Cool date extensions :D

NSDate+Extensions.m

#import "NSDate+Extensions.h"

@implementation NSDate (Extensions)

- (NSDate *)dateByMovingToBeginningOfDay {
    unsigned int flags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit |
    NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
    NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    //    [calendar setLocale:[NSLocale currentLocale]];
    [calendar setTimeZone:[NSTimeZone timeZoneWithName:@"America/Sao_Paulo"]];
    NSDateComponents* parts = [calendar components:flags fromDate:self];
    [parts setHour:0];
    [parts setMinute:0];
    [parts setSecond:0];
    NSDate *data;
    data = [calendar dateFromComponents:parts];
    return data;
}

- (NSDate *)dateByMovingToEndOfDay {
    unsigned int flags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit |
    NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
    NSDateComponents* parts = [[NSCalendar currentCalendar] components:flags fromDate:self];
    [parts setHour:23];
    [parts setMinute:59];
    [parts setSecond:59];
    [[NSCalendar currentCalendar] setTimeZone:[NSTimeZone timeZoneWithName:@"America/Sao_Paulo"]];
    return [[NSCalendar currentCalendar] dateFromComponents:parts];
}

- (NSDate *)dateByMovingToBeginningOfMonth {
    unsigned int flags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit |
    NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
    NSDateComponents* parts = [[NSCalendar currentCalendar] components:flags fromDate:self];
    [parts setDay:1];
    [parts setHour:0];
    [parts setMinute:0];
    [parts setSecond:0];
    [[NSCalendar currentCalendar] setTimeZone:[NSTimeZone timeZoneWithName:@"America/Sao_Paulo"]];
    return [[NSCalendar currentCalendar] dateFromComponents:parts];
}

- (NSDate *)dateByMovingToEndOfMonth {
    unsigned int flags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit |
    NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
    
    NSDateComponents* parts = [[NSCalendar currentCalendar] components:flags fromDate:self];
    NSRange monthRange = [[NSCalendar currentCalendar] rangeOfUnit:NSDayCalendarUnit
                                                            inUnit:NSMonthCalendarUnit
                                                           forDate:self];
    
    [parts setDay:monthRange.length];
    [parts setHour:23];
    [parts setMinute:59];
    [parts setSecond:59];
    [[NSCalendar currentCalendar] setTimeZone:[NSTimeZone timeZoneWithName:@"America/Sao_Paulo"]];
    return [[NSCalendar currentCalendar] dateFromComponents:parts];
}

- (NSDate *)dateByMovingToBeginningOfWeek {
    NSCalendar *gregorian = [NSCalendar currentCalendar];
    [gregorian setTimeZone:[NSTimeZone timeZoneWithName:@"America/Sao_Paulo"]];
    // Get the weekday component of the current date
    NSDateComponents *weekdayComponents = [gregorian components:NSWeekdayCalendarUnit fromDate:self];
    /*
     Create a date components to represent the number of days to subtract
     from the current date.
     The weekday value for Sunday in the Gregorian calendar is 1, so
     subtract 1 from the number
     of days to subtract from the date in question.  (If today's Sunday,
     subtract 0 days.)
     */
    NSDateComponents *componentsToSubtract = [[NSDateComponents alloc] init];
    /* Substract [gregorian firstWeekday] to handle first day of the week being something else than Sunday */
    [componentsToSubtract setDay: - ([weekdayComponents weekday] - [gregorian firstWeekday])];
    NSDate *beginningOfWeek = [gregorian dateByAddingComponents:componentsToSubtract toDate:self options:0];
    
    /*
     Optional step:
     beginningOfWeek now has the same hour, minute, and second as the
     original date (today).
     To normalize to midnight, extract the year, month, and day components
     and create a new date from those components.
     */
    NSDateComponents *components = [gregorian components: (NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit)
                                                fromDate: beginningOfWeek];
    [components setHour:0];
    beginningOfWeek = [gregorian dateFromComponents: components];
    
    return beginningOfWeek;
}

+(NSDate*)dateWithddMMyyyyFormat:(NSString *)dateInddMMyyyyFormat {
    NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"dd/MM/yyyy"];
    
