Delegate dance

signalForSelector.m

- (void)viewDidLoad
{
    [super viewDidLoad];
    @weakify(self);
    
    self.exploreSearchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 0, mTCTableViewFrameWidth, 44)];
    self.exploreSearchBar.placeholder = @"Search";
    
    [self.exploreSearchBar setBackgroundImage:[UIImage squareImageWithColor:mTCLightTanColor dimension:1] forBarPosition:UIBarPositionAny barMetrics:UIBarMetricsDefault];
    self.tableView.tableHeaderView = self.exploreSearchBar;

    RACSignal *enterSearchViewSignal = [[self rac_signalForSelector:@selector(searchBarTextDidBeginEditing:)] logNext];
    
    RACSignal *cancelSearch = [self rac_signalForSelector:@selector(searchBarCancelButtonClicked:)];
    
    RACSignal *textChange = [[self rac_signalForSelector:@selector(searchBar:textDidChange:)]
        reduceEach:^id(UISearchBar *searchBar, NSString *text) {
            return text;
        }];
    
    // search string
    RAC(self, viewModel.searchString) = [RACSignal merge:@[textChange, [cancelSearch mapReplace:@""]]];
    
    RAC(self.exploreSearchBar, text) = [cancelSearch mapReplace:@""];
    
    RACSignal *showSearchInterfaceSignal = [[RACSignal merge:@[[enterSearchViewSignal mapReplace:@YES], [cancelSearch mapReplace:@NO]]] distinctUntilChanged];
    
    [self.exploreSearchBar rac_liftSelector:@selector(setShowsCancelButton:animated:) withSignals:showSearchInterfaceSignal, [RACSignal return:@YES], nil];
    
    // end editing on cancel click
    [self.exploreSearchBar rac_liftSelector:@selector(endEditing:) withSignals:[cancelSearch mapReplace:@YES], nil];
    
    RACSignal *clickSearch = [self rac_signalForSelector:@selector(searchBarSearchButtonClicked:)];
    [self.viewModel rac_liftSelector:@selector(performSearch:) withSignals:clickSearch, nil];

    // show navigation bar
    // cancel button tapped or
    // will disappear
    RACSignal *showWhenDisappearing = [[self rac_signalForSelector:@selector(viewWillDisappear:)]
        mapReplace:@NO];
    
    // hide navigation bar
    // enter search or
    // view will appear and search string isn't empty
    RACSignal *viewWillAppearWithSearchText = [[[self rac_signalForSelector:@selector(viewWillAppear:)]
        filter:^BOOL(id value) {
            @strongify(self);
            return self.viewModel.searchString.length > 0;
        }]
        mapReplace:@YES];
    
    RACSignal *showHideNavBar = [RACSignal merge:@[showSearchInterfaceSignal, viewWillAppearWithSearchText, showWhenDisappearing]];
    
    [self.navigationController rac_liftSelector:@selector(setNavigationBarHidden:animated:) withSignals:showHideNavBar, [RACSignal return:@YES], nil];


    RACSignal *presented = [[RACSignal
        merge:@[
            [[self rac_signalForSelector:@selector(viewWillAppear:)] mapReplace:@YES],
            [[self rac_signalForSelector:@selector(viewWillDisappear:)] mapReplace:@NO]
        ]]
        setNameWithFormat:@"%@ presented", self];

    RACSignal *appActive = [[[RACSignal
        merge:@[
            [[NSNotificationCenter.defaultCenter rac_addObserverForName:UIApplicationDidBecomeActiveNotification object:nil] mapReplace:@YES],
            [[NSNotificationCenter.defaultCenter rac_addObserverForName:UIApplicationWillResignActiveNotification object:nil] mapReplace:@NO]
        ]]
        startWith:@YES]
        setNameWithFormat:@"%@ appActive", self];
    
    
    RAC(self, viewModel.active) = [[[RACSignal
        combineLatest:@[ presented, appActive ]]
        and]
        setNameWithFormat:@"%@ active", self];

    self.tableView.backgroundColor = mTCLightTanColor;

    [self.tableView registerClass:[TCExploreSearchHeaderView class] forHeaderFooterViewReuseIdentifier:@"TCExploreSearchHeaderView"];
    [self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:@"cell"];
    [self.tableView registerClass:[TCProfileUserCell class] forCellReuseIdentifier:@"TCProfileUserCell"];
    [self.tableView registerClass:[TCExploreSearchLoadingCell class] forCellReuseIdentifier:@"TCExploreSearchLoadingCell"];
    [self.tableView registerClass:[TCExploreHashtagCell class] forCellReuseIdentifier:@"TCExploreHashtagCell"];
    [self.tableView registerClass:[TCLoadingCell class] forCellReuseIdentifier:@"TCLoadingCell"];

    self.tableView.separatorStyle = UITableViewCellSeparatorStyleNone;
    
    
    // reload the search table on signal
    [[RACObserve(self, viewModel.tableUpdateSignal)
        switchToLatest]
        subscribeNext:^(id x) {
            @strongify(self);
            [self.tableView reloadData];
        }];

    [[RACObserve(self, viewModel.exploreErrorSignal)
        switchToLatest]
        subscribeNext:^(NSString *errorDescription) {
            [[TWMessageBarManager sharedInstance] showMessageWithTitle:@"Error" description:errorDescription type:TWMessageBarMessageTypeError];
        }];

    self.exploreSearchBar.delegate = nil;
    self.exploreSearchBar.delegate = self;
}