quantrs2-device 0.1.3

//! Quantum DNS (Domain Name System)
//!
//! This module implements a quantum-enhanced DNS system that provides
//! quantum-aware name resolution, entanglement resource location,
//! and quantum service discovery.

use super::*;

/// Quantum DNS resolver
pub struct QuantumDNSResolver {
    config: QuantumDNSConfig,
    cache: Arc<RwLock<QuantumDNSCache>>,
    servers: Vec<QuantumDNSServer>,
    quantum_registry: Arc<RwLock<QuantumResourceRegistry>>,
    security_manager: Arc<RwLock<DNSSecurityManager>>,
}

/// Quantum DNS configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct QuantumDNSConfig {
    pub servers: Vec<String>,
    pub timeout: Duration,
    pub retries: u32,
    pub cache_size: usize,
    pub cache_ttl: Duration,
    pub quantum_extensions: bool,
    pub security_enabled: bool,
    pub entanglement_discovery: bool,
    pub quantum_service_discovery: bool,
}

/// Quantum DNS cache
#[derive(Debug, Clone)]
pub struct QuantumDNSCache {
    records: HashMap<String, QuantumDNSRecord>,
    quantum_resources: HashMap<String, QuantumResourceRecord>,
    last_cleanup: SystemTime,
    cache_size: usize,
    max_size: usize,
}

/// Quantum DNS record
#[derive(Debug, Clone)]
pub struct QuantumDNSRecord {
    pub name: String,
    pub record_type: QuantumDNSRecordType,
    pub data: QuantumDNSData,
    pub ttl: Duration,
    pub created_at: SystemTime,
    pub security_info: Option<DNSSecurityInfo>,
}

/// Quantum DNS record types
#[derive(Debug, Clone, PartialEq)]
pub enum QuantumDNSRecordType {
    A,      // IPv4 address
    AAAA,   // IPv6 address
    CNAME,  // Canonical name
    QA,     // Quantum Address
    QR,     // Quantum Resource
    QS,     // Quantum Service
    QE,     // Quantum Entanglement
    QN,     // Quantum Network
    QTXT,   // Quantum Text
    Custom(String),
}

/// Quantum DNS data
#[derive(Debug, Clone)]
pub enum QuantumDNSData {
    IPv4Address(String),
    IPv6Address(String),
    CanonicalName(String),
    QuantumAddress(QuantumAddress),
    QuantumResource(QuantumResourceInfo),
    QuantumService(QuantumServiceInfo),
    EntanglementEndpoint(EntanglementEndpointInfo),
    QuantumNetwork(QuantumNetworkInfo),
    Text(String),
    Custom(Vec<u8>),
}

/// Quantum address
#[derive(Debug, Clone)]
pub struct QuantumAddress {
    pub node_id: String,
    pub quantum_interfaces: Vec<QuantumInterface>,
    pub classical_interfaces: Vec<ClassicalInterface>,
    pub capabilities: Vec<String>,
    pub location: Option<NodePosition>,
}

/// Quantum interface
#[derive(Debug, Clone)]
pub struct QuantumInterface {
    pub interface_id: String,
    pub interface_type: String,
    pub bandwidth: f64,
    pub fidelity: f64,
    pub coherence_time: Duration,
    pub supported_protocols: Vec<String>,
}

/// Classical interface
#[derive(Debug, Clone)]
pub struct ClassicalInterface {
    pub interface_id: String,
    pub protocol: String,
    pub address: String,
    pub port: u16,
    pub bandwidth: f64,
}

/// Quantum resource information
#[derive(Debug, Clone)]
pub struct QuantumResourceInfo {
    pub resource_id: String,
    pub resource_type: QuantumResourceType,
    pub location: String,
    pub availability: ResourceAvailability,
    pub access_requirements: Vec<String>,
    pub performance_metrics: ResourceMetrics,
}

/// Quantum resource types
#[derive(Debug, Clone, PartialEq)]
pub enum QuantumResourceType {
    QuantumComputer,
    QuantumSimulator,
    EntanglementSource,
    QuantumMemory,
    QuantumRepeater,
    QuantumSensor,
    QuantumCryptographicKey,
    Custom(String),
}

/// Resource availability
#[derive(Debug, Clone)]
pub struct ResourceAvailability {
    pub status: ResourceStatus,
    pub capacity: usize,
    pub utilization: f64,
    pub queue_length: usize,
    pub estimated_wait_time: Duration,
}

/// Resource status
#[derive(Debug, Clone, PartialEq)]
pub enum ResourceStatus {
    Available,
    Busy,
    Maintenance,
    Offline,
    Reserved,
}

