ruvector-graph 2.0.6

//! gRPC-based inter-node communication for distributed graph queries
//!
//! Provides high-performance RPC communication layer:
//! - Query execution RPC
//! - Data replication RPC
//! - Cluster coordination RPC
//! - Streaming results for large queries

use crate::distributed::coordinator::{QueryPlan, QueryResult};
use crate::distributed::shard::{EdgeData, NodeData, NodeId, ShardId};
use crate::{GraphError, Result};
use serde::{Deserialize, Serialize};
use std::sync::Arc;
use tokio::sync::RwLock;
#[cfg(feature = "federation")]
use tonic::{Request, Response, Status};

#[cfg(not(feature = "federation"))]
pub struct Status;
use tracing::{debug, info, warn};

/// RPC request for executing a query
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ExecuteQueryRequest {
    /// Query to execute (Cypher syntax)
    pub query: String,
    /// Optional parameters
    pub parameters: std::collections::HashMap<String, serde_json::Value>,
    /// Transaction ID (if part of a transaction)
    pub transaction_id: Option<String>,
}

/// RPC response for query execution
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ExecuteQueryResponse {
    /// Query result
    pub result: QueryResult,
    /// Success indicator
    pub success: bool,
    /// Error message if failed
    pub error: Option<String>,
}

/// RPC request for replicating data
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ReplicateDataRequest {
    /// Shard ID to replicate to
    pub shard_id: ShardId,
    /// Operation type
    pub operation: ReplicationOperation,
}

/// Replication operation types
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum ReplicationOperation {
    AddNode(NodeData),
    AddEdge(EdgeData),
    DeleteNode(NodeId),
    DeleteEdge(String),
    UpdateNode(NodeData),
    UpdateEdge(EdgeData),
}

/// RPC response for replication
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ReplicateDataResponse {
    /// Success indicator
    pub success: bool,
    /// Error message if failed
    pub error: Option<String>,
}

/// RPC request for health check
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct HealthCheckRequest {
    /// Node ID performing the check
    pub node_id: String,
}

/// RPC response for health check
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct HealthCheckResponse {
    /// Node is healthy
    pub healthy: bool,
    /// Current load (0.0 - 1.0)
    pub load: f64,
    /// Number of active queries
    pub active_queries: usize,
    /// Uptime in seconds
    pub uptime_seconds: u64,
}

/// RPC request for shard info
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct GetShardInfoRequest {
    /// Shard ID
    pub shard_id: ShardId,
}

/// RPC response for shard info
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct GetShardInfoResponse {
    /// Shard ID
    pub shard_id: ShardId,
    /// Number of nodes
    pub node_count: usize,
    /// Number of edges
    pub edge_count: usize,
    /// Shard size in bytes
    pub size_bytes: u64,
}

/// Graph RPC service trait (would be implemented via tonic in production)
#[cfg(feature = "federation")]
#[tonic::async_trait]
pub trait GraphRpcService: Send + Sync {
    /// Execute a query on this node
    async fn execute_query(
        &self,
        request: ExecuteQueryRequest,
    ) -> std::result::Result<ExecuteQueryResponse, Status>;

    /// Replicate data to this node
    async fn replicate_data(
        &self,
        request: ReplicateDataRequest,
    ) -> std::result::Result<ReplicateDataResponse, Status>;

    /// Health check
    async fn health_check(
        &self,
        request: HealthCheckRequest,
    ) -> std::result::Result<HealthCheckResponse, Status>;

    /// Get shard information
    async fn get_shard_info(
        &self,
        request: GetShardInfoRequest,
    ) -> std::result::Result<GetShardInfoResponse, Status>;
}

/// RPC client for communicating with remote nodes
pub struct RpcClient {
    /// Target node address
    target_address: String,
    /// Connection timeout in seconds
    timeout_seconds: u64,
}

impl RpcClient {
    /// Create a new RPC client
    pub fn new(target_address: String) -> Self {
        Self {
            target_address,
            timeout_seconds: 30,
        }
    }

    /// Set connection timeout
    pub fn with_timeout(mut self, timeout_seconds: u64) -> Self {
        self.timeout_seconds = timeout_seconds;
        self
    }

    /// Execute a query on the remote node
    pub async fn execute_query(
        &self,
        request: ExecuteQueryRequest,
    ) -> Result<ExecuteQueryResponse> {
        debug!(
            "Executing remote query on {}: {}",
            self.target_address, request.query
        );

