раскидал структуру для монорепозитория

backend/src/services/expense_service.rs

@@ -0,0 +1,95 @@
+use sea_orm::*;
+use sea_orm::prelude::Decimal;
+use chrono::Utc;
+use crate::models::expense::{self, Entity as Expense, Model as ExpenseModel};
+use crate::models::category::{Entity as Category};
+
+pub struct ExpenseService;
+
+impl ExpenseService {
+    pub async fn create(
+        db: &DatabaseConnection,
+        category_id: i32,
+        amount: Decimal,
+        description: Option<String>,
+    ) -> Result<ExpenseModel, DbErr> {
+        let expense = expense::ActiveModel {
+            category_id: Set(category_id),
+            amount: Set(amount),
+            description: Set(description),
+            created_at: Set(Utc::now().naive_utc()),
+            ..Default::default()
+        };
+
+        expense.insert(db).await
+    }
+
+    pub async fn find_by_id(db: &DatabaseConnection, id: i32) -> Result<Option<ExpenseModel>, DbErr> {
+        Expense::find_by_id(id).one(db).await
+    }
+
+    pub async fn find_all(db: &DatabaseConnection) -> Result<Vec<ExpenseModel>, DbErr> {
+        Expense::find().all(db).await
+    }
+
+    pub async fn find_by_category_id(
+        db: &DatabaseConnection,
+        category_id: i32,
+    ) -> Result<Vec<ExpenseModel>, DbErr> {
+        Expense::find()
+            .filter(expense::Column::CategoryId.eq(category_id))
+            .all(db)
+            .await
+    }
+
+    pub async fn update(
+        db: &DatabaseConnection,
+        id: i32,
+        amount: Option<Decimal>,
+        description: Option<String>,
+    ) -> Result<ExpenseModel, DbErr> {
+        let expense = Expense::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::RecordNotFound("Expense not found".to_string()))?;
+
+        let mut expense: expense::ActiveModel = expense.into();
+
+        if let Some(amount) = amount {
+            expense.amount = Set(amount);
+        }
+
+        if let Some(desc) = description {
+            expense.description = Set(Some(desc));
+        }
+
+        expense.update(db).await
+    }
+
+    pub async fn delete(db: &DatabaseConnection, id: i32) -> Result<DeleteResult, DbErr> {
+        let expense = Expense::find_by_id(id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::RecordNotFound("Expense not found".to_string()))?;
+
+        let expense: expense::ActiveModel = expense.into();
+        expense.delete(db).await
+    }
+
+    pub async fn calculate_remaining_limit(
+        db: &DatabaseConnection,
+        category_id: i32,
+    ) -> Result<Decimal, DbErr> {
+        let category = Category::find_by_id(category_id)
+            .one(db)
+            .await?
+            .ok_or(DbErr::RecordNotFound("Category not found".to_string()))?;
+
+        let expenses = Self::find_by_category_id(db, category_id).await?;
+
+        let total_spent: Decimal = expenses.iter().map(|e| e.amount).sum();
+        let remaining = category.limit_amount - total_spent;
+
+        Ok(remaining)
+    }
+}