/*

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

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    Defines a `MultiPaneLayout` that allows you to get a similar effect

                as the `DecoratingLayout` except that the accessory views are laid

                out in a cascade.

*/

import CoreGraphics

/**

    A layout that looks similar to a `DecoratingLayout` except that its decoration

    layout is composed of accessory layouts in a cascading layout.

*/

struct MultiPaneLayout<ChildContent: Layout, Accessory: Layout>: Layout where ChildContent.Content == Accessory.Content {

    typealias Content = ChildContent.Content

    /*

        Note that we're using **composition** here to combine smaller values together

        with other values to create a more complicated layout.

    */

    private var composedLayout: DecoratingLayout<ChildContent, CascadingLayout<Accessory>>

    init(content: ChildContent, accessories: [Accessory]) {

        // Here we're composing the `CascadingLayout` with the `DecoratingLayout`.

        let decoration = CascadingLayout(children: accessories)

        composedLayout = DecoratingLayout(content: content, decoration: decoration)

    }

    mutating func layout(in rect: CGRect) {

        composedLayout.layout(in: rect)

    }

    var contents: [Content] {

        return composedLayout.contents

    }

}