synapse 1.1.0

//! Enhanced email transport with fast relay and discovery capabilities

#[cfg(feature = "email")]
mod email_enhanced_impl {
    use crate::transport::abstraction::{
        Transport, TransportMetrics, TransportType, TransportCapabilities, 
        TransportStatus, TransportTarget, TransportEstimate, IncomingMessage,
        MessageUrgency, DeliveryReceipt, ConnectivityResult, DeliveryConfirmation,
    };
    use crate::transport::{TransportRoute, HybridConnection, ConnectionOffer};
    use crate::{
        types::SecureMessage, 
        error::Result, 
        email::EmailTransport,
        circuit_breaker::{CircuitBreaker, CircuitBreakerConfig},
    };
    use crate::synapse::blockchain::serialization::{DateTimeWrapper, UuidWrapper};
    use uuid::Uuid;
    use chrono::Utc;
    use async_trait::async_trait;
    use dashmap::DashMap;
    use std::{time::{Duration, Instant}, sync::{Arc, RwLock}};
    use serde::{Serialize, Deserialize};
    use tracing::{info, debug};

    /// Fast email relay configuration
    #[derive(Debug, Clone, Serialize, Deserialize)]
    pub struct FastEmailRelay {
        pub server_id: String,
        pub smtp_endpoint: String,
        pub imap_endpoint: String,
        pub latency_target: Duration,
        pub supported_features: Vec<String>,
        pub access_credentials: RelayCredentials,
        pub priority_queue_enabled: bool,
        pub immediate_delivery: bool,
    }

    #[derive(Debug, Clone, Serialize, Deserialize)]
    pub struct RelayCredentials {
        pub username: String,
        pub password: String,
        pub auth_method: String,
    }

    /// Enhanced email transport supporting multiple modes with circuit breaker
    pub struct EmailEnhancedTransport {
        standard_transport: EmailTransport,
        fast_relays: DashMap<String, FastEmailRelay>,
        #[allow(dead_code)]
        connection_offers: DashMap<String, ConnectionOffer>,
        discovery_timeout: Duration,
        imap_idle_enabled: bool,
        /// Circuit breaker for reliability
        circuit_breaker: Arc<CircuitBreaker>,
        /// Performance metrics
        #[allow(dead_code)]
        metrics: Arc<RwLock<TransportMetrics>>,
    }

    impl EmailEnhancedTransport {
        pub async fn new(email_config: crate::types::EmailConfig) -> Result<Self> {
            let standard_transport = EmailTransport::new(email_config).await?;
            
            info!("Creating enhanced email transport with circuit breaker");
            
            Ok(Self {
                standard_transport,
                fast_relays: DashMap::new(),
                connection_offers: DashMap::new(),
                discovery_timeout: Duration::from_secs(30),
                imap_idle_enabled: false,
                circuit_breaker: Arc::new(CircuitBreaker::new(CircuitBreakerConfig::default())),
                metrics: Arc::new(RwLock::new(TransportMetrics::default())),
            })
        }
        
        /// Get circuit breaker reference for monitoring
        pub fn get_circuit_breaker(&self) -> Arc<CircuitBreaker> {
            Arc::clone(&self.circuit_breaker)
        }
        
        /// Get circuit breaker statistics
        pub fn get_circuit_breaker_stats(&self) -> crate::circuit_breaker::CircuitStats {
            self.circuit_breaker.get_stats()
        }
        
        /// Add a fast email relay server
        pub fn add_fast_relay(&mut self, relay: FastEmailRelay) {
            info!("Added fast email relay: {} (target: {:?})", 
                   relay.server_id, relay.latency_target);
            self.fast_relays.insert(relay.server_id.clone(), relay);
        }
        
        /// Enable IMAP IDLE for push notifications
        pub fn enable_imap_idle(&mut self) {
            self.imap_idle_enabled = true;
            info!("IMAP IDLE push notifications enabled");
        }
        
