oxirs-star 0.2.4

//! External integration capabilities for RDF-star ecosystem integration.
//!
//! This module provides comprehensive integration with external systems including
//! SPARQL endpoints, federation protocols, monitoring systems, and plugin architecture.

use std::collections::HashMap;
use std::sync::{Arc, Mutex};
use std::time::{Duration, Instant};

use anyhow::{Context, Result};
use serde::{Deserialize, Serialize};
use tracing::{debug, error, info, warn};

use crate::model::{StarGraph, StarQuad, StarTerm, StarTriple};
use crate::parser::{StarFormat, StarParser};
use crate::profiling::{StarProfiler, ProfilingReport};
use crate::serializer::{SerializationOptions, StarSerializer};
use crate::{StarConfig, StarError, StarResult};

/// Configuration for external integrations
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct IntegrationConfig {
    /// SPARQL endpoint configurations
    pub endpoints: Vec<EndpointConfig>,
    /// Federation settings
    pub federation: FederationConfig,
    /// Monitoring configuration
    pub monitoring: MonitoringConfig,
    /// Plugin system configuration
    pub plugins: PluginConfig,
    /// Security settings
    pub security: SecurityConfig,
}

/// SPARQL endpoint configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct EndpointConfig {
    /// Endpoint name/identifier
    pub name: String,
    /// Base URL for the SPARQL endpoint
    pub url: String,
    /// Authentication configuration
    pub auth: Option<AuthConfig>,
    /// Request timeout in seconds
    pub timeout: u64,
    /// Connection pool size
    pub pool_size: usize,
    /// Supported RDF-star formats
    pub supported_formats: Vec<StarFormat>,
    /// Custom headers
    pub headers: HashMap<String, String>,
}

/// Authentication configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AuthConfig {
    /// Authentication type
    pub auth_type: AuthType,
    /// Username (for basic auth)
    pub username: Option<String>,
    /// Password (for basic auth)
    pub password: Option<String>,
    /// API key (for API key auth)
    pub api_key: Option<String>,
    /// OAuth token (for OAuth)
    pub oauth_token: Option<String>,
}

/// Authentication types
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum AuthType {
    None,
    Basic,
    Bearer,
    ApiKey,
    OAuth,
}

/// Federation configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct FederationConfig {
    /// Enable federation support
    pub enabled: bool,
    /// Maximum federation depth
    pub max_depth: usize,
    /// Query optimization strategy
    pub optimization: FederationOptimization,
    /// Source selection strategy
    pub source_selection: SourceSelectionStrategy,
    /// Result merging strategy
    pub result_merging: ResultMergingStrategy,
}

/// Federation optimization strategies
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum FederationOptimization {
    None,
    CostBased,
    HistoryBased,
    Adaptive,
}

/// Source selection strategies
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum SourceSelectionStrategy {
    All,
    Selective,
    CostBased,
    ReputationBased,
}

/// Result merging strategies
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum ResultMergingStrategy {
    Union,
    Intersection,
    Priority,
    Weighted,
}

/// Monitoring configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct MonitoringConfig {
    /// Enable metrics collection
    pub enabled: bool,
    /// Metrics export interval (seconds)
    pub export_interval: u64,
    /// Monitoring endpoints
    pub endpoints: Vec<MonitoringEndpoint>,
    /// Alert thresholds
    pub alerts: AlertConfig,
}

/// Monitoring endpoint configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct MonitoringEndpoint {
    /// Endpoint name
    pub name: String,
    /// Monitoring type
    pub endpoint_type: MonitoringType,
    /// Endpoint URL
    pub url: String,
    /// Export format
    pub format: MetricsFormat,
}

/// Monitoring system types
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum MonitoringType {
    Prometheus,
    InfluxDB,
    CloudWatch,
    Custom,
}

/// Metrics export formats
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum MetricsFormat {
    Prometheus,
    Json,
    Csv,
    Custom,
}

/// Alert configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AlertConfig {
    /// Performance degradation threshold (percentage)
    pub performance_threshold: f64,
    /// Error rate threshold (percentage)
    pub error_rate_threshold: f64,
    /// Memory usage threshold (MB)
    pub memory_threshold: u64,
    /// Alert notification endpoints
    pub notifications: Vec<NotificationConfig>,
}

/// Notification configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct NotificationConfig {
    /// Notification type
    pub notification_type: NotificationType,
    /// Target (email, webhook URL, etc.)
    pub target: String,
    /// Severity levels to notify about
    pub severity_levels: Vec<AlertSeverity>,
}

