From f29a14ad51d84224032419e11060d69f85ad9320 Mon Sep 17 00:00:00 2001
From: MaysWind <i@mayswind.net>
Date: Sun, 17 Jan 2021 23:41:17 +0800
Subject: [PATCH] add transaction statistics api

---
 cmd/webserver.go             |  3 ++
 pkg/api/statistics.go        | 53 ++++++++++++++++++++++++++++++++++++
 pkg/models/statistic.go      | 21 ++++++++++++++
 pkg/services/transactions.go | 19 +++++++++++++
 4 files changed, 96 insertions(+)
 create mode 100644 pkg/api/statistics.go
 create mode 100644 pkg/models/statistic.go

diff --git a/cmd/webserver.go b/cmd/webserver.go
index 6d3cbe68..a2b31630 100644
--- a/cmd/webserver.go
+++ b/cmd/webserver.go
@@ -224,6 +224,9 @@ func startWebServer(c *cli.Context) error {
 			apiV1Route.POST("/transaction/tags/move.json", bindApi(api.TransactionTags.TagMoveHandler))
 			apiV1Route.POST("/transaction/tags/delete.json", bindApi(api.TransactionTags.TagDeleteHandler))
 
+			// Statistics
+			apiV1Route.GET("/statistics/transaction.json", bindApi(api.Statistics.TransactionStatisticsHandler))
+
 			// Exchange Rates
 			apiV1Route.GET("/exchange_rates/latest.json", bindApi(api.ExchangeRates.LatestExchangeRateHandler))
 		}
diff --git a/pkg/api/statistics.go b/pkg/api/statistics.go
new file mode 100644
index 00000000..18849972
--- /dev/null
+++ b/pkg/api/statistics.go
@@ -0,0 +1,53 @@
+package api
+
+import (
+	"github.com/mayswind/lab/pkg/core"
+	"github.com/mayswind/lab/pkg/errs"
+	"github.com/mayswind/lab/pkg/log"
+	"github.com/mayswind/lab/pkg/models"
+	"github.com/mayswind/lab/pkg/services"
+)
+
+// StatisticApi represents statistic api
+type StatisticApi struct {
+	transactions *services.TransactionService
+}
+
+// Initialize an statistic api singleton instance
+var (
+	Statistics = &StatisticApi{
+		transactions: services.Transactions,
+	}
+)
+
+// TransactionStatisticsHandler returns transaction statistics of current user
+func (a *StatisticApi) TransactionStatisticsHandler(c *core.Context) (interface{}, *errs.Error) {
+	var statisticReq models.TransactionStatisticRequest
+	err := c.ShouldBindQuery(&statisticReq)
+
+	if err != nil {
+		log.WarnfWithRequestId(c, "[statistics.TransactionOverviewHandler] parse request failed, because %s", err.Error())
+		return nil, errs.NewIncompleteOrIncorrectSubmissionError(err)
+	}
+
+	uid := c.GetCurrentUid()
+	totalAmounts, err := a.transactions.GetAccountsAndCategoriesTotalIncomeAndExpense(uid, statisticReq.StartTime, statisticReq.EndTime)
+
+	statisticResp := &models.TransactionStatisticResponse{
+		StartTime: statisticReq.StartTime,
+		EndTime:   statisticReq.EndTime,
+	}
+
+	statisticResp.Items = make([]*models.TransactionStatisticResponseItem, len(totalAmounts))
+
+	for i := 0; i < len(totalAmounts); i++ {
+		totalAmountItem := totalAmounts[i]
+		statisticResp.Items[i] = &models.TransactionStatisticResponseItem{
+			CategoryId:  totalAmountItem.CategoryId,
+			AccountId:   totalAmountItem.AccountId,
+			TotalAmount: totalAmountItem.Amount,
+		}
+	}
+
+	return statisticResp, nil
+}
diff --git a/pkg/models/statistic.go b/pkg/models/statistic.go
new file mode 100644
index 00000000..421117ba
--- /dev/null
+++ b/pkg/models/statistic.go
@@ -0,0 +1,21 @@
+package models
+
+// TransactionStatisticRequest represents all parameters of transaction statistic request
+type TransactionStatisticRequest struct {
+	StartTime int64 `form:"start_time" binding:"min=0"`
+	EndTime   int64 `form:"end_time" binding:"min=0"`
+}
+
+// TransactionStatisticResponse represents an item of transaction overview
+type TransactionStatisticResponse struct {
+	StartTime int64                               `json:"startTime"`
+	EndTime   int64                               `json:"endTime"`
+	Items     []*TransactionStatisticResponseItem `json:"items"`
+}
+
+// TransactionStatisticResponseItem represents total amount item for an response
+type TransactionStatisticResponseItem struct {
+	CategoryId  int64 `json:"categoryId,string"`
+	AccountId   int64 `json:"accountId,string"`
+	TotalAmount int64 `json:"amount"`
+}
diff --git a/pkg/services/transactions.go b/pkg/services/transactions.go
index 76445b26..66fac319 100644
--- a/pkg/services/transactions.go
+++ b/pkg/services/transactions.go
@@ -955,6 +955,25 @@ func (s *TransactionService) GetAccountsTotalIncomeAndExpense(uid int64, startUn
 	return incomeAmounts, expenseAmounts, 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 {
+		return nil, errs.ErrUserIdInvalid
+	}
+
+	startTransactionTime := utils.GetMinTransactionTimeFromUnixTime(startUnixTime)
+	endTransactionTime := utils.GetMaxTransactionTimeFromUnixTime(endUnixTime)
+
+	var transactionTotalAmounts []*models.Transaction
+	err := s.UserDataDB(uid).Select("uid, category_id, account_id, SUM(amount) as 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, startTransactionTime, endTransactionTime).GroupBy("category_id, account_id").Find(&transactionTotalAmounts)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return transactionTotalAmounts, nil
+}
+
 // GetTransactionMapByList returns a transaction map by a list
 func (s *TransactionService) GetTransactionMapByList(transactions []*models.Transaction) map[int64]*models.Transaction {
 	transactionMap := make(map[int64]*models.Transaction)