UIScrollView+reachedBottom.swift

//
//  UIScrollView+rearchedBottom.swift
//  architecture
//
//  Created by MakotoAoyama on 8/18/17.
//

import Foundation
import ReactiveSwift
import Result

extension Reactive where Base: UIScrollView {

    var reachedBottom: Signal<CGPoint?, NoError> {
        get {
            let any: Signal<Any?, NoError> = self.signal(forKeyPath: #keyPath(UIScrollView.contentOffset))
            return any.map { (any) -> CGPoint? in
                guard let point = any as? CGPoint else {
                    return nil
                }
                return point
            }.filter { (point) -> Bool in
                guard let y = point?.y else {
                    return false
                }
                if y + self.base.bounds.height > self.base.contentSize.height {
                    return true
                }
                return false
            }
        }
    }

}