//! Cluster management and node coordination
//!
//! This module handles node discovery, health monitoring, topology management,
//! and cluster metadata for the distributed computing framework.

use super::types::{default_instant, DistributedComputingConfig};
use crate::error::{CoreError, CoreResult};
#[cfg(feature = "serialization")]
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::net::SocketAddr;
use std::time::{Duration, Instant};

/// Cluster management system
#[derive(Debug)]
pub struct ClusterManager {
    /// Registered nodes
    nodes: HashMap<NodeId, ComputeNode>,
    /// Node discovery service
    #[allow(dead_code)]
    discovery_service: NodeDiscoveryService,
    /// Node health monitor
    #[allow(dead_code)]
    healthmonitor: NodeHealthMonitor,
    /// Cluster topology
    #[allow(dead_code)]
    topology: ClusterTopology,
    /// Cluster metadata
    #[allow(dead_code)]
    metadata: ClusterMetadata,
}

/// Unique identifier for compute nodes

#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone, Hash, PartialEq, Eq)]
pub struct NodeId(pub String);

/// Compute node representation
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct ComputeNode {
    /// Node identifier
    pub id: NodeId,
    /// Node address
    pub address: SocketAddr,
    /// Node capabilities
    pub capabilities: NodeCapabilities,
    /// Current status
    pub status: NodeStatus,
    /// Performance metrics
    pub performance: NodePerformanceMetrics,
    /// Resource usage
    pub resource_usage: NodeResourceUsage,
    /// Last heartbeat
    #[cfg_attr(feature = "serde", serde(skip, default = "std::time::Instant::now"))]
    pub last_heartbeat: Instant,
    /// Node metadata
    pub metadata: NodeMetadata,
}

impl Default for ComputeNode {
    fn default() -> Self {
        Self {
            id: NodeId("default-node".to_string()),
            address: "127.0.0.1:8080".parse().expect("Operation failed"),
            capabilities: NodeCapabilities::default(),
            status: NodeStatus::Initializing,
            performance: NodePerformanceMetrics::default(),
            resource_usage: NodeResourceUsage::default(),
            last_heartbeat: Instant::now(),
            metadata: NodeMetadata::default(),
        }
    }
}

/// Node capabilities
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct NodeCapabilities {
    /// CPU cores
    pub cpu_cores: u32,
    /// Memory (GB)
    pub memory_gb: f64,
    /// GPU devices
    pub gpu_devices: Vec<GpuDevice>,
    /// Storage (GB)
    pub storage_gb: f64,
    /// Network bandwidth (Gbps)
    pub networkbandwidth_gbps: f64,
    /// Supported compute types
    pub supported_compute_types: Vec<ComputeType>,
    /// Special hardware features
    pub special_features: Vec<String>,
    /// Operating system
    pub operating_system: String,
    /// Architecture
    pub architecture: String,
}

impl Default for NodeCapabilities {
    fn default() -> Self {
        Self {
            cpu_cores: 1,
            memory_gb: 1.0,
            gpu_devices: Vec::new(),
            storage_gb: 10.0,
            networkbandwidth_gbps: 1.0,
            supported_compute_types: vec![ComputeType::CPU],
            special_features: Vec::new(),
            operating_system: "Linux".to_string(),
            architecture: "x86_64".to_string(),
        }
    }
}

/// GPU device information
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct GpuDevice {
    /// Device name
    pub name: String,
    /// Memory (GB)
    pub memory_gb: f64,
    /// Compute capability
    pub compute_capability: String,
    /// CUDA cores / Stream processors
    pub compute_units: u32,
    /// Device type
    pub device_type: GpuType,
}

/// GPU device types
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub enum GpuType {
    CUDA,
    OpenCL,
    Metal,
    ROCm,
    Vulkan,
}

/// Supported compute types
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub enum ComputeType {
    CPU,
    GPU,
    TPU,
    FPGA,
    QuantumSimulation,
    EdgeComputing,
    HighMemory,
    HighThroughput,
}

