refactor(backend): 添加 service 缓存端口

backend/internal/repository/billing_cache.go

@@ -0,0 +1,174 @@
+package repository
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log"
+	"strconv"
+	"time"
+
+	"sub2api/internal/service/ports"
+
+	"github.com/redis/go-redis/v9"
+)
+
+const (
+	billingBalanceKeyPrefix = "billing:balance:"
+	billingSubKeyPrefix     = "billing:sub:"
+	billingCacheTTL         = 5 * time.Minute
+)
+
+const (
+	subFieldStatus       = "status"
+	subFieldExpiresAt    = "expires_at"
+	subFieldDailyUsage   = "daily_usage"
+	subFieldWeeklyUsage  = "weekly_usage"
+	subFieldMonthlyUsage = "monthly_usage"
+	subFieldVersion      = "version"
+)
+
+var (
+	deductBalanceScript = redis.NewScript(`
+		local current = redis.call('GET', KEYS[1])
+		if current == false then
+			return 0
+		end
+		local newVal = tonumber(current) - tonumber(ARGV[1])
+		redis.call('SET', KEYS[1], newVal)
+		redis.call('EXPIRE', KEYS[1], ARGV[2])
+		return 1
+	`)
+
+	updateSubUsageScript = redis.NewScript(`
+		local exists = redis.call('EXISTS', KEYS[1])
+		if exists == 0 then
+			return 0
+		end
+		local cost = tonumber(ARGV[1])
+		redis.call('HINCRBYFLOAT', KEYS[1], 'daily_usage', cost)
+		redis.call('HINCRBYFLOAT', KEYS[1], 'weekly_usage', cost)
+		redis.call('HINCRBYFLOAT', KEYS[1], 'monthly_usage', cost)
+		redis.call('EXPIRE', KEYS[1], ARGV[2])
+		return 1
+	`)
+)
+
+type billingCache struct {
+	rdb *redis.Client
+}
+
+func NewBillingCache(rdb *redis.Client) ports.BillingCache {
+	return &billingCache{rdb: rdb}
+}
+
+func (c *billingCache) GetUserBalance(ctx context.Context, userID int64) (float64, error) {
+	key := fmt.Sprintf("%s%d", billingBalanceKeyPrefix, userID)
+	val, err := c.rdb.Get(ctx, key).Result()
+	if err != nil {
+		return 0, err
+	}
+	return strconv.ParseFloat(val, 64)
+}
+
+func (c *billingCache) SetUserBalance(ctx context.Context, userID int64, balance float64) error {
+	key := fmt.Sprintf("%s%d", billingBalanceKeyPrefix, userID)
+	return c.rdb.Set(ctx, key, balance, billingCacheTTL).Err()
+}
+
+func (c *billingCache) DeductUserBalance(ctx context.Context, userID int64, amount float64) error {
+	key := fmt.Sprintf("%s%d", billingBalanceKeyPrefix, userID)
+	_, err := deductBalanceScript.Run(ctx, c.rdb, []string{key}, amount, int(billingCacheTTL.Seconds())).Result()
+	if err != nil && !errors.Is(err, redis.Nil) {
+		log.Printf("Warning: deduct balance cache failed for user %d: %v", userID, err)
+	}
+	return nil
+}
+
+func (c *billingCache) InvalidateUserBalance(ctx context.Context, userID int64) error {
+	key := fmt.Sprintf("%s%d", billingBalanceKeyPrefix, userID)
+	return c.rdb.Del(ctx, key).Err()
+}
+
+func (c *billingCache) GetSubscriptionCache(ctx context.Context, userID, groupID int64) (*ports.SubscriptionCacheData, error) {
+	key := fmt.Sprintf("%s%d:%d", billingSubKeyPrefix, userID, groupID)
+	result, err := c.rdb.HGetAll(ctx, key).Result()
+	if err != nil {
+		return nil, err
+	}
+	if len(result) == 0 {
+		return nil, redis.Nil
+	}
+	return c.parseSubscriptionCache(result)
+}
+
+func (c *billingCache) parseSubscriptionCache(data map[string]string) (*ports.SubscriptionCacheData, error) {
+	result := &ports.SubscriptionCacheData{}
+
+	result.Status = data[subFieldStatus]
+	if result.Status == "" {
+		return nil, errors.New("invalid cache: missing status")
+	}
+
+	if expiresStr, ok := data[subFieldExpiresAt]; ok {
+		expiresAt, err := strconv.ParseInt(expiresStr, 10, 64)
+		if err == nil {
+			result.ExpiresAt = time.Unix(expiresAt, 0)
+		}
+	}
+
+	if dailyStr, ok := data[subFieldDailyUsage]; ok {
+		result.DailyUsage, _ = strconv.ParseFloat(dailyStr, 64)
+	}
+
+	if weeklyStr, ok := data[subFieldWeeklyUsage]; ok {
+		result.WeeklyUsage, _ = strconv.ParseFloat(weeklyStr, 64)
+	}
+
+	if monthlyStr, ok := data[subFieldMonthlyUsage]; ok {
+		result.MonthlyUsage, _ = strconv.ParseFloat(monthlyStr, 64)
+	}
+
+	if versionStr, ok := data[subFieldVersion]; ok {
+		result.Version, _ = strconv.ParseInt(versionStr, 10, 64)
+	}
+
+	return result, nil
+}
+
+func (c *billingCache) SetSubscriptionCache(ctx context.Context, userID, groupID int64, data *ports.SubscriptionCacheData) error {
+	if data == nil {
+		return nil
+	}
+
+	key := fmt.Sprintf("%s%d:%d", billingSubKeyPrefix, userID, groupID)
+
+	fields := map[string]interface{}{
+		subFieldStatus:       data.Status,
+		subFieldExpiresAt:    data.ExpiresAt.Unix(),
+		subFieldDailyUsage:   data.DailyUsage,
+		subFieldWeeklyUsage:  data.WeeklyUsage,
+		subFieldMonthlyUsage: data.MonthlyUsage,
+		subFieldVersion:      data.Version,
+	}
+
+	pipe := c.rdb.Pipeline()
+	pipe.HSet(ctx, key, fields)
+	pipe.Expire(ctx, key, billingCacheTTL)
+	_, err := pipe.Exec(ctx)
+	return err
+}
+
+func (c *billingCache) UpdateSubscriptionUsage(ctx context.Context, userID, groupID int64, cost float64) error {
+	key := fmt.Sprintf("%s%d:%d", billingSubKeyPrefix, userID, groupID)
+	_, err := updateSubUsageScript.Run(ctx, c.rdb, []string{key}, cost, int(billingCacheTTL.Seconds())).Result()
+	if err != nil && !errors.Is(err, redis.Nil) {
+		log.Printf("Warning: update subscription usage cache failed for user %d group %d: %v", userID, groupID, err)
+	}
+	return nil
+}
+
+func (c *billingCache) InvalidateSubscriptionCache(ctx context.Context, userID, groupID int64) error {
+	key := fmt.Sprintf("%s%d:%d", billingSubKeyPrefix, userID, groupID)
+	return c.rdb.Del(ctx, key).Err()
+}