/// Notification types
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum NotificationType {
    Email,
    Webhook,
    Slack,
    Discord,
    Custom,
}

/// Alert severity levels
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum AlertSeverity {
    Info,
    Warning,
    Error,
    Critical,
}

/// Plugin system configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PluginConfig {
    /// Enable plugin system
    pub enabled: bool,
    /// Plugin directories
    pub plugin_dirs: Vec<String>,
    /// Enabled plugins
    pub enabled_plugins: Vec<String>,
    /// Plugin security settings
    pub security: PluginSecurityConfig,
}

/// Plugin security configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PluginSecurityConfig {
    /// Enable plugin sandboxing
    pub sandbox: bool,
    /// Resource limits for plugins
    pub resource_limits: ResourceLimits,
    /// Allowed plugin permissions
    pub permissions: Vec<PluginPermission>,
}

/// Resource limits for plugins
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ResourceLimits {
    /// Maximum memory usage (MB)
    pub max_memory: u64,
    /// Maximum CPU time (seconds)
    pub max_cpu_time: u64,
    /// Maximum network connections
    pub max_connections: usize,
}

/// Plugin permissions
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum PluginPermission {
    ReadData,
    WriteData,
    NetworkAccess,
    FileSystemAccess,
    ExecuteQueries,
}

/// Security configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SecurityConfig {
    /// Enable request validation
    pub validate_requests: bool,
    /// Maximum query complexity
    pub max_query_complexity: usize,
    /// Request rate limiting
    pub rate_limiting: RateLimitConfig,
    /// IP whitelist/blacklist
    pub ip_filtering: IpFilterConfig,
}

/// Rate limiting configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RateLimitConfig {
    /// Enable rate limiting
    pub enabled: bool,
    /// Requests per minute
    pub requests_per_minute: usize,
    /// Burst allowance
    pub burst_allowance: usize,
}

/// IP filtering configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct IpFilterConfig {
    /// Enable IP filtering
    pub enabled: bool,
    /// Whitelisted IP ranges
    pub whitelist: Vec<String>,
    /// Blacklisted IP ranges
    pub blacklist: Vec<String>,
}

/// External integration manager
pub struct IntegrationManager {
    config: IntegrationConfig,
    endpoints: HashMap<String, EndpointConnector>,
    federation_engine: FederationEngine,
    monitoring_system: MonitoringSystem,
    plugin_manager: PluginManager,
    profiler: Arc<Mutex<StarProfiler>>,
}

/// SPARQL endpoint connector
pub struct EndpointConnector {
    config: EndpointConfig,
    client: reqwest::Client,
    connection_pool: Arc<Mutex<ConnectionPool>>,
}

/// Connection pool for endpoint connections
pub struct ConnectionPool {
    max_size: usize,
    active_connections: usize,
    idle_connections: Vec<Connection>,
}

/// Individual connection
pub struct Connection {
    id: String,
    created_at: Instant,
    last_used: Instant,
}

/// Federation query engine
pub struct FederationEngine {
    config: FederationConfig,
    source_registry: SourceRegistry,
    query_planner: FederationQueryPlanner,
    result_merger: ResultMerger,
}

/// Source registry for federation
pub struct SourceRegistry {
    sources: HashMap<String, DataSource>,
    capabilities: HashMap<String, SourceCapabilities>,
}

/// Data source description
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DataSource {
    /// Source identifier
    pub id: String,
    /// Source type
    pub source_type: SourceType,
    /// Endpoint URL
    pub endpoint: String,
    /// Source reliability score
    pub reliability: f64,
    /// Average response time
    pub avg_response_time: Duration,
}

/// Source types
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum SourceType {
    SparqlEndpoint,
    RdfFile,
    Database,
    Api,
}

/// Source capabilities
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SourceCapabilities {
    /// Supported SPARQL features
    pub sparql_features: Vec<SparqlFeature>,
    /// Supported RDF-star features
    pub rdf_star_features: Vec<RdfStarFeature>,
    /// Performance characteristics
    pub performance: PerformanceCharacteristics,
}

/// SPARQL features
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum SparqlFeature {
    Select,
    Construct,
    Ask,
    Describe,
    Update,
    PropertyPaths,
    Aggregates,
    Subqueries,
}

/// RDF-star features
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum RdfStarFeature {
    QuotedTriples,
    NestedAnnotations,
    SparqlStarFunctions,
    AnnotationSyntax,
}

