jellyflood/Shared/ViewModels/ItemViewModel/ItemViewModel.swift

//
// Swiftfin is subject to the terms of the Mozilla Public
// License, v2.0. If a copy of the MPL was not distributed with this
// file, you can obtain one at https://mozilla.org/MPL/2.0/.
//
// Copyright (c) 2022 Jellyfin & Jellyfin Contributors
//

import Combine
import Foundation
import JellyfinAPI
import UIKit

class ItemViewModel: ViewModel {

    @Published
    var item: BaseItemDto
    @Published
    var playButtonItem: BaseItemDto? {
        didSet {
            if let playButtonItem = playButtonItem {
                refreshItemVideoPlayerViewModel(for: playButtonItem)
            }
        }
    }

    @Published
    var similarItems: [BaseItemDto] = []
    @Published
    var isWatched = false
    @Published
    var isFavorited = false
    @Published
    var informationItems: [BaseItemDto.ItemDetail]
    @Published
    var selectedVideoPlayerViewModel: VideoPlayerViewModel?
    var videoPlayerViewModels: [VideoPlayerViewModel] = []

    init(item: BaseItemDto) {
        self.item = item

        switch item.itemType {
        case .episode, .movie:
            if !item.missing && !item.unaired {
                self.playButtonItem = item
            }
        default: ()
        }

        informationItems = item.createInformationItems()

        isFavorited = item.userData?.isFavorite ?? false
        isWatched = item.userData?.played ?? false
        super.init()

        getSimilarItems()

        Notifications[.didSendStopReport].subscribe(self, selector: #selector(receivedStopReport(_:)))

        refreshItemVideoPlayerViewModel(for: item)
    }

    @objc
    private func receivedStopReport(_ notification: NSNotification) {
        guard let itemID = notification.object as? String else { return }

        if itemID == item.id {
            updateItem()
        } else {
            // Remove if necessary. Note that this cannot be in deinit as
            // holding as an observer won't allow the object to be deinit-ed
            Notifications.unsubscribe(self)
        }
    }

    func refreshItemVideoPlayerViewModel(for item: BaseItemDto) {
        guard item.itemType == .episode || item.itemType == .movie else { return }
        guard !item.missing, !item.unaired else { return }

        item.createVideoPlayerViewModel()
            .sink { completion in
                self.handleAPIRequestError(completion: completion)
            } receiveValue: { viewModels in
                self.videoPlayerViewModels = viewModels
                self.selectedVideoPlayerViewModel = viewModels.first
            }
            .store(in: &cancellables)
    }

    func playButtonText() -> String {

        if item.unaired {
            return L10n.unaired
        }

        if item.missing {
            return L10n.missing
        }

        if let itemProgressString = item.getItemProgressString() {
            return itemProgressString
        }

        return L10n.play
    }

    func getItemDisplayName() -> String {
        item.name ?? ""
    }

    func shouldDisplayRuntime() -> Bool {
        true
    }

    func getSimilarItems() {
        LibraryAPI.getSimilarItems(
            itemId: item.id!,
            userId: SessionManager.main.currentLogin.user.id,
            limit: 10,
            fields: [.primaryImageAspectRatio, .seriesPrimaryImage, .seasonUserData, .overview, .genres, .people]
        )
        .trackActivity(loading)
        .sink(receiveCompletion: { [weak self] completion in
            self?.handleAPIRequestError(completion: completion)
        }, receiveValue: { [weak self] response in
            self?.similarItems = response.items ?? []
        })
        .store(in: &cancellables)
    }

    func updateWatchState() {
        if isWatched {
            PlaystateAPI.markUnplayedItem(
                userId: SessionManager.main.currentLogin.user.id,
                itemId: item.id!
            )
            .trackActivity(loading)
            .sink(receiveCompletion: { [weak self] completion in
                self?.handleAPIRequestError(completion: completion)
            }, receiveValue: { [weak self] _ in
                self?.isWatched = false
            })
            .store(in: &cancellables)
        } else {
            PlaystateAPI.markPlayedItem(
                userId: SessionManager.main.currentLogin.user.id,
                itemId: item.id!
            )
            .trackActivity(loading)
            .sink(receiveCompletion: { [weak self] completion in
                self?.handleAPIRequestError(completion: completion)
            }, receiveValue: { [weak self] _ in
                self?.isWatched = true
            })
            .store(in: &cancellables)
        }
    }

    func updateFavoriteState() {
        if isFavorited {
            UserLibraryAPI.unmarkFavoriteItem(userId: SessionManager.main.currentLogin.user.id, itemId: item.id!)
                .trackActivity(loading)
                .sink(receiveCompletion: { [weak self] completion in
                    self?.handleAPIRequestError(completion: completion)
                }, receiveValue: { [weak self] _ in
                    self?.isFavorited = false
                })
                .store(in: &cancellables)
        } else {
            UserLibraryAPI.markFavoriteItem(userId: SessionManager.main.currentLogin.user.id, itemId: item.id!)
                .trackActivity(loading)
                .sink(receiveCompletion: { [weak self] completion in
                    self?.handleAPIRequestError(completion: completion)
                }, receiveValue: { [weak self] _ in
                    self?.isFavorited = true
                })
                .store(in: &cancellables)
        }
    }

    // Overridden by subclasses
    func updateItem() {}
}