feat: Remove system statistics and health check methods from monitoring module and update Redis connection handling

- Remove get_system_statistics/get_uptime/health_check/get_memory_usage/get_process_memory/estimate_memory_usage/get_redis_memory_usage methods from ChargingEngine impl
- Remove SystemStats/HealthStatus struct definitions
- Update get_performance_metrics/calculate_rps/calculate_avg_response_time/get_error_statistics/get_last_error/get_redis_latency to use get_multiplexed_async_connection instead of get_async_connection
- Replace context error handling with map

apps/charging-engine/src/monitoring/monitoring.rs

@@ -4,124 +4,10 @@ use std::time::SystemTime;
 use crate::errors::{ChargingError, ChargingResult, ErrorContext};
 use super::types::{SystemStats, HealthStatus};
 
-impl super::ChargingEngine {
-    pub async fn get_system_statistics(&self) -> ChargingResult<SystemStats> {
-        let mut conn = self.redis_client.get_async_connection().await
-            .context("Failed to get Redis connection")?;
-
-        let active_sessions: u64 = conn.get("stats:active_sessions").await.unwrap_or(0);
-        let total_accounts: u64 = conn.keys("account:*").await.unwrap_or_default().len() as u64;
-        let blocked_users: u64 = conn.keys("block:*").await.unwrap_or_default().len() as u64;
-        let low_balance_alerts: u64 = conn.keys("alert:low_balance:*").await.unwrap_or_default().len() as u64;
-
-        let stats = SystemStats {
-            active_sessions,
-            total_accounts,
-            blocked_users,
-            low_balance_alerts,
-            uptime: self.get_uptime().await?,
-        };
-
-        Ok(stats)
-    }
-
-    async fn get_uptime(&self) -> ChargingResult<u64> {
-        // Calculate actual uptime since startup
-        match self.startup_time.elapsed() {
-            Ok(duration) => Ok(duration.as_secs()),
-            Err(_) => {
-                // If system time went backwards, fallback to current time
-                Ok(SystemTime::now()
-                    .duration_since(SystemTime::UNIX_EPOCH)
-                    .unwrap_or_default()
-                    .as_secs())
-            }
-        }
-    }
-
-    pub async fn health_check(&self) -> ChargingResult<HealthStatus> {
-        let mut conn = self.redis_client.get_async_connection().await
-            .context("Failed to get Redis connection")?;
-
-        // Test Redis connection
-        let _: String = conn.get("health_check").await.unwrap_or_else(|_| "ok".to_string());
-
-        let status = HealthStatus {
-            redis_connected: true,
-            active_sync: true,
-            last_sync: chrono::Utc::now(),
-            memory_usage: self.get_memory_usage().await?,
-        };
-
-        Ok(status)
-    }
-
-    async fn get_memory_usage(&self) -> ChargingResult<u64> {
-        // Get actual memory usage from system
-        match self.get_process_memory() {
-            Ok(memory_bytes) => Ok(memory_bytes),
-            Err(_) => {
-                // Fallback to Redis memory usage if system memory fails
-                self.get_redis_memory_usage().await
-            }
-        }
-    }
-
-    fn get_process_memory(&self) -> ChargingResult<u64> {
-        use std::fs;
-        
-        // Try to read from /proc/self/status for Linux systems
-        if let Ok(status) = fs::read_to_string("/proc/self/status") {
-            for line in status.lines() {
-                if line.starts_with("VmRSS:") {
-                    if let Some(memory_str) = line.split_whitespace().nth(1) {
-                        if let Ok(memory_kb) = memory_str.parse::<u64>() {
-                            return Ok(memory_kb * 1024); // Convert KB to bytes
-                        }
-                    }
-                }
-            }
-        }
-        
-        // Fallback for non-Linux systems or if reading fails
-        self.estimate_memory_usage()
-    }
-
-    fn estimate_memory_usage(&self) -> ChargingResult<u64> {
-        // Estimate memory usage based on known structures
-        // This is a rough estimate for non-Linux systems
-        let base_memory = 20_000_000; // 20MB base
-        let redis_connections = 5_000_000; // 5MB per connection estimate
-        let session_data = 10_000_000; // 10MB for session data
-        
-        Ok(base_memory + redis_connections + session_data)
-    }
-
-    async fn get_redis_memory_usage(&self) -> ChargingResult<u64> {
-        let mut conn = self.redis_client.get_async_connection().await
-            .context("Failed to get Redis connection")?;
-
-        // Get Redis memory info
-        let info: String = redis::cmd("INFO").query_async(&mut conn).await.unwrap_or_default();
-        
-        // Parse memory usage from Redis info
-        for line in info.lines() {
-            if line.starts_with("used_memory:") {
-                if let Some(memory_str) = line.split(':').nth(1) {
-                    if let Ok(memory_bytes) = memory_str.parse::<u64>() {
-                        return Ok(memory_bytes);
-                    }
-                }
-            }
-        }
-        
-        // Fallback to estimate
-        self.estimate_memory_usage()
-    }
-
+impl crate::charging::ChargingEngine {
     pub async fn get_performance_metrics(&self) -> ChargingResult<PerformanceMetrics> {
-        let mut conn = self.redis_client.get_async_connection().await
-            .context("Failed to get Redis connection")?;
+        let mut conn = self.redis_client.get_multiplexed_async_connection().await
+            .map_err(|e| crate::errors::ChargingError::RedisConnection(e.to_string()))?;
 
