try to do better

backend/src/services/expense_service.rs

@@ -1,9 +1,18 @@
 use sea_orm::*;
 use sea_orm::prelude::Decimal;
-use chrono::Utc;
+use chrono::{Utc, Datelike};
+use std::collections::HashMap;
 use crate::models::expense::{self, Entity as Expense, Model as ExpenseModel};
 use crate::models::category::{Entity as Category};
 
+#[derive(Debug, Clone)]
+pub struct MonthlyExpenseGroup {
+    pub year: i32,
+    pub month: u32,
+    pub total_amount: Decimal,
+    pub expenses: Vec<ExpenseModel>,
+}
+
 pub struct ExpenseService;
 
 impl ExpenseService {
@@ -18,6 +27,7 @@ impl ExpenseService {
             amount: Set(amount),
             description: Set(description),
             created_at: Set(Utc::now().naive_utc()),
+            active: Set(true),
             ..Default::default()
         };
 
@@ -38,6 +48,28 @@ impl ExpenseService {
     ) -> Result<Vec<ExpenseModel>, DbErr> {
         Expense::find()
             .filter(expense::Column::CategoryId.eq(category_id))
+            .filter(expense::Column::Active.eq(true))
+            .all(db)
+            .await
+    }
+
+    pub async fn find_all_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 find_inactive_by_category_id(
+        db: &DatabaseConnection,
+        category_id: i32,
+    ) -> Result<Vec<ExpenseModel>, DbErr> {
+        Expense::find()
+            .filter(expense::Column::CategoryId.eq(category_id))
+            .filter(expense::Column::Active.eq(false))
             .all(db)
             .await
     }
@@ -66,14 +98,15 @@ impl ExpenseService {
         expense.update(db).await
     }
 
-    pub async fn delete(db: &DatabaseConnection, id: i32) -> Result<DeleteResult, DbErr> {
+    pub async fn delete(db: &DatabaseConnection, id: i32) -> Result<ExpenseModel, 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
+        let mut expense: expense::ActiveModel = expense.into();
+        expense.active = Set(false);
+        expense.update(db).await
     }
 
     pub async fn calculate_remaining_limit(
@@ -92,4 +125,60 @@ impl ExpenseService {
 
         Ok(remaining)
     }
+
+    pub async fn get_expense_history(
+        db: &DatabaseConnection,
+        category_id: i32,
+        sort_order: Option<String>,
+        show_archive: bool,
+    ) -> Result<Vec<MonthlyExpenseGroup>, DbErr> {
+        let expenses = if show_archive {
+            Self::find_inactive_by_category_id(db, category_id).await?
+        } else {
+            Self::find_by_category_id(db, category_id).await?
+        };
+
+        let mut grouped: HashMap<(i32, u32), Vec<ExpenseModel>> = HashMap::new();
+
+        for expense in expenses {
+            let year = expense.created_at.year();
+            let month = expense.created_at.month();
+            grouped.entry((year, month))
+                .or_insert_with(Vec::new)
+                .push(expense);
+        }
+
+        let mut result: Vec<MonthlyExpenseGroup> = grouped
+            .into_iter()
+            .map(|((year, month), expenses)| {
+                let total_amount: Decimal = expenses
+                    .iter()
+                    .filter(|e| e.active)
+                    .map(|e| e.amount)
+                    .sum();
+                MonthlyExpenseGroup {
+                    year,
+                    month,
+                    total_amount,
+                    expenses,
+                }
+            })
+            .collect();
+
+        let sort_desc = sort_order
+            .as_deref()
+            .map(|s| s.to_lowercase() == "desc")
+            .unwrap_or(true);
+
+        result.sort_by(|a, b| {
+            let cmp = a.year.cmp(&b.year).then(a.month.cmp(&b.month));
+            if sort_desc {
+                cmp.reverse()
+            } else {
+                cmp
+            }
+        });
+
+        Ok(result)
+    }
 }