// Copyright 2019 Google
//
// 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 "Public/GULSecureCoding.h"

NSString *const kGULSecureCodingError = @"GULSecureCodingError";

@implementation GULSecureCoding

+ (nullable id)unarchivedObjectOfClass:(Class)class
                              fromData:(NSData *)data
                                 error:(NSError **)outError {
  id object;
#if __has_builtin(__builtin_available)
  if (@available(macOS 10.13, iOS 11.0, tvOS 11.0, *)) {
    object = [NSKeyedUnarchiver unarchivedObjectOfClass:class fromData:data error:outError];
  } else
#endif  // __has_builtin(__builtin_available)
  {
    @try {
      NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
      unarchiver.requiresSecureCoding = YES;

      object = [unarchiver decodeObjectOfClass:class forKey:NSKeyedArchiveRootObjectKey];
    } @catch (NSException *exception) {
      if (outError) {
        *outError = [self archivingErrorWithException:exception];
      }
    }

    if (object == nil && outError && *outError == nil) {
      NSString *failureReason = @"NSKeyedUnarchiver failed to unarchive data.";
      *outError = [NSError errorWithDomain:kGULSecureCodingError
                                      code:-1
                                  userInfo:@{NSLocalizedFailureReasonErrorKey : failureReason}];
    }
  }

  return object;
}

+ (nullable NSData *)archivedDataWithRootObject:(id<NSCoding>)object error:(NSError **)outError {
  NSData *archiveData;
#if __has_builtin(__builtin_available)
  if (@available(macOS 10.13, iOS 11.0, tvOS 11.0, *)) {
    archiveData = [NSKeyedArchiver archivedDataWithRootObject:object
                                        requiringSecureCoding:YES
                                                        error:outError];
  } else
#endif  // __has_builtin(__builtin_available)
  {
    @try {
      NSMutableData *data = [NSMutableData data];
      NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
      archiver.requiresSecureCoding = YES;

      [archiver encodeObject:object forKey:NSKeyedArchiveRootObjectKey];
      [archiver finishEncoding];

      archiveData = [data copy];
    } @catch (NSException *exception) {
      if (outError) {
        *outError = [self archivingErrorWithException:exception];
      }
    }
  }

  return archiveData;
}

+ (NSError *)archivingErrorWithException:(NSException *)exception {
  NSString *failureReason = [NSString
      stringWithFormat:@"NSKeyedArchiver exception with name: %@, reason: %@, userInfo: %@",
                       exception.name, exception.reason, exception.userInfo];
  NSDictionary *errorUserInfo = @{NSLocalizedFailureReasonErrorKey : failureReason};

  return [NSError errorWithDomain:kGULSecureCodingError code:-1 userInfo:errorUserInfo];
}

@end