import SwiftUI

/// Upload button for playlist headers — visible only when playlist has local tracks and Chad Music is configured.
/// Shows uploaded/total count (e.g., "↑ 2/9").
struct PlaylistUploadButton: View {
    let playlist: Playlist

    @State private var uploadService = UploadService.shared

    private var localTracks: [Track] {
        playlist.sortedEntries.compactMap(\.track).filter { !$0.isCloud && !$0.filePath.isEmpty }
    }

    private var uploadedCount: Int {
        localTracks.filter { $0.uploadState == .uploaded }.count
    }

    private var uploadingCount: Int {
        localTracks.filter { $0.uploadState == .uploading }.count
    }

    var body: some View {
        let local = localTracks
        if !local.isEmpty && ChadMusicAPIClient.shared.isConfigured {
            Button {
                handleTap(local)
            } label: {
                Label(buttonLabel(local), systemImage: "arrow.up.circle")
            }
            .help(helpText(local))
        }
    }

    private func buttonLabel(_ local: [Track]) -> String {
        "↑ \(uploadedCount)/\(local.count)"
    }

    private func helpText(_ local: [Track]) -> String {
        let total = local.count
        if uploadedCount == total {
            return "All local tracks uploaded to cloud"
        }
        if uploadingCount > 0 {
            return "Uploading... tap to cancel"
        }
        return "Upload \(total - uploadedCount) local tracks to cloud"
    }

    private func handleTap(_ local: [Track]) {
        if uploadingCount > 0 {
            uploadService.cancel()
        } else if uploadedCount < local.count {
            let eligible = local.filter { $0.uploadState != .uploaded }
            uploadService.uploadBatch(tracks: eligible, apiClient: ChadMusicAPIClient.shared)
        }
    }
}