//
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// RxCollectionViewSectionedAnimatedDataSource.swift
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// RxExample
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//
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// Created by Krunoslav Zaher on 7/2/15.
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// Copyright © 2015 Krunoslav Zaher. All rights reserved.
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//
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#if os(iOS) || os(tvOS)
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import Foundation
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import UIKit
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#if !RX_NO_MODULE
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import RxSwift
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import RxCocoa
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#endif
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import Differentiator
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open class RxCollectionViewSectionedAnimatedDataSource<Section: AnimatableSectionModelType>
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: CollectionViewSectionedDataSource<Section>
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, RxCollectionViewDataSourceType {
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public typealias Element = [Section]
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public typealias DecideViewTransition = (CollectionViewSectionedDataSource<Section>, UICollectionView, [Changeset<Section>]) -> ViewTransition
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// animation configuration
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public var animationConfiguration: AnimationConfiguration
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/// Calculates view transition depending on type of changes
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public var decideViewTransition: DecideViewTransition
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public init(
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animationConfiguration: AnimationConfiguration = AnimationConfiguration(),
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decideViewTransition: @escaping DecideViewTransition = { _, _, _ in .animated },
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configureCell: @escaping ConfigureCell,
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configureSupplementaryView: ConfigureSupplementaryView? = nil,
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moveItem: @escaping MoveItem = { _, _, _ in () },
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canMoveItemAtIndexPath: @escaping CanMoveItemAtIndexPath = { _, _ in false }
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) {
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self.animationConfiguration = animationConfiguration
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self.decideViewTransition = decideViewTransition
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super.init(
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configureCell: configureCell,
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configureSupplementaryView: configureSupplementaryView,
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moveItem: moveItem,
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canMoveItemAtIndexPath: canMoveItemAtIndexPath
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)
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}
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// there is no longer limitation to load initial sections with reloadData
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// but it is kept as a feature everyone got used to
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var dataSet = false
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open func collectionView(_ collectionView: UICollectionView, observedEvent: Event<Element>) {
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Binder(self) { dataSource, newSections in
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#if DEBUG
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dataSource._dataSourceBound = true
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#endif
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if !dataSource.dataSet {
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dataSource.dataSet = true
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dataSource.setSections(newSections)
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collectionView.reloadData()
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}
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else {
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// if view is not in view hierarchy, performing batch updates will crash the app
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if collectionView.window == nil {
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dataSource.setSections(newSections)
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collectionView.reloadData()
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return
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}
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let oldSections = dataSource.sectionModels
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do {
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let differences = try Diff.differencesForSectionedView(initialSections: oldSections, finalSections: newSections)
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switch dataSource.decideViewTransition(dataSource, collectionView, differences) {
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case .animated:
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// each difference must be run in a separate 'performBatchUpdates', otherwise it crashes.
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// this is a limitation of Diff tool
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for difference in differences {
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let updateBlock = {
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// sections must be set within updateBlock in 'performBatchUpdates'
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dataSource.setSections(difference.finalSections)
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collectionView.batchUpdates(difference, animationConfiguration: dataSource.animationConfiguration)
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}
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collectionView.performBatchUpdates(updateBlock, completion: nil)
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}
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case .reload:
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dataSource.setSections(newSections)
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collectionView.reloadData()
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return
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}
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}
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catch let e {
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rxDebugFatalError(e)
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dataSource.setSections(newSections)
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collectionView.reloadData()
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}
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}
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}.on(observedEvent)
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}
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}
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#endif
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