    NSTimeZone *formatterTimeZone = dateFormatter.timeZone;
    //Fix the bug caused by the fucking time zone at day 21/10/2013
    NSTimeZone *defaultTimeZone = [NSTimeZone timeZoneWithName:@"GMT"];
    [dateFormatter setTimeZone:defaultTimeZone];
    NSDate *date = [dateFormatter dateFromString:dateInddMMyyyyFormat];
    NSInteger hoursOffset = [formatterTimeZone secondsFromGMT] / 3600;
    if([formatterTimeZone isDaylightSavingTime]){
        hoursOffset -= [formatterTimeZone daylightSavingTimeOffset]/3600;
    };
    //Do the parsing :)
    date = [date dateByAddingHours:(-hoursOffset)];
    return date;
}

-(NSString*) dateToWCFFormat{
    double timeSince1970=[self timeIntervalSince1970];
    NSInteger offset = [[NSTimeZone defaultTimeZone] secondsFromGMT];
    offset=offset/3600;
    double nowMillis = 1000.0 * (timeSince1970);
    NSString *dotNetDate=[NSString stringWithFormat:@"/Date(%.0f%+03d00)/",nowMillis,offset] ;
    return  dotNetDate;
}


- (NSString *)dateByFormat:(NSString *)pattern {
	NSDateFormatter *formatterData = [[NSDateFormatter alloc] init];
    [formatterData setDateFormat:pattern];
	
	return [formatterData stringFromDate:self];
}

- (NSString *)dateWithLongStyleFormat{
    
    NSDateFormatter *formatador = [[NSDateFormatter alloc] init];
    
    NSLocale *localeBR = [[NSLocale alloc] initWithLocaleIdentifier:@"pt-br"];
    [formatador setLocale:localeBR];
    [formatador setDateStyle:NSDateFormatterLongStyle];
    
    return [formatador stringFromDate:self];
}
//Retorna uma data adicionando os dias solicitados (ou removendo se for numero negativo)
- (NSDate *)dateByAddingDays:(NSInteger)days {
    NSCalendar *gregorian = [NSCalendar currentCalendar];
    [gregorian setTimeZone:[NSTimeZone timeZoneWithName:@"America/Sao_Paulo"]];
    
    /*
     Create a date components to represent the number of days to add
     from the current date.
     */
    NSDateComponents *componentsDaysToAdd = [[NSDateComponents alloc] init];
    /* set the number of days to add into the current date*/
    [componentsDaysToAdd setDay: days];
    NSDate *finalDate = [gregorian dateByAddingComponents:componentsDaysToAdd toDate:self options:0];
    
    return finalDate;
}
- (NSDate *)dateByAddingHours:(NSInteger)hours {
    NSCalendar *gregorian = [NSCalendar currentCalendar];
    [gregorian setTimeZone:[NSTimeZone timeZoneWithName:@"America/Sao_Paulo"]];
    
    /*
     Create a date components to represent the number of days to add
     from the current date.
     */
    NSDateComponents *componentsDaysToAdd = [NSDateComponents new];
    /* set the number of days to add into the current date*/
    [componentsDaysToAdd setHour: hours];
    NSDate *finalDate = [gregorian dateByAddingComponents:componentsDaysToAdd toDate:self options:0];
    
    return finalDate;
}
- (NSDate *)dateByAddingHours:(NSInteger)hours andMinutes:(NSInteger)minutes{
    NSCalendar *gregorian = [NSCalendar currentCalendar];
    [gregorian setTimeZone:[NSTimeZone timeZoneWithName:@"America/Sao_Paulo"]];
    
