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 FLAnimatedImage
import UIKit

protocol AttachmentManagerDelegate {
    func attachmentTapped(index: Int)
}

class AttachmentManager: NSObject {
    var delegate: AttachmentManagerDelegate? = nil
    
    static private var downloader = ImageDownloader()
    static private var imageCache = AutoPurgingImageCache()
    static private let placeholderImage = UIImage(named: "Placeholder")
    
    @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 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 = FLAnimatedImageView()
            
            let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(attachmentTapped))
            tapGestureRecognizer.delegate = self
            tapGestureRecognizer.numberOfTapsRequired = 1
            tapGestureRecognizer.numberOfTouchesRequired = 1
            tapGestureRecognizer.name = "0"
            
            imageView.addGestureRecognizer(tapGestureRecognizer)
            imageView.isUserInteractionEnabled = true
            imageView.contentMode = UIImageView.ContentMode.center
            imageView.image = AttachmentManager.placeholderImage
            
            let request = URLRequest(url: attachment.url!)
            AttachmentManager.downloader.download(request, filter: filter) { response in
                imageView.contentMode = UIImageView.ContentMode.scaleAspectFill
                
                switch attachment.type {
                    case "gif":
                        imageView.animatedImage = FLAnimatedImage(animatedGIFData: response.data)
                    default:
                        imageView.image = response.result.value
                }
            }
            
            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 filter = AspectScaledToFillSizeFilter(size: CGSize(width: halfWidth, height: view.frame.width))
            
            let imageViews = [
                FLAnimatedImageView(),
                FLAnimatedImageView(),
            ]
            
            for (index, imageView) in imageViews.enumerated() {
                imageView.contentMode = UIImageView.ContentMode.scaleAspectFill
                
                let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(attachmentTapped))
                tapGestureRecognizer.delegate = self
                tapGestureRecognizer.numberOfTapsRequired = 1
                tapGestureRecognizer.numberOfTouchesRequired = 1
                tapGestureRecognizer.name = String(index)
                
                imageView.addGestureRecognizer(tapGestureRecognizer)
                imageView.isUserInteractionEnabled = true
                
                imageView.af_setImage(
                    withURL: (attachments[index] as! AttachmentMO).url!,
                    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),
                ])
            }
            
            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 = [
                FLAnimatedImageView(),
                FLAnimatedImageView(),
                FLAnimatedImageView(),
            ]
            
            for (index, imageView) in imageViews.enumerated() {
                imageView.contentMode = UIImageView.ContentMode.scaleAspectFill
                
                let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(attachmentTapped))
                tapGestureRecognizer.delegate = self
                tapGestureRecognizer.numberOfTapsRequired = 1
                tapGestureRecognizer.numberOfTouchesRequired = 1
                tapGestureRecognizer.name = String(index)
                
                imageView.addGestureRecognizer(tapGestureRecognizer)
                imageView.isUserInteractionEnabled = true
                
                imageView.af_setImage(
                    withURL: (attachments[index] as! AttachmentMO).url!,
                    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),
                    ])
                } 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 filter = AspectScaledToFillSizeFilter(size: CGSize(width: halfWidth, height: halfWidth))
            
            let imageViews = [
                FLAnimatedImageView(),
                FLAnimatedImageView(),
                FLAnimatedImageView(),
                FLAnimatedImageView(),
            ]
            
            for (index, imageView) in imageViews.enumerated() {
                imageView.contentMode = UIImageView.ContentMode.scaleAspectFill
                
                let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(attachmentTapped))
                tapGestureRecognizer.delegate = self
                tapGestureRecognizer.numberOfTapsRequired = 1
                tapGestureRecognizer.numberOfTouchesRequired = 1
                tapGestureRecognizer.name = String(index)
                
                imageView.addGestureRecognizer(tapGestureRecognizer)
                imageView.isUserInteractionEnabled = true
                
                imageView.af_setImage(
                    withURL: (attachments[index] as! AttachmentMO).url!,
                    filter: filter
                )
                
                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 {

}