠️ Socket.IO not loaded - live updates will not work');
        console.warn('Add <script src="https://cdn.socket.io/4.5.4/socket.io.min.js"></script> to your HTML');
        return;
    }
    
    // Initialize WebSocket
    window.liveUpdatesWS = new LiveUpdatesWebSocket();
    
    // Setup callbacks
    window.liveUpdatesWS.onConnectionChange = function(connected) {
        const statusElement = document.getElementById('ws-connection-status');
        if (statusElement) {
            if (connected) {
                statusElement.innerHTML = '<span class="badge bg-success">🟢 Live</span>';
            } else {
                statusElement.innerHTML = '<span class="badge bg-danger">🔴 Disconnected</span>';
            }
        }
    };
    
    window.liveUpdatesWS.onChartUpdate = function(data) {
        // Update chart with new candle
        if (window.appState && window.appState.chartManager) {
            window.appState.chartManager.updateLatestCandle(data.symbol, data.timeframe, data.candle);
        }
    };
    
    window.liveUpdatesWS.onPredictionUpdate = function(data) {
        // Update prediction display
        if (typeof updatePredictionDisplay === 'function') {
            updatePredictionDisplay(data);
        }
        
        // Add to prediction history
        if (typeof predictionHistory !== 'undefined') {
            predictionHistory.unshift(data);
            if (predictionHistory.length > 5) {
                predictionHistory = predictionHistory.slice(0, 5);
            }
            if (typeof updatePredictionHistory === 'function') {
                updatePredictionHistory();
            }
        }
    };
    
    // Auto-connect
    console.log('Auto-connecting to WebSocket...');
    window.liveUpdatesWS.connect();
});

// Cleanup on page unload
window.addEventListener('beforeunload', function() {
    if (window.liveUpdatesWS) {
        window.liveUpdatesWS.disconnect();
    }
});