LeadKit/Sources/Classes/DataLoading/GeneralDataLoading/GeneralDataLoadingViewModel...

102 lines
3.4 KiB
Swift

//
// Copyright (c) 2018 Touch Instinct
//
// 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, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 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 RxSwift
import RxCocoa
open class GeneralDataLoadingViewModel<ResultType>: BaseViewModel {
public typealias LoadingModel = GeneralDataLoadingModel<ResultType>
public typealias DataSourceType = Single<ResultType>
public typealias LoadingState = GeneralDataLoadingState<DataSourceType>
private let loadingModel: LoadingModel
private let loadingStateRelay = BehaviorRelay<LoadingState>(value: .initial)
public let disposeBag = DisposeBag()
/// Initializer with single result sequence and empty result checker closure.
///
/// - Parameters:
/// - dataSource: A single element sequence.
/// - emptyResultChecker: Closure for checking result on empty state.
public init(dataSource: DataSourceType,
emptyResultChecker: @escaping LoadingModel.EmptyResultChecker = { _ in false }) {
loadingModel = LoadingModel(dataSource: dataSource, emptyResultChecker: emptyResultChecker)
loadingModel.stateDriver
.drive(loadingStateRelay)
.disposed(by: disposeBag)
loadingModel.reload()
}
/// Returns driver that emits current loading state
open var loadingStateDriver: Driver<LoadingState> {
return loadingStateRelay.asDriver()
}
/// By default returns true if loading state == .result.
open var hasContent: Bool {
return currentLoadingState.hasResult
}
/// Returns current result if it exists.
public var currentResult: ResultType? {
return currentLoadingState.currentResult
}
/// Current state of loading process.
private(set) public var currentLoadingState: LoadingState {
get {
return loadingStateRelay.value
}
set {
loadingStateRelay.accept(newValue)
}
}
/// Manually update loading state.
/// Should be used only in specific situations on your own risk!
///
/// - Parameter newState: New loading state.
public func updateStateManually(to newState: LoadingState) {
currentLoadingState = newState
}
/// Reload data.
public func reload() {
loadingModel.reload()
}
}
public extension GeneralDataLoadingViewModel where ResultType: Collection {
convenience init(dataSource: DataSourceType) {
self.init(dataSource: dataSource) { $0.isEmpty }
}
}