elpha-ios/elpha-ios/AttachmentsManager.swift

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

import AlamofireImage
import UIKit

class AttachmentsManager {
    static func setupAttachmentsView(_ view: UIView, withAttachments attachments: NSOrderedSet?) {
        guard let attachments = attachments, attachments.count > 0 else {
            return
        }
        
        let placeholderImage = UIImage(named: "Help")
        let halfWidth = (view.frame.width / 2) - 1
        
        for subview in view.subviews as [UIView] {
            subview.removeFromSuperview()
        }
        
        switch attachments.count {
        case 0:
            return
        case 1:
            let filter = AspectScaledToFillSizeFilter(size: CGSize(width: view.frame.width, height: view.frame.width))
            
            let attachment = attachments.firstObject as! AttachmentMO
            let imageView = UIImageView()
            
            imageView.contentMode = UIImageView.ContentMode.scaleAspectFill
            imageView.af_setImage(
                withURL: attachment.url!,
                placeholderImage: placeholderImage,
                filter: filter
            )
            
            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),
                imageView.widthAnchor.constraint(equalToConstant: view.frame.width),
                imageView.heightAnchor.constraint(equalToConstant: view.frame.width),
            ])
        case 2:
            let filter = AspectScaledToFillSizeFilter(size: CGSize(width: halfWidth, height: view.frame.width))
            
            let imageViews = [
                UIImageView(),
                UIImageView(),
            ]
            
            for (index, imageView) in imageViews.enumerated() {
                imageView.contentMode = UIImageView.ContentMode.scaleAspectFill
                imageView.af_setImage(
                    withURL: (attachments[index] as! AttachmentMO).url!,
                    placeholderImage: placeholderImage,
                    filter: filter
                )
                
                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),
                    imageView.heightAnchor.constraint(equalToConstant: view.frame.width),
                ])
            }
            
            NSLayoutConstraint.activate([
                imageViews[0].leadingAnchor.constraint(equalTo: view.leadingAnchor),
                imageViews[1].trailingAnchor.constraint(equalTo: view.trailingAnchor),
            ])
        case 3:
            let primaryFilter = AspectScaledToFillSizeFilter(size: CGSize(width: halfWidth, height: view.frame.width))
            let secondaryFilter = AspectScaledToFillSizeFilter(size: CGSize(width: halfWidth, height: halfWidth))
            
            let imageViews = [
                UIImageView(),
                UIImageView(),
                UIImageView(),
            ]
            
            for (index, imageView) in imageViews.enumerated() {
                imageView.contentMode = UIImageView.ContentMode.scaleAspectFill
                imageView.af_setImage(
                    withURL: (attachments[index] as! AttachmentMO).url!,
                    placeholderImage: placeholderImage,
                    filter: index == 0 ? primaryFilter : secondaryFilter
                )
                
                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),
                        imageView.heightAnchor.constraint(equalToConstant: view.frame.width),
                    ])
                } else {
                    NSLayoutConstraint.activate([
                        imageView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
                        imageView.widthAnchor.constraint(equalToConstant: halfWidth),
                        imageView.heightAnchor.constraint(equalToConstant: halfWidth),
                    ])
                }
            }
            
            NSLayoutConstraint.activate([
                imageViews[2].topAnchor.constraint(equalTo: view.topAnchor),
                imageViews[3].bottomAnchor.constraint(equalTo: view.bottomAnchor),
            ])
        default:
            let filter = AspectScaledToFillSizeFilter(size: CGSize(width: halfWidth, height: halfWidth))
            
            let imageViews = [
                UIImageView(),
                UIImageView(),
                UIImageView(),
                UIImageView(),
            ]
            
            for (index, imageView) in imageViews.enumerated() {
                imageView.contentMode = UIImageView.ContentMode.scaleAspectFill
                imageView.af_setImage(
                    withURL: (attachments[index] as! AttachmentMO).url!,
                    placeholderImage: placeholderImage,
                    filter: filter
                )
                
                view.addSubview(imageView)
                imageView.translatesAutoresizingMaskIntoConstraints = false
                
                NSLayoutConstraint.activate([
                    imageView.widthAnchor.constraint(equalToConstant: halfWidth),
                    imageView.heightAnchor.constraint(equalToConstant: halfWidth),
                ])
            }
            
            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[3].leadingAnchor.constraint(equalTo: view.leadingAnchor),
                imageViews[3].bottomAnchor.constraint(equalTo: view.bottomAnchor),
                imageViews[4].bottomAnchor.constraint(equalTo: view.bottomAnchor),
                imageViews[4].trailingAnchor.constraint(equalTo: view.trailingAnchor),
            ])
        }
    }
}