//
//  StatusTablePrefetching.swift
//  Tusker
//
//  Created by Shadowfacts on 1/18/21.
//  Copyright © 2021 Shadowfacts. All rights reserved.
//

import Foundation
import CoreData

protocol StatusTablePrefetching: TuskerNavigationDelegate {
}

extension StatusTablePrefetching {
    
    func prefetchStatuses(with ids: [String]) {
        let context = apiController.persistentContainer.prefetchBackgroundContext
        context.perform {
            guard let statuses = getStatusesWith(ids: ids, in: context) else {
                return
            }
            for status in statuses {
                _ = ImageCache.avatars.get(status.account.avatar, completion: nil)
                for attachment in status.attachments where attachment.kind == .image {
                    _ = ImageCache.attachments.get(attachment.url, completion: nil)
                }
            }
        }
    }
    
    func cancelPrefetchingStatuses(with ids: [String]) {
        let context = apiController.persistentContainer.prefetchBackgroundContext
        context.perform {
            guard let statuses = getStatusesWith(ids: ids, in: context) else {
                return
            }
            for status in statuses {
                ImageCache.avatars.cancelWithoutCallback(status.account.avatar)
                for attachment in status.attachments where attachment.kind == .image {
                    ImageCache.attachments.cancelWithoutCallback(attachment.url)
                }
            }
        }
    }
    
}

fileprivate func getStatusesWith(ids: [String], in context: NSManagedObjectContext) -> [StatusMO]? {
    let request: NSFetchRequest<StatusMO> = StatusMO.fetchRequest()
    request.predicate = NSPredicate(format: "id IN %@", ids)
    return try? context.fetch(request)
}