gistify771602.m

- (UIView*)tableView:(UITableView*)tableView viewForHeaderInSection:(NSInteger)section
{
    // The only header is in the first section
    if (section != DeviceSettingsTableViewControllerSectionDeviceSettings) {
        return [[UIView alloc] initWithFrame:CGRectZero];
    }
    
    // If we've already created this headerView, return it, it should never change
    if (self.headerView) {
        return self.headerView;
    }
    
    DeviceSettingsHeaderView *headerView = [[DeviceSettingsHeaderView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, self.tableView.bounds.size.width, DEVICE_HEADER_HEIGHT)];
    self.headerView = headerView;
    __block DeviceSettingsTableViewController *blockSelf = self;
    headerView.tappedBack = ^{
        [blockSelf popViewController];
    };
    
    // When the battery level changes, update the string
    RACSignal *batteryChangeSignal = [[RACObserve(self, device.batteryRemaining) distinctUntilChanged] deliverOn:[RACScheduler mainThreadScheduler]];
    RACSignal *connectedStateSignal = [[RACObserve(self, device.connectedState) distinctUntilChanged] deliverOn:[RACScheduler mainThreadScheduler]];
    
    // When the connection state changes, update the font of the label
    CGFloat fontSize = headerView.batteryLabel.font.pointSize;
    RAC(headerView.batteryLabel, font) = [connectedStateSignal map:^id(id value) {
        BOOL isConnected = [value integerValue] == MorseDeviceConnectedStateConnected;
        return [UIFont fontWithName:isConnected ? FONT_BREE_THIN : FONT_BREE_THIN_OBLIQUE size:fontSize];
    }];
    
    // When the connection state changes, update the label text
    RAC(headerView.batteryLabel, text) = [RACSignal combineLatest:@[batteryChangeSignal, connectedStateSignal] reduce:^id(NSNumber *batteryRemaining, NSNumber *deviceConnectedState) {
        BOOL isConnected = [deviceConnectedState integerValue] == MorseDeviceConnectedStateConnected;
        float batteryRemainingFloat = [batteryRemaining floatValue];
        NSString *batteryRemainingString = batteryRemainingFloat == -1 ? @"..." : [NSString stringWithFormat:@"%.0f%%", batteryRemainingFloat * 100];
        NSString *batteryIsAt = [NSString stringWithFormat:@"%@ %@", NSLocalizedString(@"battery is at", nil),  batteryRemainingString];
        NSString *disconnected = NSLocalizedString(@"disconnected", nil);
        
        return isConnected ? batteryIsAt : disconnected;
    }];
    
    // When the connection state changes, update the label's color
    RAC(headerView.batteryLabel, textColor) = [connectedStateSignal map:^id(id deviceConnectedState) {
        return [deviceConnectedState integerValue] == MorseDeviceConnectedStateConnected ? [AVHexColor colorWithHex:0x666666] : [AVHexColor colorWithHex:0xF26322];
    }];
    
    // update the alpha for the cone image
    RAC(headerView, coneImageAlpha) = [connectedStateSignal map:^id(id deviceConnectedState) {
        return [deviceConnectedState integerValue] == MorseDeviceConnectedStateConnected ? @1 : @.5;
    }];

    return headerView;
}