server/bridge.ts

// ---------------------------------------------------------------------------
// Bridge -- Real persistent Antigravity CLI session management
// ---------------------------------------------------------------------------
// Spawns the Antigravity CLI as a persistent interactive subprocess.
// Relays stdin/stdout/stderr over WebSocket so the webapp mirrors the CLI.
// ---------------------------------------------------------------------------

import { Server, Socket } from 'socket.io';
import { spawn, ChildProcess } from 'child_process';
import { ToolRegistry, ToolResult } from './toolRegistry';
import { CLIDetectionResult, detectCLI } from './cliDetector';
import fs from 'fs';
import path from 'path';

const SETTINGS_FILE = path.join(__dirname, '..', 'settings.json');

interface Settings {
    cliPath: string;
    autoConnect: boolean;
}

interface CLISession {
    process: ChildProcess;
    logs: string[];
    started: number;
}

// Persistent state
let currentSession: CLISession | null = null;
let settings: Settings = loadSettings();
let latestCliStatus: CLIDetectionResult | null = null;

function loadSettings(): Settings {
    try {
        if (fs.existsSync(SETTINGS_FILE)) {
            return JSON.parse(fs.readFileSync(SETTINGS_FILE, 'utf-8'));
        }
    } catch { }
    return { cliPath: '', autoConnect: false };
}

function saveSettings(s: Settings): void {
    settings = s;
    fs.writeFileSync(SETTINGS_FILE, JSON.stringify(s, null, 2), 'utf-8');
}

export function getSettings(): Settings {
    return settings;
}

export function updateSettings(partial: Partial<Settings>): Settings {
    settings = { ...settings, ...partial };
    saveSettings(settings);
    return settings;
}

export async function redetectCLI(): Promise<CLIDetectionResult> {
    // Override detection with user-configured path
    if (settings.cliPath) {
        process.env.ANTIGRAVITY_CLI_PATH = settings.cliPath;
    }
    latestCliStatus = await detectCLI();
    return latestCliStatus;
}

export function setupBridge(
    io: Server,
    toolRegistry: ToolRegistry,
    cliStatus: CLIDetectionResult
): void {
    latestCliStatus = cliStatus;

    io.on('connection', (socket: Socket) => {
        console.log(`  [Bridge] Client connected: ${socket.id}`);

        // Send initial state
        socket.emit('bridge:init', {
            tools: toolRegistry.listTools(),
            cli: {
                detected: latestCliStatus!.detected,
                version: latestCliStatus!.version,
                method: latestCliStatus!.method,
                path: latestCliStatus!.path,
            },
            settings: settings,
            sessionActive: currentSession !== null,
            serverTime: new Date().toISOString(),
        });

        // ------------------------------------------------------------------
        // Settings management (from UI)
        // ------------------------------------------------------------------
        socket.on('settings:get', (callback: Function) => {
            if (typeof callback === 'function') {
                callback({ settings, cli: latestCliStatus });
            }
        });

        socket.on('settings:update', async (data: Partial<Settings>, callback: Function) => {
            const updated = updateSettings(data);
            console.log(`  [Bridge] Settings updated:`, updated);

            // Re-detect with new path
            const newStatus = await redetectCLI();
            latestCliStatus = newStatus;

            // Notify all clients
            io.emit('settings:changed', { settings: updated, cli: newStatus });

            if (typeof callback === 'function') {
                callback({ settings: updated, cli: newStatus });
            }
        });

        // ------------------------------------------------------------------
        // CLI Session management
        // ------------------------------------------------------------------
        socket.on('cli:start', async (data: { cliPath?: string }) => {
            const cliPath = data?.cliPath || settings.cliPath || latestCliStatus?.path;

            if (!cliPath) {
                socket.emit('cli:error', {
                    message: 'No CLI path configured. Go to Settings and set the path to your Antigravity CLI executable.',
                });
                return;
            }

            // Kill existing session
            if (currentSession) {
                try { currentSession.process.kill('SIGTERM'); } catch { }
                currentSession = null;
            }

            console.log(`  [Bridge] Starting CLI session: ${cliPath}`);
            io.emit('cli:starting', { path: cliPath });

            try {
                const child = spawn(cliPath, [], {
                    shell: true,
                    cwd: process.cwd(),
                    env: { ...process.env, TERM: 'dumb', NO_COLOR: '1' },
                    stdio: ['pipe', 'pipe', 'pipe'],
                });

                currentSession = {
                    process: child,
                    logs: [],
                    started: Date.now(),
                };

                child.stdout?.on('data', (chunk: Buffer) => {
                    const text = chunk.toString();
                    currentSession?.logs.push(text);
                    io.emit('cli:stdout', { data: text, timestamp: Date.now() });
                });

