STPPaymentCardTextField category to allow external value setting (implementation file)

STPPaymentCardTextField+ExternalConfig.m

//
//  STPPaymentCardTextField+ExternalConfig.m
//
//  Created by George Marmaridis on 18/12/15.
//  Copyright © 2015 George Marmaridis. All rights reserved.
//

#import "STPPaymentCardTextField+ExternalConfig.h"

static NSString *const kNumberFieldKey = @"numberField";
static NSString *const kExpirationFieldKey = @"expirationField";
static NSString *const kCVCFieldKey = @"cvcField";

@interface STPPaymentCardTextField ()

typedef void (^STPNumberShrunkCompletionBlock)(BOOL completed);

- (BOOL)shouldShrinkNumberField;
- (void)setNumberFieldShrunk:(BOOL)shrunk animated:(BOOL)animated
                  completion:(STPNumberShrunkCompletionBlock)completion;

@end

@implementation STPPaymentCardTextField (ExternalConfig)

- (void)configureWithCardParams:(nonnull STPCardParams*)cardParams
{
    if (cardParams.number.length)
    {
        [self p_setFieldWithName:kNumberFieldKey withValue:cardParams.number];
        
        [self setNumberFieldShrunk:[self shouldShrinkNumberField] animated:NO completion:nil];
    }
    
    if (cardParams.expMonth && cardParams.expYear)
    {
        [self p_setFieldWithName:kExpirationFieldKey
                       withValue:[NSString stringWithFormat:@"%02lu/%02lu",
                                  (unsigned long)cardParams.expMonth,
                                  (unsigned long)cardParams.expYear%100]];
    }
}

- (void)p_setFieldWithName:(nonnull NSString*)name withValue:(nonnull NSString*)value
{
    UITextField *textField = (UITextField*)[self valueForKey:name];
    id delegate = (id<UITextFieldDelegate>)self;
    NSUInteger length = textField.text.length;
    
    if ([delegate textField:textField shouldChangeCharactersInRange:NSMakeRange(0, length) replacementString:value])
    {
        textField.text = value;
    }
}

@end