// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#import <Foundation/Foundation.h>

#import "SystemConfiguration/CaptiveNetwork.h"

#include <arpa/inet.h>
#include <ifaddrs.h>

NSString* getWifiIP() {
  NSString* address = @"error";
  struct ifaddrs* interfaces = NULL;
  struct ifaddrs* temp_addr = NULL;
  int success = 0;

  // Retrieve the current interfaces - returns 0 on success.
  success = getifaddrs(&interfaces);
  if (success == 0) {
    // Loop through linked list of interfaces.
    temp_addr = interfaces;
    while (temp_addr != NULL) {
      if (temp_addr->ifa_addr->sa_family == AF_INET) {
        // Check if interface is en0 which is the wifi connection on the iPhone.
        if ([[NSString stringWithUTF8String:temp_addr->ifa_name] isEqualToString:@"en0"]) {
          // Get NSString from C String
          address = [NSString
              stringWithUTF8String:inet_ntoa(((struct sockaddr_in*)temp_addr->ifa_addr)->sin_addr)];
        }
      }

      temp_addr = temp_addr->ifa_next;
    }
  }

  // Free memory
  freeifaddrs(interfaces);

  return address;
}