/// Node status

#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone, PartialEq)]
pub enum NodeStatus {
    Initializing,
    Available,
    Busy,
    Overloaded,
    Maintenance,
    Failed,
    Disconnected,
}

/// Node performance metrics
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct NodePerformanceMetrics {
    /// Average task completion time
    pub avg_task_completion_time: Duration,
    /// Tasks completed per second
    pub tasks_per_second: f64,
    /// Success rate
    pub success_rate: f64,
    /// Error rate
    pub error_rate: f64,
    /// Communication latency
    pub communication_latency: Duration,
    /// Throughput (operations/sec)
    pub throughput: f64,
}

impl Default for NodePerformanceMetrics {
    fn default() -> Self {
        Self {
            avg_task_completion_time: Duration::from_secs(1),
            tasks_per_second: 1.0,
            success_rate: 1.0,
            error_rate: 0.0,
            communication_latency: Duration::from_millis(10),
            throughput: 1.0,
        }
    }
}

/// Node resource usage
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct NodeResourceUsage {
    /// CPU utilization (0.0..1.0)
    pub cpu_utilization: f64,
    /// Memory utilization (0.0..1.0)
    pub memory_utilization: f64,
    /// GPU utilization (0.0..1.0)
    pub gpu_utilization: Option<f64>,
    /// Storage utilization (0.0..1.0)
    pub storage_utilization: f64,
    /// Network utilization (0.0..1.0)
    pub network_utilization: f64,
    /// Power consumption (watts)
    pub power_consumption: Option<f64>,
}

impl Default for NodeResourceUsage {
    fn default() -> Self {
        Self {
            cpu_utilization: 0.0,
            memory_utilization: 0.0,
            gpu_utilization: None,
            storage_utilization: 0.0,
            network_utilization: 0.0,
            power_consumption: None,
        }
    }
}

/// Node metadata
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct NodeMetadata {
    /// Node name
    pub name: String,
    /// Node version
    pub version: String,
    /// Registration time
    #[cfg_attr(feature = "serde", serde(skip, default = "std::time::Instant::now"))]
    pub registered_at: Instant,
    /// Node tags
    pub tags: Vec<String>,
    /// Geographic location
    pub location: Option<GeographicLocation>,
    /// Security credentials
    pub credentials: SecurityCredentials,
}

impl Default for NodeMetadata {
    fn default() -> Self {
        Self {
            name: "unknown".to_string(),
            version: "0.1.0".to_string(),
            registered_at: Instant::now(),
            tags: Vec::new(),
            location: None,
            credentials: SecurityCredentials {
                public_key: Vec::new(),
                certificate: Vec::new(),
                auth_token: String::new(),
                permissions: Vec::new(),
            },
        }
    }
}

/// Geographic location
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct GeographicLocation {
    /// Latitude
    pub latitude: f64,
    /// Longitude
    pub longitude: f64,
    /// Region
    pub region: String,
    /// Data center
    pub datacenter: Option<String>,
}

/// Security credentials
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct SecurityCredentials {
    /// Public key
    pub public_key: Vec<u8>,
    /// Certificate
    pub certificate: Vec<u8>,
    /// Authentication token
    pub auth_token: String,
    /// Permissions
    pub permissions: Vec<String>,
}

/// Node discovery service
#[derive(Debug)]
pub struct NodeDiscoveryService {
    /// Discovery methods
    #[allow(dead_code)]
    discovery_methods: Vec<DiscoveryMethod>,
    /// Known nodes cache
    #[allow(dead_code)]
    known_nodes: HashMap<NodeId, DiscoveredNode>,
    /// Discovery statistics
    #[allow(dead_code)]
    discovery_stats: DiscoveryStatistics,
}

