feat: 添加预算管理功能，包括预算的创建、查询、更新、删除及进度计算。

internal/handler/budget_handler.go

@@ -3,8 +3,8 @@ package handler
 import (
 	"strconv"
 
-	"accounting-app/pkg/api"
 	"accounting-app/internal/service"
+	"accounting-app/pkg/api"
 
 	"github.com/gin-gonic/gin"
 )
@@ -60,8 +60,6 @@ func (h *BudgetHandler) CreateBudget(c *gin.Context) {
 			api.BadRequest(c, err.Error())
 		case service.ErrInvalidPeriodType:
 			api.BadRequest(c, err.Error())
-		case service.ErrCategoryOrAccountRequired:
-			api.BadRequest(c, err.Error())
 		default:
 			api.InternalError(c, "Failed to create budget")
 		}
@@ -150,8 +148,6 @@ func (h *BudgetHandler) UpdateBudget(c *gin.Context) {
 			api.BadRequest(c, err.Error())
 		case service.ErrInvalidPeriodType:
 			api.BadRequest(c, err.Error())
-		case service.ErrCategoryOrAccountRequired:
-			api.BadRequest(c, err.Error())
 		default:
 			api.InternalError(c, "Failed to update budget")
 		}

internal/models/models.go

@@ -278,6 +278,7 @@ type Account struct {
 	PiggyBanks            []PiggyBank            `gorm:"foreignKey:LinkedAccountID" json:"-"`
 	ParentAccount         *Account               `gorm:"foreignKey:ParentAccountID" json:"parent_account,omitempty"`
 	SubAccounts           []Account              `gorm:"foreignKey:ParentAccountID" json:"sub_accounts,omitempty"`
+	Tags                  []Tag                  `gorm:"many2many:account_tags;" json:"tags,omitempty"`
 }
 
 // TableName specifies the table name for Account
@@ -417,6 +418,17 @@ func (TransactionTag) TableName() string {
 	return "transaction_tags"
 }
 
+// AccountTag represents the many-to-many relationship between accounts and tags
+type AccountTag struct {
+	AccountID uint `gorm:"primaryKey" json:"account_id"`
+	TagID     uint `gorm:"primaryKey" json:"tag_id"`
+}
+
+// TableName specifies the table name for AccountTag
+func (AccountTag) TableName() string {
+	return "account_tags"
+}
+
 // Budget represents a spending budget for a category or account
 type Budget struct {
 	BaseModel
@@ -843,6 +855,7 @@ func AllModels() []interface{} {
 		&Tag{},
 		&Transaction{},
 		&TransactionTag{}, // Explicit join table for many-to-many relationship
+		&AccountTag{},     // Explicit join table for account-tag many-to-many relationship
 		&Budget{},
 		&PiggyBank{},
 		&RecurringTransaction{},

internal/service/account_service.go

@@ -32,6 +32,7 @@ type AccountInput struct {
 	PaymentDate      *int               `json:"payment_date,omitempty"`
 	WarningThreshold *float64           `json:"warning_threshold,omitempty"`
 	AccountCode      string             `json:"account_code,omitempty"`
+	TagIDs           []uint             `json:"tag_ids,omitempty"`
 }
 
 // TransferInput represents the input data for a transfer operation
@@ -99,6 +100,18 @@ func (s *AccountService) CreateAccount(userID uint, input AccountInput) (*models
 		return nil, fmt.Errorf("failed to create account: %w", err)
 	}
 
+	// Handle tags association
+	if len(input.TagIDs) > 0 {
+		var tags []models.Tag
+		if err := s.db.Where("id IN ? AND user_id = ?", input.TagIDs, userID).Find(&tags).Error; err != nil {
+			return nil, fmt.Errorf("failed to find tags: %w", err)
+		}
+		if err := s.db.Model(account).Association("Tags").Replace(tags); err != nil {
+			return nil, fmt.Errorf("failed to associate tags: %w", err)
+		}
+		account.Tags = tags
+	}
+
 	return account, nil
 }
 
@@ -117,7 +130,8 @@ func (s *AccountService) GetAccount(userID, id uint) (*models.Account, error) {
 
