elpha-ios/elpha-ios/AttachmentManager.swift

//
//  AttachmentManager.swift
//  elpha-ios
//
//  Created by Dwayne Harris on 10/6/18.
//  Copyright © 2018 Elpha. All rights reserved.
//

import AlamofireImage
import Kingfisher
import UIKit

protocol AttachmentManagerDelegate {
    func attachmentTapped(index: Int)
}

class AttachmentManager: NSObject {
    var delegate: AttachmentManagerDelegate? = nil
    
    @objc func attachmentTapped(_ gestureRecognizer: UITapGestureRecognizer) {
        if let delegate = delegate, let name = gestureRecognizer.name {
            delegate.attachmentTapped(index: Int(name)!)
        }
    }
    
    func setupAttachmentView(_ view: UIView, withAttachments attachments: NSOrderedSet?) {
        guard let attachments = attachments, attachments.count > 0 else {
            return
        }
        
        let placeholder = UIImage(named: "Help")
        let halfWidth = (view.frame.width / 2) - 1
        
        let fullSize = CGSize(width: view.frame.width, height: view.frame.width)
        let tallSize = CGSize(width: halfWidth, height: view.frame.width)
        let smallSize = CGSize(width: halfWidth, height: halfWidth)
        
        let fullResizingProcessor = ResizingImageProcessor(referenceSize: fullSize, mode: .aspectFill) >> CroppingImageProcessor(size: fullSize)
        let tallResizingProcessor = ResizingImageProcessor(referenceSize: tallSize, mode: .aspectFill) >> CroppingImageProcessor(size: tallSize)
        let smallResizingProcessor = ResizingImageProcessor(referenceSize: smallSize, mode: .aspectFill) >> CroppingImageProcessor(size: smallSize)
        
        for subview in view.subviews as [UIView] {
            subview.removeFromSuperview()
        }
        
        switch attachments.count {
        case 0:
            return
        case 1:
            let attachment = attachments.firstObject as! AttachmentMO
            
            let imageView = UIImageView()
            imageView.contentMode = UIImageView.ContentMode.scaleAspectFill
            imageView.isUserInteractionEnabled = true
            imageView.kf.setImage(with: attachment.url!, placeholder: placeholder, options: [.processor(fullResizingProcessor)])
            
            let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(attachmentTapped))
            tapGestureRecognizer.delegate = self
            tapGestureRecognizer.numberOfTapsRequired = 1
            tapGestureRecognizer.numberOfTouchesRequired = 1
            tapGestureRecognizer.name = "0"
            
            imageView.addGestureRecognizer(tapGestureRecognizer)
            
            view.addSubview(imageView)
            imageView.translatesAutoresizingMaskIntoConstraints = false
            
            NSLayoutConstraint.activate([
                imageView.topAnchor.constraint(equalTo: view.topAnchor),
                imageView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
                imageView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
                imageView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            ])
        case 2:
            let imageViews = [
                UIImageView(),
                UIImageView(),
            ]
            
            for (index, imageView) in imageViews.enumerated() {
                let attachment = attachments[index] as! AttachmentMO
                
                imageView.contentMode = UIImageView.ContentMode.scaleAspectFill
                imageView.isUserInteractionEnabled = true
                imageView.kf.setImage(with: attachment.url!, placeholder: placeholder, options: [.processor(tallResizingProcessor)])
                
                let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(attachmentTapped))
                tapGestureRecognizer.delegate = self
                tapGestureRecognizer.numberOfTapsRequired = 1
                tapGestureRecognizer.numberOfTouchesRequired = 1
                tapGestureRecognizer.name = String(index)
                
                imageView.addGestureRecognizer(tapGestureRecognizer)
                
                view.addSubview(imageView)
                imageView.translatesAutoresizingMaskIntoConstraints = false
                
                NSLayoutConstraint.activate([
                    imageView.topAnchor.constraint(equalTo: view.topAnchor),
                    imageView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
                    imageView.widthAnchor.constraint(equalToConstant: halfWidth),
                ])
            }
            