/// Discovery methods
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub enum DiscoveryMethod {
    Multicast,
    Broadcast,
    DHT,
    StaticList,
    CloudProvider,
    KubernetesAPI,
    Consul,
    Etcd,
}

/// Discovered node information
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct DiscoveredNode {
    /// Node information
    pub node: ComputeNode,
    /// Discovery method used
    pub discovered_via: DiscoveryMethod,
    /// Discovery timestamp
    #[cfg_attr(feature = "serde", serde(skip, default = "default_instant"))]
    pub discovered_at: Instant,
    /// Verification status
    pub verified: bool,
}

impl Default for DiscoveredNode {
    fn default() -> Self {
        Self {
            node: ComputeNode::default(),
            discovered_via: DiscoveryMethod::Multicast,
            discovered_at: Instant::now(),
            verified: false,
        }
    }
}

/// Discovery statistics
#[derive(Debug, Clone)]
pub struct DiscoveryStatistics {
    /// Total nodes discovered
    pub total_discovered: u64,
    /// Successful verifications
    pub successful_verifications: u64,
    /// Failed verifications
    pub failed_verifications: u64,
    /// Discovery latency
    pub avg_discovery_latency: Duration,
}

/// Node health monitoring
#[derive(Debug)]
pub struct NodeHealthMonitor {
    /// Health checks
    #[allow(dead_code)]
    health_checks: Vec<HealthCheck>,
    /// Health history
    #[allow(dead_code)]
    health_history: HashMap<NodeId, Vec<HealthRecord>>,
    /// Alert thresholds
    #[allow(dead_code)]
    alert_thresholds: HealthThresholds,
    /// Monitoring configuration
    #[allow(dead_code)]
    monitoringconfig: HealthMonitoringConfig,
}

/// Health check types
#[derive(Debug, Clone)]
pub enum HealthCheck {
    Heartbeat,
    ResourceUsage,
    TaskCompletion,
    NetworkLatency,
    ErrorRate,
    CustomMetric(String),
}

/// Health record
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct HealthRecord {
    /// Timestamp
    #[cfg_attr(feature = "serde", serde(skip, default = "default_instant"))]
    pub timestamp: Instant,
    /// Health score (0.0..1.0)
    pub health_score: f64,
    /// Specific metrics
    pub metrics: HashMap<String, f64>,
    /// Status
    pub status: NodeStatus,
}

impl Default for HealthRecord {
    fn default() -> Self {
        Self {
            timestamp: Instant::now(),
            health_score: 1.0,
            metrics: HashMap::new(),
            status: NodeStatus::Available,
        }
    }
}

/// Health alert thresholds
#[derive(Debug, Clone)]
pub struct HealthThresholds {
    /// CPU utilization threshold
    pub cpu_threshold: f64,
    /// Memory utilization threshold
    pub memory_threshold: f64,
    /// Error rate threshold
    pub error_rate_threshold: f64,
    /// Latency threshold (ms)
    pub latency_threshold_ms: u64,
    /// Health score threshold
    pub health_score_threshold: f64,
}

/// Health monitoring configuration
#[derive(Debug, Clone)]
pub struct HealthMonitoringConfig {
    /// Monitoring interval
    pub monitoring_interval: Duration,
    /// History retention
    pub history_retention: Duration,
    /// Enable predictive health analysis
    pub enable_predictive_analysis: bool,
    /// Alert destinations
    pub alert_destinations: Vec<String>,
}

/// Cluster topology
#[derive(Debug)]
pub struct ClusterTopology {
    /// Network topology type
    pub topology_type: TopologyType,
    /// Node connections
    pub connections: HashMap<NodeId, Vec<NodeConnection>>,
    /// Network segments
    pub segments: Vec<NetworkSegment>,
    /// Topology metrics
    pub metrics: TopologyMetrics,
}

/// Topology types
#[derive(Debug, Clone)]
pub enum TopologyType {
    FullyConnected,
    Star,
    Ring,
    Mesh,
    Hierarchical,
    Hybrid,
}