/// Performance characteristics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PerformanceCharacteristics {
    /// Average query time (milliseconds)
    pub avg_query_time: u64,
    /// Maximum concurrent queries
    pub max_concurrent_queries: usize,
    /// Data freshness (seconds)
    pub data_freshness: u64,
}

/// Federation query planner
pub struct FederationQueryPlanner {
    optimization_strategy: FederationOptimization,
    cost_model: CostModel,
    statistics: QueryStatistics,
}

/// Cost model for federation
pub struct CostModel {
    network_cost_factor: f64,
    processing_cost_factor: f64,
    data_transfer_cost_factor: f64,
}

/// Query statistics
pub struct QueryStatistics {
    execution_history: Vec<QueryExecution>,
    performance_metrics: HashMap<String, f64>,
}

/// Query execution record
#[derive(Debug, Clone)]
pub struct QueryExecution {
    query_hash: String,
    sources: Vec<String>,
    execution_time: Duration,
    result_size: usize,
    success: bool,
}

/// Result merger for federation
pub struct ResultMerger {
    strategy: ResultMergingStrategy,
    deduplication_enabled: bool,
}

/// Monitoring system
pub struct MonitoringSystem {
    config: MonitoringConfig,
    metrics_collector: MetricsCollector,
    alert_manager: AlertManager,
    exporters: Vec<MetricsExporter>,
}

/// Metrics collector
pub struct MetricsCollector {
    metrics: Arc<Mutex<SystemMetrics>>,
    collection_interval: Duration,
}

/// System metrics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SystemMetrics {
    /// Query metrics
    pub queries: QueryMetrics,
    /// Performance metrics
    pub performance: PerformanceMetrics,
    /// Resource metrics
    pub resources: ResourceMetrics,
    /// Error metrics
    pub errors: ErrorMetrics,
}

/// Query-related metrics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct QueryMetrics {
    /// Total queries executed
    pub total_queries: u64,
    /// Successful queries
    pub successful_queries: u64,
    /// Failed queries
    pub failed_queries: u64,
    /// Average query time
    pub avg_query_time: f64,
    /// Queries per second
    pub queries_per_second: f64,
}

/// Performance metrics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PerformanceMetrics {
    /// CPU usage percentage
    pub cpu_usage: f64,
    /// Memory usage (MB)
    pub memory_usage: u64,
    /// Network I/O (bytes/sec)
    pub network_io: u64,
    /// Disk I/O (bytes/sec)
    pub disk_io: u64,
}

/// Resource metrics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ResourceMetrics {
    /// Active connections
    pub active_connections: usize,
    /// Thread pool utilization
    pub thread_utilization: f64,
    /// Cache hit rate
    pub cache_hit_rate: f64,
    /// Queue depth
    pub queue_depth: usize,
}

/// Error metrics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ErrorMetrics {
    /// Total errors
    pub total_errors: u64,
    /// Error rate (errors/minute)
    pub error_rate: f64,
    /// Errors by type
    pub errors_by_type: HashMap<String, u64>,
    /// Critical errors
    pub critical_errors: u64,
}

/// Alert manager
pub struct AlertManager {
    config: AlertConfig,
    active_alerts: HashMap<String, Alert>,
    notification_channels: Vec<NotificationChannel>,
}

/// Alert definition
#[derive(Debug, Clone)]
pub struct Alert {
    id: String,
    severity: AlertSeverity,
    message: String,
    triggered_at: Instant,
    resolved_at: Option<Instant>,
    metadata: HashMap<String, String>,
}

/// Notification channel
pub trait NotificationChannel: Send + Sync {
    fn send_notification(&self, alert: &Alert) -> Result<()>;
    fn get_type(&self) -> NotificationType;
}

/// Metrics exporter
pub trait MetricsExporter: Send + Sync {
    fn export_metrics(&self, metrics: &SystemMetrics) -> Result<()>;
    fn get_format(&self) -> MetricsFormat;
}

/// Plugin manager
pub struct PluginManager {
    config: PluginConfig,
    loaded_plugins: HashMap<String, Box<dyn Plugin>>,
    plugin_registry: PluginRegistry,
}

/// Plugin registry
pub struct PluginRegistry {
    available_plugins: HashMap<String, PluginInfo>,
    plugin_dependencies: HashMap<String, Vec<String>>,
}

