MessageKit/Sources/Views/Cells/MessageCollectionViewCell.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 MessageCollectionViewCell: UICollectionViewCell, CollectionViewReusable {

    open class func reuseIdentifier() -> String {
        return "messagekit.cell.base-cell"
    }

    open var avatarView = AvatarView()

    open var messageContainerView: MessageContainerView = {
        let containerView = MessageContainerView()
        containerView.clipsToBounds = true
        containerView.layer.masksToBounds = true
        return containerView
    }()

    open var cellTopLabel: UILabel = {
        let label = UILabel()
        label.numberOfLines = 0
        return label
    }()

    open var cellBottomLabel: UILabel = {
        let label = UILabel()
        label.numberOfLines = 0
        return label
    }()

    open weak var delegate: MessageCellDelegate?

    override public init(frame: CGRect) {
        super.init(frame: frame)
        contentView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        setupSubviews()
        setupGestureRecognizers()
    }

    required public init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    open func setupSubviews() {
        contentView.addSubview(messageContainerView)
        contentView.addSubview(avatarView)
        contentView.addSubview(cellTopLabel)
        contentView.addSubview(cellBottomLabel)
    }

    open override func prepareForReuse() {
        cellTopLabel.text = nil
        cellTopLabel.attributedText = nil
        cellBottomLabel.text = nil
        cellBottomLabel.attributedText = nil
    }

    // MARK: - Configuration

    open override func apply(_ layoutAttributes: UICollectionViewLayoutAttributes) {
        super.apply(layoutAttributes)
        if let attributes = layoutAttributes as? MessagesCollectionViewLayoutAttributes {
            avatarView.frame = attributes.avatarFrame
            cellTopLabel.frame = attributes.topLabelFrame
            cellBottomLabel.frame = attributes.bottomLabelFrame
            messageContainerView.frame = attributes.messageContainerFrame
        }
    }

    open func configure(with message: MessageType, at indexPath: IndexPath, and messagesCollectionView: MessagesCollectionView) {
        guard let dataSource = messagesCollectionView.messagesDataSource else {
            fatalError("MessagesDataSource is not set.")
        }
        guard let displayDelegate = messagesCollectionView.messagesDisplayDelegate else {
            fatalError("MessagesDisplayDelegate is not set.")
        }

        delegate = messagesCollectionView.messageCellDelegate

        let messageColor = displayDelegate.backgroundColor(for: message, at: indexPath, in: messagesCollectionView)
        let messageStyle = displayDelegate.messageStyle(for: message, at: indexPath, in: messagesCollectionView)

        messageContainerView.backgroundColor = messageColor
        messageContainerView.style = messageStyle

        let avatar = dataSource.avatar(for: message, at: indexPath, in: messagesCollectionView)
        let topText = dataSource.cellTopLabelAttributedText(for: message, at: indexPath)
        let bottomText = dataSource.cellBottomLabelAttributedText(for: message, at: indexPath)

        avatarView.set(avatar: avatar)
        cellTopLabel.attributedText = topText
        cellBottomLabel.attributedText = bottomText
    }

    func setupGestureRecognizers() {
        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleTapGesture(_:)))
        contentView.addGestureRecognizer(tapGesture)
    }

    /// Handle tap gesture on contentView and its subviews like messageContainerView, cellTopLabel, cellBottomLabel, avatarView ....
    @objc
    open func handleTapGesture(_ gesture: UIGestureRecognizer) {
        guard gesture.state == .ended else { return }

        let touchLocation = gesture.location(in: self)

        switch true {
        case messageContainerView.frame.contains(touchLocation) && !cellContentView(canHandle: convert(touchLocation, to: messageContainerView)):
            delegate?.didTapMessage(in: self)
        case avatarView.frame.contains(touchLocation):
            delegate?.didTapAvatar(in: self)
        case cellTopLabel.frame.contains(touchLocation):
            delegate?.didTapTopLabel(in: self)
        case cellBottomLabel.frame.contains(touchLocation):
            delegate?.didTapBottomLabel(in: self)
        default:
            break
        }
    }

    /// Handle `ContentView`'s tap gesture, return false when `ContentView` doesn't needs to handle gesture
    open func cellContentView(canHandle touchPoint: CGPoint) -> Bool {
        return false
    }
}