////
////  LookupOperation.swift
////  TagTunes
////
////  Created by Kim Wittenburg on 08.04.16.
////  Copyright © 2016 Kim Wittenburg. All rights reserved.
////
//
//import AppKitPlus
//
//class LookupOperation: Operation {
//
//    /// The `NSURLSession` used to perform lookup tasks.
//    private let urlSession = NSURLSession(configuration: NSURLSessionConfiguration.defaultSessionConfiguration(), delegate: nil, delegateQueue: NSOperationQueue.mainQueue())
//
//    /// The task of the current lookup. If there is currently no lookup being
//    /// processed this is `nil`.
//    ///
//    /// If you need to know whether there is currently a active lookup you should
//    /// use the `lookupActive` property instead.
//    private var lookupTask: NSURLSessionTask?
//
//    var lookupActive = false
//
//    /// The tracks that are currently being looked up. These tracks do not
//    /// contain the tracks enqueued for lookup.
//    private var lookupTracks = [SearchAPIID: TagTunesTrack]()
//
//    private var queue = [TagTunesTrack]() {
//        didSet {
//            lookupActivity.progress.localizedAdditionalDescription = String(format: NSLocalizedString("%d Tracks Pending", comment: "Additional description format fpr the iTunes Match lookup."), queue.count)
//        }
//    }
//
//    func enqueueTracksForLookup<S : SequenceType where S.Generator.Element == TagTunesTrack>(tracks: S) {
//        queue.appendContentsOf(tracks)
//        if !lookupActive {
//            beginLookup()
//        }
//    }
//
//    @IBAction func cancelLookup(sender: AnyObject) {
//        cancelLookup()
//    }
//
//    func cancelLookup() {
//        lookupTask?.cancel()
//        lookupTask = nil
//        var tracks = queue
//        tracks.appendContentsOf(lookupTracks.values)
//        for track in tracks {
//            track.lookupState = .Error(NSCocoaError.UserCancelledError)
//        }
//        lookupDelegate?.lookupController(self, completedLookupForTracks: tracks)
//        queue = []
//        lookupTracks = [:]
//        lookupDelegate?.lookupControllerDidFinishLookup(self)
//
//        lookupActive = false
//    }
//
//    private func beginLookup() {
//        lookupActive = true
//        lookupDelegate?.lookupController(self, willBeginLookupForTracks: queue)
//
//        let tracks = queue
//        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)) { self.performLookupForTracks(tracks) }
//        queue = []
//    }
//
//    /// Actually starts the lookup for the specified tracks.
//    ///
//    /// This method does not execute the network request (but it starts it).
//    /// Still it is recommended not to invoke this method on the main thread
//    /// since it can block the current thread for quite a while (depending on the
//    /// location of the tracks).
//    private func performLookupForTracks(tracks: [TagTunesTrack]) {
//        dispatch_sync(dispatch_get_main_queue()) {
//            self.lookupActivity.progress.totalUnitCount = -1
//            self.lookupActivity.progress.localizedDescription = String(format: NSLocalizedString("Preparing Lookup for %d Tracks…", comment: "Description format for the iTunes Match lookup preparation."), tracks.count)
//        }
//        var invalidTracks = [TagTunesTrack]()
//        lookupTracks = [:]
//        for track in tracks {
//            track.lookupState = .Preparing
//            if let id = track.id {
//                lookupTracks[id] = track
//                track.lookupState = .Searching
//            } else {
//                invalidTracks.append(track)
//                track.lookupState = .Unqualified
//            }
//        }
//        dispatch_sync(dispatch_get_main_queue()) {
//            if !invalidTracks.isEmpty {
//                self.lookupDelegate?.lookupController(self, completedLookupForTracks: invalidTracks)
//            }
//            self.lookupActivity.progress.localizedDescription = String(format: NSLocalizedString("Looking up %d tracks…", comment: "Description format for the iTunes Match lookup."), self.lookupTracks.count)
//        }
//        var request = SearchAPIRequest(lookupRequestWithIDs: lookupTracks.keys)
//        request.entity = .Album
//        request.country = Preferences.sharedPreferences.iTunesStore
//        if Preferences.sharedPreferences.useEnglishTags {
//            request.language = .English
//        }
//        NSThread.sleepForTimeInterval(2)
//        lookupTask = urlSession.dataTaskWithURL(request.URL, completionHandler: finishedTrackLookupWithData)
//        lookupTask?.resume()
//    }
//
//    /// Invoked after the lookup network request has completed. This method
//    /// processes the raw lookup data and send delegate messages accordingly.
//    /// This method may send multiple delegate messages depending on the
//    /// characteristics of the `data`.
//    ///
//    /// This method must be called on the main thread.
//    private func finishedTrackLookupWithData(data: NSData?, response: NSURLResponse?, error: NSError?) {
//        assert(NSThread.isMainThread())
//        defer {
//            lookupTask = nil
//        }
//        let result = (try? data.map(SearchAPIResult.init)) ?? nil
//        for (id, track) in lookupTracks {
//            if let error = error {
//                track.lookupState = .Error(error)
//            } else if let resultTrack = result?.entityForID(id) as? Track {
//                track.lookupState = .Found(resultTrack)
//            } else {
//                track.lookupState = .NotFound
//            }
//        }
//        lookupDelegate?.lookupController(self, completedLookupForTracks: Array(lookupTracks.values))
//        if queue.isEmpty {
//            lookupDelegate?.lookupControllerDidFinishLookup(self)
//            lookupActive = false
//        } else {
//            beginLookup()
//        }
//    }
//    
//}