- add: initial database and auth services

auth-service/src/users.rs

@@ -0,0 +1,32 @@
+use crate::database_client::DatabaseClient;
+
+use argon2::{
+    password_hash::{
+        rand_core::OsRng,
+        PasswordHash, PasswordHasher, PasswordVerifier, SaltString
+    },
+    Argon2
+};
+
+pub fn hash_password(password: &str) -> String {
+    let salt = SaltString::generate(&mut OsRng);
+    let argon2 = Argon2::default();
+    argon2.hash_password(password.as_ref(), &salt).unwrap().to_string()
+}
+
+pub fn verify_password(password: &str, hash: &str) -> bool {
+    let parsed_hash = PasswordHash::new(&hash).unwrap();
+    Argon2::default().verify_password(password.as_bytes(), &parsed_hash).is_ok()
+}
+
+pub async fn verify_user(mut db_client: DatabaseClient,
+                         username: &str, password: &str) -> Option<String> {
+    // Placeholder: Replace with a gRPC call to the Database Service
+    let user = db_client.get_user_by_username(username).await.ok()?;
+
+    if verify_password(password, &user.hashed_password) {
+        Some(user.user_id.to_string())
+    } else {
+        None
+    }
+}