yml2213
8521bf4753
按买卖站点纯函数判定五种模式，分站卖主站货命中 two_party_platform_receive。 结算批次只收本站 site party，平台分成不再进入分销钱包；生产环境冻结结算入账与站点提现。
238 lines
7.5 KiB
Go
238 lines
7.5 KiB
Go
package distribution
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import (
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"errors"
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"math"
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)
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const (
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ModeTwoPartyDistributorReceive = "two_party_distributor_receive"
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ModeTwoPartyPlatformReceive = "two_party_platform_receive"
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ModeThreeParty = "three_party"
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// ModeSiteSelfSell 是分站卖本站货，不复用两方默认规则。
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ModeSiteSelfSell = "site_self_sell"
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PartyTypeSite = "site"
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PartyTypePlatform = "platform"
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ServiceFeeUnitPercent = "percent"
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ServiceFeeUnitFixedAmount = "fixed_amount"
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ServiceFeeUnitRatio = "ratio"
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)
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var (
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ErrInvalidAmount = errors.New("invalid distribution amount")
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ErrInvalidRate = errors.New("invalid distribution rate")
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ErrInvalidServiceUnit = errors.New("invalid service fee unit")
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ErrUnsupportedMode = errors.New("unsupported distribution mode")
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)
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// Rule 是后台可编辑的分账规则。比例字段按参与方角色命名，避免方向歧义。
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type Rule struct {
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Mode string
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PlatformReceiveRatio float64
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PlatformSellRatio float64
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DistributorReceiveRatio float64
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DistributorSellRatio float64
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DistributorARatio float64
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DistributorBRatio float64
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ServiceFeeValue float64
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ServiceFeeUnit string
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PaymentFeeBPS int64
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TaxEnabled bool
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TaxRateBPS int64
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}
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// SettlementInput 使用支付单和退款单的整数分快照计算分销费用。
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type SettlementInput struct {
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GrossPaidAmountCent int64
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RefundAmountCent int64
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MarkupAmountCent int64
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GrossProfitByParty []PartyProfitInput
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}
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type PartyProfitInput struct {
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PartyRole string
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IncomeAmountCent int64
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CostAmountCent int64
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}
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type PartyTaxResult struct {
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PartyRole string `json:"party_role"`
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GrossProfitCent int64 `json:"gross_profit_cent"`
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TaxAmountCent int64 `json:"tax_amount_cent"`
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}
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type SettlementResult struct {
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GrossPaidAmountCent int64
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RefundAmountCent int64
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NetPaidAmountCent int64
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PaymentFeeCent int64
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ServiceFeeCent int64
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MarkupAmountCent int64
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SplitBaseAmountCent int64
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TaxAmountCent int64
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TaxByParty []PartyTaxResult
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}
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// DefaultRule 返回文档中的第一版占位值，仅供对照，禁止当作已手算确认的生效分成。
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// 本站自卖没有默认比例，必须单独配置。
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func DefaultRule(mode string) (Rule, error) {
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base := Rule{
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Mode: mode, ServiceFeeValue: 2.5, ServiceFeeUnit: ServiceFeeUnitRatio,
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PaymentFeeBPS: 50, TaxEnabled: false, TaxRateBPS: 100,
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}
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switch mode {
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case ModeTwoPartyDistributorReceive:
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base.DistributorReceiveRatio = 3.5
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base.PlatformSellRatio = 4
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case ModeTwoPartyPlatformReceive:
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base.PlatformReceiveRatio = 3.5
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base.DistributorSellRatio = 4
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case ModeThreeParty:
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base.DistributorARatio = 3.5
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base.DistributorBRatio = 4
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case ModeSiteSelfSell:
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return Rule{}, ErrUnsupportedMode
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default:
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return Rule{}, ErrUnsupportedMode
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}
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return base, nil
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}
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// CalculateSettlement 先扣支付手续费，再计算服务费和分成基数；退款金额不能超过支付金额。
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func CalculateSettlement(rule Rule, input SettlementInput) (SettlementResult, error) {
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if input.GrossPaidAmountCent < 0 || input.RefundAmountCent < 0 || input.MarkupAmountCent < 0 || input.RefundAmountCent > input.GrossPaidAmountCent {
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return SettlementResult{}, ErrInvalidAmount
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}
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if rule.PaymentFeeBPS < 0 || rule.PaymentFeeBPS > 10000 || rule.TaxRateBPS < 0 || rule.TaxRateBPS > 10000 || rule.ServiceFeeValue < 0 {
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return SettlementResult{}, ErrInvalidRate
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}
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if rule.ServiceFeeUnit != ServiceFeeUnitPercent && rule.ServiceFeeUnit != ServiceFeeUnitFixedAmount && rule.ServiceFeeUnit != ServiceFeeUnitRatio {
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return SettlementResult{}, ErrInvalidServiceUnit
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}
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netPaid := input.GrossPaidAmountCent - input.RefundAmountCent
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paymentFee := roundHalfUp(float64(netPaid) * float64(rule.PaymentFeeBPS) / 10000)
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serviceFee, err := serviceFeeCent(rule, netPaid)
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if err != nil {
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return SettlementResult{}, err
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}
