//
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// CollectionViewSectionedDataSource.swift
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// RxDataSources
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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 RxCocoa
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#endif
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import Differentiator
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open class CollectionViewSectionedDataSource<Section: SectionModelType>
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: NSObject
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, UICollectionViewDataSource
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, SectionedViewDataSourceType {
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public typealias Item = Section.Item
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public typealias Section = Section
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public typealias ConfigureCell = (CollectionViewSectionedDataSource<Section>, UICollectionView, IndexPath, Item) -> UICollectionViewCell
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public typealias ConfigureSupplementaryView = (CollectionViewSectionedDataSource<Section>, UICollectionView, String, IndexPath) -> UICollectionReusableView
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public typealias MoveItem = (CollectionViewSectionedDataSource<Section>, _ sourceIndexPath:IndexPath, _ destinationIndexPath:IndexPath) -> Void
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public typealias CanMoveItemAtIndexPath = (CollectionViewSectionedDataSource<Section>, IndexPath) -> Bool
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public init(
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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.configureCell = configureCell
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self.configureSupplementaryView = configureSupplementaryView
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self.moveItem = moveItem
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self.canMoveItemAtIndexPath = canMoveItemAtIndexPath
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}
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#if DEBUG
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// If data source has already been bound, then mutating it
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// afterwards isn't something desired.
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// This simulates immutability after binding
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var _dataSourceBound: Bool = false
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private func ensureNotMutatedAfterBinding() {
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assert(!_dataSourceBound, "Data source is already bound. Please write this line before binding call (`bindTo`, `drive`). Data source must first be completely configured, and then bound after that, otherwise there could be runtime bugs, glitches, or partial malfunctions.")
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}
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#endif
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// This structure exists because model can be mutable
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// In that case current state value should be preserved.
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// The state that needs to be preserved is ordering of items in section
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// and their relationship with section.
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// If particular item is mutable, that is irrelevant for this logic to function
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// properly.
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public typealias SectionModelSnapshot = SectionModel<Section, Item>
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private var _sectionModels: [SectionModelSnapshot] = []
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open var sectionModels: [Section] {
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return _sectionModels.map { Section(original: $0.model, items: $0.items) }
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}
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open subscript(section: Int) -> Section {
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let sectionModel = self._sectionModels[section]
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return Section(original: sectionModel.model, items: sectionModel.items)
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}
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open subscript(indexPath: IndexPath) -> Item {
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get {
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return self._sectionModels[indexPath.section].items[indexPath.item]
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}
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set(item) {
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var section = self._sectionModels[indexPath.section]
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section.items[indexPath.item] = item
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self._sectionModels[indexPath.section] = section
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}
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}
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open func model(at indexPath: IndexPath) throws -> Any {
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guard indexPath.section < self._sectionModels.count,
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indexPath.item < self._sectionModels[indexPath.section].items.count else {
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throw RxDataSourceError.outOfBounds(indexPath: indexPath)
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}
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return self[indexPath]
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}
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open func setSections(_ sections: [Section]) {
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self._sectionModels = sections.map { SectionModelSnapshot(model: $0, items: $0.items) }
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}
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open var configureCell: ConfigureCell {
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didSet {
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#if DEBUG
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ensureNotMutatedAfterBinding()
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#endif
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}
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}
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open var configureSupplementaryView: ConfigureSupplementaryView? {
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didSet {
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#if DEBUG
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ensureNotMutatedAfterBinding()
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#endif
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}
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}
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open var moveItem: MoveItem {
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didSet {
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#if DEBUG
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ensureNotMutatedAfterBinding()
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#endif
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}
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}
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open var canMoveItemAtIndexPath: ((CollectionViewSectionedDataSource<Section>, IndexPath) -> Bool)? {
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didSet {
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#if DEBUG
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ensureNotMutatedAfterBinding()
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#endif
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}
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}
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// UICollectionViewDataSource
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open func numberOfSections(in collectionView: UICollectionView) -> Int {
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return _sectionModels.count
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}
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open func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
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return _sectionModels[section].items.count
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}
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open func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
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precondition(indexPath.item < _sectionModels[indexPath.section].items.count)
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return configureCell(self, collectionView, indexPath, self[indexPath])
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}
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open func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
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return configureSupplementaryView!(self, collectionView, kind, indexPath)
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}
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open func collectionView(_ collectionView: UICollectionView, canMoveItemAt indexPath: IndexPath) -> Bool {
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guard let canMoveItem = canMoveItemAtIndexPath?(self, indexPath) else {
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return false
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}
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return canMoveItem
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}
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open func collectionView(_ collectionView: UICollectionView, moveItemAt sourceIndexPath: IndexPath, to destinationIndexPath: IndexPath) {
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self._sectionModels.moveFromSourceIndexPath(sourceIndexPath, destinationIndexPath: destinationIndexPath)
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self.moveItem(self, sourceIndexPath, destinationIndexPath)
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}
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override open func responds(to aSelector: Selector!) -> Bool {
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if aSelector == #selector(UICollectionViewDataSource.collectionView(_:viewForSupplementaryElementOfKind:at:)) {
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return configureSupplementaryView != nil
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}
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else {
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return super.responds(to: aSelector)
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}
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}
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}
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#endif
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