add api for getting total income/expense amounts by month

pkg/api/transactions.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"sort"
+	"strings"
 
 	"github.com/mayswind/lab/pkg/core"
 	"github.com/mayswind/lab/pkg/errs"
@@ -11,6 +12,8 @@ import (
 	"github.com/mayswind/lab/pkg/utils"
 )
 
+const pageCountForLoadTransactionAmounts = 1000
+
 // TransactionsApi represents transaction api
 type TransactionsApi struct {
 	transactions          *services.TransactionService
@@ -335,6 +338,112 @@ func (a *TransactionsApi) TransactionAmountsHandler(c *core.Context) (interface{
 	return amountsResp, nil
 }
 
+// TransactionMonthAmountsHandler returns every month transaction amounts of current user
+func (a *TransactionsApi) TransactionMonthAmountsHandler(c *core.Context) (interface{}, *errs.Error) {
+	var transactionAmountsReq models.TransactionMonthAmountsRequest
+	err := c.ShouldBindQuery(&transactionAmountsReq)
+
+	if err != nil {
+		log.WarnfWithRequestId(c, "[transactions.TransactionMonthAmountsHandler] parse request failed, because %s", err.Error())
+		return nil, errs.NewIncompleteOrIncorrectSubmissionError(err)
+	}
+
+	utcOffset, err := c.GetClientTimezoneOffset()
+
+	if err != nil {
+		log.WarnfWithRequestId(c, "[transactions.TransactionMonthAmountsHandler] cannot get client timezone offset, because %s", err.Error())
+		return nil, errs.ErrClientTimezoneOffsetInvalid
+	}
+
+	startTime, endTime, err := transactionAmountsReq.GetStartTimeAndEndTime(utcOffset)
+
+	if err != nil {
+		log.WarnfWithRequestId(c, "[transactions.TransactionMonthAmountsHandler] parse request start or end date failed, because %s", err.Error())
+		return nil, errs.ErrParameterInvalid
+	}
+
+	uid := c.GetCurrentUid()
+
+	accounts, err := a.accounts.GetAllAccountsByUid(uid)
+	accountMap := a.accounts.GetAccountMapByList(accounts)
+
+	if err != nil {
+		log.ErrorfWithRequestId(c, "[transactions.TransactionMonthAmountsHandler] failed to get all accounts for user \"uid:%d\", because %s", uid, err.Error())
+		return nil, errs.ErrOperationFailed
+	}
+
+	totalAmounts, err := a.transactions.GetAccountsMonthTotalIncomeAndExpense(uid, startTime, endTime, pageCountForLoadTransactionAmounts)
+	amountsMap := make(map[string]map[string]*models.TransactionAmountsResponseItemAmountInfo)
+
+	for yearMonth, monthAccountsAmounts := range totalAmounts {
+		for accountId, monthAccountAmounts := range monthAccountsAmounts {
+			account, exists := accountMap[accountId]
+
+			if !exists {
+				log.WarnfWithRequestId(c, "[transactions.TransactionMonthAmountsHandler] cannot find account for account \"id:%d\" of user \"uid:%d\", because %s", accountId, uid)
+				continue
+			}
+
+			monthTotalAmounts, exists := amountsMap[yearMonth]
+
+			if !exists {
+				monthTotalAmounts = make(map[string]*models.TransactionAmountsResponseItemAmountInfo)
+				amountsMap[yearMonth] = monthTotalAmounts
+			}
+
+			monthTotalAmount, exists := monthTotalAmounts[account.Currency]
+
+			if !exists {
+				monthTotalAmount = &models.TransactionAmountsResponseItemAmountInfo{
+					Currency: account.Currency,
+					IncomeAmount: 0,
+					ExpenseAmount: 0,
+				}
+			}
+
+			monthTotalAmount.IncomeAmount += monthAccountAmounts.TotalIncomeAmount
+			monthTotalAmount.ExpenseAmount += monthAccountAmounts.TotalExpenseAmount
+
+			monthTotalAmounts[account.Currency] = monthTotalAmount
+		}
+	}
+
+	amountsResp := make(models.TransactionMonthAmountsResponseItemSlice, 0)
+
+	for yearMonth, monthTotalAmounts := range amountsMap {
+		yearMonthItems := strings.Split(yearMonth, "-")
+		year, err := utils.StringToInt32(yearMonthItems[0])
+
+		if err != nil {
+			log.WarnfWithRequestId(c, "[transactions.TransactionMonthAmountsHandler] cannot get year from year-month item \"%s\" for user \"uid:%d\", because %s", yearMonth, uid)
+			continue
+		}
+
+		month, err := utils.StringToInt32(yearMonthItems[1])
+
+		if err != nil {
+			log.WarnfWithRequestId(c, "[transactions.TransactionMonthAmountsHandler] cannot get month from year-month item \"%s\" for user \"uid:%d\", because %s", yearMonth, uid)
+			continue
+		}
+
+		amounts := make([]*models.TransactionAmountsResponseItemAmountInfo, 0, len(monthTotalAmounts))
+
+		for _, monthTotalAmount := range monthTotalAmounts {
+			amounts = append(amounts, monthTotalAmount)
+		}
+
+		amountsResp = append(amountsResp, &models.TransactionMonthAmountsResponseItem{
+			Year: year,
+			Month: month,
+			Amounts: amounts,
+		})
+	}
+
+	sort.Sort(amountsResp)
+
+	return amountsResp, nil
+}
+
 // TransactionGetHandler returns one specific transaction of current user
 func (a *TransactionsApi) TransactionGetHandler(c *core.Context) (interface{}, *errs.Error) {
 	var transactionGetReq models.TransactionGetRequest