MediaPlayerWindowController.swift

import Cocoa
import AVKit
import SMBClient

private let storyboardID = "MediaPlayerWindowController"

class MediaPlayerWindowController: NSWindowController, NSWindowDelegate {
  static let supportedExtensions = {
    let fileTypes: [AVFileType] = AVURLAsset.audiovisualTypes()
    let extensions = fileTypes
      .compactMap { UTType($0.rawValue)?.preferredFilenameExtension }
    return extensions
  }()

  private let treeAccessor: TreeAccessor
  private let path: String
  private lazy var asset = SMBAVAsset(accessor: treeAccessor, path: path)

  private var observation: NSKeyValueObservation?
  private var windowController: NSWindowController?

  static func instantiate(path: String, accessor: TreeAccessor) -> Self {
    let storyboard = NSStoryboard(name: storyboardID, bundle: nil)
    return storyboard.instantiateController(identifier: storyboardID) { (coder) in
      Self(coder: coder, path: path, accessor: accessor)
    }
  }

  required init?(coder: NSCoder, path: String, accessor: TreeAccessor) {
    self.path = path
    self.treeAccessor = accessor

    super.init(coder: coder)
  }

  required init?(coder: NSCoder) {
    return nil
  }

  deinit {
    observation?.invalidate()
  }

  override func windowDidLoad() {
    super.windowDidLoad()

    guard let window else { return }

    window.appearance = NSAppearance(named: .darkAqua)
    window.title = URL(fileURLWithPath: path).lastPathComponent

    window.delegate = self

    guard let videoPlayerViewController = contentViewController as? MediaPlayerViewController else { return }

    Task { @MainActor in
      do {
        let fileReader = try await treeAccessor.fileReader(path: path)
        _ = try await fileReader.read(offset: 0, length: 1)
        try await fileReader.close()

        let playerItem = AVPlayerItem(asset: asset)

        let player = AVPlayer(playerItem: playerItem)
        videoPlayerViewController.playerView.player = player

        asset.loadTracks(withMediaType: .video) { (tracks, error) in
          guard let track = tracks?.first else { return }
          Task {
            let naturalSize = try await track.load(.naturalSize)

            await MainActor.run {
              guard let currentScreen = NSScreen.screens.first(where: { $0 == window.screen }) else {
                return
              }

              let rect = AVMakeRect(
                aspectRatio: CGSize(width: naturalSize.width, height: naturalSize.height),
                insideRect: currentScreen.visibleFrame
              )
              let contentSize = NSSize(width: min(rect.width, naturalSize.width), height: min(rect.height, naturalSize.height))

              window.setContentSize(contentSize)
              window.center()

              player.play()
            }
          }
        }
      } catch {
        _ = await MainActor.run {
          NSAlert(error: error).runModal()
        }
      }
    }

    windowController = self
  }

  func windowWillClose(_ notification: Notification) {
    asset.close()
    windowController = nil
  }
}

class MediaPlayerViewController: NSViewController {
  @IBOutlet var playerView: AVPlayerView!
}