//
//  HashtagTimelineViewController.swift
//  Tusker
//
//  Created by Shadowfacts on 12/19/19.
//  Copyright © 2019 Shadowfacts. All rights reserved.
//

import UIKit
import Pachyderm

class HashtagTimelineViewController: TimelineViewController {

    let hashtag: Hashtag
    
    var toggleSaveButton: UIBarButtonItem!
    
    private var isHashtagSaved: Bool {
        mastodonController.persistentContainer.viewContext.objectExists(for: SavedHashtag.fetchRequest(name: hashtag.name))
    }
    
    private var isHashtagFollowed: Bool {
        mastodonController.followedHashtags.contains(where: { $0.name == hashtag.name })
    }
    
    init(for hashtag: Hashtag, mastodonController: MastodonController) {
        self.hashtag = hashtag
        
        super.init(for: .tag(hashtag: hashtag.name), mastodonController: mastodonController)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        let menu = UIMenu(children: [
            // uncached so that the saved/followed updates every time
            UIDeferredMenuElement.uncached({ [unowned self] elementHandler in
                elementHandler(actionsForHashtag(hashtag, source: .barButtonItem(self.navigationItem.rightBarButtonItem!)))
            })
        ])
        navigationItem.rightBarButtonItem = UIBarButtonItem(image: UIImage(systemName: "ellipsis"), menu: menu)
    }
    
    private func toggleSave() {
        let context = mastodonController.persistentContainer.viewContext
        if let existing = try? context.fetch(SavedHashtag.fetchRequest(name: hashtag.name)).first {
            context.delete(existing)
        } else {
            _ = SavedHashtag(hashtag: hashtag, context: context)
        }
        mastodonController.persistentContainer.save(context: context)
    }
    
    private func toggleFollow() {
        Task {
            await ToggleFollowHashtagService(hashtag: hashtag, presenter: self).toggleFollow()
        }
    }

}