//
//  GameStore.swift
//  Zockerhoehle
//
//  Created by Julian-Steffen Müller on 02.08.19.
//  Copyright © 2019 Julian-Steffen Müller. All rights reserved.
//

import Foundation
import SwiftUI
import CoreData
import Combine

class GameStore : NSObject, ObservableObject, NSFetchedResultsControllerDelegate {
    var objectWillChange = PassthroughSubject<Void , Never>()
    var consoleFilter : Console?
    var gameSeriesFilter : GameSeries?
    var sortDescriptors : [NSSortDescriptor] = [NSSortDescriptor(key: "name", ascending: true)]
    var fetchLimit : Int = 0
    
    var games : [Game] {
        get {
            if self.fetchResultsController.fetchedObjects == nil {
                
                do {
                    try fetchResultsController.performFetch()
                }catch {
                    print("GameStore::games Perform Fetch not possible '\(error)'")
                }
            }
            
            let result = self.fetchResultsController.fetchedObjects ?? []
            
            //Anscheinend ein Bug im FetchResultController das er das fetchLimit manchmal ignoriert
            if self.fetchLimit > 0 && result.count > self.fetchLimit {
                print("GameStore::games Fetch limit of ignored. Expected: \(self.fetchLimit) Delivered: \(result.count)")
                
                var clampedResult : [Game] = []
                for index in 0..<self.fetchLimit {
                    clampedResult.append(result[index])
                }
                
                return clampedResult
            }
            
            return result
        }
    }
    
    lazy var fetchResultsController : NSFetchedResultsController<Game> =  {
        var gamesFetch : NSFetchRequest<Game> = Game.fetchRequest()
        
        /*if let console = consoleFilter {
            gamesFetch = Game.fetchRequest(console: console)
        }else if let gameSeries = gameSeriesFilter {
            gamesFetch = Game.fetchRequest(gameSeries: gameSeries)
        }else {
            print("No filter: fetch Limit: \(self.fetchLimit)")
        }*/
        
        gamesFetch.fetchLimit = self.fetchLimit
        gamesFetch.sortDescriptors = self.sortDescriptors
        
        let gamesFetchRC =  NSFetchedResultsController(fetchRequest: gamesFetch, managedObjectContext: CDManager.shared.viewContext, sectionNameKeyPath: nil, cacheName: nil)
        
        gamesFetchRC.delegate = self
        
        return gamesFetchRC
    }()
    
    init(console : Console?, fetchLimit : Int = 0) {
        super.init()
        self.consoleFilter = console
        self.fetchLimit = fetchLimit
    }
    
    init(gameSeries: GameSeries?, fetchLimit : Int = 0) {
        super.init()
        self.gameSeriesFilter = gameSeries
        self.fetchLimit = fetchLimit
    }

    init(sortDescriptors : [NSSortDescriptor], fetchLimit : Int = 0) {
        super.init()
        self.sortDescriptors = sortDescriptors
        self.fetchLimit = fetchLimit
    }
    
    init(fetchLimit : Int = 0) {
        super.init()
        self.fetchLimit = fetchLimit
    }
    
    func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
        self.objectWillChange.send()
    }
}