/// Node connection
#[derive(Debug, Clone)]
pub struct NodeConnection {
    /// Target node
    pub target_node: NodeId,
    /// Connection type
    pub connection_type: ConnectionType,
    /// Latency
    pub latency: Duration,
    /// Bandwidth
    pub bandwidth: f64,
    /// Connection quality
    pub quality: f64,
}

/// Connection types
#[derive(Debug, Clone)]
pub enum ConnectionType {
    Ethernet,
    InfiniBand,
    Wireless,
    Internet,
    HighSpeedInterconnect,
}

/// Network segment
#[derive(Debug, Clone)]
pub struct NetworkSegment {
    /// Segment identifier
    pub id: String,
    /// Nodes in segment
    pub nodes: Vec<NodeId>,
    /// Segment type
    pub segment_type: SegmentType,
    /// Bandwidth limit
    pub bandwidth_limit: Option<f64>,
}

/// Network segment types
#[derive(Debug, Clone)]
pub enum SegmentType {
    Local,
    Regional,
    Global,
    Edge,
    Cloud,
}

/// Topology metrics
#[derive(Debug, Clone)]
pub struct TopologyMetrics {
    /// Average latency
    pub avg_latency: Duration,
    /// Total bandwidth
    pub totalbandwidth: f64,
    /// Connectivity score
    pub connectivity_score: f64,
    /// Fault tolerance score
    pub fault_tolerance_score: f64,
}

/// Cluster metadata
#[derive(Debug, Clone)]
pub struct ClusterMetadata {
    /// Cluster name
    pub name: String,
    /// Cluster version
    pub version: String,
    /// Creation time
    pub created_at: Instant,
    /// Administrator
    pub administrator: String,
    /// Security policy
    pub security_policy: SecurityPolicy,
    /// Resource limits
    pub resource_limits: ResourceLimits,
}

/// Security policy
#[derive(Debug, Clone)]
pub struct SecurityPolicy {
    /// Encryption required
    pub encryption_required: bool,
    /// Authentication required
    pub authentication_required: bool,
    /// Authorization levels
    pub authorization_levels: Vec<String>,
    /// Audit logging
    pub auditlogging: bool,
}

/// Resource limits
#[derive(Debug, Clone)]
pub struct ResourceLimits {
    /// Maximum CPU cores
    pub max_cpu_cores: Option<u32>,
    /// Maximum memory (GB)
    pub max_memory_gb: Option<f64>,
    /// Maximum storage (GB)
    pub max_storage_gb: Option<f64>,
    /// Maximum nodes
    pub max_nodes: Option<usize>,
}

// Implementations
impl ClusterManager {
    pub fn new(config: &DistributedComputingConfig) -> CoreResult<Self> {
        Ok(Self {
            nodes: HashMap::new(),
            discovery_service: NodeDiscoveryService::new()?,
            healthmonitor: NodeHealthMonitor::new()?,
            topology: ClusterTopology::new()?,
            metadata: ClusterMetadata::default(),
        })
    }

    pub fn start(&mut self) -> CoreResult<()> {
        println!("🔍 Starting node discovery...");
        Ok(())
    }

    pub fn scale_nodes(&self, _targetnodes: usize) -> CoreResult<()> {
        println!("📈 Scaling cluster...");
        Ok(())
    }

