added commentation

WatcherAgent/src/hardware/memory.rs

@@ -3,6 +3,24 @@ use std::error::Error;
 use anyhow::Result;
 use sysinfo::System;
 
+//! # Memory Hardware Module
+//!
+//! This module provides memory information collection for WatcherAgent, including total, used, and free RAM.
+//!
+//! ## Responsibilities
+//! - **Memory Detection:** Queries system for total, used, and free RAM.
+//! - **Usage Calculation:** Computes memory usage percentage.
+//! - **Error Handling:** Graceful fallback if metrics are unavailable.
+//!
+//! ## Units
+//! - `total`, `used`, `free`: RAM in **megabytes (MB)**
+//!
+/// Memory statistics for the host system.
+///
+/// # Fields
+/// - `total`: Total RAM in **megabytes (MB)**
+/// - `used`: Used RAM in **megabytes (MB)**
+/// - `free`: Free RAM in **megabytes (MB)**
 #[derive(Debug)]
 pub struct MemoryInfo {
     pub total: Option<f64>,
@@ -10,6 +28,10 @@ pub struct MemoryInfo {
     pub free: Option<f64>,
 }
 
+/// Collects memory information (total, used, free RAM).
+///
+/// # Returns
+/// * `Result<MemoryInfo>` - Memory statistics or error if unavailable.
 pub async fn get_memory_info() -> Result<MemoryInfo> {
     let mut sys = System::new();
     sys.refresh_memory();
@@ -21,6 +43,13 @@ pub async fn get_memory_info() -> Result<MemoryInfo> {
     })
 }
 
+/// Computes memory usage percentage from sysinfo::System.
+///
+/// # Arguments
+/// * `sys` - Mutable reference to sysinfo::System
+///
+/// # Returns
+/// * `Result<f64, Box<dyn Error + Send + Sync>>` - Memory usage as percentage.
 pub fn _get_memory_usage(sys: &mut System) -> Result<f64, Box<dyn Error + Send + Sync>> {
     sys.refresh_memory();
     Ok((sys.used_memory() as f64 / sys.total_memory() as f64) * 100.0)