        /// Send connection offer via email for transport discovery
        pub async fn send_connection_offer(&self, target: &str, offer: ConnectionOffer) -> Result<String> {
            let offer_json = serde_json::to_string(&offer)?;
            
            // Create special Synapse discovery message
            let discovery_message = SecureMessage {
                message_id: UuidWrapper::new(Uuid::new_v4()),
                to_global_id: target.to_string(),
                from_global_id: offer.entity_id.clone(),
                encrypted_content: offer_json.into_bytes(),
                signature: vec![],
                timestamp: DateTimeWrapper::new(Utc::now()),
                security_level: crate::types::SecurityLevel::Public,
                routing_path: vec![],
                metadata: std::collections::HashMap::new(),
            };
            
            // Send via standard email with special headers
            let simple_message = crate::types::SimpleMessage {
                to: target.to_string(),
                from_entity: offer.entity_id.clone(),
                content: "Synapse Connection Discovery".to_string(),
                message_type: crate::types::MessageType::System,
                metadata: std::collections::HashMap::new(),
            };
            
            self.standard_transport.send_message(
                &discovery_message,
                &offer.entity_id,
                target,
                &simple_message,
            ).await?;
            
            info!("Sent connection offer to {} via email", target);
            Ok(discovery_message.message_id.0.to_string())
        }
        
        /// Wait for connection response from target
        pub async fn wait_for_connection_response(&mut self, target: &str, timeout: Duration) -> Result<ConnectionOffer> {
            let start = Instant::now();
            
            while start.elapsed() < timeout {
                // Check for new messages
                if let Ok(messages) = self.standard_transport.receive_messages().await {
                    for message in messages {
                        if message.from_entity == target {
                            // Try to parse as connection offer
                            if let Ok(offer) = serde_json::from_str::<ConnectionOffer>(&message.content) {
                                info!("Received connection response from {}", target);
                                return Ok(offer);
                            }
                        }
                    }
                }
                
                // Wait before checking again
                tokio::time::sleep(Duration::from_secs(1)).await;
            }
            
            Err(crate::error::SynapseError::TransportError(
                format!("Connection response timeout from {}", target)
            ))
        }
        
        /// Send message via fast email relay
        pub async fn send_via_fast_relay(&self, relay: &FastEmailRelay, _message: &SecureMessage) -> Result<Duration> {
            let start = Instant::now();
            
            info!("Sending message via fast relay: {}", relay.server_id);
            
            // In a real implementation, this would:
            // 1. Connect to the fast relay's SMTP server
            // 2. Send with priority headers
            // 3. Use connection pooling for efficiency
            // 4. Monitor for IMAP IDLE notifications
            
            // Simulate sending via optimized relay
            tokio::time::sleep(Duration::from_millis(500)).await;
            
            let elapsed = start.elapsed();
            info!("Message sent via fast relay in {:?}", elapsed);
            Ok(elapsed)
        }
        
        /// Check if a fast relay is available for the target
        pub fn get_fast_relay_for_target(&self, _target: &str) -> Option<FastEmailRelay> {
            // In a real implementation, this would check relay availability
            // For now, return the first available relay
            self.fast_relays.iter().next().map(|entry| entry.value().clone())
        }
        
        /// Send via standard email with latency measurement
        pub async fn send_via_standard_email(&self, target: &str, message: &SecureMessage) -> Result<Duration> {
            let start = Instant::now();
            
            // Create simple message for standard transport
            let simple_message = crate::types::SimpleMessage {
                to: target.to_string(),
                from_entity: message.from_global_id.clone(),
                content: String::from_utf8_lossy(&message.encrypted_content).to_string(),
                message_type: crate::types::MessageType::Direct,
                metadata: std::collections::HashMap::new(),
            };
            
            self.standard_transport.send_message(
                message,
                &message.from_global_id,
                target,
                &simple_message,
            ).await?;
            
            let elapsed = start.elapsed();
            info!("Message sent via standard email in {:?}", elapsed);
            Ok(elapsed)
        }
        
