import { WebSocketServer, WebSocket } from 'ws';
import { LLMService } from '../services/LLMService';
import { EncryptionService } from '../services/EncryptionService';
import { v4 as uuidv4 } from 'uuid';

// Initialize Encryption Service
const encryptionService = new EncryptionService(process.env.ENCRYPTION_KEY || '');

// Types from the frontend
interface Decision {
    goTo: string;
    alsoGood: string;
    considerable: string;
    noGoes: string;
    needsDiscussion: string;
}

// Define the SessionState enum
export enum SessionState {
    SETUP = 'SETUP',
    GATHERING = 'GATHERING',
    HARMONIZING = 'HARMONIZING',
    FINAL = 'FINAL',
    ERROR = 'ERROR',
}

interface EncryptedResponseData {
    wants: string[];
    accepts: string[];
    noGoes: string[];
    afraidToAsk: string; // Encrypted afraidToAsk idea
}

// A map to hold session data, including clients and the latest state
interface SessionData {
    state: SessionState; // Current phase of the session
    topic: string | null; // The topic of the session
    description: string | null; // The description of the session
    expectedResponses: number; // The number set by the first user in State A.
    submittedCount: number; // The current count of submitted responses.
    responses: Map<string, EncryptedResponseData>; // Stores the submitted desire objects. Map<ClientID, EncryptedResponseData>
    clients: Map<string, WebSocket>; // Maps the persistent Client ID to their active WebSocket connection object.
    finalResult: any | null; // The result returned by the LLM.
}
export const sessions = new Map<string, SessionData>();

// Initialize LLM Service (API key from environment)
const llmService = new LLMService(process.env.GEMINI_API_KEY || '');

// Structured logging function
const logEvent = (eventName: string, sessionId: string, details: object = {}) => {
    console.log(JSON.stringify({ timestamp: new Date().toISOString(), eventName, sessionId, ...details }));
};

// Metrics recording function
const recordMetric = (metricName: string, value: number | string, sessionId: string, details: object = {}) => {
    console.log(JSON.stringify({ timestamp: new Date().toISOString(), metricName, value, sessionId, ...details }));
};

// Helper to create a serializable version of the session state
const getSerializableSession = (sessionData: SessionData, currentClientId: string | null = null) => {
    const filteredResponses = new Map<string, any>();
    sessionData.responses.forEach((response, clientId) => {
        if (clientId === currentClientId) {
            // For the current client, decrypt and send their own full response
            const decryptedWants = response.wants.map((d: string) => encryptionService.decrypt(d));
            const decryptedAccepts = response.accepts.map((d: string) => encryptionService.decrypt(d));
            const decryptedNoGoes = response.noGoes.map((d: string) => encryptionService.decrypt(d));
            const decryptedAfraidToAsk = encryptionService.decrypt(response.afraidToAsk);
            filteredResponses.set(clientId, { wants: decryptedWants, accepts: decryptedAccepts, noGoes: decryptedNoGoes, afraidToAsk: decryptedAfraidToAsk });
        } else {
            // For other clients, only send non-AfraidToAsk parts (wants, accepts, noGoes without AfraidToAsk)
            const decryptedWants = response.wants.map((d: string) => encryptionService.decrypt(d));
            const decryptedAccepts = response.accepts.map((d: string) => encryptionService.decrypt(d));
            const decryptedNoGoes = response.noGoes.map((d: string) => encryptionService.decrypt(d));
            filteredResponses.set(clientId, { wants: decryptedWants, accepts: decryptedAccepts, noGoes: decryptedNoGoes, afraidToAsk: "" }); // Hide afraidToAsk for other clients
        }
    });

    return {
        ...sessionData,
        responses: Object.fromEntries(filteredResponses),
        clients: Array.from(sessionData.clients.keys()), // Only send client IDs, not the WebSocket objects
    };
};

export const broadcastToSession = (sessionId: string, message: any, excludeClientId: string | null = null) => {
    const sessionData = sessions.get(sessionId);
    if (sessionData) {
        sessionData.clients.forEach((client, clientId) => {
            if (clientId !== excludeClientId && client.readyState === WebSocket.OPEN) {
                const serializableMessage = {
                    ...message,
                    payload: {
                        ...message.payload,
                        session: getSerializableSession(sessionData, clientId), // Pass clientId to getSerializableSession
                    },
                };
                client.send(JSON.stringify(serializableMessage));
            }
        });
    }
};

export const createWebSocketServer = (server: any) => {
    const wss = new WebSocketServer({ server });

    wss.on('connection', (ws, req) => {
        const url = new URL(req.url || '', `http://${req.headers.host}`);
        const sessionId = url.pathname.split('/').pop();

        if (!sessionId) {
            ws.close(1008, 'Invalid session ID');
            return;
        }

        if (!sessions.has(sessionId)) {
            sessions.set(sessionId, {
                state: SessionState.SETUP,
                topic: null,
                description: null,
                expectedResponses: 0,
                submittedCount: 0,
                responses: new Map<string, any>(),
                clients: new Map<string, WebSocket>(),
                finalResult: null,
            });
        }
        const sessionData = sessions.get(sessionId)!;

        console.log(`Client connecting to session: ${sessionId}`);

