add api for getting total income/expense amounts by month

pkg/services/transactions.go

@@ -969,6 +969,73 @@ func (s *TransactionService) GetAccountsTotalIncomeAndExpense(uid int64, startUn
 	return incomeAmounts, expenseAmounts, nil
 }
 
+// GetAccountsMonthTotalIncomeAndExpense returns the every accounts total income and expense amount in month by specific date range
+func (s *TransactionService) GetAccountsMonthTotalIncomeAndExpense(uid int64, startUnixTime int64, endUnixTime int64, pageCount int) (map[string]models.TransactionAccountsAmount, error) {
+	if uid <= 0 {
+		return nil, errs.ErrUserIdInvalid
+	}
+
+	startTransactionTime := utils.GetMinTransactionTimeFromUnixTime(startUnixTime)
+	endTransactionTime := utils.GetMaxTransactionTimeFromUnixTime(endUnixTime)
+
+	minTransactionTime := startTransactionTime
+	maxTransactionTime := endTransactionTime
+	var allTransactions []*models.Transaction
+
+	for maxTransactionTime > 0 {
+		var transactions []*models.Transaction
+
+		err := s.UserDataDB(uid).Select("uid, type, account_id, transaction_time, timezone_utc_offset, amount").Where("uid=? AND deleted=? AND (type=? OR type=?) AND transaction_time>=? AND transaction_time<=?", uid, false, models.TRANSACTION_DB_TYPE_INCOME, models.TRANSACTION_DB_TYPE_EXPENSE, minTransactionTime, maxTransactionTime).Limit(pageCount, 0).OrderBy("transaction_time desc").Find(&transactions)
+
+		if err != nil {
+			return nil, err
+		}
+
+		allTransactions = append(allTransactions, transactions...)
+
+		if len(transactions) < pageCount {
+			maxTransactionTime = 0
+			break
+		}
+
+		maxTransactionTime = transactions[len(transactions)-1].TransactionTime - 1
+	}
+
+	totalAmounts := make(map[string]models.TransactionAccountsAmount)
+
+	for i := 0; i < len(allTransactions); i++ {
+		transaction := allTransactions[i]
+		transactionTimeZone := time.FixedZone("Transaction Timezone", int(transaction.TimezoneUtcOffset)*60)
+		yearMonth := utils.FormatUnixTimeToYearMonth(utils.GetUnixTimeFromTransactionTime(transaction.TransactionTime), transactionTimeZone)
+
+		monthAccountsAmounts, exists := totalAmounts[yearMonth]
+
+		if !exists {
+			monthAccountsAmounts = make(models.TransactionAccountsAmount)
+			totalAmounts[yearMonth] = monthAccountsAmounts
+		}
+
+		monthAccountAmount, exists := monthAccountsAmounts[transaction.AccountId]
+
+		if !exists {
+			monthAccountAmount = &models.TransactionAccountAmount{
+				AccountId: transaction.AccountId,
+				TotalIncomeAmount: 0,
+				TotalExpenseAmount: 0,
+			}
+			monthAccountsAmounts[transaction.AccountId] = monthAccountAmount
+		}
+
+		if transaction.Type == models.TRANSACTION_DB_TYPE_INCOME {
+			monthAccountAmount.TotalIncomeAmount += transaction.Amount
+		} else if transaction.Type == models.TRANSACTION_DB_TYPE_EXPENSE {
+			monthAccountAmount.TotalExpenseAmount += transaction.Amount
+		}
+	}
+
+	return totalAmounts, nil
+}
+
 // GetAccountsAndCategoriesTotalIncomeAndExpense returns the every accounts and categories total income and expense amount by specific date range
 func (s *TransactionService) GetAccountsAndCategoriesTotalIncomeAndExpense(uid int64, startUnixTime int64, endUnixTime int64) ([]*models.Transaction, error) {
 	if uid <= 0 {