import Foundation
import Observation

/// `milestone list <repo> --state <s>` — milestones with their progress.
@Observable
@MainActor
final class MilestoneListViewModel {

    enum StateFilter: String, CaseIterable, Identifiable, Sendable {
        case open, closed, all
        var id: String { rawValue }
    }

    private(set) var state: LoadState<[Milestone]> = .loading
    var filter: StateFilter = .open {
        didSet {
            guard filter != oldValue else { return }
            Task { await load() }
        }
    }

    private let client: GitbayClient
    let repoPath: String

    init(client: GitbayClient, repoPath: String) {
        self.client = client
        self.repoPath = repoPath
    }

    func load() async {
        state = .loading
        do {
            let milestones = try await client.readList(
                ["milestone", "list", repoPath, "--state", filter.rawValue], of: Milestone.self
            )
            state = milestones.isEmpty
                ? .empty("No \(filter == .all ? "" : filter.rawValue + " ")milestones.")
                : .loaded(milestones)
        } catch {
            state = .from(error)
        }
    }
}