/*

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

See LICENSE.txt for this sample’s licensing information

Abstract:

A view controller that shows a photo and its metadata.

*/

import UIKit

class PhotoViewController: UIViewController {

    // MARK: Properties

    fileprivate var imageView: UIImageView?

    fileprivate var overlayView: OverlayView?

    fileprivate var ratingControl: RatingControl?

    var photo: Photo

    // MARK: Initialization

    init(photo: Photo) {

        self.photo = photo

        super.init(nibName: nil, bundle: nil)

    }

    required init(coder aDecoder: NSCoder) {

        fatalError("init(coder:) has not been implemented")

    }

    // MARK: View Controller

    override func loadView() {

        let view = UIView()

        view.backgroundColor = UIColor.white

        let imageView = UIImageView()

        imageView.contentMode = .scaleAspectFit

        imageView.translatesAutoresizingMaskIntoConstraints = false

        self.imageView = imageView

        view.addSubview(imageView)

        let ratingControl = RatingControl()

        ratingControl.translatesAutoresizingMaskIntoConstraints = false

        ratingControl.addTarget(self, action: #selector(PhotoViewController.changeRating(_:)), for: .valueChanged)

        self.ratingControl = ratingControl

        view.addSubview(ratingControl)

        let overlayView = OverlayView()

        overlayView.translatesAutoresizingMaskIntoConstraints = false

        self.overlayView = overlayView

        view.addSubview(overlayView)

        updatePhoto()

        let views = [

            "imageView":        imageView,

            "ratingControl":    ratingControl,

            "overlayView":      overlayView

        ]

        var newConstraints = [NSLayoutConstraint]()

        newConstraints += NSLayoutConstraint.constraints(withVisualFormat: "|[imageView]|", options: [], metrics: nil, views: views)

        newConstraints += NSLayoutConstraint.constraints(withVisualFormat: "V:|[imageView]|", options: [], metrics: nil, views: views)

        newConstraints += NSLayoutConstraint.constraints(withVisualFormat: "[ratingControl]-20-|", options: [], metrics: nil, views: views)

        newConstraints += NSLayoutConstraint.constraints(withVisualFormat: "[overlayView]-20-|", options: [], metrics: nil, views: views)

        newConstraints += NSLayoutConstraint.constraints(withVisualFormat: "V:[overlayView]-[ratingControl]-20-|", options: [], metrics: nil, views: views)

        NSLayoutConstraint.activate(newConstraints)

        // Now add optional constraints.

        var optionalConstraints = [NSLayoutConstraint]()

        optionalConstraints += NSLayoutConstraint.constraints(withVisualFormat: "|-(>=20)-[ratingControl]", options: [], metrics: nil, views: views)

        optionalConstraints += NSLayoutConstraint.constraints(withVisualFormat: "|-(>=20)-[overlayView]", options: [], metrics: nil, views: views)

        // We want these constraints to be able to be broken if our interface is resized to be small enough that these margins don't fit.

        for constraint in optionalConstraints {

            constraint.priority = UILayoutPriorityRequired - 1

        }

        NSLayoutConstraint.activate(optionalConstraints)

        self.view = view

    }

    /*

        Action for a change in value from the `RatingControl` (the user choose a

        different rating for the photo).

    */

    func changeRating(_ sender: RatingControl) {

        photo.rating = sender.rating

    }

    // MARK: Convenience

    // Updates the image view and meta data views with the data from the current photo.

    func updatePhoto() {

        imageView?.image = photo.image

        overlayView?.text = photo.comment

        ratingControl?.rating = photo.rating

    }

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

    override func containedPhoto() -> Photo? {

        return photo

    }

}