//

// MasterViewController.swift

// DBClient-Example

//

// Created by Serhii Butenko on 11/1/17.

// Copyright © 2017 Yalantis. All rights reserved.

//

import UIKit

import DBClient

class MasterViewController: UITableViewController, DBClientInjectable {

fileprivate var objects = [User]()

private var userChangesObservable: RequestObservable<User>?

override func viewDidLoad() {

super.viewDidLoad()

let observable = dbClient.observable(for: FetchRequest<User>(sortDescriptor: NSSortDescriptor(key: "name", ascending: true)))

observable.observe { [weak self] changeSet in

self?.observeChanges(changeSet)

}

userChangesObservable = observable

navigationItem.leftBarButtonItem = editButtonItem

}

// MARK: - Segues

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

guard segue.identifier == "showDetail",

let controller = segue.destination as? DetailViewController else {

fatalError()

}

if let indexPath = tableView.indexPathForSelectedRow {

let object = objects[indexPath.row]

controller.detailItem = object

}

}

// MARK: - Actions

@IBAction private func addObject(_ sender: Any) {

dbClient.insert(User.createRandom())

}

private func observeChanges(_ changeSet: ObservableChange<User>) {

switch changeSet {

case .initial(let initial):

objects.append(contentsOf: initial)

tableView.reloadData()

case .change(let change):

self.objects = change.objects

tableView.beginUpdates()

let insertedIndexPaths = change.insertions.map { IndexPath(row: $0.index, section: 0) }

tableView.insertRows(at: insertedIndexPaths, with: .automatic)

let deletedIndexPaths = change.deletions.map { IndexPath(row: $0, section: 0) }

tableView.deleteRows(at: deletedIndexPaths, with: .automatic)

let updatedIndexPaths = change.modifications.map { IndexPath(row: $0.index, section: 0) }

tableView.reloadRows(at: updatedIndexPaths, with: .automatic)

tableView.endUpdates()

case .error(let error):

print("Got an error: \(error)")

}

}

}

// MARK: - Table View

extension MasterViewController {

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

return objects.count

}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)

let object = objects[indexPath.row]

cell.textLabel!.text = object.name

return cell

}

override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {

return true

}

override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {

guard editingStyle == .delete else {

return

}

let user = objects[indexPath.row]

dbClient.delete(user)

}

}