//
//  UIScrollView+ScrollToBottom.swift
//  SwiftBilibili
//
//  Created by 罗文 on 2021/1/14.
//  Copyright © 2021年 罗文. All rights reserved.
//

import UIKit

extension UIScrollView {
    
    var isOverflowVertical: Bool {
        return self.contentSize.height > self.frame.height && self.frame.height > 0
    }
    
    func isReachedBottom(withTolerance tolerance: CGFloat = 0) -> Bool {
        guard self.isOverflowVertical else { return false }
        let contentOffsetBottom = self.contentOffset.y + self.frame.height
        return contentOffsetBottom >= self.contentSize.height - tolerance
    }
    
    func scrollToBottom(animated: Bool) {
        guard self.isOverflowVertical else { return }
        let targetY = self.contentSize.height + self.contentInset.bottom - self.frame.height
        let targetOffset = CGPoint(x: 0, y: targetY)
        self.setContentOffset(targetOffset, animated: true)
    }
    
}