Managed to generate a first secret

src/main.rs

@@ -1,4 +1,5 @@
 use clap::Parser;
+use totp_rfc6238::{HashAlgorithm, TotpGenerator};
 
 /// TOTP - One Time Password generator
 #[derive(Parser, Debug)]
@@ -14,18 +15,20 @@ struct Args {
 
     /// Size of generated secret
     #[clap(short, long, default_value_t = 6)]
-    len: u32,
+    len: usize,
 }
 
 fn main() {
     let args: Args = Args::parse();
 
-    let number = libotp::totp(
-        &args.secret.to_ascii_uppercase(),
-        args.len,
-        args.topt_step,
-        0,
-    );
+    let totp_generator = TotpGenerator::new()
+        .set_digit(args.len).unwrap()
+        .set_step(args.topt_step).unwrap()
+        .set_hash_algorithm(HashAlgorithm::SHA1)
+        .build();
 
-    println!("Secret len = {}", number.unwrap());
+    let key = base64::decode(args.secret).unwrap();
+    let code = totp_generator.get_code(&key);
+
+    println!("Secret len = {}", code);
 }