UIViewController+PS.swift

// PS UIViewController+PS.swift
//
// Copyright © 2015, Roy Ratcliffe, Pioneering Software, United Kingdom
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the “Software”), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in
//  all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED “AS IS,” WITHOUT WARRANTY OF ANY KIND, EITHER
// EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO
// EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
// OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
//------------------------------------------------------------------------------

import UIKit

extension UIViewController {

    /// Displays the given content within this container.
    ///
    /// :param: content Content view controller to display within this
    ///     container's content hierarchy.
    ///
    /// :param: frameForContent Optional capture describing how to set up the
    ///     new content's frame. If not given, the content's frame remains
    ///     unchanged, and therefore assumes that layout constraints will
    ///     determine the view's position and size within the new container. The
    ///     capture's argument takes this container's view and answers the new
    ///     content's frame within that view.
    ///
    /// Adds the other view controller's view to this container's view
    /// hierarchy. Automatically removes the content from any other container
    /// before adding it to this container, invoking
    /// `willMoveToParentViewController` on the content view controller.
    ///
    /// View controllers, amongst other things, can operate as containers for
    /// other content controllers; they have a self-referencing
    /// container-content relationship. Content controllers become children
    /// belonging to a parent container. Content views join the container's view
    /// hierarchy.
    public func displayContentController(content: UIViewController, frameForContent: ((UIView) -> CGRect)? = nil) {
        addChildViewController(content)
        if let frameForContent = frameForContent {
            content.view.frame = frameForContent(view)
        }
        view.addSubview(content.view)
        content.didMoveToParentViewController(self)
    }

    public func hideContentController(content: UIViewController) {
        content.willMoveToParentViewController(nil)
        content.view.removeFromSuperview()
        content.removeFromParentViewController()
    }

    public func cycleFromContentController(content: UIViewController, toContentController newContent: UIViewController, duration: NSTimeInterval, options: UIViewAnimationOptions, newContentStartFrame: CGRect?, contentEndFrame: CGRect?) {
        content.willMoveToParentViewController(nil)
        addChildViewController(newContent)
        if let frame = newContentStartFrame {
            newContent.view.frame = frame
        }
        transitionFromViewController(content, toViewController: newContent, duration: duration, options: options, animations: {
            newContent.view.frame = content.view.frame
            if let frame = contentEndFrame {
                content.view.frame = frame
            }
        }) { finished in
            content.removeFromParentViewController()
            newContent.didMoveToParentViewController(self)
        }
    }

}