 // GetAllAccounts retrieves all accounts for a specific user
 func (s *AccountService) GetAllAccounts(userID uint) ([]models.Account, error) {
-	accounts, err := s.repo.GetAll(userID)
+	var accounts []models.Account
+	err := s.db.Where("user_id = ?", userID).Preload("Tags").Order("sort_order ASC, id ASC").Find(&accounts).Error
 	if err != nil {
 		return nil, fmt.Errorf("failed to get accounts: %w", err)
 	}
@@ -164,6 +178,18 @@ func (s *AccountService) UpdateAccount(userID, id uint, input AccountInput) (*mo
 		return nil, fmt.Errorf("failed to update account: %w", err)
 	}
 
+	// Handle tags association
+	var tags []models.Tag
+	if len(input.TagIDs) > 0 {
+		if err := s.db.Where("id IN ? AND user_id = ?", input.TagIDs, userID).Find(&tags).Error; err != nil {
+			return nil, fmt.Errorf("failed to find tags: %w", err)
+		}
+	}
+	if err := s.db.Model(account).Association("Tags").Replace(tags); err != nil {
+		return nil, fmt.Errorf("failed to update tags: %w", err)
+	}
+	account.Tags = tags
+
 	return account, nil
 }
 

internal/service/budget_service.go

@@ -13,12 +13,11 @@ import (
 
 // Service layer errors for budgets
 var (
-	ErrBudgetNotFound            = errors.New("budget not found")
+	ErrBudgetNotFound      = errors.New("budget not found")
-	ErrBudgetInUse               = errors.New("budget is in use and cannot be deleted")
+	ErrBudgetInUse         = errors.New("budget is in use and cannot be deleted")
-	ErrInvalidBudgetAmount       = errors.New("budget amount must be positive")
+	ErrInvalidBudgetAmount = errors.New("budget amount must be positive")
-	ErrInvalidDateRange          = errors.New("end date must be after start date")
+	ErrInvalidDateRange    = errors.New("end date must be after start date")
-	ErrInvalidPeriodType         = errors.New("invalid period type")
+	ErrInvalidPeriodType   = errors.New("invalid period type")
-	ErrCategoryOrAccountRequired = errors.New("either category or account must be specified")
 )
 
 // BudgetInput represents the input data for creating or updating a budget
@@ -72,10 +71,7 @@ func (s *BudgetService) CreateBudget(input BudgetInput) (*models.Budget, error)
 		return nil, ErrInvalidBudgetAmount
 	}
 
-	// Validate that at least category or account is specified
+	// 分类和账户都可选，支持全局预算
-	if input.CategoryID == nil && input.AccountID == nil {
-		return nil, ErrCategoryOrAccountRequired
-	}
 
 	// Validate date range
 	if input.EndDate != nil && input.EndDate.Before(input.StartDate) {
@@ -147,10 +143,7 @@ func (s *BudgetService) UpdateBudget(userID, id uint, input BudgetInput) (*model
 		return nil, ErrInvalidBudgetAmount
 	}
 
-	// Validate that at least category or account is specified
+	// 分类和账户都可选，支持全局预算
-	if input.CategoryID == nil && input.AccountID == nil {
-		return nil, ErrCategoryOrAccountRequired
-	}
 
 	// Validate date range
 	if input.EndDate != nil && input.EndDate.Before(input.StartDate) {
@@ -222,41 +215,55 @@ func (s *BudgetService) GetBudgetProgress(userID, id uint) (*BudgetProgress, err
 	startDate, endDate := s.calculateCurrentPeriod(budget, now)
 
 	// Get spent amount for the current period
-	spent, err := s.repo.GetSpentAmount(budget, startDate, endDate)
+	currentSpent, err := s.repo.GetSpentAmount(budget, startDate, endDate)
 	if err != nil {
 		return nil, fmt.Errorf("failed to calculate spent amount: %w", err)
 	}
 
