metatext-app-ios-iphone-ipad/Shared/View Models/StatusesViewModel.swift

57 lines
2.1 KiB
Swift

// Copyright © 2020 Metabolist. All rights reserved.
import Foundation
import Combine
class StatusesViewModel: ObservableObject {
@Published private(set) var statusSections = [[Status]]()
@Published var alertItem: AlertItem?
@Published private(set) var loading = false
let scrollToStatusID: AnyPublisher<String, Never>
private let statusListService: StatusListService
private let scrollToStatusIDInput = PassthroughSubject<String, Never>()
private var hasScrolledToParentAfterContextLoad = false
private var cancellables = Set<AnyCancellable>()
init(statusListService: StatusListService) {
self.statusListService = statusListService
scrollToStatusID = scrollToStatusIDInput.eraseToAnyPublisher()
statusListService.statusSections
.assignErrorsToAlertItem(to: \.alertItem, on: self)
.assign(to: &$statusSections)
$statusSections
.sink { [weak self] in
guard let self = self else { return }
if
let contextParent = self.contextParent,
!($0.first ?? []).isEmpty || !(($0.last ?? []).isEmpty),
!self.hasScrolledToParentAfterContextLoad {
self.hasScrolledToParentAfterContextLoad = true
self.scrollToStatusIDInput.send(contextParent.id)
}
}
.store(in: &cancellables)
}
}
extension StatusesViewModel {
var contextParent: Status? { statusListService.contextParent }
func request(maxID: String? = nil, minID: String? = nil) {
statusListService.request(maxID: maxID, minID: minID)
.assignErrorsToAlertItem(to: \.alertItem, on: self)
.handleEvents(
receiveSubscription: { [weak self] _ in self?.loading = true },
receiveCompletion: { [weak self] _ in self?.loading = false })
.sink {}
.store(in: &cancellables)
}
func contextViewModel(status: Status) -> StatusesViewModel {
StatusesViewModel(statusListService: statusListService.contextService(status: status))
}
}