/*

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

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 Home screen quick action creation and handling.

 */

import UIKit

import ContactsUI

enum ShortcutItemType: String {

    case newChat

    case sendChatTo

    private static let prefix: String = {

        let bundleIdentifier = Bundle.main.bundleIdentifier!

        return bundleIdentifier + "."

    }()

    init?(prefixedString: String) {

        guard let prefixRange = prefixedString.range(of: ShortcutItemType.prefix) else { return nil }

        var rawTypeString = prefixedString

        rawTypeString.removeSubrange(prefixRange)

        self.init(rawValue: rawTypeString)

    }

    var prefixedString: String {

        return type(of: self).prefix + self.rawValue

    }

}

struct ShortcutItemUserInfo {

    static let friendIdentifierKey = "friendIdentifier"

    var friendIdentifier: FriendIdentifier?

    init(friendIdentifier: FriendIdentifier? = nil) {

        self.friendIdentifier = friendIdentifier

    }

    init(dictionaryRepresentation: [String : NSSecureCoding]?) {

        guard let dictionary = dictionaryRepresentation else { return }

        self.friendIdentifier = (dictionary[ShortcutItemUserInfo.friendIdentifierKey] as! NSString) as FriendIdentifier

    }

    var dictionaryRepresentation: [String : NSSecureCoding] {

        var dictionary: [String : NSSecureCoding] = [:]

        if let friendIdentifier = friendIdentifier {

            dictionary[ShortcutItemUserInfo.friendIdentifierKey] = friendIdentifier as NSString

        }

        return dictionary

    }

}

struct ShortcutItemHandler {

    static private func grantedAccessToContacts() -> Bool {

        return CNContactStore.authorizationStatus(for: .contacts) == .authorized

    }

    static private func requestAccessToContactsIfNeeded(_ application: UIApplication) {

        guard CNContactStore.authorizationStatus(for: .contacts) == .notDetermined else { return }

        CNContactStore().requestAccess(for: .contacts) { (granted: Bool, error: Error?) in

            if granted {

                DispatchQueue.main.async {

                    updateDynamicShortcutItems(for: application)

                }

            }

        }

    }

    /// Updates the registered dynamic shortcut items for the app.

    static func updateDynamicShortcutItems(for application: UIApplication) {

        requestAccessToContactsIfNeeded(application)

        var shortcutItems = [UIApplicationShortcutItem]()

        let top3Friends = ChatItemManager.sharedInstance.topFriends.prefix(3)

        for friend in top3Friends {

            let type = ShortcutItemType.sendChatTo

            let title = friend.name

            let subtitle = NSLocalizedString("Send a chat", comment: "Send a chat to a specific friend")

            // If we can find a matching contact for the friend use that for the icon, otherwise use the default Message system icon.

            var icon = UIApplicationShortcutIcon(type: .message)

            if grantedAccessToContacts() {

                let predicate = CNContact.predicateForContacts(matchingName: friend.name)

                let contacts = try? CNContactStore().unifiedContacts(matching: predicate, keysToFetch: [])

                if let contact = contacts?.first {

                    icon = UIApplicationShortcutIcon(contact: contact)

                }

            }

            let userInfo = ShortcutItemUserInfo(friendIdentifier: friend.identifier)

            let shortcutItem = UIApplicationShortcutItem(type: type.prefixedString, localizedTitle: title, localizedSubtitle: subtitle, icon: icon, userInfo:userInfo.dictionaryRepresentation)

            shortcutItems.append(shortcutItem)

        }

        application.shortcutItems = shortcutItems

    }

    /// Attempt to handle the shortcut item by navigating to the appropriate view controller. Returns whether the shortcut item was handled.

    static func handle(_ shortcutItem: UIApplicationShortcutItem, with rootViewController: UIViewController) -> Bool {

        guard NewChatDelegate.isCameraAvailable() else { return false }

        guard let shortcutItemType = ShortcutItemType(prefixedString: shortcutItem.type) else { return false }

        let friend: Friend?

        switch shortcutItemType {

        case .newChat:

            friend = nil

        case .sendChatTo:

            let userInfo = ShortcutItemUserInfo(dictionaryRepresentation: shortcutItem.userInfo)

            if let friendIdentifier = userInfo.friendIdentifier {

                friend = ChatItemManager.sharedInstance.friend(for: friendIdentifier)

            }

            else {

                friend = nil

            }

        }

        guard let navigationController = rootViewController as? UINavigationController else { return false }

        navigationController.popToRootViewController(animated: false)

        guard let chatTableViewController = navigationController.topViewController as? ChatTableViewController else { return false }

        chatTableViewController.view.isHidden = true

        chatTableViewController.presentNewChatController(for: friend, animated: false) {

            chatTableViewController.view.isHidden = false

        }

        return true

    }

}