feat: support fmt

current-time-rs/src/main.rs

@@ -3,10 +3,13 @@
 //! ```cargo
 //! [dependencies]
 //! clap = { version = "4.5.23", features = ["derive"] }
+//! simpledateformat = "0.1.4"
 //! ```
 
 use clap::Parser;
-use std::time::SystemTime;
+use std::ops::Add;
+use std::process::exit;
+use std::time::{Duration, SystemTime};
 
 /// Simple program to greet a person
 #[derive(Parser, Debug)]
@@ -21,6 +24,12 @@ struct Args {
     /// Output format (e.g. millis (default), s|secs)
     #[arg(short, long)]
     output_format: Option<String>,
+    /// Local time format
+    #[arg(long)]
+    local_time_format: Option<String>,
+    /// UTF time format
+    #[arg(long)]
+    utc_time_format: Option<String>,
 }
 
 fn main() {
@@ -39,10 +48,32 @@ fn main() {
         _ => final_time_millis,
     };
 
+    let mut print_time = format!("{}", final_time);
+    let final_system_time =
+        SystemTime::UNIX_EPOCH.add(Duration::from_millis(final_time_millis as u64));
+
+    if let Some(local_time_format) = &args.local_time_format {
+        print_time = match simpledateformat::fmt(local_time_format) {
+            Ok(fmt) => fmt.format_local(final_system_time),
+            Err(_) => {
+                eprintln!("Invalid local time format.");
+                exit(1);
+            }
+        };
+    } else if let Some(utc_time_format) = &args.utc_time_format {
+        print_time = match simpledateformat::fmt(utc_time_format) {
+            Ok(fmt) => fmt.format_local(final_system_time),
+            Err(_) => {
+                eprintln!("Invalid UTC time format.");
+                exit(1);
+            }
+        }
+    }
+
     if args.new_line {
-        println!("{}", final_time);
+        println!("{}", print_time);
     } else {
-        print!("{}", final_time);
+        print!("{}", print_time);
     }
 }