import Foundation
import Observation

/// `build list <repo>`, narrowed by `filter`, thirty to a page as the web
/// pages it. Rows stay in server order: a client sort would reorder them
/// across a page boundary.
@Observable
@MainActor
final class BuildListViewModel {

    let list: PagedListModel<Build>
    /// A change reloads from the first page. The sheet edits a copy and
    /// assigns once, so a typed branch does not fire a request per
    /// keystroke.
    var filter = BuildFilter() {
        didSet {
            guard filter != oldValue else { return }
            list.argv = ["build", "list", repoPath] + filter.flags()
            list.emptyMessage = filter.emptyMessage
            reloadTask?.cancel()
            reloadTask = Task { await list.reload() }
        }
    }
    private var reloadTask: Task<Void, Never>?
    /// The jobs a trigger can name. Empty when the repo has no CI
    /// config — the web hides its trigger form in that case.
    private(set) var jobs: [CIJob] = []
    private(set) var actionError: String?
    private(set) var working = false

    private let client: GitbayClient
    let repoPath: String

    init(client: GitbayClient, repoPath: String) {
        self.client = client
        self.repoPath = repoPath
        list = PagedListModel(
            client: client,
            argv: ["build", "list", repoPath] + BuildFilter().flags(),
            emptyMessage: BuildFilter().emptyMessage,
            pageSize: 30
        )
    }

    var state: LoadState<[Build]> { list.state }

    func load() async {
        reloadTask?.cancel()
        await list.reload()
    }

    /// The list's `.task`: reads only while nothing is shown yet.
    func loadIfNeeded() async {
        guard list.needsLoad else { return }
        await load()
    }

    /// `build jobs <owner/name>` — what the picker offers. A repo
    /// without a CI config answers "not found"; that means no jobs, not
    /// a failure worth showing.
    func loadJobs() async {
        jobs = (try? await client.readList(["build", "jobs", repoPath], of: CIJob.self)) ?? []
    }

    /// `build trigger <owner/name> <job>` — queue a job now.
    func trigger(job: String) async {
        working = true
        actionError = nil
        defer { working = false }
        do {
            try await client.run(["build", "trigger", repoPath, job])
            await load()
        } catch let error as GitbayError {
            actionError = error.userFacingMessage
        } catch {
            actionError = GitbayError.transport(error).userFacingMessage
        }
    }
}