MessageKit/Sources/InputBarItem.swift

/*
 MIT License
 
 Copyright (c) 2017 MessageKit
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 */

import UIKit

open class InputBarButtonItem: UIButton {
    
    public enum Spacing {
        case fixed(CGFloat)
        case flexible
        case none
    }
    
    public typealias InputBarButtonItemAction = ((InputBarButtonItem) -> Void)
    
    // MARK: - Properties
    
    /// Set automatically when using the InputBarAccessoryView method 'setStackViewItems'
    open weak var messageInputBar: MessageInputBar?
    
    public var spacing: Spacing = .none {
        didSet {
            switch spacing {
            case .flexible:
              setContentHuggingPriority(UILayoutPriority(rawValue: 1), for: .horizontal)
            case .fixed:
              setContentHuggingPriority(UILayoutPriority(rawValue: 1000), for: .horizontal)
            case .none:
              setContentHuggingPriority(UILayoutPriority(rawValue: 500), for: .horizontal)
            }
        }
    }
    
    /// When not nil this size overrides the intrinsicContentSize
    private(set) var size: CGSize? = CGSize(width: 20, height: 20) {
        didSet {
            invalidateIntrinsicContentSize()
        }
    }
    
    open override var intrinsicContentSize: CGSize {
        var contentSize = size ?? super.intrinsicContentSize
        switch spacing {
        case .fixed(let width):
            contentSize.width += width
        case .flexible, .none:
            break
        }
        return contentSize
    }
    
    internal var parentStackViewPosition: MessageInputBar.UIStackViewPosition?
    
    /// The title for the UIControlState.normal
    open var title: String? {
        get {
            return title(for: .normal)
        }
        set {
            setTitle(newValue, for: .normal)
        }
    }
    
    /// The image for the UIControlState.normal
    open var image: UIImage? {
        get {
            return image(for: .normal)
        }
        set {
            setImage(newValue, for: .normal)
        }
    }
    
    open override var isHighlighted: Bool {
        didSet {
            if isHighlighted {
                onSelectedAction?(self)
            } else {
                onDeselectedAction?(self)
            }
        }
    }
    
    open override var isEnabled: Bool {
        didSet {
            if isEnabled {
                onEnabledAction?(self)
            } else {
                onDisabledAction?(self)
            }
        }
    }
    
    // MARK: - Hooks
    
    private var onTouchUpInsideAction: InputBarButtonItemAction?
    private var onKeyboardEditingBeginsAction: InputBarButtonItemAction?
    private var onKeyboardEditingEndsAction: InputBarButtonItemAction?
    private var onTextViewDidChangeAction: ((InputBarButtonItem, InputTextView) -> Void)?
    private var onSelectedAction: InputBarButtonItemAction?
    private var onDeselectedAction: InputBarButtonItemAction?
    private var onEnabledAction: InputBarButtonItemAction?
    private var onDisabledAction: InputBarButtonItemAction?
    
    // MARK: - Initialization
    
    public convenience init() {
        self.init(frame: .zero)
    }
    
    public override init(frame: CGRect) {
        super.init(frame: frame)
        setup()
    }
    
    required public init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setup()
    }
    
    open func setup() {
        
        contentVerticalAlignment = .center
        contentHorizontalAlignment = .center
        imageView?.contentMode = .scaleAspectFit
      setContentHuggingPriority(UILayoutPriority(rawValue: 500), for: .horizontal)
      setContentHuggingPriority(UILayoutPriority(rawValue: 500), for: .vertical)
        setTitleColor(UIColor(red: 0, green: 122/255, blue: 1, alpha: 1), for: .normal)
        setTitleColor(UIColor(red: 0, green: 122/255, blue: 1, alpha: 0.3), for: .highlighted)
        setTitleColor(.lightGray, for: .disabled)
        adjustsImageWhenHighlighted = false
        addTarget(self, action: #selector(InputBarButtonItem.touchUpInsideAction), for: .touchUpInside)
    }
    
    // MARK: - Size Adjustment
    
    open func setSize(_ newValue: CGSize?, animated: Bool) {
        size = newValue
        if animated, let position = parentStackViewPosition {
            messageInputBar?.performLayout(animated) {
                self.messageInputBar?.layoutStackViews([position])
            }
        }
    }
    
    // MARK: - Hook Setup Methods
    
    @discardableResult
    open func configure(_ setup: InputBarButtonItemAction) -> Self {
        setup(self)
        return self
    }
    
    @discardableResult
    open func onKeyboardEditingBegins(_ action: @escaping InputBarButtonItemAction) -> Self {
        onKeyboardEditingBeginsAction = action
        return self
    }
    
    @discardableResult
    open func onKeyboardEditingEnds(_ action: @escaping InputBarButtonItemAction) -> Self {
        onKeyboardEditingEndsAction = action
        return self
    }
    
    @discardableResult
    open func onTextViewDidChange(_ action: @escaping (_ item: InputBarButtonItem, _ textView: InputTextView) -> Void) -> Self {
        onTextViewDidChangeAction = action
        return self
    }
    
    @discardableResult
    open func onTouchUpInside(_ action: @escaping InputBarButtonItemAction) -> Self {
        onTouchUpInsideAction = action
        return self
    }
    
    @discardableResult
    open func onSelected(_ action: @escaping InputBarButtonItemAction) -> Self {
        onSelectedAction = action
        return self
    }
    
    @discardableResult
    open func onDeselected(_ action: @escaping InputBarButtonItemAction) -> Self {
        onDeselectedAction = action
        return self
    }
    
    @discardableResult
    open func onEnabled(_ action: @escaping InputBarButtonItemAction) -> Self {
        onEnabledAction = action
        return self
    }
    
    @discardableResult
    open func onDisabled(_ action: @escaping InputBarButtonItemAction) -> Self {
        onDisabledAction = action
        return self
    }
    
    // MARK: - Hook Executors
    
    public func textViewDidChangeAction(with textView: InputTextView) {
        onTextViewDidChangeAction?(self, textView)
    }
    
    public func keyboardEditingEndsAction() {
        onKeyboardEditingEndsAction?(self)
    }
    
    public func keyboardEditingBeginsAction() {
        onKeyboardEditingBeginsAction?(self)
    }
    
  @objc public func touchUpInsideAction() {
        onTouchUpInsideAction?(self)
    }
    
    // MARK: - Static
    
    open static var flexibleSpace: InputBarButtonItem {
        let item = InputBarButtonItem()
        item.size = .zero
        item.spacing = .flexible
        return item
    }
    
    open static func fixedSpace(_ width: CGFloat) -> InputBarButtonItem {
        let item = InputBarButtonItem()
        item.size = .zero
        item.spacing = .fixed(width)
        return item
    }
}