/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

import UIKit
import Shared
import Storage

private let LastUsedShareDestinationsKey = "LastUsedShareDestinations"

@objc(InitialViewController)
class InitialViewController: UIViewController, ShareControllerDelegate {
    var shareDialogController: ShareDialogController!

    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = UIColor(white: 0.0, alpha: 0.66) // TODO: Is the correct color documented somewhere?
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        
        ExtensionUtils.extractSharedItemFromExtensionContext(self.extensionContext, completionHandler: { (item, error) -> Void in
            if let item = item, error == nil {
                DispatchQueue.main.async {
                    guard item.isShareable else {
                        let alert = UIAlertController(title: Strings.SendToErrorTitle, message: Strings.SendToErrorMessage, preferredStyle: .alert)
                        alert.addAction(UIAlertAction(title: Strings.SendToErrorOKButton, style: .default) { _ in self.finish() })
                        self.present(alert, animated: true, completion: nil)
                        return
                    }

                    self.presentShareDialog(item)
                }
            } else {
                self.extensionContext!.completeRequest(returningItems: [], completionHandler: nil)
            }
        })
    }
    
    //
    
    func shareControllerDidCancel(_ shareController: ShareDialogController) {
        UIView.animate(withDuration: 0.25, animations: { () -> Void in
            self.shareDialogController.view.alpha = 0.0
        }, completion: { (Bool) -> Void in
            self.dismissShareDialog()
            self.finish()
        })
    }

    func finish() {
        self.extensionContext!.completeRequest(returningItems: [], completionHandler: nil)
    }

    func shareController(_ shareController: ShareDialogController, didShareItem item: ShareItem, toDestinations destinations: NSSet) {
        setLastUsedShareDestinations(destinations)
        
        UIView.animate(withDuration: 0.25, animations: { () -> Void in
            self.shareDialogController.view.alpha = 0.0
        }, completion: { (Bool) -> Void in
            self.dismissShareDialog()
            
            let profile = BrowserProfile(localName: "profile")

            if destinations.contains(ShareDestinationReadingList) {
                profile.readingList?.createRecordWithURL(item.url, title: item.title ?? "", addedBy: UIDevice.current.name)
            }

            if destinations.contains(ShareDestinationBookmarks) {
                _ = profile.bookmarks.shareItem(item).value // Blocks until database has settled
            }

            profile.shutdown()

            self.finish()
        })
    }
    
    //
    
    // TODO: use Set.
    func getLastUsedShareDestinations() -> NSSet {
        if let destinations = UserDefaults.standard.object(forKey: LastUsedShareDestinationsKey) as? NSArray {
            return NSSet(array: destinations as [AnyObject])
        }
        return NSSet(object: ShareDestinationBookmarks)
    }
    
    func setLastUsedShareDestinations(_ destinations: NSSet) {
        UserDefaults.standard.set(destinations.allObjects, forKey: LastUsedShareDestinationsKey)
        UserDefaults.standard.synchronize()
    }
    
    func presentShareDialog(_ item: ShareItem) {
        shareDialogController = ShareDialogController()
        shareDialogController.delegate = self
        shareDialogController.item = item
        shareDialogController.initialShareDestinations = getLastUsedShareDestinations()
        
        self.addChildViewController(shareDialogController)
        shareDialogController.view.translatesAutoresizingMaskIntoConstraints = false
        self.view.addSubview(shareDialogController.view)
        shareDialogController.didMove(toParentViewController: self)

        // Setup constraints for the dialog. We keep the dialog centered with 16 points of padding on both
        // sides. The dialog grows to max 380 points wide so that it does not look too big on landscape or
        // iPad devices.
        
        let views: NSDictionary = ["dialog": shareDialogController.view]
        
        view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-(16@751)-[dialog(<=380@1000)]-(16@751)-|",
            options: NSLayoutFormatOptions(), metrics: nil, views: (views as? [String: AnyObject])!))
        
        let cx = NSLayoutConstraint(item: shareDialogController.view, attribute: NSLayoutAttribute.centerX,
            relatedBy: NSLayoutRelation.equal, toItem: view, attribute: NSLayoutAttribute.centerX, multiplier: 1.0, constant: 0)
        cx.priority = 1000 // TODO: Why does UILayoutPriorityRequired give a linker error? SDK Bug?
        view.addConstraint(cx)
        
        view.addConstraint(NSLayoutConstraint(item: shareDialogController.view, attribute: NSLayoutAttribute.centerY,
            relatedBy: NSLayoutRelation.equal, toItem: view, attribute: NSLayoutAttribute.centerY, multiplier: 1.0, constant: 0))
        
        // Fade the dialog in
        
        shareDialogController.view.alpha = 0.0
        UIView.animate(withDuration: 0.25, animations: { () -> Void in
            self.shareDialogController.view.alpha = 1.0
        }, completion: nil)
    }
    
    func dismissShareDialog() {
        shareDialogController.willMove(toParentViewController: nil)
        shareDialogController.view.removeFromSuperview()
        shareDialogController.removeFromParentViewController()
    }
}