101 lines
3.6 KiB
Swift
101 lines
3.6 KiB
Swift
//
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// Copyright (c) 2019 Touch Instinct
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the Software), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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//
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import RxSwift
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import RxCocoa
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/// ViewModel that loads data from a given data source and performs search among results
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open class BaseSearchViewModel<Item, ItemViewModel>: GeneralDataLoadingViewModel<[Item]> {
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public typealias ItemsList = [Item]
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private let searchTextRelay = BehaviorRelay(value: "")
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public init(dataSource: Single<ItemsList>) {
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super.init(dataSource: dataSource, emptyResultChecker: { $0.isEmpty })
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}
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open var itemsViewModelsDriver: Driver<[ItemViewModel]> {
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return loadingResultObservable
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.map { [weak self] items in
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self?.viewModels(from: items)
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}
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.filterNil()
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.share(replay: 1, scope: .forever)
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.asDriver(onErrorDriveWith: .empty())
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}
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open var searchResultsDriver: Driver<[ItemViewModel]> {
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return searchTextRelay.throttle(1, scheduler: MainScheduler.instance)
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.withLatestFrom(loadingResultObservable) { ($0, $1) }
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.flatMapLatest { [weak self] searchText, items -> Observable<ItemsList> in
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self?.search(by: searchText, from: items).asObservable() ?? .empty()
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}
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.map { [weak self] items in
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self?.viewModels(from: items)
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}
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.filterNil()
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.share(replay: 1, scope: .forever)
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.asDriver(onErrorDriveWith: .empty())
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}
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open func viewModel(from item: Item) -> ItemViewModel {
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fatalError("viewModel(from:) has not been implemented")
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}
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open func search(by searchString: String, from items: ItemsList) -> Single<ItemsList> {
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fatalError("searchEngine(for:) has not been implemented")
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}
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open func bind(searchText: Observable<String>) -> Disposable {
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return searchText.bind(to: searchTextRelay)
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}
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open func onDidSelect(item: Item) {
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// override in subclass
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}
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private func viewModels(from items: ItemsList) -> [ItemViewModel] {
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return items.map { self.viewModel(from: $0) }
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}
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open var loadingResultObservable: Observable<ResultType> {
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return loadingStateDriver
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.asObservable()
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.map { $0.result }
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.filterNil()
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}
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open var loadingErrorObservable: Observable<Error> {
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return loadingStateDriver
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.asObservable()
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.map { $0.error }
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.filterNil()
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}
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open var firstLoadingResultObservable: Single<ResultType> {
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return loadingResultObservable
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.take(1)
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.asSingle()
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}
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}
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