gen key pair and readme

Author: tizz98

README.md

@@ -1,3 +1,64 @@
 # XQR Code (eXtended QR Code) CLI
 
 A minimal CLI for generated extended QR codes.
+
+## Usage
+
+```
+eXtended QR Codes CLI
+
+Usage: xqr <COMMAND>
+
+Commands:
+  encode             Encode a value into a JWT and optionally into a QR code
+  decode             Decode a JWT from a QR code
+  generate-key-pair  Generate a new ECDSA (ES256) key pair for use with XQR codes
+  help               Print this message or the help of the given subcommand(s)
+
+Options:
+  -h, --help  Print help
+```
+
+### Encode
+
+```
+Encode a value into a JWT and optionally into a QR code
+
+Usage: xqr encode [OPTIONS] --private-key <PRIVATE_KEY> --kid <KID> [VALUE]
+
+Arguments:
+  [VALUE]  The value to encode
+
+Options:
+      --private-key <PRIVATE_KEY>
+      --kid <KID>                  The key ID to use
+      --display                    Display the QR code in the terminal
+      --save <SAVE_PATH>           Save the QR code to a file
+  -h, --help                       Print help
+```
+
+### Decode
+
+```
+Decode a JWT from a QR code
+
+Usage: xqr decode [JWT]
+
+Arguments:
+  [JWT]  The JWT to decode
+
+Options:
+  -h, --help  Print help
+```
+
+### Generate key pair
+
+```
+Generate a new ECDSA (ES256) key pair for use with XQR codes
+
+Usage: xqr generate-key-pair --save <SAVE_PATH>
+
+Options:
+      --save <SAVE_PATH>  Save the key pair to a file
+  -h, --help              Print help
+```

src/main.rs

@@ -39,6 +39,16 @@ fn cli() -> Command {
                 .arg(arg!(jwt: [JWT] "The JWT to decode"))
                 .arg_required_else_help(true),
         )
+        .subcommand(
+            Command::new("generate-key-pair")
+                .about("Generate a new ECDSA (ES256) key pair for use with XQR codes")
+                .arg(
+                    arg!(save: --save <SAVE_PATH> "Save the key pair to a file")
+                        .value_parser(value_parser!(PathBuf))
+                        .required(true),
+                )
+                .arg_required_else_help(true),
+        )
 }
 
 fn main() {
@@ -124,6 +134,40 @@ fn main() {
                 }
             }
         }
+        Some(("generate-key-pair", sub_matches)) => {
+            let save_path = sub_matches.get_one::<PathBuf>("save").unwrap();
+            let pub_key_path = save_path.with_extension("pub");
+            let key_pair = xqr::generate_key_pair();
+            let private_key_pem = match key_pair.to_pem() {
+                Ok(private_key_pem) => private_key_pem,
+                Err(e) => {
+                    eprintln!("Error generating private key: {}", e);
+                    std::process::exit(1);
+                }
+            };
+            let pub_key_pem = match key_pair.public_key().to_pem() {
+                Ok(pub_key_pem) => pub_key_pem,
+                Err(e) => {
+                    eprintln!("Error generating public key: {}", e);
+                    std::process::exit(1);
+                }
+            };
+
+            match std::fs::write(save_path, private_key_pem) {
+                Ok(_) => println!("Saved private key to {}", save_path.display()),
+                Err(e) => {
+                    eprintln!("Error saving private key: {}", e);
+                    std::process::exit(1);
+                }
+            }
+            match std::fs::write(pub_key_path.clone(), pub_key_pem) {
+                Ok(_) => println!("Saved public key to {}", pub_key_path.display()),
+                Err(e) => {
+                    eprintln!("Error saving public key: {}", e);
+                    std::process::exit(1);
+                }
+            }
+        }
         _ => unreachable!(),
     }
 }