persephone/Persephone/Components/Browser/Artist Browser/ArtistViewController.swift

//
//  ArtistViewController.swift
//  Persephone
//
//  Created by Daniel Barber on 2019/9/20.
//  Copyright © 2019 Dan Barber. All rights reserved.
//

import AppKit
import ReSwift
import Differ

class ArtistViewController: NSViewController,
                            NSCollectionViewDelegateFlowLayout {
    var dataSource = ArtistDataSource()
    let layout = FlexibleGridViewLayout(coder: NSCoder())

    @IBOutlet var artistCollectionView: NSCollectionView!

    override func viewDidLoad() {
      super.viewDidLoad()

      App.store.subscribe(self) {
        $0.select { $0.artistListState }
      }

      NotificationCenter.default.addObserver(self, selector: #selector(didConnect), name: .didConnect, object: nil)
      NotificationCenter.default.addObserver(self, selector: #selector(willDisconnect), name: .willDisconnect, object: nil)

      artistCollectionView.dataSource = dataSource
      layout?.extraHeight = 26
      artistCollectionView.collectionViewLayout = layout
  }

    deinit {
      App.store.unsubscribe(self)
    }

    @objc func didConnect() {
      App.mpdClient.fetchAllArtists()
    }

    @objc func willDisconnect() {
      DispatchQueue.main.async {
        App.store.dispatch(UpdateArtistListAction(artists: []))
      }
    }
  }

  extension ArtistViewController: StoreSubscriber {
    typealias StoreSubscriberStateType = ArtistListState

    func newState(state: StoreSubscriberStateType) {
      let oldArtists = dataSource.artists

      dataSource.artists = state.artists

      artistCollectionView.animateItemChanges(
        oldData: oldArtists,
        newData: dataSource.artists
      )
    }
}