        // Set up a ping interval to keep the connection alive
        const pingInterval = setInterval(() => {
            if (ws.readyState === WebSocket.OPEN) {
                ws.ping();
            }
        }, 30000); // Send ping every 30 seconds

        ws.on('message', async (message) => {
            const parsedMessage = JSON.parse(message.toString());
            const { type, clientId, payload } = parsedMessage;

            if (!clientId) {
                console.error(`Received message without clientId in session ${sessionId}. Type: ${type}`);
                ws.send(JSON.stringify({ type: 'ERROR', payload: { message: 'clientId is required' } }));
                return;
            }

            if (!sessionData.clients.has(clientId)) {
                sessionData.clients.set(clientId, ws);
                console.log(`Client ${clientId} registered for session: ${sessionId}. Total clients: ${sessionData.clients.size}`);
                ws.send(JSON.stringify({ type: 'STATE_UPDATE', payload: { session: getSerializableSession(sessionData, clientId) } }));
            }

            console.log(`Received message from ${clientId} in session ${sessionId}:`, type);
            await handleWebSocketMessage(ws, sessionId, parsedMessage);
        });

        ws.on('close', () => {
            clearInterval(pingInterval); // Clear the interval when the connection closes
            let disconnectedClientId: string | null = null;
            for (const [clientId, clientWs] of sessionData.clients.entries()) {
                if (clientWs === ws) {
                    disconnectedClientId = clientId;
                    break;
                }
            }

            if (disconnectedClientId) {
                sessionData.clients.delete(disconnectedClientId);
                console.log(`Client ${disconnectedClientId} disconnected from session: ${sessionId}. Remaining clients: ${sessionData.clients.size}`);
            } else {
                console.log(`An unregistered client disconnected from session: ${sessionId}.`);
            }

            if (sessionData.clients.size === 0) {
                sessions.delete(sessionId);
                logEvent('session_purged', sessionId);
                console.log(`Session ${sessionId} closed and state cleared.`);
            }
        });

        ws.on('error', (error) => {
            console.error(`WebSocket error in session ${sessionId}:`, error);
        });
    });

    return wss;
};

export const handleWebSocketMessage = async (ws: WebSocket, sessionId: string, parsedMessage: any) => {
    const { type, clientId, payload } = parsedMessage;

    if (!clientId) {
        console.error(`Received message without clientId in session ${sessionId}. Type: ${type}`);
        ws.send(JSON.stringify({ type: 'ERROR', payload: { message: 'clientId is required' } }));
        return;
    }

    const sessionData = sessions.get(sessionId)!;

    if (!sessionData.clients.has(clientId)) {
        sessionData.clients.set(clientId, ws);
        console.log(`Client ${clientId} registered for session: ${sessionId}. Total clients: ${sessionData.clients.size}`);
        ws.send(JSON.stringify({ type: 'STATE_UPDATE', payload: { session: getSerializableSession(sessionData, clientId) } }));
    }

    console.log(`Received message from ${clientId} in session ${sessionId}:`, type);

    switch (type) {
        case 'REGISTER_CLIENT':
            console.log(`Client ${clientId} registered successfully for session ${sessionId}.`);
            break;

        case 'PING':
            // Respond to client pings with a pong
            if (ws.readyState === WebSocket.OPEN) {
                ws.pong();
            }
            break;

        case 'SETUP_SESSION':
            if (sessionData.state === SessionState.SETUP) {
                const { expectedResponses, topic, description } = payload;
                if (typeof expectedResponses !== 'number' || expectedResponses <= 0) {
                    ws.send(JSON.stringify({ type: 'ERROR', payload: { message: 'Invalid expectedResponses' } }));
                    return;
                }
                sessionData.expectedResponses = expectedResponses;
                sessionData.topic = topic || 'Untitled Session';
                sessionData.description = description || null;
                sessionData.state = SessionState.GATHERING;
                broadcastToSession(sessionId, { type: 'STATE_UPDATE', payload: {} });
                console.log(`Session ${sessionId} moved to GATHERING with topic "${sessionData.topic}" and ${expectedResponses} expected responses.`);
            } else {
                ws.send(JSON.stringify({ type: 'ERROR', payload: { message: `Session is not in SETUP state. Current state: ${sessionData.state}` } }));
            }
            break;

