package middleware

import (
	"context"
	"net/http"
	"strings"

	"aggios-app/backend/internal/config"

	"github.com/golang-jwt/jwt/v5"
)

type contextKey string

const UserIDKey contextKey = "userID"
const TenantIDKey contextKey = "tenantID"

// Auth validates JWT tokens
func Auth(cfg *config.Config) func(http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			authHeader := r.Header.Get("Authorization")
			if authHeader == "" {
				http.Error(w, "Unauthorized", http.StatusUnauthorized)
				return
			}

			bearerToken := strings.Split(authHeader, " ")
			if len(bearerToken) != 2 || bearerToken[0] != "Bearer" {
				http.Error(w, "Invalid token format", http.StatusUnauthorized)
				return
			}

			token, err := jwt.Parse(bearerToken[1], func(token *jwt.Token) (interface{}, error) {
				return []byte(cfg.JWT.Secret), nil
			})

			if err != nil || !token.Valid {
				http.Error(w, "Invalid token", http.StatusUnauthorized)
				return
			}

			claims, ok := token.Claims.(jwt.MapClaims)
			if !ok {
				http.Error(w, "Invalid token claims", http.StatusUnauthorized)
				return
			}

			userID := claims["user_id"].(string)
			tenantID := claims["tenant_id"].(string)
			ctx := context.WithValue(r.Context(), UserIDKey, userID)
			ctx = context.WithValue(ctx, TenantIDKey, tenantID)
			next.ServeHTTP(w, r.WithContext(ctx))
		})
	}
}