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

backend/internal/service/profit_preview.go

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+package service
+
+// 分组利润控制离线预演：使用生产只读导出的分组配置、账号倍率、探测状态、
+// 用户覆盖倍率与主力模型清单，复用线上 U/D/epsilon 语义推演准入。
+// 探测状态仅用于解释账号倍率来源是否健康，不影响准入结论。
+
+import (
+	"math"
+	"sort"
+	"time"
+)
+
+const (
+	ProfitPreviewRateSourceManual        = "manual"
+	ProfitPreviewRateSourceUpstreamProbe = "upstream_probe_sync"
+
+	ProfitPreviewWarningProbeMissing     = "probe_snapshot_missing"
+	ProfitPreviewWarningProbeStale       = "probe_snapshot_stale"
+	ProfitPreviewWarningProbeFailed      = "probe_failed"
+	ProfitPreviewWarningProbeUnsupported = "probe_unsupported"
+	ProfitPreviewWarningManualRateOne    = "manual_rate_1_suspected_unmaintained"
+)
+
+// ProfitPreviewGroupInput 是一个分组的预演输入。
+type ProfitPreviewGroupInput struct {
+	Group *Group
+	// Accounts 为该分组绑定且状态可调度的账号，允许 Anthropic/Gemini 分组中
+	// 参与 mixed scheduling 的 Antigravity 账号。
+	Accounts []*Account
+	// UserOverrides 为该分组所有用户覆盖倍率（user_id → 倍率）。
+	UserOverrides map[int64]float64
+	// Models 为该分组近期主力模型清单。
+	Models []string
+	// AssumeEnabled 在分组当前关闭时仍按其保存配置启用利润门，供部署前执行
+	// “先关组、预演、逐组重开”。
+	AssumeEnabled bool
+}
+
+// 预演账号分类与线上否决原因一一对应。
+const (
+	ProfitPreviewClassAdmitted            = "admitted"
+	ProfitPreviewClassRejectedThreshold   = "rejected_threshold"
+	ProfitPreviewClassRejectedInvalidRate = "rejected_invalid_account_rate"
+)
+
+// ProfitPreviewAccountVerdict 是单账号的预演结论。
+type ProfitPreviewAccountVerdict struct {
+	AccountID   int64    `json:"account_id"`
+	Name        string   `json:"name"`
+	Platform    string   `json:"platform"`
+	Class       string   `json:"class"`
+	AccountRate *float64 `json:"account_rate,omitempty"`
+	RateSource  string   `json:"rate_source"`
+	Warnings    []string `json:"warnings,omitempty"`
+	// RejectedUnderMinD 表示账号在最低有效 D（用户覆盖最坏口径）下会被排除。
+	RejectedUnderMinD bool `json:"rejected_under_min_d,omitempty"`
+	// SupportedModels 为该账号支持的主力模型子集。
+	SupportedModels []string `json:"supported_models,omitempty"`
+}
+
+// ProfitPreviewGroupReport 是单分组的预演报告。
+type ProfitPreviewGroupReport struct {
+	GroupID        int64  `json:"group_id"`
+	GroupName      string `json:"group_name"`
+	Platform       string `json:"platform"`
+	EffectiveGate  bool   `json:"effective_gate"`
+	AssumedEnabled bool   `json:"assumed_enabled,omitempty"`
+	// DefaultD / MinEffectiveD：分组默认 D 与最低有效 D（含 evalAt 高峰因子；
+	// MinEffectiveD = min(分组默认, 全部非空用户覆盖) × 高峰因子）。
+	DefaultD      float64 `json:"default_d"`
+	MinEffectiveD float64 `json:"min_effective_d"`
+	// ThresholdDefault / ThresholdMinD：两档 D 对应的准入阈值。
+	ThresholdDefault float64 `json:"threshold_default"`
+	ThresholdMinD    float64 `json:"threshold_min_d"`
+	// RemainingByModel 仅表示利润门准入账号数，不模拟健康、冷却、限流或槽位。
+	RemainingByModel     map[string]int                `json:"profit_admitted_by_model"`
+	RemainingByModelMinD map[string]int                `json:"profit_admitted_by_model_min_d"`
+	Verdicts             []ProfitPreviewAccountVerdict `json:"verdicts"`
+}
+
+// PreviewProfitAdmission 对五大平台分组推演利润门准入结果。未启用的分组仅在
+// AssumeEnabled=true 时按保存配置执行门；Composite 分组始终不直接安装利润门。
+func PreviewProfitAdmission(inputs []ProfitPreviewGroupInput, evalAt time.Time) []ProfitPreviewGroupReport {
+	reports := make([]ProfitPreviewGroupReport, 0, len(inputs))
+	for _, in := range inputs {
+		if in.Group == nil {
+			continue
+		}
+		group := in.Group
+		effectiveGate := (group.ProfitControlEnabled || in.AssumeEnabled) && profitControlPlatformSupported(group.Platform)
+		report := ProfitPreviewGroupReport{
+			GroupID:              group.ID,
+			GroupName:            group.Name,
+			Platform:             group.Platform,
+			EffectiveGate:        effectiveGate,
+			AssumedEnabled:       in.AssumeEnabled && !group.ProfitControlEnabled && effectiveGate,
+			RemainingByModel:     make(map[string]int, len(in.Models)),
+			RemainingByModelMinD: make(map[string]int, len(in.Models)),
