Tusker/Tusker/Screens/Asset Picker/AssetPreviewViewController.swift

//
//  AssetPreviewViewController.swift
//  Tusker
//
//  Created by Shadowfacts on 1/4/20.
//  Copyright © 2020 Shadowfacts. All rights reserved.
//

import UIKit
import Photos
import PhotosUI
import AVKit

class AssetPreviewViewController: UIViewController {

    let attachment: CompositionAttachmentData
    
    init(attachment: CompositionAttachmentData) {
        self.attachment = attachment

        super.init(nibName: nil, bundle: nil)
    }
    
    convenience init(asset: PHAsset) {
        self.init(attachment: .asset(asset))
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.backgroundColor = .black

        switch attachment {
        case let .image(image):
            showImage(image)
        case let .video(url):
            showVideo(asset: AVURLAsset(url: url))
        case let .asset(asset):
            switch asset.mediaType {
            case .image:
                if asset.mediaSubtypes.contains(.photoLive) {
                    showLivePhoto(asset)
                } else {
                    showAssetImage(asset)
                }
            case .video:
                showAssetVideo(asset)
            default:
                fatalError("asset mediaType must be image or video")
            }
        case let .drawing(drawing):
            let image = drawing.imageInLightMode(from: drawing.bounds)
            showImage(image)
        }
    }
    
    func showImage(_ image: UIImage) {
        let imageView = UIImageView(image: image)
        imageView.translatesAutoresizingMaskIntoConstraints = false
        imageView.contentMode = .scaleAspectFit
        view.addSubview(imageView)
        NSLayoutConstraint.activate([
            imageView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            imageView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            imageView.topAnchor.constraint(equalTo: view.topAnchor),
            imageView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
        ])
        preferredContentSize = image.size
    }
    
    func showAssetImage(_ asset: PHAsset) {
        let options = PHImageRequestOptions()
        options.version = .current
        options.deliveryMode = .opportunistic
        options.resizeMode = .none
        options.isNetworkAccessAllowed = true
        PHImageManager.default().requestImage(for: asset, targetSize: view.bounds.size, contentMode: .aspectFit, options: options) { (image, _) in
            DispatchQueue.main.async {
                self.showImage(image!)
            }
        }
    }
    
    func showLivePhoto(_ asset: PHAsset) {
        let options = PHLivePhotoRequestOptions()
        options.deliveryMode = .opportunistic
        options.version = .current
        options.isNetworkAccessAllowed = true
        PHImageManager.default().requestLivePhoto(for: asset, targetSize: view.bounds.size, contentMode: .aspectFit, options: options) { (livePhoto, _) in
            guard let livePhoto = livePhoto else {
                fatalError("failed to get live photo")
            }
            DispatchQueue.main.async {
                let livePhotoView = PHLivePhotoView()
                livePhotoView.livePhoto = livePhoto
                livePhotoView.isMuted = true
                livePhotoView.startPlayback(with: .full)
                livePhotoView.translatesAutoresizingMaskIntoConstraints = false
                livePhotoView.contentMode = .scaleAspectFit
                self.view.addSubview(livePhotoView)
                NSLayoutConstraint.activate([
                    livePhotoView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
                    livePhotoView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
                    livePhotoView.topAnchor.constraint(equalTo: self.view.topAnchor),
                    livePhotoView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor)
                ])
                self.preferredContentSize = livePhoto.size
            }
        }
    }
    
    func showVideo(asset: AVAsset) {
        let playerController = AVPlayerViewController()
        let item = AVPlayerItem(asset: asset)
        let player = AVPlayer(playerItem: item)
        player.isMuted = true
        player.play()
        playerController.player = player
        self.embedChild(playerController)
        self.preferredContentSize = item.presentationSize
    }
    
    func showAssetVideo(_ asset: PHAsset) {
        let options = PHVideoRequestOptions()
        options.deliveryMode = .automatic
        options.isNetworkAccessAllowed = true
        options.version = .current
        PHImageManager.default().requestAVAsset(forVideo: asset, options: options) { (avAsset, _, _) in
            guard let avAsset = avAsset else {
                fatalError("failed to get AVAsset")
            }
            DispatchQueue.main.async {
                self.showVideo(asset: avAsset)
            }
        }
    }
    
}