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splitBase := netPaid - paymentFee - serviceFee
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if splitBase < 0 {
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splitBase = 0
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}
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result := SettlementResult{
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GrossPaidAmountCent: input.GrossPaidAmountCent,
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RefundAmountCent: input.RefundAmountCent,
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NetPaidAmountCent: netPaid,
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PaymentFeeCent: paymentFee,
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ServiceFeeCent: serviceFee,
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MarkupAmountCent: input.MarkupAmountCent,
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SplitBaseAmountCent: splitBase,
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}
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if rule.TaxEnabled {
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result.TaxByParty = make([]PartyTaxResult, 0, len(input.GrossProfitByParty))
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for _, party := range input.GrossProfitByParty {
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profit := party.IncomeAmountCent - party.CostAmountCent
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tax := roundHalfUp(float64(maxInt64(profit, 0)) * float64(rule.TaxRateBPS) / 10000)
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result.TaxAmountCent += tax
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result.TaxByParty = append(result.TaxByParty, PartyTaxResult{PartyRole: party.PartyRole, GrossProfitCent: profit, TaxAmountCent: tax})
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}
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}
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return result, nil
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}
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func serviceFeeCent(rule Rule, netPaid int64) (int64, error) {
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switch rule.ServiceFeeUnit {
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case ServiceFeeUnitPercent:
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return roundHalfUp(float64(netPaid) * rule.ServiceFeeValue / 100), nil
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case ServiceFeeUnitFixedAmount:
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return roundHalfUp(rule.ServiceFeeValue * 100), nil
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case ServiceFeeUnitRatio:
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if rule.ServiceFeeValue <= 0 {
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return 0, nil
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}
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return roundHalfUp(float64(netPaid) / rule.ServiceFeeValue), nil
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default:
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return 0, ErrInvalidServiceUnit
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}
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}
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func roundHalfUp(value float64) int64 {
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return int64(math.Floor(value + 0.5))
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}
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func maxInt64(a, b int64) int64 {
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if a > b {
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return a
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}
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return b
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}
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// PartySplit 是一次分成拆分中单个参与方的金额。
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type PartySplit struct {
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PartyRole string
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Ratio float64
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AmountCent int64
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}
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// SplitSettlement 按规则模式把分成基数以百分比拆给各分销参与方。
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// 销售加价全部计入卖出方收入（设计文档 7.6）；
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// 剩余金额（含四舍五入尾差）由调用方归入平台留存并记录 RoundingAdjustmentCent，
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// 最终业务口径以设计文档 7.2 待确认项的结论为准。
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func SplitSettlement(rule Rule, splitBase int64, markupCent int64) []PartySplit {
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roles := []struct {
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role string
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ratio float64
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}{}
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switch rule.Mode {
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case ModeTwoPartyDistributorReceive:
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roles = []struct {
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role string
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ratio float64
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}{{"distributor_receive", rule.DistributorReceiveRatio}, {"platform_sell", rule.PlatformSellRatio}}
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case ModeTwoPartyPlatformReceive:
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roles = []struct {
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role string
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ratio float64
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}{{"distributor_sell", rule.DistributorSellRatio}, {"platform_receive", rule.PlatformReceiveRatio}}
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case ModeThreeParty:
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roles = []struct {
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role string
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ratio float64
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}{{"distributor_a", rule.DistributorARatio}, {"distributor_b", rule.DistributorBRatio}}
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default:
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return nil
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}
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splits := make([]PartySplit, 0, len(roles))
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for _, item := range roles {
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amount := roundHalfUp(float64(splitBase) * item.ratio / 100)
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splits = append(splits, PartySplit{PartyRole: item.role, Ratio: item.ratio, AmountCent: maxInt64(amount, 0)})
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}
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if markupCent > 0 {
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// 加价归卖出方：两方-分销收号与三方模式的卖出方分别是 platform_sell / distributor_b。
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sellerRole := "distributor_sell"
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switch rule.Mode {
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case ModeTwoPartyDistributorReceive:
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sellerRole = "platform_sell"
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case ModeThreeParty:
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sellerRole = "distributor_b"
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}
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for i := range splits {
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if splits[i].PartyRole == sellerRole {
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splits[i].AmountCent += markupCent
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}
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}
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}
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return splits
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}
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// SplitRemainderCent 返回分成基数扣除各方分成后的平台留存金额（含尾差）。
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func SplitRemainderCent(splitBase int64, splits []PartySplit) int64 {
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sum := int64(0)
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for _, item := range splits {
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sum += item.AmountCent
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}
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return splitBase - sum
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}
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