import Foundation
import Combine

final class MainHomeFollowingViewModel: ObservableObject {
    private let repository = MainHomeFollowingRepository()
    private var subscription = Set<AnyCancellable>()

    @Published var isLoading = false
    @Published var response: HomeFollowingTabResponse?
    @Published var isLoginRequired = false
    @Published var message = ""
    @Published var hasLoaded = false

    func fetchFollowing() {
        isLoading = true
        message = ""

        repository.getFollowing()
            .sink { [weak self] result in
                guard let self else { return }

                switch result {
                case .finished:
                    DEBUG_LOG("finish")
                case .failure(let error):
                    ERROR_LOG(error.localizedDescription)
                    self.response = nil
                    self.isLoginRequired = false
                    self.message = I18n.HomeFollowing.loadFailedMessage
                    self.hasLoaded = true
                    self.isLoading = false
                }
            } receiveValue: { [weak self] response in
                guard let self else { return }

                let responseData = response.data

                do {
                    let jsonDecoder = JSONDecoder()
                    let decoded = try jsonDecoder.decode(ApiResponse<HomeFollowingTabResponse>.self, from: responseData)

                    if let data = decoded.data, decoded.success {
                        self.isLoginRequired = data.isLoginRequired
                        self.response = data.isLoginRequired ? nil : data
                        self.message = data.isLoginRequired || data.hasContent ? "" : I18n.HomeFollowing.emptyStateMessage
                    } else {
                        self.response = nil
                        self.isLoginRequired = false
                        self.message = I18n.HomeFollowing.loadFailedMessage
                    }
                } catch {
                    ERROR_LOG(error.localizedDescription)
                    self.response = nil
                    self.isLoginRequired = false
                    self.message = I18n.HomeFollowing.loadFailedMessage
                }

                self.hasLoaded = true
                self.isLoading = false
            }
            .store(in: &subscription)
    }
}

private extension HomeFollowingTabResponse {
    var hasContent: Bool {
        !followingCreators.isEmpty ||
        !onAirLives.isEmpty ||
        !recentChats.isEmpty ||
        !monthlySchedules.isEmpty ||
        !recentNews.isEmpty
    }
}