                child.stderr?.on('data', (chunk: Buffer) => {
                    const text = chunk.toString();
                    currentSession?.logs.push(`[stderr] ${text}`);
                    io.emit('cli:stderr', { data: text, timestamp: Date.now() });
                });

                child.on('close', (code: number | null) => {
                    console.log(`  [Bridge] CLI session ended: exit code ${code}`);
                    io.emit('cli:ended', { exitCode: code });
                    currentSession = null;
                });

                child.on('error', (err: Error) => {
                    console.error(`  [Bridge] CLI error: ${err.message}`);
                    io.emit('cli:error', { message: `Failed to start CLI: ${err.message}` });
                    currentSession = null;
                });

                io.emit('cli:started', { path: cliPath, timestamp: Date.now() });
            } catch (err: any) {
                io.emit('cli:error', { message: `Failed to spawn CLI: ${err.message}` });
            }
        });

        socket.on('cli:stop', () => {
            if (currentSession) {
                try { currentSession.process.kill('SIGTERM'); } catch { }
                currentSession = null;
                io.emit('cli:ended', { exitCode: null, reason: 'user-stopped' });
            }
        });

        socket.on('cli:status', (callback: Function) => {
            if (typeof callback === 'function') {
                callback({
                    active: currentSession !== null,
                    uptime: currentSession ? Date.now() - currentSession.started : 0,
                    logLength: currentSession?.logs.length || 0,
                });
            }
        });

        // ------------------------------------------------------------------
        // Prompt handling -- relay to CLI or match tools
        // ------------------------------------------------------------------
        socket.on('prompt:send', async (data: { message: string; id: string }) => {
            const { message, id } = data;
            console.log(`  [Bridge] Prompt: ${message}`);

            // Broadcast to all clients
            io.emit('prompt:received', {
                message, id, from: 'human',
                timestamp: new Date().toISOString(),
            });

            // Check for tool match first
            const match = toolRegistry.matchTool(message);

            if (match) {
                const { tool, params } = match;
                console.log(`  [Bridge] Tool matched: ${tool.name}`);

                io.emit('tool:started', { id, toolName: tool.name, params, timestamp: new Date().toISOString() });

                try {
                    const result: ToolResult = await tool.execute(params, (progress: string) => {
                        io.emit('tool:progress', { id, toolName: tool.name, progress, timestamp: new Date().toISOString() });
                    });

                    io.emit('tool:completed', { id, toolName: tool.name, result, timestamp: new Date().toISOString() });
                } catch (err: any) {
                    io.emit('tool:error', { id, toolName: tool.name, error: err.message, timestamp: new Date().toISOString() });
                }
            } else if (currentSession?.process?.stdin) {
                // Send prompt to the running CLI process
                try {
                    currentSession.process.stdin.write(message + '\n');
                    console.log(`  [Bridge] Sent to CLI stdin: ${message}`);
                } catch (err: any) {
                    io.emit('cli:error', { message: `Failed to write to CLI: ${err.message}` });
                }
            } else {
                // No tool match, no CLI session
                io.emit('agent:message', {
                    id, from: 'system',
                    message: currentSession
                        ? 'CLI session is active but stdin is unavailable.'
                        : 'No CLI session is running. Click "Connect" in Settings to start the Antigravity CLI, or configure the path first.',
                    timestamp: new Date().toISOString(),
                });
            }
        });

        // ------------------------------------------------------------------
        // MCP tool discovery & invocation
        // ------------------------------------------------------------------
        socket.on('tool:list', (callback: Function) => {
            if (typeof callback === 'function') {
                callback({ status: 'success', tools: toolRegistry.listTools() });
            }
        });

        socket.on('tool:invoke', async (data: { toolName: string; params: any }, callback: Function) => {
            const tool = toolRegistry.getTool(data.toolName);
            if (!tool) {
                if (typeof callback === 'function') callback({ status: 'error', message: `Tool "${data.toolName}" not found.` });
                return;
            }

            try {
                const result = await tool.execute(data.params, (progress: string) => {
                    io.emit('tool:progress', { toolName: data.toolName, progress, timestamp: new Date().toISOString() });
                });
                if (typeof callback === 'function') callback({ status: 'success', result });
            } catch (err: any) {
                if (typeof callback === 'function') callback({ status: 'error', message: err.message });
            }
        });

        socket.on('agent:response', (data: any) => {
            io.emit('agent:message', { ...data, from: 'agent', timestamp: new Date().toISOString() });
        });

        socket.on('disconnect', () => {
            console.log(`  [Bridge] Client disconnected: ${socket.id}`);
            // Don't kill CLI session on disconnect -- it persists
        });
    });
}