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

backend/internal/service/gateway_profit_control.go

@@ -0,0 +1,112 @@
+package service
+
+import (
+	"context"
+	"log/slog"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/ctxkey"
+)
+
+// withGatewayProfitControlGate installs the gate only for explicitly marked
+// token requests. This keeps media, metadata, and models-list paths outside
+// the profit-control surface by construction.
+func (s *GatewayService) withGatewayProfitControlGate(ctx context.Context, groupID *int64) context.Context {
+	if _, ok := gatewayTokenRequestPricingAtFromContext(ctx); !ok || groupID == nil || *groupID <= 0 {
+		return ctx
+	}
+	if existing, ok := ctx.Value(openAIProfitControlGateCtxKey{}).(*openAIProfitControlGate); ok && existing != nil && existing.groupID == *groupID {
+		return ctx
+	}
+
+	group, err := s.resolveProfitControlGroup(ctx, *groupID)
+	if err != nil {
+		slog.Warn("profit_control_group_load_failed", "group_id", *groupID, "error", err)
+		return s.clearForeignProfitControlGate(ctx, groupID)
+	}
+	if group == nil || !group.ProfitControlEnabled || !profitControlPlatformSupported(group.Platform) {
+		return s.clearForeignProfitControlGate(ctx, groupID)
+	}
+
+	pricingAt, _ := gatewayTokenRequestPricingAtFromContext(ctx)
+	billingGroup := gatewayTokenRequestBillingGroupFromContext(ctx)
+	if billingGroup == nil {
+		if ctxGroup, ok := ctx.Value(ctxkey.Group).(*Group); ok && IsGroupContextValid(ctxGroup) {
+			billingGroup = ctxGroup
+		} else {
+			billingGroup = group
+		}
+	}
+
+	downstream := billingGroup.RateMultiplier
+	if userID, _ := ctx.Value(ctxkey.UserID).(int64); userID > 0 {
+		downstream = s.ResolveUserGroupRateMultiplier(ctx, userID, billingGroup.ID, billingGroup.RateMultiplier)
+	}
+	downstream *= billingGroup.PeakMultiplierAt(pricingAt)
+	threshold := clampProfitControlThreshold(downstream * (1 - group.ProfitMinMargin - group.ProfitSafetyBuffer))
+
+	gate := &openAIProfitControlGate{
+		groupID:   group.ID,
+		platform:  group.Platform,
+		threshold: threshold,
+		pricingAt: pricingAt,
+	}
+	openAIProfitControlObserverInstance.recordInstall(gate.groupID, gate.platform, gate.threshold)
+	return context.WithValue(ctx, openAIProfitControlGateCtxKey{}, gate)
+}
+
+func (s *GatewayService) clearForeignProfitControlGate(ctx context.Context, groupID *int64) context.Context {
+	existing, ok := ctx.Value(openAIProfitControlGateCtxKey{}).(*openAIProfitControlGate)
+	if !ok || existing == nil || groupID == nil || existing.groupID == *groupID {
+		return ctx
+	}
+	return context.WithValue(ctx, openAIProfitControlGateCtxKey{}, (*openAIProfitControlGate)(nil))
+}
+
+func (s *GatewayService) resolveProfitControlGroup(ctx context.Context, groupID int64) (*Group, error) {
+	if group, ok := ctx.Value(ctxkey.Group).(*Group); ok && IsGroupContextValid(group) && group.ID == groupID {
+		return group, nil
+	}
+	if s.schedulerSnapshot != nil {
+		// Lite 读取：门只用平台/倍率/利润/高峰字段，不需要账号计数聚合。
+		return s.schedulerSnapshot.GetGroupByIDLite(ctx, groupID)
+	}
+	return s.resolveGroupByID(ctx, groupID)
+}
+
+// GatewayProfitControlVetoLatest performs the terminal post-slot check against
+// the latest scheduler snapshot. Snapshot read failures are deliberately
+// fail-open to preserve availability, but are observable.
+func (s *GatewayService) GatewayProfitControlVetoLatest(ctx context.Context, selected *Account) (*Account, bool, string) {
+	return profitControlVetoLatest(ctx, selected, s.schedulerSnapshot)
+}
+
+func profitControlVetoLatest(ctx context.Context, selected *Account, snapshot *SchedulerSnapshotService) (*Account, bool, string) {
+	gate, _ := ctx.Value(openAIProfitControlGateCtxKey{}).(*openAIProfitControlGate)
+	if gate == nil || selected == nil {
+		return selected, false, ""
+	}
+	latest := selected
+	if snapshot != nil {
+		refreshed, err := snapshot.GetAccount(ctx, selected.ID)
+		if err != nil || refreshed == nil {
+			slog.Warn("profit_control_account_refresh_failed", "group_id", gate.groupID, "platform", gate.platform, "account_id", selected.ID, "error", err)
+			openAIProfitControlObserverInstance.recordRefreshFailure(gate.groupID, gate.platform, gate.threshold)
+		} else if !refreshed.UpdatedAt.Before(selected.UpdatedAt) {
+			// 选号路径可能已做过 DB recheck，selected 比缓存快照更新鲜；只有
+			// 快照不落后时才替换，避免终检把新鲜账号换回较旧的缓存对象。
+			latest = refreshed
+		}
+	}
+	vetoed, reason := openAIProfitControlVetoReason(ctx, latest)
+	return latest, vetoed, reason
+}
+
+func (s *GatewayService) isGatewayAccountProfitEligible(ctx context.Context, account *Account) bool {
+	vetoed, _ := openAIProfitControlVetoReason(ctx, account)
+	return !vetoed
+}
+
+func gatewayProfitControlGateActive(ctx context.Context) bool {
+	gate, _ := ctx.Value(openAIProfitControlGateCtxKey{}).(*openAIProfitControlGate)
+	return gate != nil
+}