import Foundation
import Combine

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

    @Published var isLoading = false
    @Published var isShowPopup = false
    @Published var errorMessage = ""
    @Published var recommendations: HomeRecommendationResponse?
    @Published private(set) var completedFollowKeys = Set<String>()
    @Published private(set) var followingKeys = Set<String>()

    func fetchRecommendations() {
        isLoading = true

        repository.getRecommendations()
            .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.errorMessage = I18n.Common.commonError
                    self.isShowPopup = 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<HomeRecommendationResponse>.self, from: responseData)

                    if let data = decoded.data, decoded.success {
                        self.recommendations = data
                    } else {
                        self.errorMessage = decoded.message ?? I18n.Common.commonError
                        self.isShowPopup = true
                    }
                } catch {
                    self.errorMessage = I18n.Common.commonError
                    self.isShowPopup = true
                }

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

    func followAll(creatorIds: [Int], completionKey: String) {
        guard !creatorIds.isEmpty, !completionKey.isEmpty else { return }
        guard !completedFollowKeys.contains(completionKey), !followingKeys.contains(completionKey) else { return }

        followingKeys.insert(completionKey)

        repository.followRecommendedCreators(request: FollowRecommendedCreatorsRequest(creatorIds: creatorIds))
            .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.errorMessage = I18n.Common.commonError
                    self.isShowPopup = true
                    self.followingKeys.remove(completionKey)
                }
            } receiveValue: { [weak self] response in
                guard let self else { return }

                let responseData = response.data

                do {
                    let jsonDecoder = JSONDecoder()
                    let decoded = try jsonDecoder.decode(ApiResponseWithoutData.self, from: responseData)

                    if decoded.success {
                        self.completedFollowKeys.insert(completionKey)
                    } else {
                        self.errorMessage = decoded.message ?? I18n.Common.commonError
                        self.isShowPopup = true
                    }
                } catch {
                    self.errorMessage = I18n.Common.commonError
                    self.isShowPopup = true
                }

                self.followingKeys.remove(completionKey)
            }
            .store(in: &subscription)
    }

    func isFollowAllCompleted(_ completionKey: String) -> Bool {
        completedFollowKeys.contains(completionKey)
    }

    func isFollowAllLoading(_ completionKey: String) -> Bool {
        followingKeys.contains(completionKey)
    }
}