        /// Establish hybrid connection using email discovery
        pub async fn establish_hybrid_connection(&mut self, target: &str) -> Result<HybridConnection> {
            let discovery_start = Instant::now();
            
            // Phase 1: Send connection offer via email
            // In production, entity_id should come from a global configuration or identity system
            let _entity_id = "local_entity".to_string();
            
            let offer = ConnectionOffer {
                entity_id: target.to_string(),
                #[cfg(not(target_arch = "wasm32"))]
                tcp_endpoints: vec![],
                #[cfg(not(target_arch = "wasm32"))]
                udp_endpoints: vec![],
                #[cfg(not(target_arch = "wasm32"))]
                stun_servers: vec![],
                #[cfg(not(target_arch = "wasm32"))]
                turn_servers: vec![],
                capabilities: vec!["email".to_string(), "attachments".to_string()],
                public_key: "".to_string(),
                expires_at: chrono::Utc::now() + chrono::Duration::hours(1),
                priority: 128,
                #[cfg(target_arch = "wasm32")]
                websocket_endpoints: vec![],
                #[cfg(target_arch = "wasm32")]
                webrtc_endpoints: vec![],
            };
            
            self.send_connection_offer(target, offer).await?;
            
            // Phase 2: Wait for response
            let _response = self.wait_for_connection_response(target, self.discovery_timeout).await?;
            let _discovery_time = discovery_start.elapsed();
            
            // Phase 3: Attempt direct connection (simulated)
            let direct_start = Instant::now();
            tokio::time::sleep(Duration::from_millis(100)).await; // Simulate connection setup
            let direct_time = direct_start.elapsed();
            
            // Phase 4: Set up email fallback
            let _email_route = TransportRoute::StandardEmail { 
                estimated_latency_min: 60,
            };
            
            let _direct_route = TransportRoute::DirectTcp {
                address: target.to_string(),
                port: 8080,
                latency_ms: direct_time.as_millis() as u32,
                established_at: std::time::Instant::now(),
            };
            
            let _metrics = TransportMetrics {
                transport_type: TransportType::Email,
                messages_sent: 0,
                messages_received: 0,
                send_failures: 0,
                receive_failures: 0,
                bytes_sent: 0,
                bytes_received: 0,
                average_latency_ms: direct_time.as_millis() as u64,
                reliability_score: 0.90,
                active_connections: 1,
                last_updated_timestamp: std::time::SystemTime::now()
                    .duration_since(std::time::UNIX_EPOCH)
                    .unwrap()
                    .as_secs(),
                custom_metrics: std::collections::HashMap::new(),
            };
            
            Ok(HybridConnection {
                primary: TransportRoute::StandardEmail { estimated_latency_min: 60 },
                fallback: TransportRoute::StandardEmail { estimated_latency_min: 120 },
                discovery_latency: Duration::from_millis(100),
                connection_latency: Duration::from_millis(50),
                total_setup_time: Duration::from_millis(150),
                metrics: crate::transport::TransportMetrics {
                    latency: Duration::from_millis(50),
                    throughput_bps: 1_000_000, // 1 Mbps
                    packet_loss: 0.0,
                    jitter_ms: 10,
                    reliability_score: 0.95,
                    last_updated: std::time::Instant::now(),
                },
            })
        }
        
        /// Start IMAP IDLE for real-time message notifications
        pub async fn start_imap_idle(&self) -> Result<()> {
            if !self.imap_idle_enabled {
                return Err(crate::error::SynapseError::TransportError("IMAP IDLE not enabled".into()));
            }
            
            info!("Starting IMAP IDLE for push notifications");
            
            // In a real implementation, this would:
            // 1. Connect to IMAP server
            // 2. Enter IDLE mode
            // 3. Listen for EXISTS notifications
            // 4. Trigger immediate message retrieval
            
            loop {
                tokio::time::sleep(Duration::from_secs(30)).await;
                debug!("IMAP IDLE heartbeat");
                
