//
//  TrendingStatusesViewController.swift
//  Tusker
//
//  Created by Shadowfacts on 4/1/22.
//  Copyright © 2022 Shadowfacts. All rights reserved.
//

import UIKit
import Pachyderm

class TrendingStatusesViewController: EnhancedTableViewController {
    
    weak var mastodonController: MastodonController!
    
    private var dataSource: UITableViewDiffableDataSource<Section, Item>!
    
    init(mastodonController: MastodonController) {
        self.mastodonController = mastodonController
        
        super.init(style: .grouped)
        
        dragEnabled = true
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()

        title = NSLocalizedString("Trending Posts", comment: "trending posts screen title")
        
        tableView.register(UINib(nibName: "TimelineStatusTableViewCell", bundle: .main), forCellReuseIdentifier: "statusCell")
        tableView.estimatedRowHeight = 144
        
        dataSource = UITableViewDiffableDataSource(tableView: tableView, cellProvider: { tableView, indexPath, item in
            let cell = tableView.dequeueReusableCell(withIdentifier: "statusCell", for: indexPath) as! TimelineStatusTableViewCell
            cell.delegate = self
            cell.updateUI(statusID: item.id, state: item.state)
            return cell
        })
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        
        let request = Client.getTrendingStatuses()
        Task {
            guard let (statuses, _) = try? await mastodonController.run(request) else {
                return
            }
            mastodonController.persistentContainer.addAll(statuses: statuses) {
                var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
                snapshot.appendSections([.statuses])
                snapshot.appendItems(statuses.map { Item(id: $0.id, state: .unknown) })
                self.dataSource.apply(snapshot)
            }
        }
    }
    
    // MARK: - Table View Delegate
}

extension TrendingStatusesViewController {
    enum Section {
        case statuses
    }
    struct Item: Hashable {
        let id: String
        let state: StatusState
        
        static func ==(lhs: Item, rhs: Item) -> Bool {
            return lhs.id == rhs.id
        }
        
        func hash(into hasher: inout Hasher) {
            hasher.combine(id)
        }
    }
}

extension TrendingStatusesViewController: TuskerNavigationDelegate {
    var apiController: MastodonController { mastodonController }
}

extension TrendingStatusesViewController: StatusTableViewCellDelegate {
    func statusCellCollapsedStateChanged(_ cell: BaseStatusTableViewCell) {
        tableView.beginUpdates()
        tableView.endUpdates()
    }
}