    /*
     Create a date components to represent the number of days to add
     from the current date.
     */
    NSDateComponents *componentsDaysToAdd = [NSDateComponents new];
    /* set the number of days to add into the current date*/
    [componentsDaysToAdd setHour: hours];
    [componentsDaysToAdd setMinute: minutes];
    NSDate *finalDate = [gregorian dateByAddingComponents:componentsDaysToAdd toDate:self options:0];
    
    return finalDate;
}
- (NSDate *)dateByAddingMinutes:(NSInteger)minutes {
    NSCalendar *gregorian = [NSCalendar currentCalendar];
    [gregorian setTimeZone:[NSTimeZone timeZoneWithName:@"America/Sao_Paulo"]];
    
    /*
     Create a date components to represent the number of days to add
     from the current date.
     */
    NSDateComponents *componentsDaysToAdd = [NSDateComponents new];
    /* set the number of days to add into the current date*/
    [componentsDaysToAdd setMinute: minutes];
    NSDate *finalDate = [gregorian dateByAddingComponents:componentsDaysToAdd toDate:self options:0];
    
    return finalDate;
}

- (BOOL)isDateToday {
    return [self isSameDayInOtherDate:[NSDate date]];
}

- (BOOL)isDateThisMonth {
    NSUInteger dateComponents = (NSEraCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit);
    
    NSCalendar *cal = [NSCalendar currentCalendar];
    [cal setTimeZone:[NSTimeZone timeZoneWithName:@"America/Sao_Paulo"]];
    NSDateComponents *components = [cal components:dateComponents
                                          fromDate:[NSDate date]];
    components.day = 1;
    NSDate *today = [cal dateFromComponents:components];
    components = [cal components:dateComponents
                        fromDate:self];
    
    components.day = 1;
    NSDate *otherDate = [cal dateFromComponents:components];
    
    return [today isEqualToDate:otherDate];
}

- (BOOL)isSameDayInOtherDate:(NSDate *)otherDate {
    NSUInteger dateComponents = (NSEraCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit);
    
    NSCalendar *cal = [NSCalendar currentCalendar];
    [cal setTimeZone:[NSTimeZone timeZoneWithName:@"America/Sao_Paulo"]];
    NSDateComponents *components = [cal components:dateComponents
                                          fromDate:self];
    
    NSDate *date1 = [cal dateFromComponents:components];
    
    components = [cal components:dateComponents
                        fromDate:otherDate];
    NSDate *date2 = [cal dateFromComponents:components];
    
    return [date1 isEqualToDate:date2];
}
-(NSInteger)daysUntilDate:(NSDate *)otherDate{
    //    //Instancia um calendario gregoriano
    NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    [calendar setTimeZone:[NSTimeZone timeZoneWithName:@"America/Sao_Paulo"]];
    
    NSDate *fromDate;
    NSDate *toDate;
    
    //Pega o range em dias das datas (self e a passada por parametro)
    [calendar rangeOfUnit:NSDayCalendarUnit startDate:&fromDate
                 interval:NULL forDate:self];
    [calendar rangeOfUnit:NSDayCalendarUnit startDate:&toDate
                 interval:NULL forDate:otherDate];
    
    //Pega a diferença em dias dos ranges
    NSDateComponents *difference = [calendar components:NSDayCalendarUnit
                                               fromDate:fromDate toDate:toDate options:0];
    