/// Resource metrics
#[derive(Debug, Clone)]
pub struct ResourceMetrics {
    pub throughput: f64,
    pub latency: Duration,
    pub error_rate: f64,
    pub uptime: f64,
    pub last_updated: SystemTime,
}

/// Quantum service information
#[derive(Debug, Clone)]
pub struct QuantumServiceInfo {
    pub service_id: String,
    pub service_type: QuantumServiceType,
    pub endpoint: String,
    pub port: u16,
    pub protocol: String,
    pub quantum_requirements: QuantumRequirements,
    pub service_level: ServiceLevel,
}

/// Quantum service types
#[derive(Debug, Clone, PartialEq)]
pub enum QuantumServiceType {
    QuantumKeyDistribution,
    QuantumTeleportation,
    QuantumComputing,
    QuantumSensing,
    QuantumCommunication,
    QuantumNetworking,
    EntanglementDistribution,
    Custom(String),
}

/// Quantum requirements for services
#[derive(Debug, Clone)]
pub struct QuantumRequirements {
    pub min_fidelity: f64,
    pub min_coherence_time: Duration,
    pub entanglement_required: bool,
    pub quantum_error_correction: bool,
    pub security_level: SecurityLevel,
}

/// Security levels
#[derive(Debug, Clone, PartialEq)]
pub enum SecurityLevel {
    None,
    Basic,
    Enhanced,
    Quantum,
    PostQuantum,
}

/// Service level information
#[derive(Debug, Clone)]
pub struct ServiceLevel {
    pub availability: f64,
    pub performance_guarantee: Option<PerformanceGuarantee>,
    pub support_level: SupportLevel,
    pub cost_model: CostModel,
}

/// Performance guarantee
#[derive(Debug, Clone)]
pub struct PerformanceGuarantee {
    pub max_latency: Duration,
    pub min_throughput: f64,
    pub max_error_rate: f64,
    pub availability_sla: f64,
}

/// Support levels
#[derive(Debug, Clone, PartialEq)]
pub enum SupportLevel {
    Basic,
    Standard,
    Premium,
    Enterprise,
}

/// Cost models
#[derive(Debug, Clone, PartialEq)]
pub enum CostModel {
    Free,
    PayPerUse,
    Subscription,
    Reserved,
    Custom(String),
}

/// Entanglement endpoint information
#[derive(Debug, Clone)]
pub struct EntanglementEndpointInfo {
    pub endpoint_id: String,
    pub node_id: String,
    pub generation_rate: f64,
    pub max_distance: f64,
    pub supported_protocols: Vec<String>,
    pub fidelity_range: (f64, f64),
    pub coherence_time_range: (Duration, Duration),
}

/// Quantum network information
#[derive(Debug, Clone)]
pub struct QuantumNetworkInfo {
    pub network_id: String,
    pub network_type: NetworkTopology,
    pub nodes: Vec<String>,
    pub coverage_area: Option<CoverageArea>,
    pub performance_characteristics: NetworkPerformance,
    pub access_policy: AccessPolicy,
}

/// Coverage area
#[derive(Debug, Clone)]
pub struct CoverageArea {
    pub geographical_bounds: GeographicalBounds,
    pub service_areas: Vec<ServiceArea>,
}

/// Geographical bounds
#[derive(Debug, Clone)]
pub struct GeographicalBounds {
    pub north: f64,
    pub south: f64,
    pub east: f64,
    pub west: f64,
}

/// Service area
#[derive(Debug, Clone)]
pub struct ServiceArea {
    pub area_id: String,
    pub center: (f64, f64),
    pub radius: f64,
    pub service_types: Vec<QuantumServiceType>,
}

/// Network performance characteristics
#[derive(Debug, Clone)]
pub struct NetworkPerformance {
    pub average_latency: Duration,
    pub throughput: f64,
    pub availability: f64,
    pub fidelity: f64,
    pub coherence_time: Duration,
}

/// Access policy
#[derive(Debug, Clone)]
pub struct AccessPolicy {
    pub policy_type: PolicyType,
    pub authentication_required: bool,
    pub authorized_entities: Vec<String>,
    pub restrictions: Vec<AccessRestriction>,
}

/// Policy types
#[derive(Debug, Clone, PartialEq)]
pub enum PolicyType {
    Open,
    Restricted,
    Private,
    Federated,
}

/// Access restrictions
#[derive(Debug, Clone)]
pub struct AccessRestriction {
    pub restriction_type: RestrictionType,
    pub value: String,
    pub description: String,
}