-	// Calculate effective budget amount (considering rolling budget)
+	// Calculate effective budget amount
 	effectiveAmount := budget.Amount
+	totalSpent := currentSpent
+
 	if budget.IsRolling {
-		// For rolling budgets, add the previous period's remaining balance
+		// 滚动预算：结余自动累加到下一周期
-		prevStartDate, prevEndDate := s.calculatePreviousPeriod(budget, now)
+		// 当期可用额度 = 总额度 - 历史支出
-		prevSpent, err := s.repo.GetSpentAmount(budget, prevStartDate, prevEndDate)
+
-		if err != nil {
+		// 计算已过的完整周期数（不含当期）
-			return nil, fmt.Errorf("failed to calculate previous period spent: %w", err)
+		periodsElapsed := s.calculatePeriodsElapsed(budget, startDate)
-		}
+
-		prevRemaining := budget.Amount - prevSpent
+		// 总额度 = (已过周期数 + 当期) × 单期额度
-		if prevRemaining > 0 {
+		totalBudget := budget.Amount * float64(periodsElapsed+1)
-			effectiveAmount += prevRemaining
+
+		// 获取历史支出（从预算开始到当期开始前一秒）
+		historyEnd := startDate.Add(-time.Second)
+		historySpent := 0.0
+		if historyEnd.After(budget.StartDate) {
+			historySpent, err = s.repo.GetSpentAmount(budget, budget.StartDate, historyEnd)
+			if err != nil {
+				return nil, fmt.Errorf("failed to calculate history spent: %w", err)
+			}
 		}
+
+		// 当期可用额度 = 总额度 - 历史支出
+		effectiveAmount = totalBudget - historySpent
+		totalSpent = currentSpent
 	}
 
 	// Calculate progress metrics
-	remaining := effectiveAmount - spent
+	remaining := effectiveAmount - totalSpent
 	progress := 0.0
 	if effectiveAmount > 0 {
-		progress = (spent / effectiveAmount) * 100
+		progress = (totalSpent / effectiveAmount) * 100
 	}
 
-	isOverBudget := spent > effectiveAmount
+	isOverBudget := totalSpent > effectiveAmount
 	isNearLimit := progress >= 80.0 && !isOverBudget
 
 	return &BudgetProgress{
 		BudgetID:      budget.ID,
 		Name:          budget.Name,
 		Amount:        effectiveAmount,
-		Spent:         spent,
+		Spent:         totalSpent,
 		Remaining:     remaining,
 		Progress:      progress,
 		PeriodType:    budget.PeriodType,
@@ -353,6 +360,41 @@ func (s *BudgetService) calculatePreviousPeriod(budget *models.Budget, reference
 	}
 }
 
+// calculatePeriodsElapsed 计算从预算开始日期到当前周期开始日期之间的完整周期数
+func (s *BudgetService) calculatePeriodsElapsed(budget *models.Budget, currentPeriodStart time.Time) int {
+	if currentPeriodStart.Before(budget.StartDate) || currentPeriodStart.Equal(budget.StartDate) {
+		return 0
+	}
+
+	var periods int
+	switch budget.PeriodType {
+	case models.PeriodTypeDaily:
+		periods = int(currentPeriodStart.Sub(budget.StartDate).Hours() / 24)
+
+	case models.PeriodTypeWeekly:
+		periods = int(currentPeriodStart.Sub(budget.StartDate).Hours() / (24 * 7))
+
+	case models.PeriodTypeMonthly:
+		yearDiff := currentPeriodStart.Year() - budget.StartDate.Year()
+		monthDiff := int(currentPeriodStart.Month()) - int(budget.StartDate.Month())
+		periods = yearDiff*12 + monthDiff
+
+	case models.PeriodTypeYearly:
+		periods = currentPeriodStart.Year() - budget.StartDate.Year()
+
+	default:
+		yearDiff := currentPeriodStart.Year() - budget.StartDate.Year()
+		monthDiff := int(currentPeriodStart.Month()) - int(budget.StartDate.Month())
+		periods = yearDiff*12 + monthDiff
+	}
+
+	// 确保返回非负数
+	if periods < 0 {
+		return 0
+	}
+	return periods
+}
+
 // isValidPeriodType checks if a period type is valid
 func isValidPeriodType(periodType models.PeriodType) bool {
 	switch periodType {