        case 'SUBMIT_RESPONSE':
            if (sessionData.state === SessionState.GATHERING) {
                if (sessionData.responses.has(clientId)) {
                    ws.send(JSON.stringify({ type: 'ERROR', payload: { message: 'You have already submitted a response for this session.' } }));
                    return;
                }

                const { wants, accepts, noGoes, afraidToAsk } = payload.response;
                if ([...wants, ...accepts, ...noGoes].some(desire => desire.length > 500) || afraidToAsk.length > 500) {
                    ws.send(JSON.stringify({ type: 'ERROR', payload: { message: 'One of your desires or afraidToAsk exceeds the 500 character limit.' } }));
                    return;
                }

                const hasContradictionsGist = await llmService.checkForInnerContradictions(payload.response);
                if (hasContradictionsGist) {
                    ws.send(JSON.stringify({ type: 'ERROR', payload: { message: `Your submission contains inner contradictions: ${hasContradictionsGist} Please resolve them and submit again.` } }));
                    return;
                }

                const encryptedWants = wants.map((d: string) => encryptionService.encrypt(d));
                const encryptedAccepts = accepts.map((d: string) => encryptionService.encrypt(d));
                const encryptedNoGoes = noGoes.map((d: string) => encryptionService.encrypt(d));
                const encryptedAfraidToAsk = encryptionService.encrypt(afraidToAsk);

                sessionData.responses.set(clientId, { wants: encryptedWants, accepts: encryptedAccepts, noGoes: encryptedNoGoes, afraidToAsk: encryptedAfraidToAsk });
                sessionData.submittedCount++;
                logEvent('response_submitted', sessionId, { clientId, submittedCount: sessionData.submittedCount });
                console.log(`Client ${clientId} submitted response. Submitted count: ${sessionData.submittedCount}/${sessionData.expectedResponses}`);

                if (sessionData.submittedCount === sessionData.expectedResponses) {
                    sessionData.state = SessionState.HARMONIZING;
                    broadcastToSession(sessionId, { type: 'STATE_UPDATE', payload: {} });
                    logEvent('session_harmonizing', sessionId, { expectedResponses: sessionData.expectedResponses });
                    console.log(`Session ${sessionId} moved to HARMONIZING. Triggering LLM analysis.`);

                                                // Perform LLM analysis asynchronously
                                                (async () => {
                                                    let durationMs: number = 0; // Declare here
                                                    try {
                                                        logEvent('llm_analysis_started', sessionId);
                                                        const startTime = process.hrtime.bigint();                            const allDecryptedDesires = Array.from(sessionData.responses.values()).map(encryptedResponse => {
                                const decryptedWants = encryptedResponse.wants.map((d: string) => encryptionService.decrypt(d));
                                const decryptedAccepts = encryptedResponse.accepts.map((d: string) => encryptionService.decrypt(d));
                                const decryptedNoGoes = encryptedResponse.noGoes.map((d: string) => encryptionService.decrypt(d));
                                const decryptedAfraidToAsk = encryptionService.decrypt(encryptedResponse.afraidToAsk);
                                return { wants: decryptedWants, accepts: decryptedAccepts, noGoes: decryptedNoGoes, afraidToAsk: decryptedAfraidToAsk };
                            });
                            const decision = await llmService.analyzeDesires(allDecryptedDesires);

                            sessionData.finalResult = decision;
                            sessionData.state = SessionState.FINAL;
                            broadcastToSession(sessionId, { type: 'STATE_UPDATE', payload: {} });
                            logEvent('llm_analysis_completed', sessionId, { result: decision });
                                                                recordMetric('llm_analysis_duration', durationMs, sessionId, { status: 'success' });                            recordMetric('llm_analysis_availability', 'available', sessionId);
                            console.log(`Analysis complete for session ${sessionId}. Result:`, decision);

                        } catch (error: any) {
                            console.error(`Error during analysis for session ${sessionId}:`, error.message);
                            sessionData.state = SessionState.ERROR;
                            broadcastToSession(sessionId, { type: 'STATE_UPDATE', payload: {} });
                            logEvent('llm_analysis_error', sessionId, { error: error.message });
                            recordMetric('llm_analysis_availability', 'unavailable', sessionId, { error: error.message });
                        }
                    })();
                } else {
                    // Only broadcast the latest count if the session is not yet harmonizing
                    broadcastToSession(sessionId, { type: 'STATE_UPDATE', payload: {} });
                }
            } else {
                ws.send(JSON.stringify({ type: 'ERROR', payload: { message: `Session is not in GATHERING state. Current state: ${sessionData.state}` } }));
            }
            break;

        default:
            console.warn(`Unknown message type: ${type} from client ${clientId} in session ${sessionId}`);
            ws.send(JSON.stringify({ type: 'ERROR', payload: { message: `Unknown message type: ${type}` } }));
            break;
    }
};
