// Package auditcontext 提供跨 HTTP、异步任务和外部回调传播的审计上下文。
package auditcontext

import "context"

type contextKey struct{}

// Context 保存入口提供的真实操作者与链路信息，不包含业务动作或资源事实。
type Context struct {
	ActorKind         string
	ActorID           string
	ActorName         string
	ActorShopID       *uint
	ActorEnterpriseID *uint
	Source            string
	RequestID         string
	CorrelationID     string
	ParentEventID     string
	RequestPath       string
	RequestMethod     string
	IPAddress         string
	UserAgent         string
}

// With 合并审计上下文；非空新值覆盖旧值，便于认证中间件覆盖 HTTP 基础信息。
func With(ctx context.Context, value Context) context.Context {
	if ctx == nil {
		ctx = context.Background()
	}
	merged := From(ctx)
	merge(&merged, value)
	return context.WithValue(ctx, contextKey{}, merged)
}

// From 读取审计上下文；未设置时返回零值。
func From(ctx context.Context) Context {
	if ctx == nil {
		return Context{}
	}
	value, _ := ctx.Value(contextKey{}).(Context)
	return value
}

func merge(target *Context, value Context) {
	if value.ActorKind != "" {
		target.ActorKind = value.ActorKind
	}
	if value.ActorID != "" {
		target.ActorID = value.ActorID
	}
	if value.ActorName != "" {
		target.ActorName = value.ActorName
	}
	if value.ActorShopID != nil {
		target.ActorShopID = value.ActorShopID
	}
	if value.ActorEnterpriseID != nil {
		target.ActorEnterpriseID = value.ActorEnterpriseID
	}
	if value.Source != "" {
		target.Source = value.Source
	}
	if value.RequestID != "" {
		target.RequestID = value.RequestID
	}
	if value.CorrelationID != "" {
		target.CorrelationID = value.CorrelationID
	}
	if value.ParentEventID != "" {
		target.ParentEventID = value.ParentEventID
	}
	if value.RequestPath != "" {
		target.RequestPath = value.RequestPath
	}
	if value.RequestMethod != "" {
		target.RequestMethod = value.RequestMethod
	}
	if value.IPAddress != "" {
		target.IPAddress = value.IPAddress
	}
	if value.UserAgent != "" {
		target.UserAgent = value.UserAgent
	}
}