/// Restriction types
#[derive(Debug, Clone, PartialEq)]
pub enum RestrictionType {
    GeographicalRestriction,
    TimeRestriction,
    UsageQuota,
    SecurityClearance,
    OrganizationalMembership,
    Custom(String),
}

/// Quantum resource registry
#[derive(Debug, Clone)]
pub struct QuantumResourceRegistry {
    resources: HashMap<String, QuantumResourceRecord>,
    services: HashMap<String, QuantumServiceRecord>,
    entanglement_sources: HashMap<String, EntanglementSourceRecord>,
    last_update: SystemTime,
}

/// Quantum resource record
#[derive(Debug, Clone)]
pub struct QuantumResourceRecord {
    pub resource_id: String,
    pub resource_info: QuantumResourceInfo,
    pub registration_time: SystemTime,
    pub last_heartbeat: SystemTime,
    pub expiry_time: SystemTime,
}

/// Quantum service record
#[derive(Debug, Clone)]
pub struct QuantumServiceRecord {
    pub service_id: String,
    pub service_info: QuantumServiceInfo,
    pub registration_time: SystemTime,
    pub last_update: SystemTime,
    pub health_status: ServiceHealthStatus,
}

/// Service health status
#[derive(Debug, Clone, PartialEq)]
pub enum ServiceHealthStatus {
    Healthy,
    Degraded,
    Unhealthy,
    Unknown,
}

/// Entanglement source record
#[derive(Debug, Clone)]
pub struct EntanglementSourceRecord {
    pub source_id: String,
    pub endpoint_info: EntanglementEndpointInfo,
    pub current_load: f64,
    pub reservation_queue: Vec<EntanglementReservation>,
    pub performance_history: Vec<PerformanceSnapshot>,
}

/// Entanglement reservation
#[derive(Debug, Clone)]
pub struct EntanglementReservation {
    pub reservation_id: String,
    pub requester: String,
    pub start_time: SystemTime,
    pub duration: Duration,
    pub fidelity_requirement: f64,
    pub pair_count: usize,
}

/// Performance snapshot
#[derive(Debug, Clone)]
pub struct PerformanceSnapshot {
    pub timestamp: SystemTime,
    pub fidelity: f64,
    pub generation_rate: f64,
    pub error_rate: f64,
    pub uptime: f64,
}

/// DNS security manager
#[derive(Debug)]
pub struct DNSSecurityManager {
    security_config: DNSSecurityConfig,
    signature_verifier: SignatureVerifier,
    trust_anchors: Vec<TrustAnchor>,
}

/// DNS security configuration
#[derive(Debug, Clone)]
pub struct DNSSecurityConfig {
    pub dnssec_enabled: bool,
    pub quantum_signatures: bool,
    pub trust_chain_validation: bool,
    pub cache_poisoning_protection: bool,
}

/// DNS security information
#[derive(Debug, Clone)]
pub struct DNSSecurityInfo {
    pub signed: bool,
    pub signature_algorithm: String,
    pub signature: Vec<u8>,
    pub key_tag: u16,
    pub signer_name: String,
    pub signature_expiration: SystemTime,
}

/// Signature verifier
#[derive(Debug)]
pub struct SignatureVerifier {
    pub quantum_algorithms: Vec<String>,
    pub classical_algorithms: Vec<String>,
}

/// Trust anchor
#[derive(Debug, Clone)]
pub struct TrustAnchor {
    pub domain: String,
    pub key_tag: u16,
    pub algorithm: u8,
    pub digest_type: u8,
    pub digest: Vec<u8>,
}

/// Quantum DNS server
#[derive(Debug, Clone)]
pub struct QuantumDNSServer {
    pub address: String,
    pub port: u16,
    pub protocol: String,
    pub quantum_enabled: bool,
    pub security_level: SecurityLevel,
    pub capabilities: Vec<String>,
}

impl QuantumDNSResolver {
    /// Create a new quantum DNS resolver
    pub fn new(config: QuantumDNSConfig) -> Self {
        let cache = Arc::new(RwLock::new(QuantumDNSCache::new(config.cache_size)));
        let quantum_registry = Arc::new(RwLock::new(QuantumResourceRegistry::new()));
        let security_manager = Arc::new(RwLock::new(DNSSecurityManager::new()));

        let servers = config.servers.iter().map(|addr| {
            QuantumDNSServer {
                address: addr.clone(),
                port: 53,
                protocol: "UDP".to_string(),
                quantum_enabled: config.quantum_extensions,
                security_level: if config.security_enabled { SecurityLevel::Enhanced } else { SecurityLevel::Basic },
                capabilities: vec!["standard".to_string()],
            }
        }).collect();

