package middleware

import (
	"log"
	"net/http"
	"strings"

	"gophergate/internal/db"
	"gophergate/internal/models"

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

func AuthMiddleware(database *db.DB, requireAuth bool) gin.HandlerFunc {
	return func(c *gin.Context) {
		authHeader := c.GetHeader("Authorization")
		if authHeader == "" {
			// Fallback to checking "Authentication" header in case the client library used the wrong name
			authHeader = c.GetHeader("Authentication")
		}

		if authHeader == "" {
			if requireAuth {
				c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
					"error": gin.H{
						"message": "Missing Authorization or Authentication header.",
						"type":    "invalid_request_error",
						"param":   nil,
						"code":    "401",
					},
				})
				return
			}
			c.Next()
			return
		}

		token := strings.TrimPrefix(authHeader, "Bearer ")
		if token == authHeader { // No "Bearer " prefix
			if requireAuth {
				c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
					"error": gin.H{
						"message": "Invalid authorization header format. Bearer token required.",
						"type":    "invalid_request_error",
						"param":   nil,
						"code":    "401",
					},
				})
				return
			}
			c.Next()
			return
		}

		// Try to resolve client from database with a read-only SELECT
		var clientID string
		err := database.Get(&clientID, "SELECT client_id FROM client_tokens WHERE token = ? AND is_active = 1", token)

		if err == nil {
			c.Set("auth", models.AuthInfo{
				Token:    token,
				ClientID: clientID,
			})
			
			// Update last_used_at asynchronously so that database locks or write delays
			// do not block or fail the client's request authentication.
			go func(t string) {
				if _, updateErr := database.Exec("UPDATE client_tokens SET last_used_at = CURRENT_TIMESTAMP WHERE token = ?", t); updateErr != nil {
					log.Printf("Warning: failed to update client token last_used_at: %v", updateErr)
				}
			}(token)

			c.Next()
		} else {
			log.Printf("Token not found, inactive or error in DB: %s (err: %v)", token, err)
			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
				"error": gin.H{
					"message": "Invalid or inactive client token.",
					"type":    "invalid_request_error",
					"param":   nil,
					"code":    "401",
				},
			})
		}
	}
}