+		}
+		for _, model := range in.Models {
+			report.RemainingByModel[model] = 0
+			report.RemainingByModelMinD[model] = 0
+		}
+
+		peak := group.PeakMultiplierAt(evalAt)
+		defaultD := group.RateMultiplier * peak
+		minRate := group.RateMultiplier
+		for _, override := range in.UserOverrides {
+			if math.IsNaN(override) || math.IsInf(override, 0) || override < 0 {
+				continue
+			}
+			if override < minRate {
+				minRate = override
+			}
+		}
+		minD := minRate * peak
+		deduction := group.ProfitMinMargin + group.ProfitSafetyBuffer
+		thresholdDefault := clampProfitControlThreshold(defaultD * (1 - deduction))
+		thresholdMinD := clampProfitControlThreshold(minD * (1 - deduction))
+		report.DefaultD = defaultD
+		report.MinEffectiveD = minD
+		report.ThresholdDefault = thresholdDefault
+		report.ThresholdMinD = thresholdMinD
+
+		for _, account := range in.Accounts {
+			if account == nil {
+				continue
+			}
+			verdict := previewAccountProfitAdmission(account, effectiveGate, thresholdDefault, thresholdMinD, evalAt)
+			admittedDefault := verdict.Class == ProfitPreviewClassAdmitted
+			admittedMinD := admittedDefault && !verdict.RejectedUnderMinD
+			for _, model := range in.Models {
+				if !account.IsModelSupported(model) {
+					continue
+				}
+				verdict.SupportedModels = append(verdict.SupportedModels, model)
+				if admittedDefault {
+					report.RemainingByModel[model]++
+				}
+				if admittedMinD {
+					report.RemainingByModelMinD[model]++
+				}
+			}
+			sort.Strings(verdict.SupportedModels)
+			report.Verdicts = append(report.Verdicts, verdict)
+		}
+		sort.Slice(report.Verdicts, func(i, j int) bool { return report.Verdicts[i].AccountID < report.Verdicts[j].AccountID })
+		reports = append(reports, report)
+	}
+	return reports
+}
+
+func previewAccountProfitAdmission(
+	account *Account,
+	effectiveGate bool,
+	thresholdDefault float64,
+	thresholdMinD float64,
+	evalAt time.Time,
+) ProfitPreviewAccountVerdict {
+	verdict := ProfitPreviewAccountVerdict{
+		AccountID:  account.ID,
+		Name:       account.Name,
+		Platform:   account.Platform,
+		RateSource: ProfitPreviewRateSourceManual,
+	}
+	if enabled, _ := account.Extra[UpstreamBillingRateSyncEnabledExtraKey].(bool); enabled {
+		verdict.RateSource = ProfitPreviewRateSourceUpstreamProbe
+		verdict.Warnings = append(verdict.Warnings, profitPreviewProbeWarnings(account, evalAt)...)
+	} else if account.RateMultiplier != nil && *account.RateMultiplier == 1 {
+		verdict.Warnings = append(verdict.Warnings, ProfitPreviewWarningManualRateOne)
+	}
+
+	validRate := account.RateMultiplier != nil &&
+		!math.IsNaN(*account.RateMultiplier) &&
+		!math.IsInf(*account.RateMultiplier, 0) &&
+		*account.RateMultiplier >= 0
+	if validRate {
+		rate := *account.RateMultiplier
+		verdict.AccountRate = &rate
+	}
+	switch {
+	case !effectiveGate:
+		verdict.Class = ProfitPreviewClassAdmitted
+	case !validRate:
+		verdict.Class = ProfitPreviewClassRejectedInvalidRate
+	case profitControlOverThreshold(*account.RateMultiplier, thresholdDefault):
+		verdict.Class = ProfitPreviewClassRejectedThreshold
+	default:
+		verdict.Class = ProfitPreviewClassAdmitted
+		verdict.RejectedUnderMinD = profitControlOverThreshold(*account.RateMultiplier, thresholdMinD)
+	}
+	return verdict
+}
+
+func profitPreviewProbeWarnings(account *Account, evalAt time.Time) []string {
+	snapshot := decodeUpstreamBillingProbeSnapshot(account.Extra)
+	if snapshot == nil {
+		return []string{ProfitPreviewWarningProbeMissing}
+	}
+	switch snapshot.Status {
+	case UpstreamBillingProbeStatusFailed:
+		return []string{ProfitPreviewWarningProbeFailed}
+	case UpstreamBillingProbeStatusUnsupported:
+		return []string{ProfitPreviewWarningProbeUnsupported}
+	case UpstreamBillingProbeStatusOK:
+		if snapshot.FreshUntil == nil || !evalAt.Before(*snapshot.FreshUntil) {
+			return []string{ProfitPreviewWarningProbeStale}
+		}
+	}
+	return nil
+}