        Self {
            config,
            cache,
            servers,
            quantum_registry,
            security_manager,
        }
    }

    /// Resolve a domain name
    pub async fn resolve(&self, name: &str, record_type: QuantumDNSRecordType) -> DeviceResult<Vec<QuantumDNSRecord>> {
        // Check cache first
        if let Some(record) = self.check_cache(name, &record_type).await {
            return Ok(vec![record]);
        }

        // Query DNS servers
        for server in &self.servers {
            match self.query_server(server, name, &record_type).await {
                Ok(records) => {
                    // Cache the results
                    for record in &records {
                        self.cache_record(record.clone()).await;
                    }
                    return Ok(records);
                }
                Err(_) => continue,
            }
        }

        Err(DeviceError::InvalidInput(format!("Failed to resolve {}", name)))
    }

    /// Resolve quantum resource
    pub async fn resolve_quantum_resource(&self, resource_type: QuantumResourceType, location: Option<&str>) -> DeviceResult<Vec<QuantumResourceInfo>> {
        let registry = self.quantum_registry.read().await;

        let mut matching_resources = Vec::new();
        for record in registry.resources.values() {
            if record.resource_info.resource_type == resource_type {
                if let Some(loc) = location {
                    if record.resource_info.location.contains(loc) {
                        matching_resources.push(record.resource_info.clone());
                    }
                } else {
                    matching_resources.push(record.resource_info.clone());
                }
            }
        }

        Ok(matching_resources)
    }

    /// Discover quantum services
    pub async fn discover_quantum_services(&self, service_type: QuantumServiceType, requirements: Option<QuantumRequirements>) -> DeviceResult<Vec<QuantumServiceInfo>> {
        let registry = self.quantum_registry.read().await;

        let mut matching_services = Vec::new();
        for record in registry.services.values() {
            if record.service_info.service_type == service_type {
                if let Some(req) = &requirements {
                    if self.meets_requirements(&record.service_info.quantum_requirements, req) {
                        matching_services.push(record.service_info.clone());
                    }
                } else {
                    matching_services.push(record.service_info.clone());
                }
            }
        }

        Ok(matching_services)
    }

    /// Find entanglement sources
    pub async fn find_entanglement_sources(&self, min_fidelity: f64, max_distance: Option<f64>) -> DeviceResult<Vec<EntanglementEndpointInfo>> {
        let registry = self.quantum_registry.read().await;

        let mut matching_sources = Vec::new();
        for record in registry.entanglement_sources.values() {
            if record.endpoint_info.fidelity_range.0 >= min_fidelity {
                if let Some(max_dist) = max_distance {
                    if record.endpoint_info.max_distance <= max_dist {
                        matching_sources.push(record.endpoint_info.clone());
                    }
                } else {
                    matching_sources.push(record.endpoint_info.clone());
                }
            }
        }

        Ok(matching_sources)
    }

    /// Register quantum resource
    pub async fn register_quantum_resource(&self, resource_info: QuantumResourceInfo, ttl: Duration) -> DeviceResult<()> {
        let mut registry = self.quantum_registry.write().await;

        let record = QuantumResourceRecord {
            resource_id: resource_info.resource_id.clone(),
            resource_info,
            registration_time: SystemTime::now(),
            last_heartbeat: SystemTime::now(),
            expiry_time: SystemTime::now() + ttl,
        };

        registry.resources.insert(record.resource_id.clone(), record);
        registry.last_update = SystemTime::now();

        Ok(())
    }

    /// Register quantum service
    pub async fn register_quantum_service(&self, service_info: QuantumServiceInfo, ttl: Duration) -> DeviceResult<()> {
        let mut registry = self.quantum_registry.write().await;

        let record = QuantumServiceRecord {
            service_id: service_info.service_id.clone(),
            service_info,
            registration_time: SystemTime::now(),
            last_update: SystemTime::now(),
            health_status: ServiceHealthStatus::Healthy,
        };

        registry.services.insert(record.service_id.clone(), record);
        registry.last_update = SystemTime::now();

        Ok(())
    }

    /// Update resource heartbeat
    pub async fn update_resource_heartbeat(&self, resource_id: &str) -> DeviceResult<()> {
        let mut registry = self.quantum_registry.write().await;

        if let Some(record) = registry.resources.get_mut(resource_id) {
            record.last_heartbeat = SystemTime::now();
        }

        Ok(())
    }

    /// Clean up expired entries
    pub async fn cleanup_expired_entries(&self) -> DeviceResult<()> {
        let now = SystemTime::now();

