package requestid

import (
	"strings"

	"github.com/gin-gonic/gin"
)

func New(opts ...Option) gin.HandlerFunc {
	var cfg config = config{
		generator: DefaultFenerator,
	}
	for _, opt := range opts {
		opt(&cfg)
	}
	return func(c *gin.Context) {
		rid := strings.TrimSpace(c.GetHeader(HeaderKey))
		clientProvided := rid != "" && len(rid) <= 128
		if !clientProvided {
			rid = cfg.generator()
		}
		c.Request.Header.Set(HeaderKey, rid)
		c.Header(HeaderKey, rid)
		c.Set(ContextKey, rid)
		c.Set(ClientProvidedContextKey, clientProvided)
	}
}

// FromClient 仅返回客户端显式提供且长度合规的请求ID。
func FromClient(c *gin.Context) (string, bool) {
	if c == nil {
		return "", false
	}
	provided, ok := c.Get(ClientProvidedContextKey)
	if !ok || provided != true {
		return "", false
	}
	return c.GetHeader(HeaderKey), true
}