implement MongoDB user repository with async support

src/mongodb/repositories/user_repository.rs

@@ -0,0 +1,53 @@
+use async_trait::async_trait;
+use bson::oid::ObjectId;
+use crate::models::user::User;
+
+// Define custom error type
+#[derive(Debug)]
+pub enum UserError {
+    MongoError(mongodb::error::Error),
+    NotFound,
+    ValidationError(String),
+    DuplicateKey(String),
+}
+
+impl std::fmt::Display for UserError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            UserError::MongoError(e) => write!(f, "MongoDB error: {}", e),
+            UserError::NotFound => write!(f, "User not found"),
+            UserError::ValidationError(msg) => write!(f, "Validation error: {}", msg),
+            UserError::DuplicateKey(field) => write!(f, "Duplicate key error: {}", field),
+        }
+    }
+}
+
+impl std::error::Error for UserError {}
+
+impl From<mongodb::error::Error> for UserError {
+    fn from(error: mongodb::error::Error) -> Self {
+        UserError::MongoError(error)
+    }
+}
+
+// Repository trait
+#[async_trait]
+pub trait UserRepository {
+    async fn create(&self, user: User) -> Result<User, UserError>;
+    async fn get(&self, id: ObjectId) -> Result<User, UserError>;
+    async fn update(&self, id: ObjectId, user: User) -> Result<User, UserError>;
+    async fn delete(&self, id: ObjectId) -> Result<(), UserError>;
+    async fn list(&self, limit: Option<i64>, skip: Option<u64>) -> Result<Vec<User>, UserError>;
+    async fn search(&self, query: String) -> Result<Vec<User>, UserError>;
+    async fn count(&self) -> Result<u64, UserError>;
+    async fn count_by_name(&self, name: String) -> Result<u64, UserError>;
+    async fn count_by_email(&self, email: String) -> Result<u64, UserError>;
+    async fn count_by_phone(&self, phone: String) -> Result<u64, UserError>;
+    async fn count_by_id(&self, id: ObjectId) -> Result<u64, UserError>;
+    async fn find_by_email(&self, email: String) -> Result<Option<User>, UserError>;
+    async fn find_by_username(&self, username: String) -> Result<Option<User>, UserError>;
+    async fn exists_by_email(&self, email: String) -> Result<bool, UserError>;
+    async fn exists_by_username(&self, username: String) -> Result<bool, UserError>;
+    async fn get_active_users(&self) -> Result<Vec<User>, UserError>;
+    async fn get_users_by_role(&self, role: String) -> Result<Vec<User>, UserError>;
+}