        // In production, make actual gRPC call using tonic
        // For now, simulate response
        Ok(ExecuteQueryResponse {
            result: QueryResult {
                query_id: uuid::Uuid::new_v4().to_string(),
                nodes: Vec::new(),
                edges: Vec::new(),
                aggregates: std::collections::HashMap::new(),
                stats: crate::distributed::coordinator::QueryStats {
                    execution_time_ms: 0,
                    shards_queried: 0,
                    nodes_scanned: 0,
                    edges_scanned: 0,
                    cached: false,
                },
            },
            success: true,
            error: None,
        })
    }

    /// Replicate data to the remote node
    pub async fn replicate_data(
        &self,
        request: ReplicateDataRequest,
    ) -> Result<ReplicateDataResponse> {
        debug!(
            "Replicating data to {} for shard {}",
            self.target_address, request.shard_id
        );

        // In production, make actual gRPC call
        Ok(ReplicateDataResponse {
            success: true,
            error: None,
        })
    }

    /// Perform health check on remote node
    pub async fn health_check(&self, node_id: String) -> Result<HealthCheckResponse> {
        debug!("Health check on {}", self.target_address);

        // In production, make actual gRPC call
        Ok(HealthCheckResponse {
            healthy: true,
            load: 0.5,
            active_queries: 0,
            uptime_seconds: 3600,
        })
    }

    /// Get shard information from remote node
    pub async fn get_shard_info(&self, shard_id: ShardId) -> Result<GetShardInfoResponse> {
        debug!(
            "Getting shard info for {} from {}",
            shard_id, self.target_address
        );

        // In production, make actual gRPC call
        Ok(GetShardInfoResponse {
            shard_id,
            node_count: 0,
            edge_count: 0,
            size_bytes: 0,
        })
    }
}

/// RPC server for handling incoming requests
#[cfg(feature = "federation")]
pub struct RpcServer {
    /// Server address to bind to
    bind_address: String,
    /// Service implementation
    service: Arc<dyn GraphRpcService>,
}

#[cfg(not(feature = "federation"))]
pub struct RpcServer {
    /// Server address to bind to
    bind_address: String,
}

#[cfg(feature = "federation")]
impl RpcServer {
    /// Create a new RPC server
    pub fn new(bind_address: String, service: Arc<dyn GraphRpcService>) -> Self {
        Self {
            bind_address,
            service,
        }
    }

    /// Start the RPC server
    pub async fn start(&self) -> Result<()> {
        info!("Starting RPC server on {}", self.bind_address);

        // In production, start actual gRPC server using tonic
        // For now, just log
        debug!("RPC server would start on {}", self.bind_address);

        Ok(())
    }

    /// Stop the RPC server
    pub async fn stop(&self) -> Result<()> {
        info!("Stopping RPC server");
        Ok(())
    }
}

#[cfg(not(feature = "federation"))]
impl RpcServer {
    /// Create a new RPC server
    pub fn new(bind_address: String) -> Self {
        Self { bind_address }
    }

    /// Start the RPC server
    pub async fn start(&self) -> Result<()> {
        info!("Starting RPC server on {}", self.bind_address);

        // In production, start actual gRPC server using tonic
        // For now, just log
        debug!("RPC server would start on {}", self.bind_address);

        Ok(())
    }

    /// Stop the RPC server
    pub async fn stop(&self) -> Result<()> {
        info!("Stopping RPC server");
        Ok(())
    }
}

/// Default implementation of GraphRpcService
#[cfg(feature = "federation")]
pub struct DefaultGraphRpcService {
    /// Node ID
    node_id: String,
    /// Start time for uptime calculation
    start_time: std::time::Instant,
    /// Active queries counter
    active_queries: Arc<RwLock<usize>>,
}

#[cfg(feature = "federation")]
impl DefaultGraphRpcService {
    /// Create a new default service
    pub fn new(node_id: String) -> Self {
        Self {
            node_id,
            start_time: std::time::Instant::now(),
            active_queries: Arc::new(RwLock::new(0)),
        }
    }
}

#[cfg(feature = "federation")]
#[tonic::async_trait]
impl GraphRpcService for DefaultGraphRpcService {
    async fn execute_query(
        &self,
        request: ExecuteQueryRequest,
    ) -> std::result::Result<ExecuteQueryResponse, Status> {
        // Increment active queries
        {
            let mut count = self.active_queries.write().await;
            *count += 1;
        }

        debug!("Executing query: {}", request.query);

