Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

backend/internal/service/user_subscription.go

@@ -0,0 +1,225 @@
+package service
+
+import (
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/timezone"
+)
+
+const subscriptionDayDuration = 24 * time.Hour
+
+type UserSubscription struct {
+	ID      int64
+	UserID  int64
+	GroupID int64
+
+	StartsAt  time.Time
+	ExpiresAt time.Time
+	Status    string
+
+	DailyWindowStart   *time.Time
+	WeeklyWindowStart  *time.Time
+	MonthlyWindowStart *time.Time
+
+	DailyUsageUSD   float64
+	WeeklyUsageUSD  float64
+	MonthlyUsageUSD float64
+
+	AssignedBy *int64
+	AssignedAt time.Time
+	Notes      string
+
+	CreatedAt time.Time
+	UpdatedAt time.Time
+	DeletedAt *time.Time
+
+	User           *User
+	Group          *Group
+	AssignedByUser *User
+}
+
+func (s *UserSubscription) IsActive() bool {
+	return s.Status == SubscriptionStatusActive && time.Now().Before(s.ExpiresAt)
+}
+
+func (s *UserSubscription) IsExpired() bool {
+	return time.Now().After(s.ExpiresAt)
+}
+
+func (s *UserSubscription) DaysRemaining() int {
+	return s.daysRemainingAt(time.Now())
+}
+
+func (s *UserSubscription) daysRemainingAt(now time.Time) int {
+	remaining := s.ExpiresAt.Sub(now)
+	if remaining <= 0 {
+		return 0
+	}
+
+	days := int(remaining / subscriptionDayDuration)
+	if remaining%subscriptionDayDuration != 0 {
+		days++
+	}
+	return days
+}
+
+func (s *UserSubscription) IsWindowActivated() bool {
+	return s.DailyWindowStart != nil || s.WeeklyWindowStart != nil || s.MonthlyWindowStart != nil
+}
+
+func (s *UserSubscription) HasOneTimeDailyQuota() bool {
+	if s == nil || s.StartsAt.IsZero() || s.ExpiresAt.IsZero() {
+		return false
+	}
+	return !s.ExpiresAt.After(s.StartsAt.AddDate(0, 0, 1))
+}
+
+func (s *UserSubscription) NeedsDailyReset() bool {
+	return s.NeedsDailyResetAt(time.Now())
+}
+
+func (s *UserSubscription) NeedsDailyResetAt(now time.Time) bool {
+	_, ok := s.automaticDailyWindowStartAt(now)
+	return ok
+}
+
+func (s *UserSubscription) NeedsWeeklyReset() bool {
+	return s.NeedsWeeklyResetAt(time.Now())
+}
+
+func (s *UserSubscription) NeedsWeeklyResetAt(now time.Time) bool {
+	if s.WeeklyWindowStart == nil {
+		return false
+	}
+	return !now.Before(s.WeeklyWindowStart.Add(7 * 24 * time.Hour))
+}
+
+func (s *UserSubscription) NeedsMonthlyReset() bool {
+	return s.NeedsMonthlyResetAt(time.Now())
+}
+
+func (s *UserSubscription) NeedsMonthlyResetAt(now time.Time) bool {
+	if s.MonthlyWindowStart == nil {
+		return false
+	}
+	return !now.Before(s.MonthlyWindowStart.Add(30 * 24 * time.Hour))
+}
+
+func (s *UserSubscription) canAutomaticallyResetDailyAt(now time.Time) bool {
+	_, ok := s.automaticDailyWindowStartAt(now)
+	return ok
+}
+
+// automaticDailyWindowStartAt 计算日窗口按“配置时区日历日”对齐后的当前窗口起点。
+// 日额度固定在每天 0 点刷新（与周/月的期限对齐滚动窗口语义不同），因此只要持久化
+// 的窗口起点落在更早的日历日，就允许推进到今天 0 点。手动重置、激活等写入的任何
+// 非 0 点锚点都会在下一个 0 点被拉回日历日边界，不会永久漂移刷新时刻。
+func (s *UserSubscription) automaticDailyWindowStartAt(now time.Time) (time.Time, bool) {
+	if s.DailyWindowStart == nil {
+		return time.Time{}, false
+	}
+	if s.HasOneTimeDailyQuota() {
+		return time.Time{}, false
+	}
