fin-check-api/db/expense.go

129 lines
2.7 KiB
Go

package db
import (
"errors"
"time"
"gorm.io/gorm"
)
type Expense struct {
gorm.Model
CardID uint
Card *Card
Value uint64
Comment string
Date time.Time
UserID uint
User *User
TypeID uint
Type *Type
}
// Implements db.UserIdentifiable:1
func (e Expense) GetID() uint {
return e.ID
}
// Implements db.UserIdentifiable:2
func (e Expense) GetUserID() uint {
return e.UserID
}
// Implements db.UserIdentifiable:3
func (e *Expense) SetUserID(id uint) {
e.UserID = id
}
var (
ERROR_EXPENSE_INVALID_USERID = errors.New("Expense's `UserID` and Card's `UserID` are not equal")
ERROR_EXPENSE_CARD_INSUFFICIENT_BALANCE = errors.New("Card's `Balance` is lower than Expense's Value")
ERROR_EXPENSE_INVALID_TYPE_USERID = errors.New("Expense's `UserID` and Type's `UserID` are not equal")
)
func (e *Expense) BeforeCreate(tx *gorm.DB) error {
card := &Card{}
if err := tx.Find(card, e.CardID).Error; err != nil {
return err
}
if card.UserID != e.UserID {
return ERROR_EXPENSE_INVALID_USERID
}
if card.Balance < e.Value {
return ERROR_EXPENSE_CARD_INSUFFICIENT_BALANCE
}
card.Balance -= e.Value
if err := tx.Save(card).Error; err != nil {
return err
}
typ := &Type{}
if err := tx.Find(typ, e.TypeID).Error; err != nil {
return err
}
if typ.UserID != e.UserID {
return ERROR_EXPENSE_INVALID_TYPE_USERID
}
return nil
}
func (e *Expense) BeforeUpdate(tx *gorm.DB) (err error) {
var original Expense
if err := tx.Model(&Expense{}).Select("card_id", "value").Where("id = ?", e.ID).First(&original).Error; err != nil {
return err
}
if original.CardID != 0 {
oldCard := &Card{}
if err := tx.Find(oldCard, original.CardID).Error; err != nil {
return err
}
if oldCard.UserID != e.UserID {
return ERROR_EXPENSE_INVALID_USERID
}
oldCard.Balance += original.Value
if err := tx.Save(oldCard).Error; err != nil {
return err
}
}
if e.CardID != 0 {
newCard := &Card{}
if err := tx.Find(newCard, e.CardID).Error; err != nil {
return err
}
if newCard.UserID != e.UserID {
return ERROR_EXPENSE_INVALID_USERID
}
if newCard.Balance < e.Value {
return ERROR_EXPENSE_CARD_INSUFFICIENT_BALANCE
}
newCard.Balance -= e.Value
if err := tx.Save(newCard).Error; err != nil {
return err
}
}
typ := &Type{}
if err := tx.Find(typ, e.TypeID).Error; err != nil {
return err
}
if typ.UserID != e.UserID {
return ERROR_EXPENSE_INVALID_TYPE_USERID
}
return nil
}
func (e *Expense) AfterDelete(tx *gorm.DB) (err error) {
card := &Card{}
if err := tx.Find(card, e.CardID).Error; err != nil {
return err
}
if card.UserID != e.UserID {
return ERROR_EXPENSE_INVALID_USERID
}
card.Balance += e.Value
if err := tx.Save(card).Error; err != nil {
return err
}
return nil
}