UnderlinedTextField.swift

//
//  UnderlinedTextField.swift
//  Halo
//
//  Created by Alan Fineberg on 7/25/17.
//
//

import Foundation
import ReactiveKit
import UIKit

class UnderlinedTextField: UITextField {
    
    let placeholderLabel = UILabel()
    @IBOutlet weak var underlineView: UIView!
    
    var animateOpenControlEvent: UIControlEvents {
        return .editingDidBegin
    }
    
    var animateClosedControlEvent: UIControlEvents? {
        return .editingDidEnd
    }
    
    override func awakeFromNib() {
        super.awakeFromNib()
        
        textColor = Sport.Color.LightGrey
        clipsToBounds = false
        
        setupPlaceholderLabel()
        setupUnderline()
    }
    
    override internal var text: String? {
        willSet {
            if !open, text?.isEmpty == true, newValue?.isEmpty == false {
                placeholderLabel.transform = placeholderLabel.transform.scaledBy(x: scaleFactor, y: scaleFactor).translatedBy(x: 0.0, y: -self.frame.size.height / (scaleFactor * 2.0))
                placeholderLabel.textColor = Sport.Color.Green
                textColor = Sport.Color.Green
                open = true
            }
        }
    }
    
    private var open = false
    private func animateOpen(originalTransform: CGAffineTransform, scaleFactor: CGFloat) {
        guard !open else { return }
        placeholder = nil
        
        UIView.animate(withDuration: 0.30, delay: 0.0, options: .curveEaseInOut, animations: { [weak self] in
            guard let `self` = self else { return }
            self.open = true
            
            if self.text?.isEmpty == true {
                self.placeholderLabel.transform = originalTransform.scaledBy(x: scaleFactor, y: scaleFactor).translatedBy(x: 0.0, y: -self.frame.size.height / (scaleFactor * 2.0))
            }
            self.placeholderLabel.textColor = Sport.Color.Green
            }, completion: { [weak self] _ in
                self?.textColor = Sport.Color.Green
        })
    }
    
    private func animateClosed(originalTransform: CGAffineTransform, scaleFactor: CGFloat, originalPlaceholder: String?) {
        guard open else { return }
        placeholder = nil
        
        UIView.animate(withDuration: 0.30, delay: 0.0, options: .curveEaseInOut, animations: { [weak self] in
            guard let `self` = self else { return }
            
            if self.text?.isEmpty == true {
                self.placeholderLabel.transform = originalTransform
            }
            self.placeholderLabel.textColor = Sport.Color.LightGrey
            }, completion: { [weak self] _ in
                self?.textColor = Sport.Color.LightGrey
                self?.placeholder = originalPlaceholder
                self?.open = false
        })
    }
    
    let scaleFactor: CGFloat = 0.4
    private func setupPlaceholderLabel() {
        addSubview(placeholderLabel)
        placeholderLabel.anchorPoint = CGPoint.zero
        placeholderLabel.text = placeholder
        placeholderLabel.textColor = Sport.Color.LightGrey
        placeholderLabel.font = font
        placeholderLabel.frame = frame
        let originalPlaceholder = placeholder
        placeholder = nil
        
        let originalTransform = placeholderLabel.transform
        reactive.controlEvents(animateOpenControlEvent).observeNext { [weak self] _ in
            guard let `self` = self else { return }
            self.animateOpen(originalTransform: originalTransform, scaleFactor: self.scaleFactor)
            }.dispose(in: reactive.bag)
        
        if let animatedClosedControlEvent = animateClosedControlEvent {
            reactive.controlEvents(animatedClosedControlEvent).observeNext { [weak self] _ in
                guard let `self` = self else { return }
                self.animateClosed(originalTransform: originalTransform, scaleFactor: self.scaleFactor, originalPlaceholder: originalPlaceholder)
                }.dispose(in: reactive.bag)
        }
    }
    
    private func setupUnderline() {
        underlineView.backgroundColor = Sport.Color.LightGrey
        
        reactive.controlEvents(animateOpenControlEvent).map { _ in
            return Sport.Color.Green
            }.bind(to: underlineView.reactive.backgroundColor).dispose(in: reactive.bag)
        
        if let animatedClosedControlEvent = animateClosedControlEvent {
            reactive.controlEvents(animatedClosedControlEvent).map { _ in
                return Sport.Color.LightGrey
                }.bind(to: underlineView.reactive.backgroundColor).dispose(in: reactive.bag)
        }
    }
}

/// A text field that doesn't actually allow editing to occur, but still wants to be highlighted on tap.
class UneditableUnderlinedTextField: UnderlinedTextField {
    override var animateOpenControlEvent: UIControlEvents {
        return .touchDown
    }
    override var animateClosedControlEvent: UIControlEvents? {
        return nil
    }
}