import * as vscode from 'vscode';
import * as crypto from 'crypto';
import { RspadeFormattingProvider } from './formatting_provider';

// Use the global WebSocket available in VS Code extension host
declare const WebSocket: any;

interface WebSocketMessage {
    type: string;
    data?: any;
    timestamp?: number;
}

export class DebugClient {
    private ws: any = null; // WebSocket instance
    private outputChannel: vscode.OutputChannel;
    private formattingProvider: RspadeFormattingProvider;
    private isConnecting: boolean = false;
    private reconnectTimer: NodeJS.Timer | null = null;
    private pingTimer: NodeJS.Timer | null = null;
    private sessionId: string | null = null;
    private serverKey: string | null = null;

    constructor(formattingProvider: RspadeFormattingProvider) {
        this.formattingProvider = formattingProvider;
        this.outputChannel = vscode.window.createOutputChannel('RSPade Debug Proxy');
        this.outputChannel.show();
        this.log('Debug client initialized');
    }

    public async start(): Promise<void> {
        this.log('Starting debug client...');
        await this.connect();
    }

    private async connect(): Promise<void> {
        if (this.isConnecting || this.ws?.readyState === WebSocket.OPEN) {
            return;
        }

        this.isConnecting = true;

        try {
            // Get authentication from formatting provider
            await this.ensureAuthenticated();

            const serverUrl = await this.formattingProvider.get_server_url();
            if (!serverUrl) {
                throw new Error('No server URL configured');
            }

            // Parse URL and construct WebSocket URL
            const url = new URL(serverUrl);
            const wsProtocol = url.protocol === 'https:' ? 'wss:' : 'ws:';
            const wsUrl = `${wsProtocol}//${url.host}/_ide/debug/ws`;

            this.log(`Connecting to WebSocket: ${wsUrl}`);

            // Create WebSocket (standard API doesn't support headers in constructor)
            // We'll send auth after connection
            this.ws = new WebSocket(wsUrl);

            this.setupEventHandlers();

        } catch (error: any) {
            this.log(`Connection failed: ${error.message}`);
            this.isConnecting = false;
            this.scheduleReconnect();
        }
    }

    private setupEventHandlers(): void {
        if (!this.ws) return;

        this.ws.onopen = () => {
            this.isConnecting = false;
            this.log('WebSocket connected, sending authentication...');

            // Send authentication as first message
            const signature = crypto
                .createHmac('sha256', this.serverKey!)
                .update(this.sessionId!)
                .digest('hex');

            this.sendMessage({
                type: 'auth',
                data: {
                    sessionId: this.sessionId,
                    signature: signature
                }
            });

            // Send initial hello message after auth
            setTimeout(() => {
                this.sendMessage({
                    type: 'hello',
                    data: { name: 'VS Code Debug Client' }
                });

                // Start ping timer
                this.startPingTimer();
            }, 100);
        };

        this.ws.onmessage = (event: any) => {
            try {
                const message = JSON.parse(event.data) as WebSocketMessage;
                this.handleMessage(message);
            } catch (error) {
                this.log(`Failed to parse message: ${error}`);
            }
        };

        this.ws.onclose = () => {
            this.log('WebSocket disconnected');
            this.ws = null;
            this.stopPingTimer();
            this.scheduleReconnect();
        };

        this.ws.onerror = (error: any) => {
            this.log(`WebSocket error: ${error}`);
        };
    }

    private handleMessage(message: WebSocketMessage): void {
        this.log(`Received: ${message.type}`, message.data);

        switch (message.type) {
            case 'welcome':
                this.log('✅ Authentication successful! Connected to debug proxy');
                this.log(`Session ID: ${message.data?.sessionId}`);
                break;

            case 'pong':
                this.log(`PONG received! Server responded to ping`);
                break;

            case 'hello_response':
                this.log(`Server says: ${message.data?.message}`);
                break;

            case 'error':
                this.log(`❌ Error: ${message.data?.message}`);
                break;

            default:
                this.log(`Unknown message type: ${message.type}`);
        }
    }

    private sendMessage(message: WebSocketMessage): void {
        if (this.ws?.readyState === 1) { // 1 = OPEN in standard WebSocket API
            this.ws.send(JSON.stringify(message));
            this.log(`Sent: ${message.type}`, message.data);
        }
    }

    private startPingTimer(): void {
        this.stopPingTimer();

        // Send ping every 5 seconds
        this.pingTimer = setInterval(() => {
            this.sendMessage({
                type: 'ping',
                data: { timestamp: Date.now() }
            });
            this.log('PING sent to server');
        }, 5000);
    }

    private stopPingTimer(): void {
        if (this.pingTimer) {
            clearInterval(this.pingTimer);
            this.pingTimer = null;
        }
    }

    private scheduleReconnect(): void {
        if (this.reconnectTimer) {
            return;
        }

        this.log('Scheduling reconnection in 5 seconds...');
        this.reconnectTimer = setTimeout(() => {
            this.reconnectTimer = null;
            this.connect();
        }, 5000);
    }

    private async ensureAuthenticated(): Promise<void> {
        // Get auth data from formatting provider
        const authData = await this.formattingProvider.ensure_auth();
        if (!authData) {
            throw new Error('Failed to authenticate');
        }

        // Extract session ID and server key
        this.sessionId = authData.session_id;
        this.serverKey = authData.server_key;

        if (!this.sessionId || !this.serverKey) {
            throw new Error('Invalid auth data');
        }
    }

    private log(message: string, data?: any): void {
        const timestamp = new Date().toISOString();
        const logMessage = `[${timestamp}] ${message}`;

        if (data) {
            this.outputChannel.appendLine(`${logMessage}\n${JSON.stringify(data, null, 2)}`);
        } else {
            this.outputChannel.appendLine(logMessage);
        }
    }

    public dispose(): void {
        this.stopPingTimer();

        if (this.reconnectTimer) {
            clearTimeout(this.reconnectTimer);
            this.reconnectTimer = null;
        }

        if (this.ws) {
            this.ws.close();
            this.ws = null;
        }

        this.outputChannel.dispose();
    }
}