//  AlbumItem.swift
//  TagTunes
//
//  Created by Kim Wittenburg on 29.05.15.
//  Copyright (c) 2015 Kim Wittenburg. All rights reserved.
//

import SearchAPI

/// Represents an `Album` from the Search API.
public class AlbumItem: TagTunesGroupItem {

    /// Returns the `entity` as an `Album`.
    public var album: Album {
        return entity as! Album
    }

    public override var children: [TagTunesEntityItem] {
        didSet {
            super.children.sortInPlace { (item1: TagTunesEntityItem, item2: TagTunesEntityItem) in
                let song1 = (item1 as! SongItem).song
                let song2 = (item2 as! SongItem).song
                return song1.discNumber < song2.discNumber || (song1.discNumber == song2.discNumber && song1.trackNumber < song2.trackNumber)
            }
        }
    }

    public override func addAssociatedTracks<S : SequenceType where S.Generator.Element == TagTunesTrack>(tracks: S) -> Set<TagTunesTrack> {
        var unmatchedTracks = Set<TagTunesTrack>()
        for track in tracks {
            var inserted = false
            for child in children where child is SongItem {
                let songItem = child as! SongItem
                if (track.discNumber == songItem.song.discNumber || track.discNumber == 0) && track.trackNumber == songItem.song.trackNumber {
                    songItem.addAssociatedTracks([track])
                    inserted = true
                    break
                }
            }
            if !inserted {
                unmatchedTracks.insert(track)
            }
        }
        return unmatchedTracks
    }

    public override func addAssociatedTrack(track: TagTunesTrack, forChildEntity childEntity: SearchAPIEntity) {
        for child in children where child.entity.id == childEntity.id {
            child.addAssociatedTracks([track])
            return
        }
        let child = SongItem(entity: childEntity, parentItem: self)
        child.addAssociatedTracks([track])
        children.append(child)
    }

    public override var hasCommonArtist: Bool {
        for child in children where child is SongItem {
            if album.artist != (child as! SongItem).song.artist {
                return false
            }
        }
        return true
    }

    override class var childEntityType: SearchAPIRequest.EntityType {
        return .Song
    }
    
    override func processLookupResult(result: SearchAPIResult) {
        for song in result.contentsOfCollectionWithID(album.id) where !children.contains({ $0.entity == song }) {
            let item = SongItem(entity: song, parentItem: self)
            children.append(item)
        }
    }

}