SideStore/AltStore/Apps/AppDetailViewController.swift

//
//  AppDetailViewController.swift
//  AltStore
//
//  Created by Riley Testut on 5/9/19.
//  Copyright © 2019 Riley Testut. All rights reserved.
//

import UIKit
import Roxas

@objc(ScreenshotCollectionViewCell)
private class ScreenshotCollectionViewCell: UICollectionViewCell
{
    @IBOutlet var imageView: UIImageView!
}

extension AppDetailViewController
{
    private enum Row: Int
    {
        case general
        case screenshots
        case description
    }
}

class AppDetailViewController: UITableViewController
{
    var app: App!
    
    private lazy var screenshotsDataSource = self.makeScreenshotsDataSource()
    
    @IBOutlet private var nameLabel: UILabel!
    @IBOutlet private var developerButton: UIButton!
    @IBOutlet private var appIconImageView: UIImageView!
    
    @IBOutlet private var downloadButton: UIButton!
    
    @IBOutlet private var screenshotsCollectionView: UICollectionView!
    
    @IBOutlet private var descriptionLabel: UILabel!
    
    override func viewDidLoad()
    {
        super.viewDidLoad()
        
        self.tableView.delegate = self
        self.screenshotsCollectionView.dataSource = self.screenshotsDataSource
        
        self.downloadButton.activityIndicatorView.style = .white
        
        self.update()
    }
    
    override func viewWillAppear(_ animated: Bool)
    {
        super.viewWillAppear(animated)
        
        self.update()
    }
    
    override func viewDidLayoutSubviews()
    {
        super.viewDidLayoutSubviews()
        
        guard let image = self.screenshotsDataSource.items.first else { return }
        
        let aspectRatio = image.size.width / image.size.height
        
        let height = self.screenshotsCollectionView.bounds.height
        let width = self.screenshotsCollectionView.bounds.height * aspectRatio
        
        let layout = self.screenshotsCollectionView.collectionViewLayout as! UICollectionViewFlowLayout
        layout.itemSize = CGSize(width: width, height: height)
    }
}

private extension AppDetailViewController
{
    func update()
    {
        self.nameLabel.text = self.app.name
        self.developerButton.setTitle(self.app.developerName, for: .normal)
        self.appIconImageView.image = UIImage(named: self.app.iconName)
        
        self.descriptionLabel.text = self.app.localizedDescription
        
        if !self.downloadButton.isIndicatingActivity
        {
            if self.app.installedApp == nil
            {
                let text = String(format: NSLocalizedString("Download %@", comment: ""), self.app.name)
                self.downloadButton.setTitle(text, for: .normal)
                self.downloadButton.isEnabled = true
            }
            else
            {
                self.downloadButton.setTitle(NSLocalizedString("Installed", comment: ""), for: .normal)
                self.downloadButton.isEnabled = false
            }
        }
    }
    
    func makeScreenshotsDataSource() -> RSTArrayCollectionViewDataSource<UIImage>
    {
        let screenshots = self.app.screenshotNames.compactMap(UIImage.init(named:))
        
        let dataSource = RSTArrayCollectionViewDataSource(items: screenshots)
        dataSource.cellConfigurationHandler = { (cell, screenshot, indexPath) in
            let cell = cell as! ScreenshotCollectionViewCell
            cell.imageView.image = screenshot
        }
        
        return dataSource
    }
}

private extension AppDetailViewController
{
    @IBAction func downloadApp(_ sender: UIButton)
    {
        guard self.app.installedApp == nil else { return }

        sender.isIndicatingActivity = true
        
        AppManager.shared.install(self.app, presentingViewController: self) { (result) in
            do
            {
                let installedApp = try result.get()
                
                do { try installedApp.managedObjectContext?.save() }
                catch { print("Failed to save context.", error) }
                
                DispatchQueue.main.async {
                    let toastView = RSTToastView(text: "Installed \(self.app.name)!", detailText: nil)
                    toastView.tintColor = .altPurple
                    toastView.show(in: self.navigationController!.view, duration: 2)
                }
            }
            catch AppManager.AppError.authentication(AuthenticationOperation.Error.cancelled)
            {
                // Ignore
            }
            catch
            {
                DispatchQueue.main.async {
                    let toastView = RSTToastView(text: "Failed to install \(self.app.name)", detailText: error.localizedDescription)
                    toastView.tintColor = .altPurple
                    toastView.show(in: self.navigationController!.view, duration: 2)
                }
            }
            
            DispatchQueue.main.async {
                sender.isIndicatingActivity = false
                self.update()
            }
        }
    }
}

extension AppDetailViewController
{
    override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat
    {
        guard indexPath.row == Row.screenshots.rawValue else { return super.tableView(tableView, heightForRowAt: indexPath) }
        guard !self.screenshotsDataSource.items.isEmpty else { return 0.0 }
        
        let height = self.view.bounds.height * 0.67
        return height
    }
}