feat: expand admin user management

admin_users.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"errors"
+	"fmt"
 	"strconv"
 	"strings"
 
@@ -28,10 +30,26 @@ func (a *App) adminListUsers(c *gin.Context) {
 		c.JSON(500, gin.H{"error": err.Error()})
 		return
 	}
-	for i := range users {
-		users[i].PasswordHash = ""
+	type userView struct {
+		User
+		Balance        int64 `json:"balance"`
+		Reserved       int64 `json:"reserved"`
+		Available      int64 `json:"available"`
+		TaskCount      int64 `json:"taskCount"`
+		CompletedCount int64 `json:"completedCount"`
 	}
-	c.JSON(200, gin.H{"data": users})
+	out := make([]userView, 0, len(users))
+	for i := range users {
+		u := users[i]
+		u.PasswordHash = ""
+		var account CreditAccount
+		_ = a.db.Where("user_id = ?", u.ID).First(&account).Error
+		var taskCount, completedCount int64
+		_ = a.db.Model(&Task{}).Where("user_id = ?", u.ID).Count(&taskCount).Error
+		_ = a.db.Model(&Task{}).Where("user_id = ? AND status = ?", u.ID, "done").Count(&completedCount).Error
+		out = append(out, userView{User: u, Balance: account.Balance, Reserved: account.Reserved, Available: account.Balance - account.Reserved, TaskCount: taskCount, CompletedCount: completedCount})
+	}
+	c.JSON(200, gin.H{"data": out})
 }
 
 func (a *App) adminCreateUser(c *gin.Context) {
@@ -88,6 +106,62 @@ func (a *App) adminCreateUser(c *gin.Context) {
 	c.JSON(201, u)
 }
 
+func (a *App) adminAdjustUserCredits(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
+	if err != nil {
+		c.JSON(400, gin.H{"error": "invalid user id"})
+		return
+	}
+	var in struct {
+		Amount int64  `json:"amount"`
+		Reason string `json:"reason"`
+	}
+	if c.BindJSON(&in) != nil || in.Amount == 0 {
+		c.JSON(400, gin.H{"error": "amount must not be zero"})
+		return
+	}
+	operator := c.MustGet("user").(*User)
+	var account CreditAccount
+	err = a.db.Transaction(func(tx *gorm.DB) error {
+		var u User
+		if err := tx.First(&u, id).Error; err != nil {
+			return err
+		}
+		if err := tx.Where("user_id = ?", u.ID).First(&account).Error; err != nil {
+			if err != gorm.ErrRecordNotFound {
+				return err
+			}
+			account = CreditAccount{UserID: u.ID}
+			if err := tx.Create(&account).Error; err != nil {
+				return err
+			}
+		}
+		newBalance := account.Balance + in.Amount
+		if newBalance < account.Reserved {
+			return errors.New("balance cannot be lower than reserved credits")
+		}
+		account.Balance = newBalance
+		if err := tx.Save(&account).Error; err != nil {
+			return err
+		}
+		reason := strings.TrimSpace(in.Reason)
+		if reason == "" {
+			reason = "admin credit adjustment"
+		}
+		return tx.Create(&CreditTransaction{UserID: u.ID, Type: "adjust", Amount: in.Amount, BalanceAfter: account.Balance, ReferenceType: "admin", ReferenceID: strconv.FormatUint(uint64(operator.ID), 10), Reason: reason}).Error
+	})
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			c.JSON(404, gin.H{"error": "user not found"})
+			return
+		}
+		c.JSON(400, gin.H{"error": err.Error()})
+		return
+	}
+	a.audit(operator.ID, "user.credit.adjust", "user", strconv.FormatUint(id, 10), fmt.Sprintf("amount=%d;reason=%s", in.Amount, strings.TrimSpace(in.Reason)))
+	c.JSON(200, gin.H{"balance": account.Balance, "reserved": account.Reserved, "available": account.Balance - account.Reserved})
+}
+
 func (a *App) adminAudit(c *gin.Context) {
 	var logs []AuditLog
 	q := a.db.Order("id desc").Limit(200)