package middleware

import (
	"net/http"
	"strings"

	"github.com/gin-gonic/gin"
	"go.uber.org/zap"
)

// HeaderInternalAPIKey is the header name for Stream Server callback authentication
const HeaderInternalAPIKey = "X-Internal-API-Key"

// StreamCallbackAuth returns a Gin middleware that validates X-Internal-API-Key
// for the stream-ready callback route. Used to authenticate callbacks from the Stream Server.
// If expectedKey is empty, all requests are rejected (fail-secure).
func StreamCallbackAuth(expectedKey string, logger *zap.Logger) gin.HandlerFunc {
	return func(c *gin.Context) {
		if expectedKey == "" {
			logger.Warn("Stream callback auth: STREAM_SERVER_INTERNAL_API_KEY not configured, rejecting request")
			c.JSON(http.StatusUnauthorized, gin.H{
				"success": false,
				"error": gin.H{
					"code":    1001,
					"message": "Internal API key required",
				},
			})
			c.Abort()
			return
		}

		provided := c.GetHeader(HeaderInternalAPIKey)
		if provided == "" {
			provided = c.GetHeader("X-Stream-Server-API-Key")
		}
		provided = strings.TrimSpace(provided)

		if provided != expectedKey {
			logger.Warn("Stream callback auth: invalid or missing API key",
				zap.String("path", c.Request.URL.Path),
			)
			c.JSON(http.StatusUnauthorized, gin.H{
				"success": false,
				"error": gin.H{
					"code":    1001,
					"message": "Invalid or missing internal API key",
				},
			})
			c.Abort()
			return
		}

		c.Next()
	}
}