ARDSL.m

//
//  ARDSL.m
//  Artsy
//
//  Created by Ash Furrow on 04/29/14.
//  Copyright (c) 2014 Artsy. All rights reserved.
//

#import "ARDSL.h"
#import <Aspects/Aspects.h>

NSString * const ARAnalyticsTrackedEvents = @"trackedEvents";
NSString * const ARAnalyticsTrackedScreens = @"trackedScreens";

NSString * const ARAnalyticsClass = @"class";
NSString * const ARAnalyticsDetails = @"details";
NSString * const ARAnalyticsPageName = @"pageName";
NSString * const ARAnalyticsPageNameKeyPath = @"keypath";
NSString * const ARAnalyticsEventName = @"event";
NSString * const ARAnalyticsSelectorName = @"selector";
NSString * const ARAnalyticsEventProperties = @"properties";
NSString * const ARAnalyticsShouldFire = @"shouldFire";;

static NSMutableDictionary *ARAnalyticsHooksStore;

static BOOL ar_shouldFireForInstance (NSDictionary *dictionary, id instance, NSArray *arguments) {
    ARAnalyticsEventShouldFireBlock shouldFireBlock = dictionary[ARAnalyticsShouldFire];

    BOOL shouldFire;
    if (shouldFireBlock) {
        shouldFire = shouldFireBlock(instance, arguments);
    } else {
        shouldFire = YES;
    }

    return shouldFire;
}

@implementation ARAnalytics (DSL)

+ (void)setupWithAnalytics:(NSDictionary *)analyticsDictionary configuration:(NSDictionary *)configurationDictionary {
    [self setupWithAnalytics:analyticsDictionary];

    NSArray *trackedScreenClasses = configurationDictionary[ARAnalyticsTrackedScreens];
    [trackedScreenClasses enumerateObjectsUsingBlock:^(NSDictionary *screenDictionary, NSUInteger idx, BOOL *stop) {
        [self addScreenMonitoringAnalyticsHook:screenDictionary];
    }];

    NSArray *trackedEventClasses = configurationDictionary[ARAnalyticsTrackedEvents];
    [trackedEventClasses enumerateObjectsUsingBlock:^(NSDictionary *eventDictionary, NSUInteger idx, BOOL *stop) {
        [self addEventAnalyticsHooks:eventDictionary];
    }];
}

+ (void)addEventAnalyticsHooks:(NSDictionary *)eventDictionary {
    Class klass = eventDictionary[ARAnalyticsClass];

    NSArray *analyticsDetails = eventDictionary[ARAnalyticsDetails];

    [analyticsDetails enumerateObjectsUsingBlock:^(NSDictionary *detailsDictionary, NSUInteger idx, BOOL *stop) {
        NSError *error = nil;
        SEL selector = [self selectorForEventAnalyticsDetails:detailsDictionary];
        NSString *event = detailsDictionary[ARAnalyticsEventName];

        id aspectRef = [klass aspect_hookSelector:selector withOptions:AspectPositionAfter usingBlock:^(__unsafe_unretained id instance, NSArray *arguments) {

            BOOL shouldFire = ar_shouldFireForInstance(detailsDictionary, instance, arguments);

            if (shouldFire) {
                NSDictionary *properties = nil;
                ARAnalyticsEventPropertiesBlock propertiesBlock = detailsDictionary[ARAnalyticsEventProperties];
                if (propertiesBlock) {
                    properties = propertiesBlock(instance, arguments);
                }

                [ARAnalytics event:event withProperties:properties];
            }
        } error:&error];

        if (error) {
            NSLog(@"ARAnalytics DSL: Error setting up hook for %@ on %@ -  %@", klass, NSStringFromSelector(selector), error.localizedDescription);

        } else {
            [self storeAspectRef:aspectRef forClass:klass andSelector:selector];
        }
    }];
}


+ (void)addScreenMonitoringAnalyticsHook:(NSDictionary *)screenDictionary {

    Class klass = screenDictionary[ARAnalyticsClass];
    NSArray *analyticsDetails = screenDictionary[ARAnalyticsDetails];

    [analyticsDetails enumerateObjectsUsingBlock:^(id analyticsDictionary, NSUInteger idx, BOOL *stop) {
        NSError *error = nil;
        SEL selector = [self selectorForScreenAnalyticsDetails:analyticsDictionary class:klass];