                // Check for new messages
                if let Ok(messages) = self.standard_transport.receive_messages().await {
                    if !messages.is_empty() {
                        info!("IMAP IDLE: {} new messages received", messages.len());
                        
                        // Forward messages to the Synapse message processing system
                        for message in messages {
                            // In production, this would forward to a central message processor
                            // or emit an event for the router to handle
                            debug!("Processing incoming message from: {}", message.from_entity);
                            
                            // For now, we just log the message content
                            // A full implementation would:
                            // 1. Parse the message for Synapse protocol data
                            // 2. Validate signatures and decrypt if needed
                            // 3. Route to the appropriate handler
                            // 4. Send acknowledgment if required
                        }
                    }
                }
            }
        }
    }

    #[async_trait]
    impl Transport for EmailEnhancedTransport {
        fn transport_type(&self) -> TransportType {
            TransportType::Email
        }

        fn capabilities(&self) -> TransportCapabilities {
            TransportCapabilities {
                max_message_size: 25_000_000, // 25MB
                reliable: true,
                real_time: false,
                broadcast: false,
                bidirectional: true,
                encrypted: false,
                network_spanning: true,
                supported_urgencies: vec![
                    MessageUrgency::Background,
                    MessageUrgency::Batch,
                ],
                features: vec![
                    "store_and_forward".to_string(),
                    "attachments".to_string(),
                ],
            }
        }

        async fn start(&self) -> Result<()> {
            Ok(())
        }

        async fn stop(&self) -> Result<()> {
            Ok(())
        }

        async fn status(&self) -> TransportStatus {
            TransportStatus::Running
        }

        async fn metrics(&self) -> TransportMetrics {
            TransportMetrics::default()
        }

        async fn estimate_metrics(&self, _target: &TransportTarget) -> Result<TransportEstimate> {
            Ok(TransportEstimate {
                latency: Duration::from_millis(5000), // Typical email latency
                reliability: 0.99,
                bandwidth: 100_000, // 100KB/s
                cost: 1.0,
                available: true,
                confidence: 0.8,
            })
        }

        async fn send_message(&self, target: &TransportTarget, _message: &SecureMessage) -> Result<DeliveryReceipt> {
            let email = target.address.as_ref().ok_or_else(|| {
                crate::error::SynapseError::TransportError("Email address not specified".to_string())
            })?;
            
            // TODO: Implement actual email sending
            Ok(DeliveryReceipt {
                message_id: "email-msg-id".to_string(),
                transport_used: TransportType::Email,
                delivery_time: Duration::from_millis(100),
                target_reached: email.clone(),
                confirmation: DeliveryConfirmation::Sent,
                metadata: std::collections::HashMap::new(),
            })
        }

        async fn receive_messages(&self) -> Result<Vec<IncomingMessage>> {
            // TODO: Implement actual email receiving
            Ok(vec![])
        }

        async fn can_reach(&self, target: &TransportTarget) -> bool {
            target.address.as_ref().map_or(false, |addr| addr.contains('@'))
        }

        async fn test_connectivity(&self, target: &TransportTarget) -> Result<ConnectivityResult> {
            if !self.can_reach(target).await {
                return Ok(ConnectivityResult {
                    connected: false,
                    rtt: None,
                    error: Some("Invalid email address".to_string()),
                    quality: 0.0,
                    details: std::collections::HashMap::new(),
                });
            }

            Ok(ConnectivityResult {
                connected: true,
                rtt: Some(Duration::from_millis(100)),
                error: None,
                quality: 0.8,
                details: {
                    let mut details = std::collections::HashMap::new();
                    details.insert("transport".to_string(), "email".to_string());
                    details
                },
            })
        }
    }
} // end email_enhanced_impl module

#[cfg(feature = "email")]
pub use email_enhanced_impl::*;