yass/client/pipewire.js

const { exec } = require('child_process');
const util = require('util');
const execAsync = util.promisify(exec);

const VIRT_MIC_NAME = 'simplescreenshare-audio';

// Pipewire helper class to isolate application audio
class PipewireHelper {
    
    // Create a virtual microphone (a null-audio-sink) that Electron can listen to
    static async createVirtualMic() {
        try {
            await execAsync(`pw-cli destroy ${VIRT_MIC_NAME}`).catch(() => {}); // Cleanup old
            
            const cmd = `pw-cli create-node adapter '{ factory.name=support.null-audio-sink node.name=${VIRT_MIC_NAME} node.description="SimpleScreenshare Audio" media.class=Audio/Source/Virtual object.linger=1 audio.position=[FL,FR] }'`;
            const { stdout } = await execAsync(cmd);
            console.log("Created virtual mic:", stdout.trim());
            
            // Wait a moment for Pipewire to register it
            await new Promise(resolve => setTimeout(resolve, 500));
            return true;
        } catch (error) {
            console.error("Failed to create virtual mic:", error);
            return false;
        }
    }

    // Destroy the virtual microphone
    static async destroyVirtualMic() {
        try {
            // Find node ID
            const { stdout } = await execAsync(`pw-cli dump short Node`);
            const lines = stdout.split('\\n');
            for (const line of lines) {
                if (line.includes(VIRT_MIC_NAME)) {
                    const id = line.split(',')[0].trim();
                    await execAsync(`pw-cli destroy ${id}`);
                    console.log(`Destroyed virtual mic (ID: ${id})`);
                }
            }
        } catch (error) {
            console.error("Failed to destroy virtual mic:", error);
        }
    }

    // Get all running applications currently playing audio
    static async getAudioApplications() {
        try {
            // pw-dump outputs the entire graph as JSON, increase buffer!
            const { stdout } = await execAsync('pw-dump', { maxBuffer: 1024 * 1024 * 50 });
            const dump = JSON.parse(stdout);
            
            // Filter out audio output streams (applications playing sound)
            const apps = dump.filter(node => 
                node.info && 
                node.info.props && 
                node.info.props['media.class'] === 'Stream/Output/Audio' &&
                node.info.props['application.name']
            ).map(node => ({
                id: node.id,
                name: node.info.props['application.name'],
                mediaName: node.info.props['media.name'] || 'Unknown Stream'
            }));
            
            // Deduplicate by application name and return
            const uniqueApps = [];
            const seen = new Set();
            for (const app of apps) {
                if (!seen.has(app.name)) {
                    seen.add(app.name);
                    uniqueApps.push(app);
                }
            }
            return uniqueApps;
            
        } catch (error) {
            console.error("Failed to get audio applications:", error);
            return [];
        }
    }

    // Link a target application's output to our Virtual Microphone
    static async linkApplicationToMic(targetAppName) {
        try {
            // 1. Get the dump with massive buffer
            const { stdout: dumpOut } = await execAsync('pw-dump', { maxBuffer: 1024 * 1024 * 50 });
            const dump = JSON.parse(dumpOut);
            
            // 2. Find the target application node
            const targetNode = dump.find(node => 
                node.info && 
                node.info.props && 
                node.info.props['media.class'] === 'Stream/Output/Audio' &&
                node.info.props['application.name'] === targetAppName
            );
            
            // 3. Find our virtual mic node
            const micNode = dump.find(node => 
                node.info && 
                node.info.props && 
                node.info.props['node.name'] === VIRT_MIC_NAME
            );
            
            if (!targetNode || !micNode) {
                console.error("Could not find target node or virtual mic node");
                return false;
            }

            console.log(`Linking ${targetAppName} (ID: ${targetNode.id}) to ${VIRT_MIC_NAME} (ID: ${micNode.id})`);

            // 4. Find the Ports for both nodes
            const ports = dump.filter(n => n.type === 'PipeWire:Interface:Port');
            
            // Target App Output Ports
            const targetPorts = ports.filter(p => p.info.props['node.id'] === targetNode.id && p.info.direction === 'output');
            const targetFL = targetPorts.find(p => p.info.props['audio.channel'] === 'FL');
            const targetFR = targetPorts.find(p => p.info.props['audio.channel'] === 'FR');

            // Virtual Mic Input Ports
            const micPorts = ports.filter(p => p.info.props['node.id'] === micNode.id && p.info.direction === 'input');
            const micFL = micPorts.find(p => p.info.props['audio.channel'] === 'FL');
            const micFR = micPorts.find(p => p.info.props['audio.channel'] === 'FR');

            if (!targetFL || !targetFR || !micFL || !micFR) {
                console.error("Could not find stereo ports for linking");
                return false;
            }

            // 5. Link them using port aliases!
            const targetFlAlias = targetFL.info.props['port.alias'] || targetFL.info.props['object.path'] || targetFL.id;
            const targetFrAlias = targetFR.info.props['port.alias'] || targetFR.info.props['object.path'] || targetFR.id;
            const micFlAlias = micFL.info.props['port.alias'] || micFL.info.props['object.path'] || micFL.id;
            const micFrAlias = micFR.info.props['port.alias'] || micFR.info.props['object.path'] || micFR.id;

            await execAsync(`pw-link "${targetFlAlias}" "${micFlAlias}"`).catch(e => console.log("pw-link output:", e.message));
            await execAsync(`pw-link "${targetFrAlias}" "${micFrAlias}"`).catch(e => console.log("pw-link output:", e.message));
            
            console.log("Successfully linked audio.");
            return true;

        } catch (error) {
            console.error("Failed to link application:", error);
            return false;
        }
    }
}

module.exports = PipewireHelper;