add some basic config file parsing

src/main.rs

@@ -1,4 +1,7 @@
 use clap::{Parser, Subcommand};
+use monitor::Monitor;
+
+mod monitor;
 
 #[derive(Subcommand)]
 pub enum Commands {
@@ -6,9 +9,11 @@ pub enum Commands {
 }
 
 impl Commands {
-    pub fn execute(self) {
+    pub fn execute(self, config_file: &str) {
         match self {
             Self::Monitor => {
+                let _m = Monitor::new_from_file(config_file).unwrap();
+
                 println!("[TODO] Power: ----W")
             }
         }
@@ -17,13 +22,15 @@ impl Commands {
 
 #[derive(Parser)]
 pub struct Cli {
+    #[arg(short, long)]
+    config_file: String,
     #[command(subcommand)]
     command: Commands,
 }
 
 impl Cli {
     pub fn execute(self) {
-        self.command.execute();
+        self.command.execute(&self.config_file);
     }
 }
 

src/monitor.rs

@@ -0,0 +1,34 @@
+use serde::Deserialize;
+use std::fs;
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum Error {
+    #[error("io error")]
+    IoError(#[from] std::io::Error),
+    #[error("toml parsing error")]
+    ParseError(#[from] toml::de::Error),
+}
+
+#[derive(Deserialize)]
+pub struct MonitorConfig {
+    target: Vec<String>,
+}
+impl MonitorConfig {
+    fn print(&self) {
+        for t in &self.target {
+            println!("* {}", t);
+        }
+    }
+}
+
+pub struct Monitor {}
+
+impl Monitor {
+    pub fn new_from_file(config_file: &str) -> Result<Self, Error> {
+        let config_str = fs::read_to_string(config_file)?;
+        let config: MonitorConfig = toml::from_str(&config_str)?;
+        config.print();
+        Ok(Self {})
+    }
+}