/// Plugin information
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PluginInfo {
    /// Plugin name
    pub name: String,
    /// Plugin version
    pub version: String,
    /// Plugin description
    pub description: String,
    /// Plugin author
    pub author: String,
    /// Required permissions
    pub permissions: Vec<PluginPermission>,
    /// Plugin dependencies
    pub dependencies: Vec<String>,
}

/// Plugin trait
pub trait Plugin: Send + Sync {
    fn name(&self) -> &str;
    fn version(&self) -> &str;
    fn initialize(&mut self, config: &HashMap<String, String>) -> Result<()>;
    fn execute(&self, input: &PluginInput) -> Result<PluginOutput>;
    fn shutdown(&mut self) -> Result<()>;
}

/// Plugin input
#[derive(Debug, Clone)]
pub struct PluginInput {
    pub operation: String,
    pub data: Vec<u8>,
    pub metadata: HashMap<String, String>,
}

/// Plugin output
#[derive(Debug, Clone)]
pub struct PluginOutput {
    pub data: Vec<u8>,
    pub metadata: HashMap<String, String>,
    pub success: bool,
}

impl Default for IntegrationConfig {
    fn default() -> Self {
        Self {
            endpoints: Vec::new(),
            federation: FederationConfig {
                enabled: false,
                max_depth: 3,
                optimization: FederationOptimization::CostBased,
                source_selection: SourceSelectionStrategy::Selective,
                result_merging: ResultMergingStrategy::Union,
            },
            monitoring: MonitoringConfig {
                enabled: true,
                export_interval: 60,
                endpoints: Vec::new(),
                alerts: AlertConfig {
                    performance_threshold: 50.0,
                    error_rate_threshold: 5.0,
                    memory_threshold: 1024,
                    notifications: Vec::new(),
                },
            },
            plugins: PluginConfig {
                enabled: false,
                plugin_dirs: vec!["./plugins".to_string()],
                enabled_plugins: Vec::new(),
                security: PluginSecurityConfig {
                    sandbox: true,
                    resource_limits: ResourceLimits {
                        max_memory: 512,
                        max_cpu_time: 30,
                        max_connections: 10,
                    },
                    permissions: Vec::new(),
                },
            },
            security: SecurityConfig {
                validate_requests: true,
                max_query_complexity: 1000,
                rate_limiting: RateLimitConfig {
                    enabled: true,
                    requests_per_minute: 100,
                    burst_allowance: 20,
                },
                ip_filtering: IpFilterConfig {
                    enabled: false,
                    whitelist: Vec::new(),
                    blacklist: Vec::new(),
                },
            },
        }
    }
}

impl IntegrationManager {
    /// Create a new integration manager
    pub fn new(config: IntegrationConfig) -> Self {
        Self {
            endpoints: HashMap::new(),
            federation_engine: FederationEngine::new(config.federation.clone()),
            monitoring_system: MonitoringSystem::new(config.monitoring.clone()),
            plugin_manager: PluginManager::new(config.plugins.clone()),
            profiler: Arc::new(Mutex::new(StarProfiler::new())),
            config,
        }
    }

    /// Initialize all integrations
    pub async fn initialize(&mut self) -> Result<()> {
        info!("Initializing integration manager");

        // Initialize SPARQL endpoints
        for endpoint_config in &self.config.endpoints {
            let connector = EndpointConnector::new(endpoint_config.clone()).await?;
            self.endpoints.insert(endpoint_config.name.clone(), connector);
        }

        // Initialize federation engine
        if self.config.federation.enabled {
            self.federation_engine.initialize().await?;
        }

        // Initialize monitoring system
        if self.config.monitoring.enabled {
            self.monitoring_system.initialize().await?;
        }

        // Initialize plugin manager
        if self.config.plugins.enabled {
            self.plugin_manager.initialize().await?;
        }

        info!("Integration manager initialized successfully");
        Ok(())
    }

    /// Execute a federated SPARQL query
    pub async fn execute_federated_query(&self, query: &str) -> Result<StarGraph> {
        if !self.config.federation.enabled {
            return Err(anyhow::anyhow!("Federation is not enabled"));
        }

        let start_time = Instant::now();

        // Profile the operation
        if let Ok(mut profiler) = self.profiler.lock() {
            profiler.start_operation("federated_query");
        }

        let result = self.federation_engine.execute_query(query).await;

