qssh 0.5.0

//! Quantum Harmony Validator with QSSH Integration
//!
//! This example demonstrates how Quantum Harmony validators use QSSH for:
//! 1. Validator-to-validator P2P communication
//! 2. Remote management access
//! 3. RPC endpoints for wallets (Drista)

use qssh::{client::QsshClient, server::QsshServer, Result};
use std::sync::Arc;
use tokio::sync::Mutex;

/// Represents a Quantum Harmony validator node
#[allow(dead_code)]
struct QuantumHarmonyValidator {
    /// Node identifier
    node_id: String,

    /// QSSH server for incoming connections
    qssh_server: Arc<Mutex<Option<QsshServer>>>,

    /// Connected peers (other validators)
    peers: Arc<Mutex<Vec<ValidatorPeer>>>,

    /// Current block height
    block_height: Arc<Mutex<u64>>,
}

/// A peer validator connected via QSSH
#[allow(dead_code)]
struct ValidatorPeer {
    node_id: String,
    qssh_client: QsshClient,
    last_seen_block: u64,
}

impl QuantumHarmonyValidator {
    /// Create a new validator node
    fn new(node_id: String) -> Self {
        Self {
            node_id,
            qssh_server: Arc::new(Mutex::new(None)),
            peers: Arc::new(Mutex::new(Vec::new())),
            block_height: Arc::new(Mutex::new(0)),
        }
    }

    /// Start the validator with QSSH transport
    async fn start(self: Arc<Self>, listen_addr: &str) -> Result<()> {
        println!("🚀 Starting Quantum Harmony Validator: {}", self.node_id);
        println!("📡 QSSH Transport Layer: Falcon-512 + SPHINCS+");

        // Start QSSH server for incoming connections
        self.start_qssh_server(listen_addr).await?;

        // Start P2P networking
        self.start_p2p_networking().await?;

        // Start RPC server for wallets
        self.start_rpc_server().await?;

        // Start block production/validation
        self.start_consensus().await?;

        Ok(())
    }

    /// Start QSSH server for incoming validator connections
    async fn start_qssh_server(&self, listen_addr: &str) -> Result<()> {
        println!("🔐 Starting QSSH server on {}", listen_addr);

        // In real implementation:
        // let config = QsshServerConfig {
        //     listen_addr: listen_addr.to_string(),
        //     falcon_key: generate_falcon_key(),
        //     sphincs_key: generate_sphincs_key(),
        //     enable_qkd: true,
        // };
        // let server = QsshServer::new(config).await?;

        println!("✅ QSSH server ready for validator connections");
        println!("   - Post-quantum authentication active");
        println!("   - QKD integration enabled");

        Ok(())
    }

    /// Connect to other validators using QSSH
    async fn start_p2p_networking(&self) -> Result<()> {
        println!("🔗 Establishing P2P connections via QSSH...");

        // Bootstrap nodes to connect to
        let bootstrap_nodes = vec![
            "validator1.quantum:42",
            "validator2.quantum:42",
            "validator3.quantum:42",
        ];

        for node in bootstrap_nodes {
            if let Err(e) = self.connect_to_peer(node).await {
                eprintln!("Failed to connect to {}: {}", node, e);
            }
        }

        Ok(())
    }

    /// Connect to a peer validator via QSSH
    async fn connect_to_peer(&self, peer_addr: &str) -> Result<()> {
        println!("  → Connecting to peer: {}", peer_addr);

        // In real implementation:
        // let client = QsshClient::connect(peer_addr, "validator").await?;
        //
        // // Exchange validator certificates (Falcon-512 signed)
        // let peer_cert = client.get_peer_certificate()?;
        // let peer_id = extract_node_id(peer_cert)?;
        //
        // // If QKD available, enhance with quantum keys
        // if let Some(qkd_key) = client.get_qkd_key().await? {
        //     println!("    ✨ QKD key established with {}", peer_id);
        // }

        println!("    ✅ QSSH connection established");
        println!("    📊 Syncing blockchain state...");

        Ok(())
    }

    /// Start RPC server over QSSH for wallet connections
    async fn start_rpc_server(&self) -> Result<()> {
        println!("💼 Starting RPC-over-QSSH for Drista wallet...");

        // This is where Drista wallet connects
        // Uses QSSH instead of HTTP/WebSocket for quantum safety

        println!("✅ RPC server ready on qssh://localhost:42/rpc");
        println!("   - Drista wallet can now connect securely");
        println!("   - All wallet operations are quantum-safe");

