import Foundation

@Observable @MainActor
final class DetailViewModel {
    var detail: ContentDetail?
    var selectedSourceIndex = 0
    var selectedEpisodeIndex = 0
    var isLoading = false
    var error: String?

    var currentSource: StreamSource? {
        guard let detail, selectedSourceIndex < detail.sources.count else { return nil }
        return detail.sources[selectedSourceIndex]
    }

    var currentEpisode: Episode? {
        guard let source = currentSource,
              selectedEpisodeIndex < source.episodes.count else { return nil }
        return source.episodes[selectedEpisodeIndex]
    }

    var hasMultipleEpisodes: Bool {
        guard let source = currentSource else { return false }
        return source.episodes.count > 1
    }

    func loadDetail(path: String) async {
        isLoading = true
        error = nil

        do {
            let html = try await APIClient.shared.fetchDetailPage(path: path)
            let parsedDetail = try HTMLParser.parseContentDetail(html: html)
            self.detail = parsedDetail
            self.selectedSourceIndex = 0
            self.selectedEpisodeIndex = 0
        } catch is CancellationError {
            // 被取消时不清除 loading 状态，让视图继续显示加载中
            return
        } catch let error as URLError where error.code == .cancelled {
            return
        } catch {
            self.error = error.localizedDescription
        }
        isLoading = false
    }

    func selectSource(_ index: Int) {
        selectedSourceIndex = index
        selectedEpisodeIndex = 0
    }

    func selectEpisode(_ index: Int) {
        selectedEpisodeIndex = index
    }

    func nextEpisode() -> Bool {
        guard let source = currentSource else { return false }
        if selectedEpisodeIndex + 1 < source.episodes.count {
            selectedEpisodeIndex += 1
            return true
        }
        return false
    }
}