/*

Copyright (C) 2016 Apple Inc. All Rights Reserved.

See LICENSE.txt for this sample’s licensing information

Abstract:

A view controller that shows the contents of a conversation.

*/

import UIKit

class ConversationViewController: UITableViewController {

    // MARK: Properties

    var conversation: Conversation?

    static let cellIdentifier = "PhotoCell"

    // MARK: Initialization

    deinit {

        NotificationCenter.default.removeObserver(self)

    }

    // MARK: View Controller

    override func viewDidLoad() {

        super.viewDidLoad()

        NotificationCenter.default.addObserver(self, selector: #selector(ConversationViewController.showDetailTargetDidChange(_:)), name: NSNotification.Name.UIViewControllerShowDetailTargetDidChange, object: nil)

    }

    override func viewWillAppear(_ animated: Bool) {

        super.viewWillAppear(animated)

        for indexPath in tableView.indexPathsForSelectedRows ?? [] {

            let indexPathPushes = willShowingDetailViewControllerPushWithSender(self)

            if indexPathPushes {

                // If we're pushing for this indexPath, deselect it when we appear.

                tableView.deselectRow(at: indexPath, animated: animated)

            }

        }

        let visiblePhoto = currentVisibleDetailPhotoWithSender(self)

        for indexPath in tableView.indexPathsForVisibleRows ?? [] {

            let photo = photoForIndexPath(indexPath)

            if photo == visiblePhoto {

                tableView.selectRow(at: indexPath, animated: false, scrollPosition: .none)

            }

        }

    }

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

        guard let indexPath = tableView.indexPathForSelectedRow,

                  let photo = photoForIndexPath(indexPath)

              , segue.identifier == "ShowPhoto" else { return }

        let destination = segue.destination as! PhotoViewController

        destination.photo = photo

        let photoNumber = (indexPath as NSIndexPath).row + 1

        let photoCount = conversation?.photos.count ?? 0

        let localizedStringFormat = NSLocalizedString("%d of %d", comment: "X of X")

        destination.title = String.localizedStringWithFormat(localizedStringFormat, photoNumber, photoCount)

    }

    // This method is originally declared in the PhotoContents extension on `UIViewController`.

    override func containsPhoto(_ photo: Photo) -> Bool {

        return conversation?.photos.contains(photo) ?? false

    }

    func showDetailTargetDidChange(_ notification: Notification) {

        for cell in tableView.visibleCells {

            if let indexPath = tableView.indexPath(for: cell) {

                tableView(tableView, willDisplay: cell, forRowAt: indexPath)

            }

        }

    }

    // MARK: Table View

    func photoForIndexPath(_ indexPath: IndexPath) -> Photo? {

        return conversation?.photos[(indexPath as NSIndexPath).row]

    }

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

        return conversation?.photos.count ?? 0

    }

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

        return tableView.dequeueReusableCell(withIdentifier: ConversationViewController.cellIdentifier, for: indexPath)

    }

    override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {

        let pushes = willShowingDetailViewControllerPushWithSender(self)

        // Only show a disclosure indicator if we're pushing.

        cell.accessoryType = pushes ? .disclosureIndicator : .none

        let photo = photoForIndexPath(indexPath)

        cell.textLabel?.text = photo?.comment ?? ""

    }

}