        Ok(())
    }

    /// Start consensus mechanism
    async fn start_consensus(self: Arc<Self>) -> Result<()> {
        println!("⚡ Starting quantum consensus...");

        // Consensus messages travel over QSSH connections
        tokio::spawn(async move {
            self.consensus_loop().await;
        });

        Ok(())
    }

    /// Main consensus loop
    async fn consensus_loop(&self) {
        loop {
            // Simulate block production
            tokio::time::sleep(tokio::time::Duration::from_secs(6)).await;

            let mut height = self.block_height.lock().await;
            *height += 1;

            println!("📦 Block {} produced and broadcast via QSSH", *height);

            // In real implementation:
            // - Create block with transactions
            // - Sign with Falcon-512
            // - Broadcast to peers via QSSH
            // - If QKD available, use quantum entropy for randomness
        }
    }
}

/// Example of how Drista wallet connects to validator
async fn drista_wallet_connection_example() -> Result<()> {
    println!("\n📱 Drista Wallet Connection Example:");
    println!("=====================================");

    // Wallet connects to validator using QSSH
    println!("1. Wallet initiates QSSH connection to validator");
    println!("   → Using Falcon-512 for key exchange");
    println!("   → SPHINCS+ for authentication");

    // In real implementation:
    // let wallet_client = QsshClient::connect("validator.quantum:42", "wallet").await?;

    println!("2. Establish quantum-safe channel");
    println!("   → All data encrypted with AES-256-GCM");
    println!("   → Forward secrecy via Double Ratchet");

    println!("3. Execute RPC calls over QSSH");
    println!("   → get_balance()");
    println!("   → send_transaction()");
    println!("   → subscribe_events()");

    println!("\n✅ Wallet has quantum-safe access to blockchain!");

    Ok(())
}

/// Demonstrate the complete integration
#[tokio::main]
async fn main() -> Result<()> {
    println!("╔══════════════════════════════════════════════════════╗");
    println!("║    Quantum Harmony + QSSH Integration Demo           ║");
    println!("║    Quantum-Safe Blockchain Infrastructure            ║");
    println!("╚══════════════════════════════════════════════════════╝\n");

    // Create validator node
    let validator = Arc::new(QuantumHarmonyValidator::new("validator-1".to_string()));

    // Start validator with QSSH transport
    validator.start("0.0.0.0:42").await?;

    // Demonstrate wallet connection
    tokio::time::sleep(tokio::time::Duration::from_secs(2)).await;
    drista_wallet_connection_example().await?;

    // Show the architecture
    println!("\n🏗️  Architecture Overview:");
    println!("========================");
    println!("┌─────────────────────────────────────────┐");
    println!("│         Drista Wallet (User)            │");
    println!("└────────────────┬────────────────────────┘");
    println!("                 │ QSSH (Port 42)");
    println!("                 │ Falcon-512 + SPHINCS+");
    println!("┌────────────────▼────────────────────────┐");
    println!("│      Quantum Harmony Validator          │");
    println!("│  - P2P via QSSH Transport               │");
    println!("│  - BB84 Quantum Key Exchange            │");
    println!("│  - QKD Hardware Integration             │");
    println!("└────────────────┬────────────────────────┘");
    println!("                 │ QSSH P2P");
    println!("┌────────────────▼────────────────────────┐");
    println!("│        Other Validators (P2P)           │");
    println!("└─────────────────────────────────────────┘");

    println!("\n🎯 Key Benefits:");
    println!("================");
    println!("1. All validator communication is quantum-safe");
    println!("2. Wallet connections are protected from quantum attacks");
    println!("3. Management access (SSH) uses post-quantum crypto");
    println!("4. Optional QKD integration for perfect forward secrecy");
    println!("5. Same operational model as traditional blockchain");

    println!("\n💡 Innovation:");
    println!("=============");
    println!("• First blockchain with native QSSH transport");
    println!("• Quantum-safe from network layer to application");
    println!("• Drop-in replacement for SSH in blockchain ops");
    println!("• Enables secure remote validator management");
    println!("• Future-proof against quantum computer attacks");

    // Keep running
    println!("\n✨ Validator running with quantum-safe transport...");
    println!("Press Ctrl+C to stop");

    // Simulate running validator
    loop {
        tokio::time::sleep(tokio::time::Duration::from_secs(60)).await;
    }
}