watcheragent/WatcherAgent/src/hardware/memory.rs

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 **bytes**
///
/// Memory statistics for the host system.
///
/// # Fields
/// - `total`: Total RAM in **bytes**
/// - `used`: Used RAM in **bytes**
/// - `free`: Free RAM in **bytes**
#[derive(Debug)]
pub struct MemoryInfo {
    pub total_size: Option<f64>,
    pub used: Option<f64>,
    pub free: Option<f64>,
    pub current_load: 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, Box<dyn Error + Send + Sync>> {
    let mut sys = System::new();
    sys.refresh_memory();

    Ok(MemoryInfo {
        total_size: Some(sys.total_memory() as f64),
        used: Some(sys.used_memory() as f64),
        free: Some(sys.free_memory() as f64),
        current_load: Some(get_memory_usage(&mut sys).unwrap() as f64)
    })
}

/// 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)
}