            NSLayoutConstraint.activate([
                imageViews[0].leadingAnchor.constraint(equalTo: view.leadingAnchor),
                imageViews[1].trailingAnchor.constraint(equalTo: view.trailingAnchor),
            ])
        case 3:
            let imageViews = [
                UIImageView(),
                UIImageView(),
                UIImageView(),
            ]
            
            for (index, imageView) in imageViews.enumerated() {
                let attachment = attachments[index] as! AttachmentMO
                var processor: ImageProcessor
                
                if index == 0 {
                    processor = tallResizingProcessor
                } else {
                    processor = smallResizingProcessor
                }
                
                imageView.contentMode = UIImageView.ContentMode.scaleAspectFill
                imageView.isUserInteractionEnabled = true
                imageView.kf.setImage(with: attachment.url!, placeholder: placeholder, options: [.processor(processor)])
                
                let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(attachmentTapped))
                tapGestureRecognizer.delegate = self
                tapGestureRecognizer.numberOfTapsRequired = 1
                tapGestureRecognizer.numberOfTouchesRequired = 1
                tapGestureRecognizer.name = String(index)
                
                imageView.addGestureRecognizer(tapGestureRecognizer)
                
                view.addSubview(imageView)
                imageView.translatesAutoresizingMaskIntoConstraints = false
                
                if index == 0 {
                    NSLayoutConstraint.activate([
                        imageView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
                        imageView.topAnchor.constraint(equalTo: view.topAnchor),
                        imageView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
                        imageView.widthAnchor.constraint(equalToConstant: halfWidth),
                    ])
                } else {
                    NSLayoutConstraint.activate([
                        imageView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
                        imageView.widthAnchor.constraint(equalToConstant: halfWidth),
                        imageView.heightAnchor.constraint(equalToConstant: halfWidth),
                    ])
                }
            }
            
            NSLayoutConstraint.activate([
                imageViews[1].topAnchor.constraint(equalTo: view.topAnchor),
                imageViews[2].bottomAnchor.constraint(equalTo: view.bottomAnchor),
            ])
        default:
            let imageViews = [
                UIImageView(),
                UIImageView(),
                UIImageView(),
                UIImageView(),
            ]
            
            for (index, imageView) in imageViews.enumerated() {
                let attachment = attachments[index] as! AttachmentMO
                
                imageView.contentMode = UIImageView.ContentMode.scaleAspectFill
                imageView.isUserInteractionEnabled = true
                imageView.kf.setImage(with: attachment.url!, placeholder: placeholder, options: [.processor(smallResizingProcessor)])
                
                let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(attachmentTapped))
                tapGestureRecognizer.delegate = self
                tapGestureRecognizer.numberOfTapsRequired = 1
                tapGestureRecognizer.numberOfTouchesRequired = 1
                tapGestureRecognizer.name = String(index)
                
                imageView.addGestureRecognizer(tapGestureRecognizer)
                
                view.addSubview(imageView)
                imageView.translatesAutoresizingMaskIntoConstraints = false
            }
            
            NSLayoutConstraint.activate([
                imageViews[0].topAnchor.constraint(equalTo: view.topAnchor),
                imageViews[0].leadingAnchor.constraint(equalTo: view.leadingAnchor),
                imageViews[1].topAnchor.constraint(equalTo: view.topAnchor),
                imageViews[1].trailingAnchor.constraint(equalTo: view.trailingAnchor),
                imageViews[2].leadingAnchor.constraint(equalTo: view.leadingAnchor),
                imageViews[2].bottomAnchor.constraint(equalTo: view.bottomAnchor),
                imageViews[3].bottomAnchor.constraint(equalTo: view.bottomAnchor),
                imageViews[3].trailingAnchor.constraint(equalTo: view.trailingAnchor),
            ])
        }
    }
}

extension AttachmentManager: UIGestureRecognizerDelegate {

}