//
//  TOTPGenerator.m
//
//  Copyright 2011 Google Inc.
//
//  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 "TOTPGenerator.h"
#import "OTPDefines.h"

@interface TOTPGenerator ()
@property (nonatomic, readwrite) NSTimeInterval period;
@end

@implementation TOTPGenerator

+ (NSTimeInterval)defaultPeriod {
  return 30;
}

- (id)initWithSecret:(NSData *)secret
           algorithm:(NSString *)algorithm
              digits:(uint32_t)digits
              period:(NSTimeInterval)period {
	if (period <= 0 || period > 300) {
		OTPDevLog(@"Bad Period: %f", period);
		return (self = nil);
	}

	self = [super initWithSecret:secret algorithm:algorithm digits:digits];
	if (self) {
		self.period = period;
	}
	return self;
}

- (NSString *)generateOTP {
  return [self generateOTPForDate:[NSDate date]];
}

- (NSString *)generateOTPForDate:(NSDate *)date {
  if (!date) {
    // If no now date specified, use the current date.
    date = [NSDate date];
  }

  NSTimeInterval seconds = [date timeIntervalSince1970];
  uint64_t counter = (uint64_t)(seconds / self.period);
  return [super generateOTPForCounter:counter];
}

@end