+	today := timezone.StartOfDay(now)
+	if !today.After(timezone.StartOfDay(*s.DailyWindowStart)) {
+		return time.Time{}, false
+	}
+	return today, true
+}
+
+func (s *UserSubscription) canAutomaticallyResetWeeklyAt(now time.Time) bool {
+	_, ok := s.automaticWindowStartAt(s.WeeklyWindowStart, 7*24*time.Hour, now)
+	return ok
+}
+
+func (s *UserSubscription) canAutomaticallyResetMonthlyAt(now time.Time) bool {
+	_, ok := s.automaticWindowStartAt(s.MonthlyWindowStart, 30*24*time.Hour, now)
+	return ok
+}
+
+// automaticWindowStartAt 计算周/月窗口（期限对齐滚动窗口）的当前窗口起点。
+// 窗口从锚点按整数个 period 步进，且不越过订阅到期时间，避免最后一个不完整
+// 周期重复发放额度（issue #5051）。日窗口不走此函数，见 automaticDailyWindowStartAt。
+func (s *UserSubscription) automaticWindowStartAt(previous *time.Time, period time.Duration, now time.Time) (time.Time, bool) {
+	if previous == nil {
+		return time.Time{}, false
+	}
+
+	anchor := *previous
+	// Older subscriptions initialized their first windows at midnight on their
+	// start date. Only that initial value is unambiguous; later midnight anchors
+	// may be manual resets and must remain authoritative.
+	legacyAnchor := startOfDay(s.StartsAt)
+	if legacyAnchor.Before(s.StartsAt) && anchor.Equal(legacyAnchor) {
+		anchor = s.StartsAt
+	}
+	next := anchor.Add(period)
+	if now.Before(next) || !next.Before(s.ExpiresAt) {
+		return time.Time{}, false
+	}
+
+	periods := now.Sub(anchor) / period
+	lastPeriodBeforeExpiry := (s.ExpiresAt.Sub(anchor) - 1) / period
+	if periods > lastPeriodBeforeExpiry {
+		periods = lastPeriodBeforeExpiry
+	}
+	return anchor.Add(periods * period), true
+}
+
+func (s *UserSubscription) DailyResetTime() *time.Time {
+	if s.DailyWindowStart == nil {
+		return nil
+	}
+	if s.HasOneTimeDailyQuota() {
+		t := s.ExpiresAt
+		return &t
+	}
+	// 日窗口按日历日对齐：下次刷新固定在窗口起点所在日的次日 0 点。
+	t := timezone.StartOfDay(*s.DailyWindowStart).AddDate(0, 0, 1)
+	return &t
+}
+
+func (s *UserSubscription) WeeklyResetTime() *time.Time {
+	if s.WeeklyWindowStart == nil {
+		return nil
+	}
+	t := s.WeeklyWindowStart.Add(7 * 24 * time.Hour)
+	return &t
+}
+
+func (s *UserSubscription) MonthlyResetTime() *time.Time {
+	if s.MonthlyWindowStart == nil {
+		return nil
+	}
+	t := s.MonthlyWindowStart.Add(30 * 24 * time.Hour)
+	return &t
+}
+
+func (s *UserSubscription) CheckDailyLimit(group *Group, additionalCost float64) bool {
+	if !group.HasDailyLimit() {
+		return true
+	}
+	return s.DailyUsageUSD+additionalCost <= *group.DailyLimitUSD
+}
+
+func (s *UserSubscription) CheckWeeklyLimit(group *Group, additionalCost float64) bool {
+	if !group.HasWeeklyLimit() {
+		return true
+	}
+	return s.WeeklyUsageUSD+additionalCost <= *group.WeeklyLimitUSD
+}
+
+func (s *UserSubscription) CheckMonthlyLimit(group *Group, additionalCost float64) bool {
+	if !group.HasMonthlyLimit() {
+		return true
+	}
+	return s.MonthlyUsageUSD+additionalCost <= *group.MonthlyLimitUSD
+}
+
+func (s *UserSubscription) CheckAllLimits(group *Group, additionalCost float64) (daily, weekly, monthly bool) {
+	daily = s.CheckDailyLimit(group, additionalCost)
+	weekly = s.CheckWeeklyLimit(group, additionalCost)
+	monthly = s.CheckMonthlyLimit(group, additionalCost)
+	return
+}