    /// Scale cluster to target number of nodes
    pub fn scale_to(&self, targetnodes: usize) -> CoreResult<()> {
        self.scale_nodes(targetnodes)
    }

    pub fn get_availablenodes(
        &self,
    ) -> CoreResult<HashMap<NodeId, crate::distributed::cluster::NodeInfo>> {
        // Return available nodes from cluster
        let mut availablenodes = HashMap::new();
        for (nodeid, node) in &self.nodes {
            if node.status == NodeStatus::Available {
                // Convert ComputeNode to cluster::NodeInfo
                let nodeinfo = crate::distributed::cluster::NodeInfo {
                    id: node.id.0.clone(),
                    address: node.address,
                    node_type: crate::distributed::cluster::NodeType::Compute, // Default type
                    capabilities: crate::distributed::cluster::NodeCapabilities {
                        cpu_cores: node.capabilities.cpu_cores as usize,
                        memory_gb: node.capabilities.memory_gb as usize,
                        gpu_count: node.capabilities.gpu_devices.len(),
                        disk_space_gb: node.capabilities.storage_gb as usize,
                        networkbandwidth_gbps: node.capabilities.networkbandwidth_gbps,
                        specialized_units: Vec::new(),
                    },
                    status: crate::distributed::cluster::NodeStatus::Healthy, // Convert status
                    last_seen: node.last_heartbeat,
                    metadata: crate::distributed::cluster::NodeMetadata {
                        hostname: node.metadata.name.clone(),
                        operating_system: node.capabilities.operating_system.clone(),
                        kernel_version: "unknown".to_string(),
                        container_runtime: Some("none".to_string()),
                        labels: node
                            .metadata
                            .tags
                            .iter()
                            .enumerate()
                            .map(|(i, tag)| (format!("tag_{i}"), tag.clone()))
                            .collect(),
                    },
                };
                availablenodes.insert(nodeid.clone(), nodeinfo);
            }
        }
        Ok(availablenodes)
    }
}

impl NodeDiscoveryService {
    pub fn new() -> CoreResult<Self> {
        Ok(Self {
            discovery_methods: vec![DiscoveryMethod::Multicast, DiscoveryMethod::Broadcast],
            known_nodes: HashMap::new(),
            discovery_stats: DiscoveryStatistics {
                total_discovered: 0,
                successful_verifications: 0,
                failed_verifications: 0,
                avg_discovery_latency: Duration::from_millis(100),
            },
        })
    }
}

impl NodeHealthMonitor {
    pub fn new() -> CoreResult<Self> {
        Ok(Self {
            health_checks: vec![
                HealthCheck::Heartbeat,
                HealthCheck::ResourceUsage,
                HealthCheck::NetworkLatency,
            ],
            health_history: HashMap::new(),
            alert_thresholds: HealthThresholds {
                cpu_threshold: 0.9,
                memory_threshold: 0.9,
                error_rate_threshold: 0.05,
                latency_threshold_ms: 1000,
                health_score_threshold: 0.7,
            },
            monitoringconfig: HealthMonitoringConfig {
                monitoring_interval: Duration::from_secs(30),
                history_retention: Duration::from_secs(24 * 60 * 60),
                enable_predictive_analysis: true,
                alert_destinations: vec!["admin@cluster.local".to_string()],
            },
        })
    }
}

impl ClusterTopology {
    pub fn new() -> CoreResult<Self> {
        Ok(Self {
            topology_type: TopologyType::Mesh,
            connections: HashMap::new(),
            segments: vec![],
            metrics: TopologyMetrics {
                avg_latency: Duration::from_millis(50),
                totalbandwidth: 1000.0,
                connectivity_score: 0.95,
                fault_tolerance_score: 0.85,
            },
        })
    }
}

impl ClusterMetadata {
    fn default() -> Self {
        Self {
            name: "advanced-cluster".to_string(),
            version: "0.1.0".to_string(),
            created_at: Instant::now(),
            administrator: "system".to_string(),
            security_policy: SecurityPolicy {
                encryption_required: true,
                authentication_required: true,
                authorization_levels: vec![
                    "read".to_string(),
                    "write".to_string(),
                    "admin".to_string(),
                ],
                auditlogging: true,
            },
            resource_limits: ResourceLimits {
                max_cpu_cores: Some(1024),
                max_memory_gb: Some(2048.0),
                max_storage_gb: Some(10000.0),
                max_nodes: Some(256),
            },
        }
    }
}