        // End profiling
        if let Ok(mut profiler) = self.profiler.lock() {
            let mut metadata = HashMap::new();
            metadata.insert("query_length".to_string(), query.len().to_string());
            metadata.insert("execution_time".to_string(), start_time.elapsed().as_millis().to_string());
            profiler.end_operation_with_metadata(metadata);
        }

        result
    }

    /// Query a specific SPARQL endpoint
    pub async fn query_endpoint(&self, endpoint_name: &str, query: &str) -> Result<StarGraph> {
        let connector = self.endpoints.get(endpoint_name)
            .ok_or_else(|| anyhow::anyhow!("Endpoint '{}' not found", endpoint_name))?;

        connector.execute_query(query).await
    }

    /// Get current system metrics
    pub async fn get_metrics(&self) -> Result<SystemMetrics> {
        self.monitoring_system.get_current_metrics().await
    }

    /// Get profiling report
    pub fn get_profiling_report(&self) -> Result<ProfilingReport> {
        if let Ok(profiler) = self.profiler.lock() {
            Ok(profiler.generate_report())
        } else {
            Err(anyhow::anyhow!("Failed to access profiler"))
        }
    }

    /// Load a plugin
    pub async fn load_plugin(&mut self, plugin_name: &str) -> Result<()> {
        self.plugin_manager.load_plugin(plugin_name).await
    }

    /// Execute a plugin operation
    pub async fn execute_plugin(&self, plugin_name: &str, input: PluginInput) -> Result<PluginOutput> {
        self.plugin_manager.execute_plugin(plugin_name, input).await
    }

    /// Register a new data source for federation
    pub async fn register_data_source(&mut self, source: DataSource) -> Result<()> {
        self.federation_engine.register_source(source).await
    }

    /// Add monitoring endpoint
    pub async fn add_monitoring_endpoint(&mut self, endpoint: MonitoringEndpoint) -> Result<()> {
        self.monitoring_system.add_endpoint(endpoint).await
    }

    /// Shutdown the integration manager
    pub async fn shutdown(&mut self) -> Result<()> {
        info!("Shutting down integration manager");

        // Shutdown plugin manager
        self.plugin_manager.shutdown().await?;

        // Shutdown monitoring system
        self.monitoring_system.shutdown().await?;

        // Shutdown federation engine
        self.federation_engine.shutdown().await?;

        // Close endpoint connections
        for connector in self.endpoints.values() {
            connector.close().await?;
        }

        info!("Integration manager shutdown complete");
        Ok(())
    }
}

// Implementation stubs for the various components
// In a full implementation, these would contain complete logic

impl EndpointConnector {
    pub async fn new(config: EndpointConfig) -> Result<Self> {
        let client = reqwest::Client::builder()
            .timeout(Duration::from_secs(config.timeout))
            .build()?;

        let connection_pool = Arc::new(Mutex::new(ConnectionPool {
            max_size: config.pool_size,
            active_connections: 0,
            idle_connections: Vec::new(),
        }));

        Ok(Self {
            config,
            client,
            connection_pool,
        })
    }

    pub async fn execute_query(&self, query: &str) -> Result<StarGraph> {
        // Implementation would execute SPARQL query against endpoint
        // and parse results into StarGraph
        debug!("Executing query against endpoint: {}", self.config.name);
        Ok(StarGraph::new())
    }

    pub async fn close(&self) -> Result<()> {
        debug!("Closing connections for endpoint: {}", self.config.name);
        Ok(())
    }
}

impl FederationEngine {
    pub fn new(config: FederationConfig) -> Self {
        Self {
            config,
            source_registry: SourceRegistry {
                sources: HashMap::new(),
                capabilities: HashMap::new(),
            },
            query_planner: FederationQueryPlanner {
                optimization_strategy: config.optimization.clone(),
                cost_model: CostModel {
                    network_cost_factor: 1.0,
                    processing_cost_factor: 1.0,
                    data_transfer_cost_factor: 1.0,
                },
                statistics: QueryStatistics {
                    execution_history: Vec::new(),
                    performance_metrics: HashMap::new(),
                },
            },
            result_merger: ResultMerger {
                strategy: config.result_merging.clone(),
                deduplication_enabled: true,
            },
        }
    }

    pub async fn initialize(&mut self) -> Result<()> {
        debug!("Initializing federation engine");
        Ok(())
    }

    pub async fn execute_query(&self, query: &str) -> Result<StarGraph> {
        debug!("Executing federated query");
        // Implementation would:
        // 1. Parse the query
        // 2. Determine relevant sources
        // 3. Decompose query into sub-queries
        // 4. Execute sub-queries
        // 5. Merge results
        Ok(StarGraph::new())
    }

