package middleware

import (
	"crypto/rand"
	"encoding/hex"
	"strings"
	"time"

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

// RequestID ensures every request has an X-Request-ID and echoes it back to the client.
func RequestID() gin.HandlerFunc {
	return func(c *gin.Context) {
		id := strings.TrimSpace(c.GetHeader("X-Request-ID"))
		if id == "" {
			id = strings.TrimSpace(c.GetHeader("X-Request-Id"))
		}
		if id == "" {
			id = newRequestID()
		}
		c.Request.Header.Set("X-Request-ID", id)
		c.Writer.Header().Set("X-Request-ID", id)
		c.Set("request_id", id)
		c.Next()
	}
}

func newRequestID() string {
	var b [16]byte
	if _, err := rand.Read(b[:]); err != nil {
		return hex.EncodeToString([]byte(time.Now().Format(time.RFC3339Nano)))
	}
	return hex.EncodeToString(b[:])
}