        // In production, execute actual query
        let result = QueryResult {
            query_id: uuid::Uuid::new_v4().to_string(),
            nodes: Vec::new(),
            edges: Vec::new(),
            aggregates: std::collections::HashMap::new(),
            stats: crate::distributed::coordinator::QueryStats {
                execution_time_ms: 0,
                shards_queried: 0,
                nodes_scanned: 0,
                edges_scanned: 0,
                cached: false,
            },
        };

        // Decrement active queries
        {
            let mut count = self.active_queries.write().await;
            *count -= 1;
        }

        Ok(ExecuteQueryResponse {
            result,
            success: true,
            error: None,
        })
    }

    async fn replicate_data(
        &self,
        request: ReplicateDataRequest,
    ) -> std::result::Result<ReplicateDataResponse, Status> {
        debug!("Replicating data for shard {}", request.shard_id);

        // In production, perform actual replication
        Ok(ReplicateDataResponse {
            success: true,
            error: None,
        })
    }

    async fn health_check(
        &self,
        _request: HealthCheckRequest,
    ) -> std::result::Result<HealthCheckResponse, Status> {
        let uptime = self.start_time.elapsed().as_secs();
        let active = *self.active_queries.read().await;

        Ok(HealthCheckResponse {
            healthy: true,
            load: 0.5, // Would calculate actual load
            active_queries: active,
            uptime_seconds: uptime,
        })
    }

    async fn get_shard_info(
        &self,
        request: GetShardInfoRequest,
    ) -> std::result::Result<GetShardInfoResponse, Status> {
        // In production, get actual shard info
        Ok(GetShardInfoResponse {
            shard_id: request.shard_id,
            node_count: 0,
            edge_count: 0,
            size_bytes: 0,
        })
    }
}

/// RPC connection pool for managing connections to multiple nodes
pub struct RpcConnectionPool {
    /// Map of node_id to RPC client
    clients: Arc<dashmap::DashMap<String, Arc<RpcClient>>>,
}

impl RpcConnectionPool {
    /// Create a new connection pool
    pub fn new() -> Self {
        Self {
            clients: Arc::new(dashmap::DashMap::new()),
        }
    }

    /// Get or create a client for a node
    pub fn get_client(&self, node_id: &str, address: &str) -> Arc<RpcClient> {
        self.clients
            .entry(node_id.to_string())
            .or_insert_with(|| Arc::new(RpcClient::new(address.to_string())))
            .clone()
    }

    /// Remove a client from the pool
    pub fn remove_client(&self, node_id: &str) {
        self.clients.remove(node_id);
    }

    /// Get number of active connections
    pub fn connection_count(&self) -> usize {
        self.clients.len()
    }
}

impl Default for RpcConnectionPool {
    fn default() -> Self {
        Self::new()
    }
}

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

    #[tokio::test]
    async fn test_rpc_client() {
        let client = RpcClient::new("localhost:9000".to_string());

        let request = ExecuteQueryRequest {
            query: "MATCH (n) RETURN n".to_string(),
            parameters: std::collections::HashMap::new(),
            transaction_id: None,
        };

        let response = client.execute_query(request).await.unwrap();
        assert!(response.success);
    }

    #[tokio::test]
    async fn test_default_service() {
        let service = DefaultGraphRpcService::new("test-node".to_string());

        let request = ExecuteQueryRequest {
            query: "MATCH (n) RETURN n".to_string(),
            parameters: std::collections::HashMap::new(),
            transaction_id: None,
        };

        let response = service.execute_query(request).await.unwrap();
        assert!(response.success);
    }

    #[tokio::test]
    async fn test_connection_pool() {
        let pool = RpcConnectionPool::new();

        let client1 = pool.get_client("node-1", "localhost:9000");
        let client2 = pool.get_client("node-2", "localhost:9001");

        assert_eq!(pool.connection_count(), 2);

        pool.remove_client("node-1");
        assert_eq!(pool.connection_count(), 1);
    }

    #[tokio::test]
    async fn test_health_check() {
        let service = DefaultGraphRpcService::new("test-node".to_string());

        let request = HealthCheckRequest {
            node_id: "test".to_string(),
        };

        let response = service.health_check(request).await.unwrap();
        assert!(response.healthy);
        assert_eq!(response.active_queries, 0);
    }
}