config: modularize; add config watcher and move error variants

src/daemon.rs

@@ -1,4 +1,5 @@
 use crate::config::{AppConfig, LogLevel};
+use crate::config::watcher::ConfigWatcher;
 use crate::conflict;
 use crate::core::SystemReport;
 use crate::engine;
@@ -10,7 +11,7 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use std::time::{Duration, Instant};
 
 /// Run the daemon
-pub fn run_daemon(config: AppConfig, verbose: bool) -> Result<(), Box<dyn std::error::Error>> {
+pub fn run_daemon(mut config: AppConfig, verbose: bool) -> Result<(), Box<dyn std::error::Error>> {
     // Set effective log level based on config and verbose flag
     let effective_log_level = if verbose {
         LogLevel::Debug
@@ -63,6 +64,34 @@ pub fn run_daemon(config: AppConfig, verbose: bool) -> Result<(), Box<dyn std::e
         );
     }
 
+    // Initialize config file watcher if a path is available
+    let config_file_path = if let Ok(path) = std::env::var("SUPERFREQ_CONFIG") { Some(path) } else {
+        let default_paths = [
+            "/etc/superfreq/config.toml",
+            "/etc/superfreq.toml",
+        ];
+        
+        default_paths.iter()
+            .find(|&path| std::path::Path::new(path).exists())
+            .map(|path| (*path).to_string())
+    };
+    
+    let config_watcher: Option<ConfigWatcher> = match config_file_path {
+        Some(path) => {
+            match ConfigWatcher::new(&path) {
+                Ok(watcher) => {
+                    println!("Watching config file: {path}");
+                    Some(watcher)
+                },
+                Err(e) => {
+                    eprintln!("Failed to initialize config file watcher: {e}");
+                    None
+                }
+            }
+        },
+        None => None,
+    };
+
     // Variables for adaptive polling
     let mut current_poll_interval = config.daemon.poll_interval_sec;
     let mut last_settings_change = Instant::now();
@@ -72,6 +101,24 @@ pub fn run_daemon(config: AppConfig, verbose: bool) -> Result<(), Box<dyn std::e
     while running.load(Ordering::SeqCst) {
         let start_time = Instant::now();
 
+        // Check for configuration changes
+        if let Some(watcher) = &config_watcher {
+            if let Some(config_result) = watcher.check_for_changes() {
+                match config_result {
+                    Ok(new_config) => {
+                        if verbose {
+                            println!("Config file changed, updating configuration");
+                        }
+                        config = new_config;
+                    },
+                    Err(e) => {
+                        eprintln!("Error loading new configuration: {e}");
+                        // Continue with existing config
+                    }
+                }
+            }
+        }
+
         match monitor::collect_system_report(&config) {
             Ok(report) => {
                 log_message(