         // Get Redis info
         let info: String = redis::cmd("INFO").query_async(&mut conn).await.unwrap_or_default();
@@ -151,8 +37,8 @@ impl super::ChargingEngine {
     }
 
     async fn calculate_rps(&self) -> ChargingResult<f64> {
-        let mut conn = self.redis_client.get_async_connection().await
-            .context("Failed to get Redis connection")?;
+        let mut conn = self.redis_client.get_multiplexed_async_connection().await
+            .map_err(|e| crate::errors::ChargingError::RedisConnection(e.to_string()))?;
 
         // Get Redis instantaneous ops per second
         let info: String = redis::cmd("INFO").query_async(&mut conn).await.unwrap_or_default();
@@ -179,17 +65,17 @@ impl super::ChargingEngine {
     }
 
     async fn calculate_avg_response_time(&self) -> ChargingResult<f64> {
-        let mut conn = self.redis_client.get_async_connection().await
-            .context("Failed to get Redis connection")?;
+        let mut conn = self.redis_client.get_multiplexed_async_connection().await
+            .map_err(|e| crate::errors::ChargingError::RedisConnection(e.to_string()))?;
 
         // Track response times in Redis for calculation
         let response_times_key = "metrics:response_times";
         
         // Get recent response times (last 100 operations)
-        let response_times: Vec<f64> = conn
-            .lrange(response_times_key, 0, 99)
+        let response_times_raw: Vec<String> = redis::AsyncCommands::lrange(&mut conn, response_times_key, 0, 99)
             .await
-            .unwrap_or_default()
+            .unwrap_or_default();
+        let response_times: Vec<f64> = response_times_raw
             .into_iter()
             .filter_map(|s| s.parse::<f64>().ok())
             .collect();
@@ -205,7 +91,7 @@ impl super::ChargingEngine {
         }
     }
 
-    async fn get_redis_latency(&self, conn: &mut redis::aio::Connection) -> ChargingResult<f64> {
+    async fn get_redis_latency(&self, conn: &mut redis::aio::MultiplexedConnection) -> ChargingResult<f64> {
         use std::time::Instant;
         
         // Measure Redis ping latency
@@ -217,18 +103,18 @@ impl super::ChargingEngine {
     }
 
     pub async fn get_error_statistics(&self) -> ChargingResult<ErrorStats> {
-        let mut conn = self.redis_client.get_async_connection().await
-            .context("Failed to get Redis connection")?;
+        let mut conn = self.redis_client.get_multiplexed_async_connection().await
+            .map_err(|e| crate::errors::ChargingError::RedisConnection(e.to_string()))?;
 
         let pattern = "error:*".to_string();
-        let keys: Vec<String> = conn.keys(&pattern).await
-            .context("Failed to get error keys")?;
+        let keys: Vec<String> = redis::AsyncCommands::keys(&mut conn, &pattern).await
+            .map_err(|e| crate::errors::ChargingError::RedisOperation(e.to_string()))?;
 
         let mut total_errors = 0u64;
         let mut error_types = std::collections::HashMap::new();
 
         for key in keys {
-            if let Ok(count) = conn.get::<_, u64>(&key).await {
+            if let Ok(count) = redis::AsyncCommands::get::<_, u64>(&mut conn, &key).await {
                 total_errors += count;
                 
                 let error_type = key.split(':').nth(1).unwrap_or("unknown");
@@ -246,30 +132,14 @@ impl super::ChargingEngine {
     }
 
     async fn get_last_error(&self) -> ChargingResult<Option<String>> {
-        let mut conn = self.redis_client.get_async_connection().await
-            .context("Failed to get Redis connection")?;
+        let mut conn = self.redis_client.get_multiplexed_async_connection().await
+            .map_err(|e| crate::errors::ChargingError::RedisConnection(e.to_string()))?;
 
-        let last_error: Option<String> = conn.get("last_error").await.unwrap_or(None);
+        let last_error: Option<String> = redis::AsyncCommands::get(&mut conn, "last_error").await.unwrap_or(None);
         Ok(last_error)
     }
 }
 
-#[derive(Debug, Clone)]
-pub struct SystemStats {
-    pub active_sessions: u64,
-    pub total_accounts: u64,
-    pub blocked_users: u64,
-    pub low_balance_alerts: u64,
-    pub uptime: u64,
-}
-
-#[derive(Debug, Clone)]
-pub struct HealthStatus {
-    pub redis_connected: bool,
-    pub active_sync: bool,
-    pub last_sync: chrono::DateTime<chrono::Utc>,
-    pub memory_usage: u64,
-}
 
 #[derive(Debug, Clone)]
 pub struct PerformanceMetrics {