    pub async fn register_source(&mut self, source: DataSource) -> Result<()> {
        debug!("Registering data source: {}", source.id);
        self.source_registry.sources.insert(source.id.clone(), source);
        Ok(())
    }

    pub async fn shutdown(&mut self) -> Result<()> {
        debug!("Shutting down federation engine");
        Ok(())
    }
}

impl MonitoringSystem {
    pub fn new(config: MonitoringConfig) -> Self {
        Self {
            config,
            metrics_collector: MetricsCollector {
                metrics: Arc::new(Mutex::new(SystemMetrics {
                    queries: QueryMetrics {
                        total_queries: 0,
                        successful_queries: 0,
                        failed_queries: 0,
                        avg_query_time: 0.0,
                        queries_per_second: 0.0,
                    },
                    performance: PerformanceMetrics {
                        cpu_usage: 0.0,
                        memory_usage: 0,
                        network_io: 0,
                        disk_io: 0,
                    },
                    resources: ResourceMetrics {
                        active_connections: 0,
                        thread_utilization: 0.0,
                        cache_hit_rate: 0.0,
                        queue_depth: 0,
                    },
                    errors: ErrorMetrics {
                        total_errors: 0,
                        error_rate: 0.0,
                        errors_by_type: HashMap::new(),
                        critical_errors: 0,
                    },
                })),
                collection_interval: Duration::from_secs(config.export_interval),
            },
            alert_manager: AlertManager {
                config: config.alerts.clone(),
                active_alerts: HashMap::new(),
                notification_channels: Vec::new(),
            },
            exporters: Vec::new(),
        }
    }

    pub async fn initialize(&mut self) -> Result<()> {
        debug!("Initializing monitoring system");
        Ok(())
    }

    pub async fn get_current_metrics(&self) -> Result<SystemMetrics> {
        if let Ok(metrics) = self.metrics_collector.metrics.lock() {
            Ok(metrics.clone())
        } else {
            Err(anyhow::anyhow!("Failed to access metrics"))
        }
    }

    pub async fn add_endpoint(&mut self, endpoint: MonitoringEndpoint) -> Result<()> {
        debug!("Adding monitoring endpoint: {}", endpoint.name);
        Ok(())
    }

    pub async fn shutdown(&mut self) -> Result<()> {
        debug!("Shutting down monitoring system");
        Ok(())
    }
}

impl PluginManager {
    pub fn new(config: PluginConfig) -> Self {
        Self {
            config,
            loaded_plugins: HashMap::new(),
            plugin_registry: PluginRegistry {
                available_plugins: HashMap::new(),
                plugin_dependencies: HashMap::new(),
            },
        }
    }

    pub async fn initialize(&mut self) -> Result<()> {
        debug!("Initializing plugin manager");
        Ok(())
    }

    pub async fn load_plugin(&mut self, plugin_name: &str) -> Result<()> {
        debug!("Loading plugin: {}", plugin_name);
        Ok(())
    }

    pub async fn execute_plugin(&self, plugin_name: &str, input: PluginInput) -> Result<PluginOutput> {
        debug!("Executing plugin: {}", plugin_name);
        Ok(PluginOutput {
            data: Vec::new(),
            metadata: HashMap::new(),
            success: true,
        })
    }

    pub async fn shutdown(&mut self) -> Result<()> {
        debug!("Shutting down plugin manager");
        for plugin in self.loaded_plugins.values_mut() {
            plugin.shutdown()?;
        }
        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[tokio::test]
    async fn test_integration_manager_creation() {
        let config = IntegrationConfig::default();
        let manager = IntegrationManager::new(config);
        assert_eq!(manager.endpoints.len(), 0);
    }

    #[tokio::test]
    async fn test_endpoint_connector_creation() {
        let config = EndpointConfig {
            name: "test".to_string(),
            url: "http://localhost:3030/test".to_string(),
            auth: None,
            timeout: 30,
            pool_size: 10,
            supported_formats: vec![StarFormat::TurtleStar],
            headers: HashMap::new(),
        };

        let connector = EndpointConnector::new(config).await;
        assert!(connector.is_ok());
    }

    #[test]
    fn test_federation_engine_creation() {
        let config = FederationConfig {
            enabled: true,
            max_depth: 3,
            optimization: FederationOptimization::CostBased,
            source_selection: SourceSelectionStrategy::Selective,
            result_merging: ResultMergingStrategy::Union,
        };

        let engine = FederationEngine::new(config);
        assert_eq!(engine.source_registry.sources.len(), 0);
    }
}