//
//  AlbumDataSource.swift
//  Persephone
//
//  Created by Daniel Barber on 2019/2/20.
//  Copyright © 2019 Dan Barber. All rights reserved.
//

import Cocoa
import PromiseKit

class AlbumDataSource: NSObject, NSCollectionViewDataSource {
  var albums: [Album] = []

  func collectionView(_ collectionView: NSCollectionView, numberOfItemsInSection section: Int) -> Int {
    return albums.count
  }

  func resetCoverArt() {
    albums = albums.map {
      var album = $0
      album.coverArtFetched = false
      return album
    }
  }

  func collectionView(_ collectionView: NSCollectionView, itemForRepresentedObjectAt indexPath: IndexPath) -> NSCollectionViewItem {
    let item = collectionView.makeItem(withIdentifier: .albumViewItem, for: indexPath)
    guard let albumViewItem = item as? AlbumViewItem else { return item }

    albumViewItem.view.wantsLayer = true
    albumViewItem.setAlbum(albums[indexPath.item])

    if albums[indexPath.item].coverArt == nil &&
      !albums[indexPath.item].coverArtFetched {

      AppDelegate.mpdClient.getAlbumFirstSong(for: albums[indexPath.item].mpdAlbum) {
        guard let song = $0 else { return }
        
        AlbumArtService(song: Song(mpdSong: song))
          .fetchAlbumArt()
          .done { image in
            self.albums[indexPath.item].coverArt = image
            self.albums[indexPath.item].coverArtFetched = true

            DispatchQueue.main.async {
              collectionView.reloadItems(at: [indexPath])
            }
          }
      }
    }

    return albumViewItem
  }
}