//
// 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 Defaults
import JellyfinAPI
import SwiftUI

protocol EpisodesRowManager: ViewModel {
    var item: BaseItemDto { get }
    var seasonsEpisodes: [BaseItemDto: [BaseItemDto]] { get set }
    var selectedSeason: BaseItemDto? { get set }

    func getSeasons()
    func getEpisodesForSeason(_ season: BaseItemDto)
    func select(season: BaseItemDto)
    func select(seasonID: String)
}

extension EpisodesRowManager {

    var sortedSeasons: [BaseItemDto] {
        Array(seasonsEpisodes.keys).sorted(by: { $0.indexNumber ?? 0 < $1.indexNumber ?? 0 })
    }

    var currentEpisodes: [BaseItemDto]? {
        if let selectedSeason = selectedSeason {
            return seasonsEpisodes[selectedSeason]
        } else {
            guard let firstSeason = seasonsEpisodes.keys.first else { return nil }
            return seasonsEpisodes[firstSeason]
        }
    }

    // Also retrieves the current season episodes if available
    func getSeasons() {
        TvShowsAPI.getSeasons(
            seriesId: item.id ?? "",
            userId: SessionManager.main.currentLogin.user.id,
            isMissing: Defaults[.shouldShowMissingSeasons] ? nil : false
        )
        .sink { completion in
            self.handleAPIRequestError(completion: completion)
        } receiveValue: { response in
            let seasons = response.items ?? []

            seasons.forEach { season in
                self.seasonsEpisodes[season] = []
            }

            self.selectedSeason = seasons.first
        }
        .store(in: &cancellables)
    }

    func getEpisodesForSeason(_ season: BaseItemDto) {
        guard let seasonID = season.id else { return }

        TvShowsAPI.getEpisodes(
            seriesId: item.id ?? "",
            userId: SessionManager.main.currentLogin.user.id,
            fields: [.primaryImageAspectRatio, .seriesPrimaryImage, .seasonUserData, .overview, .genres, .people],
            seasonId: seasonID,
            isMissing: Defaults[.shouldShowMissingEpisodes] ? nil : false
        )
        .trackActivity(loading)
        .sink { completion in
            self.handleAPIRequestError(completion: completion)
        } receiveValue: { episodes in
            self.seasonsEpisodes[season] = episodes.items ?? []
        }
        .store(in: &cancellables)
    }

    func select(season: BaseItemDto) {
        self.selectedSeason = season

        if seasonsEpisodes[season]!.isEmpty {
            getEpisodesForSeason(season)
        }
    }

    func select(seasonID: String) {
        guard let selectedSeason = Array(seasonsEpisodes.keys).first(where: { $0.id == seasonID }) else { return }
        select(season: selectedSeason)
    }
}