        // Try to grab the page name from the dictionary.
        NSString *dictionaryPageName = analyticsDictionary[ARAnalyticsPageName];

        // If there wasn't one, then try to invoke keypath.
        NSString *pageNameKeypath = analyticsDictionary[ARAnalyticsPageNameKeyPath];

       id aspectRef = [klass aspect_hookSelector:selector withOptions:AspectPositionAfter usingBlock:^(__unsafe_unretained id instance, NSArray *arguments) {

            BOOL shouldFire = ar_shouldFireForInstance(analyticsDictionary, instance, arguments);

            if (shouldFire) {
                NSString *pageName;
                if (dictionaryPageName) {
                    pageName = dictionaryPageName;
                } else {
                    pageName = [instance valueForKeyPath:pageNameKeypath];
                    NSAssert(pageName, @"Value for Key on `%@` returned nil from instance of class: `%@`", pageNameKeypath, NSStringFromClass([instance class]));
                }

                [ARAnalytics pageView:pageName];
            }
        } error:&error];

        if (error) {
            NSLog(@"ARAnalytics DSL: Error setting up hook for %@ on %@ -  %@", klass, NSStringFromSelector(selector), error.localizedDescription);

        } else {
            [self storeAspectRef:aspectRef forClass:klass andSelector:selector];
        }
    }];
}

+ (SEL)selectorForEventAnalyticsDetails:(NSDictionary *)detailsDictionary
{
    NSString *selectorName = detailsDictionary[ARAnalyticsSelectorName];
    SEL selector = NSSelectorFromString(selectorName);
    NSAssert(selector != NULL, @"Event selector lookup failed.");
    return selector;
}


+ (SEL)selectorForScreenAnalyticsDetails:(NSDictionary *)dictionary class:(Class)klass
{
    SEL selector;
    NSString *selectorName = dictionary[ARAnalyticsSelectorName];
    if (selectorName) {
        selector = NSSelectorFromString(selectorName);

    } else {

#if TARGET_OS_IPHONE
        selector = @selector(viewDidAppear:);
        NSAssert([[klass new] isKindOfClass:[UIViewController class]], @"Default selector of viewDidAppear: must only be used on classes extending UIViewController. ");
#else
            @throw [NSException exceptionWithName:NSInternalInconsistencyException
                                           reason:@"You must specify a selector name for page views on OS X."
                                         userInfo:nil];
#endif
    }
    return selector;
}


NSString *ARKeyForClassAndSelector(Class klass, SEL selector) {
    return [NSStringFromClass(klass) stringByAppendingFormat:@"-%@", NSStringFromSelector(selector)];
}

+ (void)storeAspectRef:(id)ref forClass:(Class)klass andSelector:(SEL)selector {
    if(!ARAnalyticsHooksStore){
        ARAnalyticsHooksStore = [NSMutableDictionary dictionary];
    }

    NSString *key = ARKeyForClassAndSelector(klass, selector);
    ARAnalyticsHooksStore[key] = ref;
}

+ (BOOL)removeEventsAnalyticsHooks:(NSDictionary *)analyticsDictionary
{
    SEL selector = [self selectorForEventAnalyticsDetails:analyticsDictionary];
    Class klass = analyticsDictionary[ARAnalyticsClass];

    NSString *key = ARKeyForClassAndSelector(klass, selector);
    id <Aspect> aspectRef = ARAnalyticsHooksStore[key];

    return [aspectRef remove];
}

+ (BOOL)removeScreenMonitoringAnalyticsHooks:(NSDictionary *)screenDictionary
{
    Class klass = screenDictionary[ARAnalyticsClass];
    SEL selector = [self selectorForScreenAnalyticsDetails:screenDictionary[ARAnalyticsDetails] class:klass];

    NSString *key = ARKeyForClassAndSelector(klass, selector);
    id <Aspect> aspectRef = ARAnalyticsHooksStore[key];

    return [aspectRef remove];
}

+ (BOOL)removeAllAnalyticsHooks
{
    __block BOOL success = YES;
    [ARAnalyticsHooksStore enumerateKeysAndObjectsUsingBlock:^(NSString *key, id <Aspect> aspectRef, BOOL *stop) {

        if ([aspectRef remove] == NO){
            success = NO;
        }
    }];
    [ARAnalyticsHooksStore removeAllObjects];
    return success;
}

@end