SSYAppInfo.m

#import "SSYAppInfo.h"
#import "NSBundle+MainApp.h"

NSString * const constKeyLastVersion = @"lastVersion" ;

static SSYAppInfo *sharedInfo = nil ;


@implementation SSYAppInfo

+ (SSYAppInfo*)sharedInfo {
	@synchronized(self) {
        if (sharedInfo == nil) {
            sharedInfo = [[self alloc] init] ;
            [sharedInfo setUpgradeState:SSYNotDefined] ;
        }
	}
    return sharedInfo ;
}

+ (enum SSYAppInfoUpgradeState)upgradeStateForCurrentVersionTriplet:(SSYVersionTriplet*)currentVersion
											 previousVersionTriplet:(SSYVersionTriplet*)previousVersion {    
	enum SSYAppInfoUpgradeState upgradeState ;

	if (previousVersion == nil) {
		upgradeState = SSYNewUser ;
	}
	else {
		upgradeState = (enum SSYAppInfoUpgradeState)[previousVersion compare:currentVersion] ;
	}
	
	return upgradeState ;	
}

- (SSYVersionTriplet *)previousVersionTriplet {
    return _previousVersionTriplet ;
}

- (void)setPreviousVersionTriplet:(SSYVersionTriplet *)value {
    if (_previousVersionTriplet != value) {
        [_previousVersionTriplet release];
        _previousVersionTriplet = [value retain];
    }
}

- (SSYVersionTriplet *)currentVersionTriplet {
    return _currentVersionTriplet ;
}

- (void)setCurrentVersionTriplet:(SSYVersionTriplet *)value {
    if (_currentVersionTriplet != value) {
        [_currentVersionTriplet release];
        _currentVersionTriplet = [value retain];
    }
}

- (enum SSYAppInfoUpgradeState)upgradeState {
	return _upgradeState ;
}

- (void)setUpgradeState:(enum SSYAppInfoUpgradeState)upgradeState {
	_upgradeState = upgradeState ;
}

// Keep this method private, because it gives the value from User Defaults, which
// will already have been changed to the current version after the SSYAppInfo
// singleton instance has been created, which is probably not what you expect.
// You probably want +previousVersionTriplet instead.
+ (SSYVersionTriplet*)rawPreviousVersionTriplet {
	NSString* string = [[NSUserDefaults standardUserDefaults] stringForKey:constKeyLastVersion] ;
	SSYVersionTriplet* triplet = [SSYVersionTriplet versionTripletFromString:string] ;
	return triplet ;
}

+ (SSYVersionTriplet*)rawCurrentVersionTriplet {
	NSString* versionString = [SSYVersionTriplet rawVersionStringFromBundle:[NSBundle mainAppBundle]] ;
	SSYVersionTriplet* cvt = [SSYVersionTriplet versionTripletFromString:versionString] ;
	return cvt ;
}

- (void)calculateUpgradeState {
    SSYVersionTriplet* previousVersionTriplet = [SSYAppInfo rawPreviousVersionTriplet] ;
    [self setPreviousVersionTriplet:previousVersionTriplet] ;
    [self setCurrentVersionTriplet:[SSYAppInfo rawCurrentVersionTriplet]] ;
    enum SSYAppInfoUpgradeState upgradeState = [SSYAppInfo upgradeStateForCurrentVersionTriplet:[self currentVersionTriplet]
                                                                         previousVersionTriplet:[self previousVersionTriplet]] ;
    [self setUpgradeState:upgradeState] ;
    if ([self upgradeState] != SSYCurrentRev) {
        // Get a nice, clean, filtered versionString of the form "major.minor.bugFix" using SSVersionTriplet methods
        SSYVersionTriplet* currentVersionTriplet = [SSYVersionTriplet versionTripletFromBundle:[NSBundle mainAppBundle]] ;
        NSString* currentVersionString = [currentVersionTriplet string] ;
        
        // Record currently-launched version into prefs
        // Note that this must be done AFTER the above reading,
        // or else the pref constKeyLastVersion will be written as the previous version!
        NSUserDefaults* userDefaults = [NSUserDefaults standardUserDefaults] ;
        [userDefaults setObject:currentVersionString
                         forKey:constKeyLastVersion] ;
        [userDefaults synchronize] ;
    }
}


+ (BOOL)isNewUser {
    enum SSYAppInfoUpgradeState upgradeState = [[self sharedInfo] upgradeState] ;
    BOOL answer = (upgradeState >= SSYNewUser) ;
	return answer ;
}

+ (BOOL)didUpgradeSinceLastRun {
	return ([[self sharedInfo] upgradeState] > SSYCurrentRev) ;
}

+ (SSYVersionTriplet*)currentVersionTriplet {
	return [[self sharedInfo] currentVersionTriplet] ;
}

+ (SSYVersionTriplet*)previousVersionTriplet {
	return [[self sharedInfo] previousVersionTriplet] ;
}

+ (void)calculateUpgradeState {
    [[self sharedInfo] calculateUpgradeState] ;
}


@end