NSDate+Pretty.m

//
//  NSDate+Pretty.m
//  AaronWheeler
//
//  Created by Aaron Wheeler on 10/4/10.
//  Copyright 2010 n/a. All rights reserved.
//

#import "NSDate+Pretty.h"

@interface NSDate (Pretty)

- (NSString *) toAgoString;

@end

@implementation NSDate (Pretty)

// Pretty prints the date as a string, formatted as "<unit of time> ago",
// for example, "3 days ago" or "25 minutes ago"
- (NSString *) toAgoString {
  // Ported from John Resig's Pretty Date JS function
  // http://ejohn.org/files/pretty.js
  NSTimeInterval diff    = -1 * [self timeIntervalSinceNow];
  NSTimeInterval dayDiff = floor(diff / 86400);

  NSLog(@"Date: %@ and diff: %f and dayDiff: %f, %f", self, diff, dayDiff, dayDiff / 30.0);
  
  if      ( dayDiff < 0.0 )  { return @""; }
  else if ( diff < 60.0 )    { return @"just now"; }
  else if ( diff < 120.0 )   { return @"1 minute ago"; }
  else if ( diff < 3600.0 )  { return [NSString stringWithFormat:@"%.f minutes ago", floor(diff/60.0)]; }
  else if ( diff < 7200.0 )  { return @"1 hour ago"; }
  else if ( diff < 86400.0 ) { return [NSString stringWithFormat:@"%.f hours ago", floor(diff/3600.0)]; }
  else if ( dayDiff == 1.0 ) { return @"Yesterday"; }
  else if ( dayDiff < 7.0 )  { return [NSString stringWithFormat:@"%.f days ago", dayDiff]; }
  else if ( dayDiff < 62.0 ) { return [NSString stringWithFormat:@"%.f weeks ago", ceil( dayDiff / 7.0 )]; }
  // Up to 15 months
  else if ( dayDiff < 455.0 ){ return [NSString stringWithFormat:@"%.f months ago", ceil( dayDiff / 30.0 )]; }
  else if ( dayDiff < 730.5 ){ return @"1 year ago"; }
  else                       { return [NSString stringWithFormat:@"%.f years ago", ceil( dayDiff / 365.25 )]; }
}

@end