Tusker/Tusker/Screens/Conversation/ConversationViewController.swift

//
//  ConversationTableViewController.swift
//  Tusker
//
//  Created by Shadowfacts on 8/28/18.
//  Copyright © 2018 Shadowfacts. All rights reserved.
//

import UIKit
import Pachyderm

class ConversationViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {

    static func create(for mainStatusID: String) -> ConversationViewController {
        guard let conversationController = UIStoryboard(name: "Conversation", bundle: nil).instantiateInitialViewController() as? ConversationViewController else { fatalError() }
        conversationController.mainStatusID = mainStatusID
        return conversationController
    }
    
    @IBOutlet weak var tableView: UITableView!
    
    var mainStatusID: String!
    
    var statusIDs: [String] = [] {
        didSet {
            DispatchQueue.main.async {
                self.tableView.reloadData()
            }
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()

        tableView.delegate = self
        tableView.dataSource = self
        
        tableView.register(UINib(nibName: "StatusTableViewCell", bundle: nil), forCellReuseIdentifier: "statusCell")
        tableView.register(UINib(nibName: "ConversationMainStatusTableViewCell", bundle: nil), forCellReuseIdentifier: "mainStatusCell")
        
        statusIDs = [mainStatusID]
        
        guard let mainStatus = StatusCache.get(id: mainStatusID) else { fatalError("Missing cached status \(mainStatusID!)") }
        
        let request = Status.getContext(mainStatus)
        MastodonController.shared.client.run(request) { response in
            guard case let .success(context, _) = response else { fatalError() }
            let parents = self.getDirectParents(of: mainStatus, from: context.ancestors)
            StatusCache.addAll(parents)
            StatusCache.addAll(context.descendants)
            self.statusIDs = parents.map { $0.id } + [self.mainStatusID] + context.descendants.map { $0.id }
            let indexPath = IndexPath(row: self.statusIDs.firstIndex(of: self.mainStatusID)!, section: 0)
            DispatchQueue.main.async {
                self.tableView.scrollToRow(at: indexPath, at: .middle, animated: false)
            }
        }
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        
        for cell in tableView.visibleCells {
            if let cell = cell as? PreferencesAdaptive {
                cell.updateUIForPreferences()
            }
        }
    }
    
    func getDirectParents(of status: Status, from statuses: [Status]) -> [Status] {
        var statuses = statuses
        var parents: [Status] = []
        var currentStatus: Status? = status
        while currentStatus != nil {
            guard let index = statuses.firstIndex(where: { $0.id == currentStatus!.inReplyToID }) else { break }
            let parent = statuses.remove(at: index)
            parents.insert(parent, at: 0)
            currentStatus = parent
        }
        return parents
    }

    /*
     // MARK: - Navigation
     
     // In a storyboard-based application, you will often want to do a little preparation before navigation
     override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
     // Get the new view controller using segue.destination.
     // Pass the selected object to the new view controller.
     }
     */
    
    // MARK: - Table view data source

    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return statusIDs.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let statusID = statusIDs[indexPath.row]
        
        if statusID == mainStatusID {
            guard let cell = tableView.dequeueReusableCell(withIdentifier: "mainStatusCell", for: indexPath) as? ConversationMainStatusTableViewCell else { fatalError() }
            cell.selectionStyle = .none
            cell.updateUI(for: statusID)
            cell.delegate = self
            return cell
        } else {
            guard let cell = tableView.dequeueReusableCell(withIdentifier: "statusCell", for: indexPath) as? StatusTableViewCell else { fatalError() }
            cell.updateUI(for: statusID)
            cell.delegate = self
            return cell
        }
    }
    
    func tableView(_ tableView: UITableView, willSelectRowAt indexPath: IndexPath) -> IndexPath? {
        let statusID = statusIDs[indexPath.row]
        return statusID == mainStatusID ? nil : indexPath
    }
    
    func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
        return tableView.cellForRow(at: indexPath) is TableViewSwipeActionProvider
    }
    
    func tableView(_ tableView: UITableView, leadingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
        return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.leadingSwipeActionsConfiguration()
    }
    
    func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
        return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.trailingSwipeActionsConfiguration()
    }

}

extension ConversationViewController: StatusTableViewCellDelegate {}
extension ConversationViewController: LargeImageViewControllerDelegate {}