refactor: restructure project architecture

internal/key/key.go

@@ -0,0 +1,67 @@
+package key
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"log"
+	"os"
+	"path/filepath"
+
+	"golang.org/x/crypto/ssh"
+)
+
+func GenerateSSHKeyIfNotExist(keyPath string) error {
+	if _, err := os.Stat(keyPath); err == nil {
+		log.Printf("SSH key already exists at %s", keyPath)
+		return nil
+	}
+
+	log.Printf("SSH key not found at %s, generating new key pair...", keyPath)
+
+	privateKey, err := rsa.GenerateKey(rand.Reader, 4096)
+	if err != nil {
+		return err
+	}
+
+	privateKeyPEM := &pem.Block{
+		Type:  "RSA PRIVATE KEY",
+		Bytes: x509.MarshalPKCS1PrivateKey(privateKey),
+	}
+
+	dir := filepath.Dir(keyPath)
+	if err := os.MkdirAll(dir, 0700); err != nil {
+		return err
+	}
+
+	privateKeyFile, err := os.OpenFile(keyPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
+	if err != nil {
+		return err
+	}
+	defer privateKeyFile.Close()
+
+	if err := pem.Encode(privateKeyFile, privateKeyPEM); err != nil {
+		return err
+	}
+
+	publicKey, err := ssh.NewPublicKey(&privateKey.PublicKey)
+	if err != nil {
+		return err
+	}
+
+	pubKeyPath := keyPath + ".pub"
+	pubKeyFile, err := os.OpenFile(pubKeyPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+	if err != nil {
+		return err
+	}
+	defer pubKeyFile.Close()
+
+	_, err = pubKeyFile.Write(ssh.MarshalAuthorizedKey(publicKey))
+	if err != nil {
+		return err
+	}
+
+	log.Printf("SSH key pair generated successfully at %s and %s", keyPath, pubKeyPath)
+	return nil
+}