    return difference.day;
}
- (NSInteger)dayOfWeek
{
    NSDateComponents* parts = [[NSCalendar currentCalendar] components:NSWeekdayCalendarUnit fromDate:self];
    return parts.weekday;
}
- (NSDate *)getNextWednesday
{
    NSDate * nxtWed = [NSDate dateWithTimeIntervalSince1970:[self timeIntervalSince1970]];
    NSInteger dow = [nxtWed dayOfWeek];
    NSDate *retorno = nil;
    if(dow == kDayOfWeekWednesday)
        retorno = [nxtWed dateByAddingDays:7];
    else if(dow < kDayOfWeekWednesday)
        retorno = [nxtWed dateByAddingDays:kDayOfWeekWednesday-dow];
    else
        retorno = [nxtWed dateByAddingDays:kDayOfWeekWednesday-dow+7];
    return retorno;
}
- (NSInteger)day
{
    NSDateComponents* parts = [[NSCalendar currentCalendar] components:NSDayCalendarUnit fromDate:self];
    return parts.day;
}
- (NSInteger)month
{
    NSDateComponents* parts = [[NSCalendar currentCalendar] components:NSMonthCalendarUnit fromDate:self];
    return parts.month;
}
- (NSInteger)year
{
    NSDateComponents* parts = [[NSCalendar currentCalendar] components:NSYearCalendarUnit fromDate:self];
    return parts.year;
}
- (NSInteger)hour
{
    NSDateComponents* parts = [[NSCalendar currentCalendar] components:NSHourCalendarUnit fromDate:self];
    return parts.hour;
}
- (CGPoint)hourAndMinute
{
    NSDateComponents* parts = [[NSCalendar currentCalendar] components:NSHourCalendarUnit|NSMinuteCalendarUnit fromDate:self];
    return CGPointMake(parts.hour, parts.minute);
}
-(NSInteger)yearsToDate:(NSDate *)otherDate {
    NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit
                                               fromDate:self
                                                 toDate:otherDate
                                                options:0];
    return components.year;
}
-(BOOL)isSameWeekOfDate:(NSDate *)otherDate {
    if(otherDate == nil) return NO;
    NSDateComponents* lastParts = [[NSCalendar currentCalendar] components:NSWeekOfYearCalendarUnit fromDate:self];
    NSInteger weekLast = lastParts.weekOfYear;
    NSDateComponents* newParts = [[NSCalendar currentCalendar] components:NSWeekOfYearCalendarUnit fromDate:otherDate];
    NSInteger weekNew = newParts.weekOfYear;
    return weekLast == weekNew;
}
-(BOOL) compareDayMonthYear:(NSDate*)date2
{
    if([date2 day] != [self day])
        return NO;
    if([date2 month] != [self month])
        return NO;
    if([date2 year] != [self year])
        return NO;
    return YES;
}

@end

NSDate_Extensions.h

#import <Foundation/Foundation.h>
typedef enum {
    kDayOfWeekSunday = 1,
    kDayOfWeekMonday = 2,
    kDayOfWeekTuesday = 3,
    kDayOfWeekWednesday = 4,
    kDayOfWeekThursday = 5,
    kDayOfWeekFriday= 6,
    kDayOfWeekSaturday = 7
} kDayOfTheWeek;

@interface NSDate (Extensions)
- (NSDate *)dateByMovingToBeginningOfDay;
- (NSDate *)dateByMovingToEndOfDay;
- (NSDate *)dateByMovingToBeginningOfMonth;
- (NSDate *)dateByMovingToEndOfMonth;
- (NSDate *)dateByMovingToBeginningOfWeek;
+ (NSDate *)dateWithddMMyyyyFormat:(NSString*)dateInddMMyyyyFormat;
- (NSDate *)dateByAddingDays:(NSInteger)days;
- (NSDate*) dateByAddingHours:(NSInteger)hours;
- (NSDate*) dateByAddingHours:(NSInteger)hours andMinutes:(NSInteger)minutes;
- (NSDate *)dateByAddingMinutes:(NSInteger)minutes;
- (NSString *)dateToWCFFormat;
- (NSString *)dateByFormat:(NSString *)pattern;
- (NSString *)dateWithLongStyleFormat;
- (BOOL)isDateToday;
- (BOOL)isDateThisMonth;
- (BOOL)isSameDayInOtherDate:(NSDate *)otherDate;
- (NSInteger)daysUntilDate:(NSDate *)otherDate;
- (NSInteger)dayOfWeek;
- (NSDate *)getNextWednesday;
- (NSInteger)day;
- (NSInteger)month;
- (NSInteger)year;
- (NSInteger)hour;
- (CGPoint)hourAndMinute;
- (NSInteger)yearsToDate:(NSDate*)otherDate;
- (BOOL) isSameWeekOfDate:(NSDate*)otherDate;
- (BOOL) compareDayMonthYear:(NSDate*)date2;
@end