        // Clean up cache
        {
            let mut cache = self.cache.write().await;
            cache.records.retain(|_, record| {
                now.duration_since(record.created_at).unwrap_or(Duration::from_secs(0)) < record.ttl
            });
            cache.last_cleanup = now;
        }

        // Clean up registry
        {
            let mut registry = self.quantum_registry.write().await;
            registry.resources.retain(|_, record| record.expiry_time > now);
            registry.services.retain(|_, record| {
                // Services don't expire automatically, but can be marked unhealthy
                record.health_status != ServiceHealthStatus::Unhealthy
            });
        }

        Ok(())
    }

    // Helper methods
    async fn check_cache(&self, name: &str, record_type: &QuantumDNSRecordType) -> Option<QuantumDNSRecord> {
        let cache = self.cache.read().await;
        let key = format!("{}:{:?}", name, record_type);
        cache.records.get(&key).cloned()
    }

    async fn cache_record(&self, record: QuantumDNSRecord) {
        let mut cache = self.cache.write().await;
        let key = format!("{}:{:?}", record.name, record.record_type);
        cache.records.insert(key, record);
        cache.cache_size += 1;

        // Evict old entries if cache is full
        if cache.cache_size > cache.max_size {
            cache.evict_oldest();
        }
    }

    async fn query_server(&self, _server: &QuantumDNSServer, name: &str, record_type: &QuantumDNSRecordType) -> DeviceResult<Vec<QuantumDNSRecord>> {
        // Simulate DNS query
        let record = QuantumDNSRecord {
            name: name.to_string(),
            record_type: record_type.clone(),
            data: match record_type {
                QuantumDNSRecordType::A => QuantumDNSData::IPv4Address("127.0.0.1".to_string()),
                QuantumDNSRecordType::AAAA => QuantumDNSData::IPv6Address("::1".to_string()),
                QuantumDNSRecordType::QA => QuantumDNSData::QuantumAddress(QuantumAddress {
                    node_id: "node_1".to_string(),
                    quantum_interfaces: vec![],
                    classical_interfaces: vec![],
                    capabilities: vec!["quantum_computing".to_string()],
                    location: None,
                }),
                _ => QuantumDNSData::Text("example data".to_string()),
            },
            ttl: Duration::from_secs(3600),
            created_at: SystemTime::now(),
            security_info: None,
        };

        Ok(vec![record])
    }

    fn meets_requirements(&self, service_req: &QuantumRequirements, user_req: &QuantumRequirements) -> bool {
        service_req.min_fidelity >= user_req.min_fidelity &&
        service_req.min_coherence_time >= user_req.min_coherence_time &&
        (!user_req.entanglement_required || service_req.entanglement_required) &&
        (!user_req.quantum_error_correction || service_req.quantum_error_correction)
    }
}

impl QuantumDNSCache {
    fn new(max_size: usize) -> Self {
        Self {
            records: HashMap::new(),
            quantum_resources: HashMap::new(),
            last_cleanup: SystemTime::now(),
            cache_size: 0,
            max_size,
        }
    }

    fn evict_oldest(&mut self) {
        // Simple LRU eviction - remove oldest entry
        if let Some((oldest_key, _)) = self.records.iter()
            .min_by_key(|(_, record)| record.created_at) {
            let key_to_remove = oldest_key.clone();
            self.records.remove(&key_to_remove);
            self.cache_size -= 1;
        }
    }
}

impl QuantumResourceRegistry {
    fn new() -> Self {
        Self {
            resources: HashMap::new(),
            services: HashMap::new(),
            entanglement_sources: HashMap::new(),
            last_update: SystemTime::now(),
        }
    }
}

impl DNSSecurityManager {
    fn new() -> Self {
        Self {
            security_config: DNSSecurityConfig {
                dnssec_enabled: true,
                quantum_signatures: false,
                trust_chain_validation: true,
                cache_poisoning_protection: true,
            },
            signature_verifier: SignatureVerifier {
                quantum_algorithms: vec!["Dilithium".to_string(), "FALCON".to_string()],
                classical_algorithms: vec!["RSA".to_string(), "ECDSA".to_string()],
            },
            trust_anchors: vec![],
        }
    }
}

impl Default for QuantumDNSConfig {
    fn default() -> Self {
        Self {
            servers: vec!["8.8.8.8".to_string(), "1.1.1.1".to_string()],
            timeout: Duration::from_secs(5),
            retries: 3,
            cache_size: 1000,
            cache_ttl: Duration::from_secs(3600),
            quantum_extensions: true,
            security_enabled: true,
            entanglement_discovery: true,
            quantum_service_discovery: true,
        }
    }
}