ReObjectiveC.m

#import "MinReact.h"

@implementation ActionStateInit
@end

@implementation Subscription
@end

@interface Store ()

@property (nonatomic) id<StateType> _Nullable state;
@property (nonatomic) NSMutableArray<Subscription *>* _Nonnull subscriptions;
@property (nonatomic) id<AnyReducer> _Nonnull reducer;
@property (nonatomic) BOOL isDispatching;
@end


@interface NSArray (Reduce)
-(id)reduceWithBlock:(id (^)(id memo, id element))block
          startValue:(id)memo;
@end
@implementation NSArray (Reduce)

-(id)reduceWithBlock:(id (^)(id memo, id element))block
          startValue:(id)memo
{
    for (id obj in self) {
        memo = block(memo, obj);
    }
    
    return memo;
}
@end

@implementation Store

-(void)setState:(id<StateType> _Nullable) state {
    _state = state;
    for (Subscription* sub in self.subscriptions) {
        
        __strong id<AnyStoreSubscriber> subscriber = sub.subscriber;
        if (subscriber != nil) {
            [subscriber newState:state];
        }
    }
}

-(instancetype _Nonnull)initWithReducer:(id<AnyReducer> _Nonnull)reducer
                                  state:(id<StateType> _Nullable)state
                             middleware:(NSArray<Middleware>* _Nullable)middleware;
{
    self = [super init];
    if (self) {
        self.reducer = reducer;
        self.state = state;
        self.subscriptions = [NSMutableArray new];
        if (self.state == nil) {
            [self dispatch:[ActionStateInit new]];
        }
    }
    return self;
}

-(id)dispatch:(id<Action>)action {
    return [self _dispatch:action];
}

-(id)_dispatch:(id<Action>)action
{
    guard(!self.isDispatching) else {
        NSAssert(false, @"Reducers may not dispatch actions.");
        return nil;
    }
    
    self.isDispatching = YES;
    id<StateType> newState = [self.reducer handleAction:action state:self.state];
    self.isDispatching = NO;
    
    // set state and alert all subscribers
    self.state = newState;
    return action;
}

-(BOOL)isNewSubscriber:(id<AnyStoreSubscriber>)subscriber {
    for (Subscription* sub in self.subscriptions) {
        if (sub.subscriber == subscriber) {
            return NO;
        }
    }
    return YES;
}
-(void)subscribe:(id<AnyStoreSubscriber>)subscriber selector:(StateSelector)selector {
    if (![self isNewSubscriber:subscriber]) {
        NSLog(@"adding an existing subscriber %@ to store", subscriber);
        return;
    }
    
    Subscription* sub = [Subscription new];
    sub.subscriber = subscriber;
    sub.selector = selector;
    [self.subscriptions addObject:sub];
}

-(void)unscubscribe:(id<AnyStoreSubscriber>)subscriber {
    
    NSInteger idx =
    [self.subscriptions indexOfObjectPassingTest:^BOOL(Subscription * _Nonnull obj, NSUInteger i, BOOL * _Nonnull stop) {
        if (obj.subscriber == subscriber) {
            *stop = YES;
            return YES;
        }
        return NO;
    }];
    
    if (idx != NSNotFound) {
        [self.subscriptions removeObjectAtIndex:idx];
    }
}

@end