Core Apps » ChatSecure:Android

//

//  OTRMessagesCollectionViewFlowLayout.swift

//  ChatSecure

//

//  Created by David Chiles on 3/4/16.

//  Copyright © 2016 Chris Ballinger. All rights reserved.

//

import Foundation

import JSQMessagesViewController

@objc public protocol OTRMessagesCollectionViewFlowLayoutSizeProtocol {

    func hasBubbleSizeForCellAtIndexPath(_ indexPath: IndexPath) -> Bool

}

@objc public class OTRMessagesCollectionSupplementaryViewInfo: NSObject {

    public var kind:String

    public var height:CGFloat

    @objc public init(kind:String, height:CGFloat) {

        self.kind = kind

        self.height = height

        super.init()

    }

}

@objc public protocol OTRMessagesCollectionViewFlowLayoutSupplementaryViewProtocol {

    func supplementaryViewsForCellAtIndexPath(_ indexPath: IndexPath) -> [OTRMessagesCollectionSupplementaryViewInfo]?

}

@objc open class OTRMessagesCollectionViewFlowLayout:JSQMessagesCollectionViewFlowLayout {

    @objc open weak var sizeDelegate:OTRMessagesCollectionViewFlowLayoutSizeProtocol?

    @objc open weak var supplementaryViewDelegate:OTRMessagesCollectionViewFlowLayoutSupplementaryViewProtocol?

    @objc override open func messageBubbleSizeForItem(at indexPath: IndexPath!) -> CGSize {

        guard let delegate = self.sizeDelegate, !delegate.hasBubbleSizeForCellAtIndexPath(indexPath) else {

            return super.messageBubbleSizeForItem(at: indexPath)

        }

        //Set width to one because of an Assert inside of JSQMessagesViewController

        return CGSize(width: 1, height: 0)

    }

    open override var collectionViewContentSize: CGSize {

        var size = super.collectionViewContentSize

        if let delegate = self.supplementaryViewDelegate {

            for section in 0..<self.collectionView.numberOfSections {

                for item in 0..<self.collectionView.numberOfItems(inSection: section) {

                    if let views = delegate.supplementaryViewsForCellAtIndexPath(IndexPath(item: item, section: section)) {

                        for view in views {

                            size.height += view.height

                        }

                    }

                }

            }

        }

        return size

    }

    override open func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {

        guard var attributes = super.layoutAttributesForElements(in: rect) else { return nil }

        var offset:CGFloat = 0

        for attribute in attributes {

            if (attribute.representedElementCategory == UICollectionElementCategory.cell) {

                attribute.frame = attribute.frame.offsetBy(dx: 0, dy: offset)

                if let delegate = self.supplementaryViewDelegate {

                    if let views = delegate.supplementaryViewsForCellAtIndexPath(attribute.indexPath) {

                        for view in views {

                            offset += view.height

                            let suppViewAttrs = UICollectionViewLayoutAttributes(forSupplementaryViewOfKind: view.kind, with: attribute.indexPath)

                            suppViewAttrs.frame = CGRect(x: attribute.frame.origin.x, y: attribute.frame.origin.y+attribute.frame.size.height, width: attribute.frame.size.width, height: view.height)

                            attributes.append(suppViewAttrs)

                        }

                    }

                }

            }

        }

        return attributes

    }

}