oxirs-stream 0.2.4

//! OPC UA Client Implementation
//!
//! Async OPC UA client for industrial data streaming

use super::subscription::SubscriptionManager;
use super::types::{NodeSubscription, OpcUaConfig, OpcUaDataChange, OpcUaStats};
use crate::error::StreamResult;
use crate::event::{EventMetadata, StreamEvent};
use chrono::Utc;
use std::collections::HashMap;
use std::sync::Arc;
use tokio::sync::{broadcast, RwLock};
use tracing::info;

/// OPC UA Client for streaming
pub struct OpcUaClient {
    config: OpcUaConfig,
    subscription_manager: Arc<RwLock<SubscriptionManager>>,
    stats: Arc<RwLock<OpcUaStats>>,
    event_sender: broadcast::Sender<StreamEvent>,
    connected: Arc<RwLock<bool>>,
    subscriptions: Arc<RwLock<Vec<NodeSubscription>>>,
}

impl OpcUaClient {
    /// Create a new OPC UA client
    pub fn new(config: OpcUaConfig) -> Self {
        let (tx, _) = broadcast::channel(10000);

        Self {
            config,
            subscription_manager: Arc::new(RwLock::new(SubscriptionManager::new())),
            stats: Arc::new(RwLock::new(OpcUaStats::default())),
            event_sender: tx,
            connected: Arc::new(RwLock::new(false)),
            subscriptions: Arc::new(RwLock::new(Vec::new())),
        }
    }

    /// Connect to OPC UA server
    pub async fn connect(&mut self) -> StreamResult<()> {
        // Future enhancement: Implement actual OPC UA connection (requires opcua crate).
        // For v0.1.0: Stub implementation provides API surface for future OPC UA integration.
        // OPC UA is an industrial IoT protocol - integration is optional for initial release.

        *self.connected.write().await = true;

        // Update stats
        {
            let mut stats = self.stats.write().await;
            stats.session_count += 1;
            stats.last_connected_at = Some(Utc::now());
        }

        info!("OPC UA client connected to {}", self.config.endpoint_url);

        Ok(())
    }

    /// Disconnect from OPC UA server
    pub async fn disconnect(&mut self) -> StreamResult<()> {
        *self.connected.write().await = false;

        // Update stats
        {
            let mut stats = self.stats.write().await;
            stats.last_disconnected_at = Some(Utc::now());
        }

        info!("OPC UA client disconnected");

        Ok(())
    }

    /// Subscribe to nodes with RDF mappings
    pub async fn subscribe_nodes(&self, subscriptions: Vec<NodeSubscription>) -> StreamResult<()> {
        // Future enhancement: Create OPC UA monitored items for subscriptions.
        // For v0.1.0: Tracks subscription count. Full OPC UA monitoring is future work.

        // Update stats
        {
            let mut stats = self.stats.write().await;
            stats.subscription_count += 1;
            stats.monitored_items_count += subscriptions.len() as u64;
        }

        // Store subscriptions
        *self.subscriptions.write().await = subscriptions;

        Ok(())
    }

    /// Convert data change to StreamEvent
    fn data_change_to_event(
        &self,
        change: &OpcUaDataChange,
        mapping: &NodeSubscription,
    ) -> StreamEvent {
        let metadata = EventMetadata {
            event_id: uuid::Uuid::new_v4().to_string(),
            timestamp: change.source_timestamp.unwrap_or(change.server_timestamp),
            source: format!("opcua:{}", self.config.endpoint_url),
            user: None,
            context: mapping.rdf_graph.clone(),
            caused_by: None,
            version: "1.0".to_string(),
            properties: HashMap::new(),
            checksum: None,
        };

        let object = change.value.to_rdf_literal();

        StreamEvent::TripleAdded {
            subject: mapping.rdf_subject.clone(),
            predicate: mapping.rdf_predicate.clone(),
            object,
            graph: mapping.rdf_graph.clone(),
            metadata,
        }
    }

    /// Get current statistics
    pub async fn get_stats(&self) -> OpcUaStats {
        self.stats.read().await.clone()
    }

    /// Check if connected
    pub async fn is_connected(&self) -> bool {
        *self.connected.read().await
    }

    /// Subscribe to event stream
    pub fn subscribe_events(&self) -> broadcast::Receiver<StreamEvent> {
        self.event_sender.subscribe()
    }
}

/// OPC UA StreamBackend implementation
pub struct OpcUaBackend {
    client: Arc<OpcUaClient>,
}

impl OpcUaBackend {
    /// Create a new OPC UA backend
    pub fn new(config: OpcUaConfig) -> Self {
        Self {
            client: Arc::new(OpcUaClient::new(config)),
        }
    }

    /// Get the underlying client
    pub fn client(&self) -> Arc<OpcUaClient> {
        Arc::clone(&self.client)
    }
}

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

    #[test]
    fn test_opcua_client_creation() {
        let config = OpcUaConfig::default();
        let client = OpcUaClient::new(config);

        let rt = tokio::runtime::Runtime::new().expect("runtime creation failed");
        assert!(!rt.block_on(client.is_connected()));
    }
}