feat: add transfer api with test and custom validation

api/account.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"database/sql"
+	"errors"
 	"net/http"
 
 	db "github.com/cukhoaimon/SimpleBank/db/sqlc"
@@ -10,7 +11,7 @@ import (
 
 type createAccountRequest struct {
 	Owner    string `json:"owner" binding:"required"`
-	Currency string `json:"currency" binding:"required,oneof=USD EUR VND"`
+	Currency string `json:"currency" binding:"required,currency"`
 }
 
 func (server *Server) createAccount(ctx *gin.Context) {
@@ -50,7 +51,7 @@ func (server *Server) getAccount(ctx *gin.Context) {
 
 	account, err := server.store.GetAccount(ctx, req.ID)
 	if err != nil {
-		if err == sql.ErrNoRows {
+		if errors.Is(err, sql.ErrNoRows) {
 			ctx.JSON(http.StatusNotFound, errorResponse(err))
 			return
 		}

api/server.go

@@ -1,8 +1,11 @@
 package api
 
 import (
+	"fmt"
 	db "github.com/cukhoaimon/SimpleBank/db/sqlc"
 	"github.com/gin-gonic/gin"
+	"github.com/gin-gonic/gin/binding"
+	"github.com/go-playground/validator/v10"
 )
 
 type Server struct {
@@ -15,11 +18,21 @@ func NewServer(store db.Store) *Server {
 	server := &Server{store: store}
 	router := gin.Default()
 
+	if v, ok := binding.Validator.Engine().(*validator.Validate); ok {
+		err := v.RegisterValidation("currency", validCurrency)
+		if err != nil {
+			fmt.Printf("err %v", err.Error())
+			return nil
+		}
+	}
+
 	// routing here
 	router.GET("/api/v1/account", server.listAccount)
 	router.POST("/api/v1/account", server.createAccount)
 	router.GET("/api/v1/account/:id", server.getAccount)
 
+	router.POST("/api/v1/transfer", server.createTransfer)
+
 	server.router = router
 	return server
 }

api/transfer.go

@@ -0,0 +1,69 @@
+package api
+
+import (
+	"database/sql"
+	"errors"
+	"fmt"
+	db "github.com/cukhoaimon/SimpleBank/db/sqlc"
+	"github.com/gin-gonic/gin"
+	"net/http"
+)
+
+type transferRequest struct {
+	FromAccountID int64  `json:"from_account_id" binding:"required,min=1"`
+	ToAccountID   int64  `json:"to_account_id" binding:"required,min=1"`
+	Amount        int64  `json:"amount" binding:"required,min=1"`
+	Currency      string `json:"currency" binding:"required,currency"`
+}
+
+func (server *Server) createTransfer(ctx *gin.Context) {
+	var req transferRequest
+
+	if err := ctx.ShouldBindJSON(&req); err != nil {
+		ctx.JSON(http.StatusBadRequest, errorResponse(err))
+		return
+	}
+
+	if !server.validAccount(ctx, req.FromAccountID, req.Currency) {
+		return
+	}
+
+	if !server.validAccount(ctx, req.ToAccountID, req.Currency) {
+		return
+	}
+
+	arg := db.TransferTxParams{
+		FromAccountID: req.FromAccountID,
+		ToAccountID:   req.ToAccountID,
+		Amount:        req.Amount,
+	}
+
+	account, err := server.store.TransferTxAccount(ctx, arg)
+	if err != nil {
+		ctx.JSON(http.StatusInternalServerError, errorResponse(err))
+		return
+	}
+
+	ctx.JSON(http.StatusCreated, account)
+}
+
+func (server *Server) validAccount(ctx *gin.Context, accountID int64, currency string) bool {
+	account, err := server.store.GetAccount(ctx, accountID)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			ctx.JSON(http.StatusNotFound, errorResponse(err))
+			return false
+		}
+
+		ctx.JSON(http.StatusInternalServerError, errorResponse(err))
+		return false
+	}
+
+	if account.Currency != currency {
+		err := fmt.Errorf("account [%d] mismatch: %s vs %s ", accountID, account.Currency, currency)
+		ctx.JSON(http.StatusBadRequest, errorResponse(err))
+		return false
+	}
+
+	return true
+}